Patterns of Reading Impairments in Cases of Anomia - Dr Christopher Williams

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TABLE OF CONTENTS
List of Figures .............................................................................................................. iv
List of Tables................................................................................................................. v
Acknowledgements ...................................................................................................... vii
Abstract........................................................................................................................ ix
Chapter 1. General introduction..................................................................................1:1
Cognitive models of language processing ...................................................................1:1
A simple model to explore language abilities: The ‘basic model’ ................................1:2
Two lexicons or four? ............................................................................................. 1:8
Different accounts of reading aloud ........................................................................ 1:9
The relationship between reading aloud and oral picture naming........................... 1:11
Research Aims...................................................................................................... 1:14
Chapter 2. Method .....................................................................................................2:17
Participants..............................................................................................................2:17
Recruitment of aphasic participants ...................................................................... 2:17
Recruitment of unimpaired controls ...................................................................... 2:18
Materials..................................................................................................................2:19
Procedures ...............................................................................................................2:23
Scoring.....................................................................................................................2:25
Analyses ...................................................................................................................2:25
Chapter 3. Control group – results and discussion ...................................................3:31
Regularity effects of unpublished tests ......................................................................3:31
Oral naming versus written naming..........................................................................3:32
Methodological issues ..............................................................................................3:33
Chapter 4. A simple case to explain? .........................................................................4:37
Case description.......................................................................................................4:37
Results......................................................................................................................4:37
Input processes ..................................................................................................... 4:38
Reading and repetition of words and nonwords..................................................... 4:38
The semantic system............................................................................................. 4:38
Picture naming...................................................................................................... 4:39
Discussion................................................................................................................4:40

Chapter 5. Three cases of phonological dyslexia ...................................................... 5:45
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Case 1 – RPD........................................................................................................... 5:45
Results for RPD........................................................................................................ 5:45
Input processes..................................................................................................... 5:46
Reading and repetition of words and nonwords .................................................... 5:46
The semantic system ............................................................................................ 5:47
Picture naming ..................................................................................................... 5:48
Discussion – RPD .................................................................................................... 5:49
Case 2 – DHT .......................................................................................................... 5:53
Results for DHT ....................................................................................................... 5:53
Input processes..................................................................................................... 5:53
Picture naming ..................................................................................................... 5:56
Item consistency and comparisons........................................................................ 5:57
Discussion – DHT.................................................................................................... 5:58
Case 3 – DPC .......................................................................................................... 5:62
Results for DPC ....................................................................................................... 5:62
Input processes..................................................................................................... 5:63
Picture naming ..................................................................................................... 5:65
Discussion – DPC.................................................................................................... 5:67
Phonological dyslexia – general discussion.............................................................. 5:70
Chapter 6. Interpreting results for a bilingual aphasic ............................................ 6:73
Case description....................................................................................................... 6:73
Control M2........................................................................................................... 6:74
Results ..................................................................................................................... 6:74
Input processes..................................................................................................... 6:74
Picture naming ..................................................................................................... 6:77
Discussion................................................................................................................ 6:80
Chapter 7. A case of deep dyslexia ............................................................................ 7:87
Deep dyslexia........................................................................................................... 7:87
Case description....................................................................................................... 7:88
Results ..................................................................................................................... 7:89
Input processes..................................................................................................... 7:89
Picture naming ..................................................................................................... 7:92
Item consistency................................................................................................... 7:95
Discussion................................................................................................................ 7:96

Chapter 8. Collective results for aphasic participants ............................................ 8:101
Collective results .................................................................................................... 8:101
Severity of aphasia and dissociations...................................................................... 8:105
Severity .............................................................................................................. 8:105
Dissociations and double dissociations................................................................ 8:106
Chapter 9. General discussion ................................................................................. 9:109
The basic model - conclusions ................................................................................ 9:109
Reading aloud..................................................................................................... 9:109
Semantic errors on oral naming........................................................................... 9:110
Comments on methodological issues....................................................................... 9:113
References.................................................................................................................... 117
Appendices................................................................................................................... 123
Appendix 1. Materials................................................................................................ 124
Appendix 2. Analyses................................................................................................. 132
Appendix 3. Control group results ............................................................................. 133
Appendix 4. Nonword reading ................................................................................... 135
Appendix 5. Error analysis for aphasic participants .................................................. 136
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List of Figures
Figure 1:1. The ‘basic model’ of language processing. ............................................... 1:3
Figure 1:2. The three reading routes of the basic model: ........................................... 1:5
Figure 1:3. The central components of any four-lexicon model. ................................ 1:8
Figure 1:4. The hypothesis described by Orpwood and Warrington (1995). .......... 1:12
Figure 2:1. Example Item from the comprehension test: ......................................... 2:21
Figure 3:1. Control group performance on repetition tasks. ................................... 3:36
Figure 4:1. The basic model, showing MWN’s proposed lesion site. ....................... 4:41
Figure 5:1. The basic model as it applies to RPD...................................................... 5:49
Figure 5:2. The basic model as it applies to DHT. .................................................... 5:59
Figure 5:3. The basic model as it applies to DPC...................................................... 5:68
Figure 6:1. Sample of written naming responses for JWS. ...................................... 6:79
Figure 6:2. Attempted alphabet by JWS................................................................... 6:80
Figure 6:3. The basic model as it applies to JWS...................................................... 6:82
Figure 7:1. The basic model as it applies to SJS. ...................................................... 7:97
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List of Tables
Table 2:1. Descriptive data for the aphasic participants. .........................................2:18
Table 2:2. List and order of tests in each session. .....................................................2:24
Table 3:1. Summary of control results on published tests. .......................................3:31
Table 3:2. Summary of control group results on unpublished tests. ........................3:32
Table 3:3. Most frequently incorrect items on PPT for controls. .............................3:34
Table 4:1. MWN’s performance on tests of input processes.....................................4:38
Table 4:2. MWN’s performance on reading and repetition tests. ............................4:38
Table 4:3. MWN’s performance on semantic tests. ..................................................4:39
Table 4:4. MWN’s performance on the oral naming test. ........................................4:39
Table 4:5. MWN’s performance on the written naming test. ...................................4:40
Table 5:1. RPD’s performance on tests of input processes. ......................................5:46
Table 5:2. RPD’s performance on reading and repetition tests................................5:47
Table 5:3. RPD’s performance on semantic tests. .....................................................5:47
Table 5:4. RPD’s performance on the oral naming test............................................5:48
Table 5:5. RPD’s performance on the written naming test. .....................................5:48
Table 5:6. DHT’s performance on tests of input processes.......................................5:54
Table 5:7. DHT’s performance on reading and repetition tests. ..............................5:54
Table 5:8. DHT’s performance on semantic tests. ....................................................5:55
Table 5:9. DHT’s performance on the oral naming test. ..........................................5:56
Table 5:10. DHT’s performance on the written naming test. ...................................5:57
Table 5:11. Item consistency between tests of verbal output for DHT. ....................5:58
Table 5:12. DPC’s performance on tests of input processes. ....................................5:63
Table 5:13. DPC’s performance on reading and repetition tests..............................5:64
Table 5:14. DPC’s performance on semantic tests. ...................................................5:65
Table 5:15. DPC’s performance on the oral naming test. .........................................5:65
Table 5:16. DPC’s performance on the written naming test.....................................5:66
Table 5:17. Item consistency between oral naming and other tasks for DPC. .........5:67
Table 6:1.JWS’ performance on tests of input processes..........................................6:75
Table 6:2. JWS’ performance on reading and repetition tests. ................................6:76
Table 6:3. JWS’ performance on semantic tests. ......................................................6:77
Table 6:4. JWS’ results on the oral naming test........................................................6:78
Table 6:5. JWS’ performance on the written naming test. .......................................6:79
Table 7:1. SJS’ performance on tests of input processes. .........................................7:90

Table 7:2. SJS’ performance on reading and repetition tests. ................................. 7:90
Table 7:3. Reading errors for SJS. ............................................................................ 7:91
Table 7:4. SJS’ performance on semantic tests......................................................... 7:92
Table 7:5. SJS’ performance on the oral naming test............................................... 7:93
Table 7:6. Examples of oral naming errors for SJS.................................................. 7:93
Table 7:7. SJS’ performance on the written naming test. ........................................ 7:94
Table 7:8. Examples of written naming errors for SJS. ........................................... 7:95
Table 7:9. Item consistency between comprehension and naming for SJS. ............. 7:95
Table 7:10. Item consistency between several tests for SJS...................................... 7:96
Table 8:1. Performance of aphasic participants on tests of input processes. ......... 8:101
Table 8:2. Performance of aphasic participants on reading and repetition tests. . 8:102
Table 8:3. Performance of aphasic participants on semantic tests......................... 8:103
Table 8:4. Performance of aphasic participants on the oral naming tests. ............ 8:104
Table 8:5. Performance of aphasic participants on the written naming test ......... 8:105
Table 8:6. Comparison of the regular and exception word groups........................ 8:105
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Acknowledgements
First and foremost, I would like to thank all of the wonderful people who participated in
this project, without whom none of this would have been possible. For most of these
individuals, the assessment procedure involved several hours of testing, and I am eternally
grateful for the time and effort that you all devoted to the project. I must also thank two
participants, TB and FME, whose results were not included in the final report but who
gave there time nevertheless.
Second, I would like to acknowledge the professional assistance I received from various
people. In particular, my supervisors, Professor Max Coltheart and Associate Professor
Lindsey Nickels, who gave their time and effort over a period of many years, and who
never lost faith that I would eventually submit. For your time, advice, and understanding, I
cannot thank you enough. I am also grateful to the speech pathologists as St Joseph’s
Hospital and the Royal Rehabilitation Centre Sydney for their assistance in referring
patients and for being extremely accommodating in providing me with their time and other
resources. I am also indebted to many other academics and support staff of the Macquarie
Centre for Cognitive Science and the Psychology Department of Macquarie University for
their professional advice and assistance with resources.
Third, I would like to thank the many amazing people in my life who I am lucky enough to
have as family and friends. I am especially grateful to my parents, who not only provided
me with the love and support that they always have, but who also went out of their way to
help me with finding control participants. To all of my friends, including student peers,
team mates, work colleagues, flat mates, and long-term friends, I cannot express how
grateful I am for your professional support (including assistance with proof reading,
material preparation and other advice) and, more importantly, your moral support – I
would not have attained this feat without your compassion, reassurance, and
understanding.
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Abstract
Over recent decades, research-based cognitive models of language have become
increasingly sophisticated. However, with increasing sophistication has come an equivalent
increase in complexity, to the extent that it is now more difficult than ever for clinicians to
utilise the model for testing hypotheses about patients and devise appropriate therapeutic
interventions. A series of six cases is presented to explore the capacity of the ‘basic model’
to account for various aphasic profiles, with a particular focus on hypotheses about reading
pathways. To this end, a series of experiments was designed using a single set of picture-word
items, with a focus on the balance between words with and without regular spelling-sound
correspondence. Various theoretical positions are discussed including the lexical
non-semantic route, the summation hypothesis, and the hypothesis that reading aloud and
oral naming are subserved by different phonological output lexicons (e.g. Orpwood &
Warrington, 1995).
Most of the aphasic participants presented with ‘output’ anomia, but for some this was in
the context of mild semantic deficits that may have contributed to their poor oral naming.
One of the participants was also completely unable to read nonwords, yet his reading of
real words, although impaired, did not contain semantic errors. This is an uncommon
finding and one that is incongruent with the summation hypothesis. Other participants
demonstrated intact reading of exception words despite being impaired on the oral naming
task, which further supports the inclusion of the lexical non-semantic route.
Another of the aphasic participants was considered in the context of being a late-acquired
bilingual speaker. He was compared not only to the main control group, but also to an
unimpaired, late-acquired bilingual speaker with the same language background. The basic
model was unable to account for his pattern of deficits, but it was determined that most
cognitive models, no matter how intricate, are inadequate to account for aphasic syndromes
in bilingual speakers.
The final case examines the profile of a participant with deep dyslexia. Although the basic
model is able to account for this participant’s profile, consideration is given to the right-hemisphere
hypothesis and to the notion that, due to wide ranging and as yet unknown
variables, standard cognitive models of language processing may again be inappropriate
for use with these cases.

It was concluded that the evidence supported the potential of the basic model and the
assumptions associated with it, including the lexical non-semantic route and the depiction
of only two lexicons, one each for spoken and written lexical entries. Additionally, several
methodological issues are discussed including poor sensitivity of several tests.
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Chapter 1. General introduction
Anomia is usually characterised as general word-finding difficulties. It can exist as a
syndrome in itself or, more often, as a feature of a more general aphasic disorder (Garman,
1990). Almost every aphasic individual experiences some degree of impaired word
retrieval (e.g. Garrett, 1992; Weigel-Crump & Koenigsknecht, 1973), which is made
evident by the fact that the most common finding of aphasic research is the inability to
name pictures correctly (Goodglass, 1983). Analysis of the various causes of naming
failure, and the myriad of other lexical deficits associated with it, can reveal a great deal
about the cognitive architecture of language processing. This chapter introduces and briefly
discusses a range of issues surrounding cognitive models of language processing. In the
chapters that follow, some of these issues will be explored through a case series involving
six individuals with various anomic syndromes and degrees of impairment. In particular,
the potential for a ‘basic’ model of language processing to account for the deficits of these
individuals will be examined, and it will be argued that this relatively uncomplicated
model is sufficient to explain and understand acquired language deficits at a clinical level.
Cognitive models of language processing
In any cognitive model of lexical processing, the ability to perform normal linguistic
functions is explained by an array of processing modules linked to each other by a network
of pathways. These models do not aim to account for neural processing centres and
connections, rather, they are attempts to explain the processes involved in normal lexical
functioning, and are often constructed around hypotheses that are generated from case
studies of individuals with language impairments. Such hypotheses are generally based on
dissociations (i.e. when a certain process is impaired while another is intact) and, more
importantly, double dissociations (i.e. when two separate processes can be differentially
impaired) – for example, there are cases of impaired written naming with intact oral
naming and vice versa, indicating a double dissociation between the process involved in
each form of naming.
Whilst there are many ways in which the various models differ, by their very nature there
are many aspects that they must have in common. Specifically, all lexical models must be
able to explain the different processes involved in understanding and producing language,
at least at the level of single words. Therefore, all models must account for orthographic
processing (the way we process written words), phonological processing (spoken words),

recognition of 2- and 3-dimensional objects, and semantic processing (comprehension of
words and objects). The full range of everyday skills encompassed by a model should
include: Confrontation naming (naming of pictures and objects), both oral and written;
spontaneous speech and writing; recognition and comprehension of pictures, written words
and spoken words; reading aloud; written ‘copying’ and verbal repetition; and writing to
dictation. Also, models must account not only for our ability to process words that are
known to us, but also words that are novel or made up.
A simple model to explore language abilities: The ‘basic model’
The primary objective of this report is to show that a simple cognitive model of language is
sufficient to account for most aphasic individuals. Being able to precisely identify a
patient’s deficit within the context of a cognitive model can have significant implications
for the design of therapeutic intervention. However, due to their complex nature, the
practical application of the more sophisticated research-based models are often difficult for
clinicians to apply and interpret. Therefore, simplifying models to a degree that they can be
easily applied to the majority of cases could have significant implications for clinical
practice.
Keeping in mind the language abilities of normal speakers, in addition to the most
commonly reported and generally agreed upon aspects, the simplest model that could be
considered for clinical application is presented in Figure 1:1 (e.g. Allport, 1984; Allport &
Funnell, 1981; Jackson & Coltheart, 2001). The most peripheral, non-language features
such as initial acoustic processing and motor output are omitted, and internal processing of
modules is not defined.
At the centre of the basic model in Figure 1:1 is the semantic system, which stores and
processes conceptual information about the meanings of words and objects; it represents an
intricate network of semantic features (i.e. all the characteristics of the things that an
individual knows). To either side of the semantic system are the phonological lexicon and
orthographic lexicon, stores of all the spoken and written words (respectively) that an
individual knows.
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1:3
Figure 1:1. The ‘basic model’ of language processing.
Input to the model can be auditory or visual. Auditory information first reaches the
phonological input buffer, which temporarily stores and processes phonemes (small units
of sound) before forwarding the information on to the phonological lexicon for activation
of the appropriate word forms, and to the phonological output buffer, where phonological
information is reorganised as speech. The pathway between the phonological input and
output buffers is the sublexical repetition route, and allows auditory input to be re-processed
as speech output – this is the mechanism that allows us to quickly repeat verbal
information (both real words and nonwords). Repetition of known words can also occur via
the phonological lexicon. Information from the phonological lexicon is also forwarded to
the semantic system where relevant semantic nodes are activated, enabling comprehension
of spoken words.
Visual input to the system can take two forms. Firstly, 2- and 3-dimensional objects are
identified and processed by the object recognition system, which then activates relevant
nodes in the semantic system. Naming of these objects is then made possible via the
phonological lexicon and phonological output buffer (for oral naming) or the orthographic
lexicon and orthographic output buffer (for written naming). Secondly, written input is

processed initially by a stage of letter identification, which associates the almost infinite
array of forms that each letter of the alphabet can take with the single letter that they
represent (i.e. no matter how the letter a is written – e.g. a, a, A, or A – it is usually
recognisable).
According to the basic model, reading aloud is made possible by three different routes, all
beginning at the stage of letter identification. The first, called the semantic route (Figure
1:2a), proceeds to the orthographic lexicon, through the semantic system, and on to the
phonological lexicon and phonological output buffer. The second (Figure 1:2b) is called
the lexical non-semantic route, and also proceeds to the orthographic lexicon. At this point
however, information is sent directly to the phonological lexicon, bypassing the semantic
system, before being forwarded on to the phonological output buffer. This pathway allows
for written words to be read aloud without necessarily activating semantic representations,
and is discussed in greater detail later in the chapter. The third route (Figure 1:2c) is a
direct connection from letter identification to the phonological output buffer via grapheme-phoneme
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conversion. This pathway, also known as the sublexical route, allows for the
processing of strings of graphemes (a grapheme is a letter or group of letters that represent
a single phoneme) that do not have entries in the lexicons – that is, unfamiliar words,
foreign words and nonwords (i.e. plausible made-up words such as ploon and chup).
a.

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b.
c.
Figure 1:2. The three reading routes of the basic model:
(a) the semantic route; (b) the lexical non-semantic route; and (c) grapheme-phoneme conversion.
From the perspective of the basic model, reading aloud is made possible by these three
pathways. Words with regular spelling (i.e. those that have predictable grapheme-phoneme
correspondence and therefore sound the way they are spelled, such as dog and arm) can be
read via any of the three routes. In contrast, exception words (words that do not sound the
way they are spelled, such as bowl and yacht) cannot be read via grapheme-phoneme
conversion – since grapheme-phoneme conversion only allows for direct translation of
graphemes into phonemes, this would cause regularisation errors (e.g. bowl would be read

as ‘bowel’ and yacht would be read as ‘yatched’ or ‘yacked’). However, exception words
can be read using either the semantic or lexical non-semantic route, since all words are
represented in the lexicons and simply need to be activated, first in the orthographic
lexicon, then in the phonological lexicon. Finally, novel words and nonwords can only be
read via grapheme-phoneme conversion, since these letter strings are not represented in the
lexicons. Damage to grapheme-phoneme conversion impairs the individual’s ability to read
nonwords, which will often (but not always) be read as lexicalisations (e.g. ploon might be
read as ‘plume’ or ‘prune,’ while chup might be read as ‘chap’).
Finally, the model needs to include components that can process novel words not only in
their written form, but also via auditory input. Repetition of novel words is achieved by the
sublexical repetition route, which connects the phonological input and output buffers.
Written dictation of novel words is achieved via phoneme-grapheme conversion, which is
responsible for converting sequences of phonemes into graphemes, thus allowing a person
to write novel strings of sounds that are heard. This process is not examined in the case
series, but is shown in the model because its existence is well supported by evidence in the
literature (e.g. Alario, Schiller, Domoto-Reilly, & Caramazza, 2003; Miceli, Capasso, &
Caramazza, 1999).
Damage to the model will result in a variety of deficits, depending on which component or
components are damaged, and the degree to which the components are still able to function
(see Allport, 1984; Allport & Funnell, 1981; Jackson & Coltheart, 2001). In broad terms,
there are two ways that lesions might affect the functioning of the core components of the
language system (i.e. the semantic system, phonological lexicon and orthographic lexicon)
– damage to the representations within the process, or reduced activation of those
representations. Generally, damage to the representations should lead to consistency of
errors. In other words, if the actual representations are damaged, then the same errors will
appear repeatedly, and for all tasks that rely on that module. On the other hand, reduced
activation, which is generally conceptualised as damage to the connections between
modules, is less likely to result in error consistency.
Damage to individual components will obviously lead to a particular set of impairments. If
the semantic system is damaged, comprehension will be impaired regardless of the method
of input (i.e. the individual will have difficulty understanding the meanings of pictures,
spoken words and written words). However, the most distinctive feature of ‘semantic
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anomia’ is bimodal naming failure to all forms of input (Rothi, Raymer, Maher,
Greenwald, & Morris, 1991). That is, an impaired ability to name words both orally and in
writing, whether the stimuli are presented as pictures, written definitions or auditory
definitions. Semantic errors (meaning-related errors e.g. naming a car as a truck) should be
common because damage to particular semantic representations increases the likelihood of
lexical entries that are related by meaning being activated in the relevant lexicon (Miceli,
Amitrano, Capasso, & Caramazza, 1996).
Damage to a lexicon will lead to the inability to activate representations within that
lexicon. From the perspective of the basic model, this will lead to: a) reduced ability to
name pictures in that modality, with a range of error types including semantic and
phonological errors; b) difficulties with lexical decision (i.e. distinguishing between real
and made-up words) in that modality; and c) difficulties with comprehension of words
input from that modality. Other abilities might be partially affected. In particular, reading
aloud of exception words should lead to regularisation errors if either lexicon is damaged,
and if grapheme-phoneme conversion is intact. Likewise, writing of exception words to
dictation should be affected by damage to the phonological lexicon. However, nonword
reading, repetition and writing to dictation should all be possible, even if both lexicons are
damaged. In contrast, reduced activation of the lexicons from the semantic system should
lead to impaired picture naming of that modality, without affecting any other language
skill. Errors should be similar in nature to those seen for lexicon damage, including
semantic errors, but with less consistency predicted.
Post-lexical damage should also have similarities to lexical damage. In particular, damage
to the connection between the phonological lexicon and phonological output buffer should
impact on oral naming and reading of exception words. For naming, semantic errors would
not be expected since the lexical entry has already been selected. On the other hand,
auditory lexical decision should still be possible, as should repetition of words (via the
sublexical repetition route). Damage to the connection between the orthographic lexicon
and orthographic output buffer should mirror this pattern for writing. Finally, damage to
the input or output buffers should affect all input or output for that modality, while damage
to the object recognition process should affect all tasks that involve some aspect of
interpreting pictures or objects.
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Two lexicons or four?
Perhaps the most audacious argument presented in the basic model is that only two
lexicons are defined, one each for spoken and written words. In contrast, the majority of
mainstream models describe separate lexicons for input and for output for each modality,
as depicted in Figure 1:3 below. Only the central components are shown, with peripheral
features omitted (e.g. input and output buffers, grapheme-phoneme conversion and direct
links between the lexicons), as are any hypothesised feedback mechanisms and
connections between the lexicons. This is because of the diverse range of configurations
that the various models hypothesise. On the other hand, the central features that are
pictured are common to most cognitive models of language processing (e.g. Hillis &
Caramazza, 1991; Martin & Saffran, 2002; Miceli et al., 1996; Nickels, 2000; Southwood
& Chatterjee, 2001).
Figure 1:3. The central components of any four-lexicon model.
A considerable number of debates surround this issue (refer to Howard, 1995, for an
extensive discussion on the topic; also see Martin & Saffran, 2002). However, despite the
general consensus of four lexicons, the objective of this report is to show that a simple
model is sufficient to account for the language of people with aphasia in a clinical setting.
Therefore, judgments as to whether or not aspects of particular models are fundamental
should not be restricted to peripheral components and pathways; determining the relevance
of core components, in particular the number of lexicons, is just as crucial. A
demonstration that two lexicons are sufficient would considerably decrease the complexity
of cognitive models of language. The majority of evidence that favours the position of a
distinction between input and output lexicons is not based on cases for which
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representations are clearly lost in one but preserved in the other. Rather, the arguments are
based primarily on findings from intricate research methodology such as ‘dual-task
decrement’ (Shallice, McLeod, & Lewis, 1985) and research findings as they relate to
certain theoretical assumptions (see Howard & Franklin, 1988). However, at a clinical
level there is often a lack of distinction between input and output modules when
identifying deficits. Therefore, for the sake of simplicity the lexicons were not divided into
input and output processes, in accordance with previous advocates of this approach (e.g.
Allport & Funnell, 1981; Funnell, 1983; Jackson & Coltheart, 2001)
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Different accounts of reading aloud
At first glance, the lexical non-semantic reading route might appear to be redundant.
Indeed, it is not entirely clear what purpose it serves for normal language, and is not
included in many models, such as the summation hypothesis (e.g. Hillis & Caramazza,
1991) and Plaut’s computational model (Plaut, McClelland, Seidenberg, & Patterson,
1996). However, omission of the lexical non-semantic route leads to certain predictions
concerning word reading for individuals with damage to the semantic reading route. First
of all, if grapheme-phoneme conversion is impaired, then reading aloud of real words
should include frequent semantic intrusions or omissions (Miceli et al., 1996). Indeed, this
is the profile observed for deep dyslexia. However, not all individuals with impaired
semantic processing and non-functional grapheme-phoneme conversion produce semantic
errors on word reading. For example, WB (Funnell, 1983) performed poorly on tests of
semantic processing and was completely unable to read nonwords, to the extent that he was
unable to generate a response for more than half of the items. Nevertheless, he performed
reading tasks with very few semantic errors or omissions.
The second prediction is that even if reading aloud is impaired (and includes semantic
errors) in addition to non-functional grapheme-phoneme conversion, as is generally the
case in deep dyslexia, then this function should be just as severely compromised as oral
naming, since the absence of grapheme-phoneme conversion should lead to a complete
reliance on the semantic reading route. However, reading aloud is consistently reported to
be superior to oral naming provided orthographic input is intact, even for individuals with
deep dyslexia. This phenomenon is “only consistent with the partial operation of (the
lexical non-semantic route)” (Howard, 1985, p403).

A third prediction is that if grapheme-phoneme conversion is intact or at least partially
active, then regularisation errors should occur on reading of exception words. In other
words, surface dyslexia should be evident (Patterson, Marshall, & Coltheart, 1985).
However, Weekes and Robinson (1997) report BP, whose performance on semantic tasks
such as word-picture and picture-picture matching was impaired. Furthermore, he was able
to name barely more than half of the picture items in the Snodgrass and Vanderwart
corpus, and nearly half of his errors were semantic errors. His nonword reading was also
impaired, though he successfully read approximately half of the items on a nonword
reading task. Nevertheless, on a set of 40 exception words, BP made only one error
(reading thumb as thump, most likely a visual error). This is considered by Weekes as
strong evidence that BP is reading via a lexical pathway that does not involve semantic
processing. This prediction also applies to post-semantic naming impairments – MRF was
considered to have an intact semantic system but was impaired on oral naming, with
partially active grapheme-phoneme conversion, yet there was no effect of regularity
observed (Orpwood & Warrington, 1995).
Although the predictions made by most cognitive models of language processing with only
two reading pathways are not supported by the literature, the summation hypothesis (e.g.
Hillis & Caramazza, 1991; Hillis, Rapp, & Caramazza, 1999; Miceli et al., 1996; Miceli,
Capasso, & Caramazza, 1994; Miceli, Giustolisi, & Caramazza, 1991), considers reading
aloud of real words to be achieved by the ‘summation’ of lexical and sublexical processes.
If the semantic reading route is only partially operational but the sublexical process is also
providing full or partial activation, reading of words, both regular and irregular, is still
possible. Partial semantic activation means that semantically appropriate representations in
the phonological output lexicon, including the target, are partially activated (e.g. the word
yacht will activate representations such as boat, mast, sail, and of course yacht). At the
same time, the sublexical process activates all phonologically appropriate representations
in the phonological lexicon (so yacht might activate representations for words such as yet,
yurt and, again, yacht). Therefore, the only node in the phonological output lexicon that
will be activated above threshold is the target word, yacht. All other representations that
are activated will fail to reach threshold.
However, an important assumption of the summation hypothesis is that a complete lack of
input from the sublexical process, in conjunction with a lesion at some stage of the
semantic reading route, should lead to frequent semantic errors in word reading (i.e. deep
1:10

dyslexia). On the other hand, partial activation from the sublexical process should all but
eliminate semantic errors (and reduce total errors), as seen in phonological dyslexia. As
mentioned, however, evidence from the phonological dyslexic WB (Funnell, 1983)
suggests that this distinction between phonological and deep dyslexia does not always hold
true. This debate is examined further in the case of DHT, who is presented in Chapter 5.
The relationship between reading aloud and oral picture naming
While there are many different interpretations of how word reading can be achieved
through lexical, sublexical and lexical non-semantic processes, language researchers agree
almost universally that the phonological process of reading words aloud overlaps with the
phonological process of oral picture naming. However, a challenge to this principle was
the suggestion that reading and oral naming have distinct phonological stores that can each
be selectively damaged. The first clear presentation of this hypothesis appeared in a 1995
article by Orpwood and Warrington. They described MRF, an individual with poor oral
naming of pictures and poor naming to definition, with frequent semantic errors. As
demonstrated by his poor nonword reading, MRF had only partial access to grapheme-phoneme
conversion. MRF was able to read real words, with no difference between regular
and exception items, and his repetition of nonwords was intact; therefore he must have had
a lesion affecting the grapheme-phoneme conversion process. Comprehension was also
intact, suggesting a lesion of the phonological output lexicon. However, from the
perspective of most serial models, this should also impair word reading.
As can be seen in Figure 1:4, the authors propose that the lesion affecting oral naming is
located at a phonological output lexicon that is unique for oral naming tasks (lesion a).
Grapheme-phoneme conversion is also impaired (lesion b), but all other processes are
intact, including an additional phonological output store for word reading; the presence of
semantic errors in oral naming, and complete absence of them in reading, is considered
further justification for their position. The authors reject the summation hypothesis as a
plausible account on the basis that his grapheme-phoneme conversion is too severely
impaired to adequately contribute to reading.
Support for this hypothesis was provided by an apparent double dissociation between
reading and oral naming. BF was described by Goldblum (1985), and was remarkable in
that he was described as having intact oral naming yet impaired word reading (despite
intact comprehension for words). According to Breen and Warrington (1995), BF contrasts
with the many individuals reported for whom reading is intact while oral naming is
1:11

impaired, thus representing a double dissociation between these two abilities. In the
context of most mainstream models, there is no way to account for this phenomenon. The
solution, according to the authors, is independent stores for each task. Extending this
hypothesis, the authors conducted a series of priming experiments with participant NOR.
They found that priming by first reading the word had very little effect on NOR’s oral
naming unless the delay was extremely short. Although they concede that very little is
known about the specific effects of priming at the level of the phonological lexicon, they
consider this finding to represent a possible dissociation between the phonological
processes involved in reading aloud and oral naming.
Figure 1:4. The hypothesis described by Orpwood and Warrington (1995).
Green boxes and arrows indicate intact processing; red boxes and arrows represent the hypothesised
lesions. Only relevant processes are shown.
The most significant feature of the hypothesis of independent phonological stores is the
claim of a double dissociation between oral naming and reading aloud. However, this
position is challenged by Lambon Ralph, Cippoloti and Patterson (1999), who argue that
BF’s naming was not necessarily superior to oral reading, as purported by Goldblum
(1985). Three reason are given for this challenge: First, BF’s profile represented a complex
pattern of various dyslexic syndromes, rather than a single syndrome that could be
accounted for by an isolated lesion of output phonology; second, and most significantly,
1:12

reading and oral naming were not compared for the same set of words; finally, Goldblum
considered BF’s naming to be less impaired than reading partly because the majority of his
errors were almost always corrected – Lambon Ralph and colleagues (1999) argue that this
is far from a clear demonstration of normal functioning.
The claim that the summation hypothesis is unable to account for NOR and MRF is also
disputed by Lambon Ralph and colleagues. Rather, the presence of semantic errors in
naming but not in reading can be attributed to direct input from sublexical processes
because only minimal orthographic information is needed to block semantic errors. For
their participant MOS, who also performed poorly on oral naming and well on reading
aloud, they suggest that the phonological output lexicon itself is preserved, as is the
semantic system. Instead, it is the connection between these systems that is severed, with
reading aided by the sublexical process.
In accordance with the summation hypothesis, Lambon Ralph and colleagues (1999) go
further by suggesting that the reason why oral naming is frequently found to be impaired in
the context of intact reading is that oral naming is simply more vulnerable. There are two
factors that contribute to this vulnerability. First, there is no direct correspondence between
conceptual knowledge about an object and the phonological representation of that object’s
name, while reading is largely aided by the ‘quasi-regular’ mapping between orthography
and phonology. Second, only one source of phonological activation is available to oral
naming, while reading has at least two. In support of this claim is evidence that oral
naming in anomic participants can be improved by an additional source of phonological
activation such as phonemic cueing, making it as robust as reading aloud with its two
sources of phonological activation (Lambon Ralph, 1998; Lambon Ralph et al., 1999).
In a third article aimed at supporting the notion of multiple phonological output stores,
Crutch and Warrington (2001) present VYG, whose spontaneous speech was intact, but
whose oral naming and reading aloud were both impaired. Oral naming responses
consisted mostly of circumlocutions, with few phonological errors, while reading errors
were all phonological. Since VYG was able to comprehend words that he was unable to
read aloud, the authors concluded that the site of damage must be at the level of a
phonological output store, or perhaps access to the output store from semantics. Despite
the fact that VYG’s naming was more severely impaired than his reading, the authors
claim that damage to the ‘stronger’ reading process should affect naming in the same way
1:13

– the high number of phonological errors in reading, and almost complete absence of them
in naming, is therefore considered evidence for a double dissociation between the tasks.
However, there are several flaws in the logic of the articles discussed above. Firstly, if
reading aloud and oral naming are enabled by separate phonological stores, then the double
dissociation between them should not be restricted to differences in error patterns. There
should be individuals reported in the literature for whom reading is worse than oral naming
for the same items, a phenomenon which has not yet been described. Secondly, Crutch and
Warrington (2001) claim that VYG’s comprehension of words that he is unable to read
aloud indicates that his semantic system is unaffected. They fail to observe the principle
that receptive tasks such as word-picture matching place considerably less strain on the
semantic system than do expressive tasks (e.g. Howard, 1985; Laine, Kujala, Niemi, &
Uusipaikka, 1992; Lambon Ralph, Sage, & Roberts, 2000). If VYG does have a mild
semantic deficit, this could have a noticeable impact on oral naming, including generation
of semantic errors, with less of an impact on reading, which is assisted by partially intact
grapheme-phoneme conversion – thus leading to more phonological errors. Thirdly, many
authors argue that discrepancies of error types should actually be expected for the same
reason that reading aloud is considered to be less vulnerable to impairment than oral
naming (e.g. Newcombe & Marshall, 1980; Southwood & Chatterjee, 2000, 2001). If
additional phonological input constrains the responses, then more phonological errors, and
less semantic/circumlocutory errors should be evident.
Research Aims
The general aim of this report is to demonstrate that the basic model of language
processing, as described in this chapter, could be a useful clinical tool to aid the
understanding of aphasic patients. To this end, the following predictions were made:
1) The basic model will be sufficient to account for each individual’s profile, or at least as
capable as any existing model.
2) Two lexicons, one each for phonological and orthographic representations, are
sufficient to explain the majority of aphasic participants.
3) The lexical non-semantic route is an essential component of serial models. Therefore:
a) Participants with significantly impaired oral naming (that is not caused by pre-semantic
1:14
damage) but with intact reading are best accounted for by the existence of
this pathway.

b) If grapheme-phoneme conversion is completely abolished for an individual with
damage to the semantic reading route, deep dyslexia will only result if the lexical
non-semantic route is also damaged.
c) Reading impairments exhibited by anomic participants will conform to models of
language retrieval that assume a shared phonological process for reading aloud and
for oral naming (i.e. Orpwood and Warrington’s (1995) hypothesis of distinct
phonological stores will not be supported).
The critical motivation for this study was the paucity of literature in which a single set of
stimuli is used for a variety of language tasks. By developing a range of tests with a single
set of words-picture items, aphasic participants could be assessed in such a way that intact
and defective functions could be determined with much greater confidence than if a variety
of different tests had been used, thus providing insight into what aspects of cognitive
architecture are required to account for the participants. Furthermore, by carefully
balancing the group of items so that half would have word names with regular spelling and
the other half irregular, it was expected that a great deal more might be revealed about the
process of reading aloud.
The next chapter describes the processes involved in material preparation, recruitment of
suitable participants, assessment procedures and analysis of results.
1:15

2:17
Chapter 2. Method
As was described in the previous section, one aim of this project was to assess the validity
of claims made initially by Orpwood and Warrington (1995) that reading aloud and oral
naming are subserved by distinct phonological stores. This chapter describes the
recruitment of participants and the tests used, including the development of the five
unpublished tests that were designed to investigate the Orpwood and Warrington (1995)
hypothesis. It also describes the procedures that were followed for administration, scoring
and analysis of the battery of tests. As will be made clear, the lack of evidence for or
against this hypothesis did little to diminish the value of the results.
Participants
Recruitment of aphasic participants
Aphasic participants were recruited with the assistance of Speech Pathologists at the Royal
Rehabilitation Centre Sydney and St Joseph’s Hospital, through the Macquarie University
Psychology Clinic, and researchers at the Macquarie Centre for Cognitive Science. The
criteria for recruitment were adults with aphasia sustained at least 6 months prior to the
assessment, who presented primarily with anomia, without excessive interference from
complicating factors such as impaired hearing or vision, global cognitive dysfunction or
prominent motor-speech deficits, including dysarthria or verbal dyspraxia. Individuals with
mild complicating deficits were still requested with the understanding that they would be
excluded if necessary, though none were excluded on this basis. Individuals were also
excluded if they were identified as having recent psychiatric risk factors such as suicidal
ideation, depression or heightened anxiety.
A total of 12 potential participants were recruited. Of these, 7 were considered appropriate
based on the inclusion and exclusion criteria. One was excluded due to a near-ceiling
performance on most tests, two had recovered to the point that they were speaking fluently
in conversational speech, and two individuals who showed interest were excluded on the
basis of psychiatric conditions as it was considered unethical to risk placing them into a
potentially stressful situation. One participant, FME, was described in a separate report in
relation to her diagnosis of herpes simplex encephalitis, and is not discussed any further in
this dissertation. Descriptive data for the six remaining participants appear in Table 2:1
below. Each participant is described in detail in the following chapters.

Chapter
Partic-ipant
2:18
Age
Education
Sex
Description of
injury/illness
Months
Since
Injury
Acute deficits
(immediately
post-onset)
Relevant Medical
History
Vision/
Glasses
4 MWN 76 10 F
LMCA
ischaemic with
minor cortical
atrophy
8
Broca's aphasia;
dysarthria; mild
verbal dyspraxia;
mild right arm
weakness
AMI 1990; mitral
valve repair; TIA;
hypercholesterole
mia
Bifocals
5 RPD 65 10 M LMCA infarct 29 Unknown
Right meningioma
and debulking
surgery; CABG;
high cholesterol
Glasses
(short and
reading)
5 DPC 51 11 F
LMCA
haemorrhagic
56
Confusion;
aphasia
Type II DM;
migraines; anxiety
disorder
Reading
5 DHT 62 9 M
LMCA cerebral
embolic infarct
35
Right hemiplegia;
non-fluent
aphasia,
agrammatism
Infective
endocarditis;
CABG
Bifocals
6 JWS 69 9 M
LMCA
ischaemic
24
Right hemiparesis;
hemisensory loss;
global aphasia
Unknown Reading
7 SJS 43 10 M
LMCA
haemorrhagic
with bifurcation
aneurism
83
Severe frontal
headache;
vomiting; global
aphasia/dysphonia
Hypertension
Glasses
(short)
Table 2:1. Descriptive data for the aphasic participants.
Education = total years of formal education; LMCA = left middle cerebral artery; CABG = coronary
artery bypass graft; AMI = acute myocardial infarction; TIA = transient ischaemic attack; DM =
diabetes mellitus.
Recruitment of unimpaired controls
Unimpaired controls were recruited through personal contacts, and were seen in two
groups. The first group took part in the validation stage, and consisted of 10 age
appropriate controls (M = 59.63, SD = 4.35) with appropriate anticipated years of
education (M = 11.7, SD = 2.63). These participants were selected on the basis of expected
age and education levels of the ABI participants, who had not yet been identified. For the
second control group, 16 unimpaired participants were initially recruited, of which two had
also been involved in the validation stage. One participant, M2, emigrated from the
Netherlands at the age of 21. Because English is his second language, he was excluded
from the main control group. However, his data are presented in Chapter 6 as a comparison
for JWS, an aphasic participant with a similar background.

The remaining 15 individuals, 8 females and 7 males, were included in the main group.
Independent t-tests revealed no significant difference between the seven original aphasics
and the control group for either age (aphasics M = 61.00, SD = 12.08; controls M = 60.20,
SD = 6.35; t(19) = 0.20, p = 0.84) or years of formal education (aphasics M = 9.83, SD =
0.75; controls M = 10.07, SD = 1.16; t(19) = 0.45, p = 0.66).
Many of the control participants wore glasses, and several had mild visual impairments
(e.g. cataracts) though testing did not reveal any obvious visual difficulties (i.e. they did
not perform any worse than other controls on tests that might be sensitive to visual
impairment). Also, four members of the main control group (three males, one female)
reported mild hearing difficulties, which were not identified until nonword repetition was
attempted. The justification for including these individuals is that such mild hearing loss
and visual difficulties are clearly common in this population, and difficult to identify.
Therefore, similar difficulties cannot be eliminated as a cause of poor performance for
some of the aphasic participants; the effect of mild hearing loss on repetition tasks is
discussed in Chapter 3. Two participants emigrated from England about 25 years ago, and
the results of these individuals are also examined more closely in Chapter 3.
2:19
Materials
One of the key predictions made by the Orpwood and Warrington (1995) hypothesis is that
if oral naming is impaired, and the cause of this impairment can be localised to the
phonological output lexicon, then words with regular spelling should be less affected on a
reading task than words with irregular spelling, assuming that grapheme-phoneme
conversion is still involved. Determining the effects of regularity on reading performance
is also tantamount to hypotheses relating to the lexical non-semantic route. Therefore, the
primary objective when preparing the materials was to focus on this contrast between
regular and exception words by gathering two word lists that differed only in this respect.
That is, the word items needed to be matched on criteria such as frequency and linguistic
complexity. In order to further limit potential differences in linguistic complexity, only
monosyllabic words were chosen. Since the items also needed to be named, only words
that could be easily elicited by their pictures were appropriate, which considerably limited
the number of appropriate items. For example, a picture of a yacht will just as often be
named as a boat; pictures of a buoy and a raft proved to be difficult to identify for many
people.

After an extensive period of item selection and refinement, including informal testing and
discussion with peers, 104 items were selected from the list of monosyllabic words in the
CELEX lexical database (Baayen, Piepenbrock, & Van Rijn, 1993). The pictures were
obtained primarily from Hemera Photo Objects (Hemera, 1997-2000), with gaps filled by
non-copyright pictures obtained from the internet. Alterations were made where necessary
to exclude distracting aspects of the images or to highlight the relevant part of the picture.
The regular and exception word sets were matched for spoken and written frequency
(Baayen et al., 1993), number of phonemes, number of letters, the number of plural words
(only one item in each set (shorts/blinds) was a plural word), and whether the item was
animate or inanimate. Since many nouns also act as verbs (e.g. axe, bowl, or comb), which
can have a considerable impact on frequency effects, only items that were deemed to be
used most often as nouns were selected. Comparisons were analysed using t-test and
Fisher’s exact calculations, with the results presented in Appendix 1. Following the
validation phase of the research (see the Procedures section that follows) the final
word/picture set included 40 items with regular spelling and 40 exception items, with
classification determined by the set of grapheme to phoneme correspondence rules listed
by Rastle and Coltheart (1999).
These 80 items were used for four simple tests of language ability: Oral naming, written
naming, reading aloud and repetition. As it was anticipated that some participants might
have considerable difficulties with written picture naming and that they would be unable to
complete the test, the first 20 items on this test were also matched as per the criteria listed
above. Again, comparisons were by way of t-tests and Fisher’s exact, with the results
appearing in Appendix 1. Presentation order of items in each test was pseudorandom –
items were selected at random but relocated to ensure that no more than three consecutive
items were related by regularity, semantic field or phonological similarity.
Additionally, a word-picture matching task was designed to determine whether or not
participants had intact access to the semantic representations of the test items from the
written word. A multiple-choice format was used. For each item, the target word appeared
in the middle, with four pictures around the word. The pictures were equated in size as
much as possible, but often needed to be slightly different to remain size appropriate (e.g. a
picture of a cat needs to be larger than a picture of a mouse). An example item from the
2:20

2:21
comprehension test appears in Figure 2:1. For each written word item, the pictures
included:
a) The target picture;
b) A semantic distractor – the regular and exception word groups were matched for
degree of semantic relatedness between the distractor and the target based on
figures sourced from Maki, McKinley and Thompson (2004) as well as the type of
semantic relationship (each pair was broadly classified as either related by
association, such as bowl and spoon, or simply being members of the same
category, such as an axe and a saw);
c) A phonological/orthographic distractor – the two groups were matched for degree
of phonological relatedness; and
d) An unrelated distractor.
bowl
Figure 2:1. Example Item from the comprehension test:
The given word item (bowl), the target picture, the semantic distractor (spoon), the phonological
distractor (bell), and the unrelated distractor (tricycle).
Most pictures appeared more than once throughout the test, though none appeared more
than three times in total (including once as the target, for many of the pictures). The full
list of items for the comprehension test appears in Appendix 1, along with relatedness
figures and classifications, and statistical calculations.
Other tests: Aphasic participants were also assessed on several published tests in order to
assess the integrity of other aspects of the lexical system. The following tests were
administered:
• Tests from the Psycholinguistic Assessment of Language Processing in Aphasia
(PALPA, Kay, Lesser, & Coltheart, 1992):

2:22
o Visual lexical decision (subtest 25) – spelling-sound regularity
(distinguishing real words (regular and exception) from nonwords
(pseudohomophones and non-homophonic nonwords)). This test was used
to assess the integrity of the orthographic lexicon and input to it. Chance is
50% on this test.
o Homophone decision (subtest 28) – judging whether or not pairs of words
(with regular and irregular spelling) or nonwords sound the same. This test
relies on the integrity of multiple components of lexical processing,
including the orthographic lexicon, phonological lexicon, grapheme-phoneme
conversion and the phonological output buffer. The error pattern
of this task, in particular the contrast between real word and nonword pairs,
is often more important than the total score. Chance is 50% for this test also.
o Nonword reading and repetition (subtest 36) – grapheme-phoneme
conversion and the sublexical repetition route can potentially play an
important role in processing of words, particularly when other abilities are
impaired. Therefore, assessment of nonword reading and repetition was
vital. To enable relevant comparisons, it was also crucial that the nonword
items be comparable to items used for the unpublished tests (i.e. the 80
regular and exception words discussed previously). Indeed, two-tailed
independent t-tests revealed no significant difference between the 80 test
items and the 24 nonwords used in PALPA for either number of letters (for
real words M = 4.30, SD = 0.79; for nonwords M = 4.50, SD = 1.14, t (102)
= 0.98, p = 0.33) or number of phonemes (for real words M = 3.30, SD =
0.80; for nonwords M = 3.42, SD = 0.72, t (102) = 0.64, p = 0.52).
o Cross-case matching (subtest 19) and, for participants who made errors on
this test, mirror reversal (subtest 18). These tests were intended to eliminate
an impairment of letter identification as the cause of a participant’s
difficulties with processing written words.
• Pyramids and Palm Trees test (PPT, Howard & Patterson, 1992) – this test requires
the participant to match the stimulus item (picture, written word or spoken word) to an
associated item from a choice of two semantically related pictures. Three versions
were utilised in order to assess the integrity of the semantic system and input to it:
o 3 pictures version – poor performance relative to the other versions might
suggest reduced input from object recognition.

o 2 pictures + 1 written word version – relatively poor performance suggests
2:23
reduced input to the semantic system from the orthographic lexicon.
o 2 pictures + 1 spoken word version – relatively poor performance suggests
reduced input to the semantic system from the phonological lexicon.
Equal difficulty with all three versions is indicative of damage to representations
within the semantic system.
• From the Birmingham Object Recognition Battery (BORB, Riddoch & Humphreys,
1993):
o Subtest A (hard). This subtest is comprised of 32 black and white drawings
of which half are real and half are made up from two different objects (e.g.
the body of a cow with the head of a horse). This tests the integrity of the
object recognition process.
Procedures
Validation phase: The original 104 pictures were shown to the validation group of controls
on the screen of a 17” laptop computer using Microsoft PowerPoint. In cases where the
target was provided in conjunction with an appropriate non-target word (e.g. ‘crow, bird’
for the desired target of crow), the target was considered to have been achieved (on testing,
aphasic participants and members of the second control group were prompted to provide
another response if they answered with an appropriate non-target word). Likewise, if the
target response was included as part of a larger, similarly appropriate response (e.g. steak
‘t-bone steak’; plane ‘aeroplane’), the item was considered appropriate for inclusion,
and hence correct if produced by the aphasic participants and members of the second
control group. Items were only included if the target word was achieved by nine out of ten
controls in the validation group, and the two word groups (regular/exception words) were
matched for the number of participants who named each word correctly (mean number
correct out of 10 for the regular group was 9.85 (SD = 0.33) and for the exception word
group 9.75 (SD = 0.44), t(78) = 0.42; p = 0.68).
Experimental phase: The items for four tests were shown to all participants on a 17” laptop
screen using Microsoft PowerPoint – the items for the repetition task were read by the
examiner. For picture naming (oral and written) and reading, five seconds was allowed for
the response, with the timing controlled by the computer (a further 5 seconds was allowed
if the participant was prompted to provide a different response, as described for the
validation study). For written naming, the time limit only applied to the commencement of

writing a name to allow for any motor difficulties (i.e. extra time was allowed for slow
writing, within reason). For repetition, the 80 items were read to the participant, with 5
seconds allowed for each response. Ten seconds was allowed for each item on the
comprehension test. A five second gap (a blank screen) separated each item on all tests
except for repetition, for which one to two seconds separated each response from the
following item. Participants were permitted to move through the computerised tests faster
by pressing an appropriate key on the keyboard.
The assessments with all participants were conducted over four sessions, with each session
a week apart (or within 2 days). The tests administered in each session are listed in Table
2:2 below. The unpublished tests were spread out over the sessions to reduce the effects of
priming. The exception was the last session, during which written naming was followed
soon after by repetition; it was considered too impractical and burdensome on the
participants to extend testing beyond four sessions. Controls were assessed on all tests
except for cross-case matching, on which unimpaired individuals are assumed to be 100%
accurate.
2:24
Session 1
Interview
Comprehension test
PPT (3 pictures)
Session 2
Oral naming test
PPT (2 pictures, 1 written word)
Visual lexical decision – regularity (PALPA: 25)
Object decision (BORB: Subtest A – Hard)
Homophone decision (PALPA: 28)
Nonword reading (PALPA: 36)
Session 3
Reading test
PPT (2 pictures, 1 spoken word)
Nonword repetition (PALPA: 36)
Cross-case matching (PALPA: 19)
Session 4
Written naming test
Repetition test
Table 2:2. List and order of tests in each session.
Italics indicate unpublished tests.
The structure of testing was not varied between participants; all aphasic and unimpaired
participants completed the tests in the same order. This was to ensure consistency with, and
therefore enable accurate interpretation of, practice effects and priming.

2:25
Scoring
For the unpublished tests, clarification of certain error types is needed:
• Phonological error was scored when at least half of the target phonemes were
produced in the correct position.
• Spelling error was scored for written naming if at least half of the target letters were
produced in the correct position (e.g. chefchark).
• Mixed errors were considered unrelated unless there was an obvious connection
with the target item (e.g. bone dag (presumably dog) in written naming was
considered a semantic error).
• Errors that were self-corrected within the time limit were considered correct without
further consideration.
• Morphological errors were primarily inflectional errors (mostly addition or deletion
of the plural –s).
• Based on the responses of controls, plural variation in picture naming was
considered acceptable for two items, blind/s, for which both variants are common, and
gate/s (which was generally named as the singular, but since the picture was of a two-part
gate this could not be considered an error). Also, the pronunciation of vase varied
(either pronounced /vaz/ or /veIs/).
• No response errors included items for which some effort was made but nothing
meaningful (i.e. only one phoneme or letter) was generated.
Finally, although errors on the comprehension test appear fairly straightforward, there is at
least two ways that the actual error types could reflect problems such as reduced visual
acuity or scanning. First, the phonological distractors more often than not had names that
were visually similar to the target (e.g. ball/bell; nose/hose) – therefore, many phonological
errors could actually be visual or orthographic errors. Second, many of the semantic
distractors were not only visually similar to the target, but in some cases were actually
more prominent (especially when the distractor picture, but not the target, had the
background removed) – therefore, some semantic errors could actually reflect failure to
adequately scan all components of the item, which might account for the rare control
errors.
Analyses
Measures of impairment: To ascertain whether or not an aphasic participant performed
significantly worse than the control group, the Bayesian methodology of Crawford and

Garthwaite (2007) was employed (using the software for simple difference, cited in the
same article). This was the primary calculation used for determining whether or not a
participant had performed significantly worse than the control group on a particular task.
Because the regular and exception groups were so well matched in terms of control
performance, Fisher’s exact test (an unstardardised method of comparing independent
groups) was used to determine differences, rather than Crawford and Garthwaite’s
standardised calculation, which was influenced by ceiling effects.
For certain participants, the discrepancy between two unpublished tests was measured with
McNemar’s Test, with the obvious caveat that the tests differ slightly in their levels of
difficulty, meaning a certain level of subjective interpretation was unavoidable. The
Crawford and Garthwaite method (2007) proved to be inappropriate for judging these
discrepancies and dissociations due to the differing influences of ceiling effects on the
different tests.
Item consistency: An important consideration for error analysis is item consistency, or the
comparison between two tasks for a particular set of items. Since language based entries
are conceptualised as representations stored within the semantic system and each of the
lexicons, damage to particular representations should lead to errors on the relevant items
regardless of the task, assuming that the same processing module is necessary for each of
the tasks being compared. For example, damage to representations in the semantic system
might lead to item consistency for oral naming, written naming and word-picture matching
for particular items, but not necessarily for repetition or reading; damage to representations
in the orthographic lexicon might lead to consistency for reading, word-picture matching
and written naming, but not repetition or oral naming. On the other hand, a lesion that
causes reduced activation of a processing module, rather than damage to the
representations in the module, would not be expected to result in such consistency.
Therefore, item consistency can, in certain conditions, provide an indication of the extent
to which two deficits might be related by a single lesion.
However, there are several aspects of item consistency that warrant caution when
interpreting the results. First of all, not all tasks have the same ‘degree of difficulty’ – even
for unimpaired individuals, written naming is usually performed less well than oral
naming, at least for English in which written naming entails not only naming the picture,
but also retrieving details about complex spelling rules and a large number of memorised
2:26

word spellings that do not abide by rules or even a consistent exception to the rule (for
example, it would not be unusual for some unimpaired individuals to be unable to spell
words such as yacht). Furthermore, impaired participants could easily have multiple lesion
sites affecting particular abilities, yet it is still relevant to investigate the possibility that
one of the lesions is at least partially responsible for two or more of the deficits. Therefore,
calculation of item consistency between different tasks should include an element of
maximum consistency or ‘maximum overlap,’ which is discussed shortly.
The second caution relating to item consistency is that a certain level of similarity is often
expected between two tasks even if the difficulties on the tasks are not the result of a single
lesion. This argument relates most prominently to the relationship between oral and written
naming, and arose from observations that certain participants with post-semantic naming
impairments would demonstrate statistical consistency between the two tasks, suggesting
to many that there could be an additional process after the semantic system but before the
lexicons (e.g. Levelt et al., 1991; Raymer et al., 1997; Raymer, Maher, Foundas, Rothi,
Heilman, 2000). However, several authors have questioned the need for this additional
process in accounting for item consistency. For example, Miceli and colleagues (1991)
consider a certain level of consistency to simply represent deficits resulting from co-occurring
2:27
lesions affected by the same linguistic factors such as word frequency,
imageability and linguistic complexity. That is, for any particular set of words, it is likely
that the least frequent and most complex words will be the most vulnerable. This can lead
to consistency between any tasks that happen to share the same common pressures.
Furthermore, the particular common pressures are different for different pairs of tasks. For
example, for oral and written naming, word frequency and imageability are likely to play a
role, while for reading aloud and written naming, word frequency and grapheme-phoneme
regularity might lead to consistency, and the effect of imageability is perhaps less
predictable. Therefore, it is important to keep in mind that a certain level of consistency
between tasks, even beyond what would be predicted from mathematical chance, could
simply be the result of the factors that affect both tasks.
Despite these cautions about interpreting item consistency, the benefit of being able to
judge the relationship between two deficits makes this form of analysis extremely
worthwhile. There are numerous methodologies for calculating and interpreting
consistency (see Howard, 1995, for a statistical procedure that attempts to negate the
effects of some of the variables that affect word retrieval). Although it is theoretically

possible to use or devise a procedure for determining statistically significant consistency
that takes into account frequency, visual complexity, phonological and orthographic
complexity and so on, the nature of comparing the results of two different tests is so
complex that it is not reasonable to consider such a method to be entirely accurate.
Furthermore, attempting to compare five different tests with such a methodology would
mean calculating the effects of the various factors for up to ten comparisons, each with
different common factors with varying degrees of impact for each. For these reasons, a
straightforward method was used to allow qualitative judgement of item consistency
between tests.
Simply put, the actual overlap (of correct plus incorrect responses) is compared to the
maximum overlap and the chance overlap. The maximum overlap is the greatest that the
overlap between two tests can be, given the difference in test scores, and is found by
adding the number of errors of the more accurate test to the number of correct responses on
the less accurate test. For example, if the score on oral naming is 60/80 and the score on
written naming is 30/80, then the maximum overlap is 50 (20 errors on oral naming plus 30
correct on written naming). In other words, the overlap between the two tests, given the
difference in performance, cannot be higher than 50. The closer the scores are for two tests,
the higher the maximum overlap. The chance overlap, which is derived from Cohen’s
Kappa, is the overlap that would be predicted by chance alone, given the difference in
scores (assuming complete independence). This figure is found by multiplying the number
of errors on test a by the percentage of errors on test b, added to the number correct on test
a multiplied by the percentage correct on test b. Since the figure does not attempt to
incorporate item frequency or complexity, there is no illusion that the comparison can
render a statistically sound comparison. Rather, it simply allows an estimate that can be
used for all of the comparison regardless of the common pressures that would be expected.
This allows for a more honest comparison by allowing a much greater depth of
interpretation and debate, instead of relying on a statistical procedure that may or may not
encompass all of the relevant factors. Calculation of overlap is explained further in
Appendix 2.
By considering the actual overlap as it compares with the chance overlap and maximum
overlap, a qualitative judgement can be made about the relationship between two tasks: An
overlap closer to chance than to the maximum suggests little or no relationship; a score
midway between chance and the maximum suggests a possible relationship, with possible
2:28

involvement from common pressures; finally, an overlap that is close to the maximum is a
good indication of a relationship between the tasks, provided the maximum is reasonably
high (if tests differ too greatly in score, the maximum overlap can be too low to allow a
meaningful interpretation).
Nonword reading and repetition: In addition to presenting the results of the two nonword
tasks in terms of number of items correct, an additional calculation was performed to
assess the level of accuracy of the individual phonemes produced. This phoneme overlap is
a simple method of displaying a participant’s accuracy when their total score on the test is
below normal levels. For each item, the number of phonemes in the target response is
compared with the number of correct phonemes in the actual response. The lesser of the
two is then divided by the greater to achieve a figure that represents the percentage of
correct phonemes that were achieved for that item. For example, if ploon is read as ‘foon,’
two of the 4 target phonemes have been achieved, or a 50% overlap. The mean overlap for
all 24 items can then be calculated.
The number of lexicalisations is also recorded. These are items that are generated as real
words that are similar to the target (usually within a single phoneme or grapheme of the
target). A relatively high number of lexicalisations for a particular test suggests that the
lexicons are being employed to process novel grapheme or phoneme sequences, rather than
grapheme-phoneme conversion (for nonword reading) and the sublexical repetition route
(for nonword repetition). A high number of lexicalisations also reduces the relevance of
phoneme overlap; for example, DHT (Chapter 4) had an overlap of 31% on nonword
reading, but it came almost entirely from his lexicalisations suggesting that nonwords were
being read via lexical processes and not at all by grapheme-phoneme conversion. On the
other hand, a reasonable overlap with a lower number of lexicalisations would suggest at
least partial access to grapheme-phoneme conversion.
The following chapter presents and discusses the results of the 15 unimpaired participants
whose data allowed enabled effective analysis of the aphasic participants.
2:29

3:31
Chapter 3. Control group – results and discussion
Before reporting and discussing each of the aphasic participants, several issues arose from
the control group data that are worth discussing. Summary data of testing with control
participants appear in Tables 3:1 and 3:2. Full results are reported in Appendix 3.
BORB PALPA PPT
Object
decision
Lexical
decision
Homophone
decision
Nonword
reading
Nonword
repetition
Mean 3P 2P1W 2P1S
n 32 60 60 24 24 52 52 52 52
Mean 25.93 58.33 55.65 22.94 21.73 50.44 50.07 50.73 50.53
StDev 2.66 2.38 3.46 1.18 3.16 1.42 1.94 1.33 1.30
Lowest 20 53 50 21 13 46.33 45 47 47
Table 3:1. Summary of control results on published tests.
Mean, standard deviation (StDev) and lowest score for each of the published tests. For PPT, Mean =
mean of all 3 versions; 3P = 3-picture version; 2P1W = 2-picture/1-written word version; 2P1S = 2-
picture/1-spoken word version.
Regularity effects of unpublished tests
Since one of the aims of the research focused on the issue of regularity effects, the first
comparison was between regular and exception words for the unpublished tests. Although
there is a slight discrepancy between word groups for each test, efforts to match the groups
were fairly successful. The only meaningful difference was for written naming,
presumably due to less predictable spelling of some words. This was a significant
discrepancy (t(14) = 2.69, p = 0.02). Since the balance of imageability between the two
groups was based only on the oral naming performance of the validation control group, it
was not surprising that differences were revealed for the written naming test, for which
regularity should, theoretically, play a much greater role. Having said that, the effect of
regularity should only be evident in spelling errors. While there mean of spelling errors
was higher for the exception words (0.93 to 0.53), so too was the mean of semantic errors
(0.67 to 0.20).
The only other significant discrepancy was for the comprehension test (t(14) = 2.26, p =
0.04), though the actual difference was minimal (summed across the 15 participants, there
were 4 errors on regular words and none on exception). Means and standard deviations for
these tests, as well as the discrepancy between means of the regular and exception word
groups, appear in Table 3:1.

3:32
Compre-hension
Oral
Naming
Reading
Written
Naming
Repetition
n 80 80 80 80 80
Mean 79.73 79.00 79.87 77.07 79.20
Standard Deviation 0.46 1.00 0.35 2.63 1.08
Regular - exception -0.27 0.33 0.13 1.07 0.40
Table 3:2. Summary of control group results on unpublished tests.
Descriptive data for each test and for the discrepancies between regular and exception word groups on
each test (mean of total scores for each participant on regular words minus mean for exception words).
Oral naming versus written naming
It was not unexpected that some aphasic participants would have greater difficulty with
written naming than with oral. Therefore, it is important to be able to judge whether this
discrepancy is the result of differing effects of lesions, or the effects of a single lesion
affecting both output modalities, with the written naming score lower simply because this
task is more difficult. Indeed, control data suggest that written naming is significantly more
difficult, with the range of scores much lower (lowest control score 72 for written naming,
77 for oral). Therefore, a small difference between scores might simply relate to the degree
of difficulty on each task, and this needs to be taken into account when comparing
participants’ scores for each task. On the other hand, a significant difference in the
opposite direction is a strong indication that oral naming is defective, and more so than
written naming if both are impaired. Written naming was significantly more difficult than
oral naming for the control group t(14) = 3.08, p 0.01. Strangely, however, it was not just
spelling errors that distinguished the two naming tasks (a mean of 1.47 compared with 0
phonological errors on oral naming) – the mean number of semantic errors also increased
from oral naming (0.47) to written naming (0.87). Other error types were fairly consistent
between the two tasks. In terms of item consistency across participants, one item on written
naming (scroll) was scored incorrectly by three participants, while 10 other items were
incorrect for two different participants.
Written naming was also significantly more difficult than comprehension (t(14) = 3.73, p
0.01), reading (t(14) = 2.85, p = 0.01), and repetition (t(14) = 4.05, p 0.01), though on
each of these tasks the mean number of errors was less than one, as can be seen in Table
3:1.

3:33
Methodological issues
Several methodological issues became apparent when the results of the control group were
analysed:
1. Written naming: One problem with the added difficulty of written naming is a reduction
of sensitivity for the test. Some people are simply ‘bad spellers,’ which lowers the mean
and range of the control scores. Unfortunately, this erodes the test’s ability to detect mild
deficits of written naming amongst aphasic participants who were premorbidly ‘good
spellers.’ If an individual who would have premorbidly scored close to 100% on written
naming then sustains an injury that reduces their performance to the level of unimpaired
‘bad spellers,’ any assertion of a deficit is much less conclusive. This problem can be
addressed to some extent with error patterns: Errors of unimpaired individuals with low
scores should be predominantly spelling mistakes, with ‘appropriate’ misspellings (e.g.
waspwosp). A high number of semantic errors (no control made more than 2) or very
unusual spellings (e.g. beeeeb; kitekert) might indicate that a lesion is affecting this
process.
2. PPT: Two members of the control group, F6 and M6, emigrated from England about 25
years ago. Despite performing at similar levels to the rest of the control group on most
tests, there was an obvious advantage for F6 and M6 on PPT, achieving 100% accuracy on
all three versions. Only one other control, F5, achieved full scores on all three version –
predictably, F5 was also educated in England. Only one Australian educated control
achieved a perfect score, and only on one version. The difference between controls
educated in England and those educated in Australia was significant (t (13) = 2.47, p =
0.03), Nevertheless, merging the scores of all 15 control participants had only a small
impact on group scores – the mean for the 12 Australian-educated controls across all three
versions was 50.06 (SD = 1.32) compared with 50.44 (SD = 1.42) when the three England-educated
participants are included.
For most of the aphasic participants, the inclusion of the England-educated controls made
little difference. Nevertheless, the apparent cultural bias in PPT suggests that there should
be concern as to the appropriateness of using English norms for a clinical population
educated in Australia. Howard and Patterson (1992) report a mean score of 98-99% (less
than one error) for the 3-picture and 3-word versions, with no participant making more
than three errors. In contrast, three of the twelve unimpaired, Australian-educated

participants made more than three errors on at least one occasion, and the mean for the 3-
picture version was considerably lower than that given by the authors of the test (95%, or
about 2 errors more on average). This finding should serve as a warning to clinicians who
use the PPT in practice that the results of the PPT, although very useful, need to be
interpreted within the context of this possible cultural bias. On the other hand, lowering the
cut-off score for PPT reduces its sensitivity, so it is important to balance these
considerations. The items that were most unreliable for the Australian educated members
of the control group are listed below. While most items were unreliable on just a few
occasions and for only two to three participants, the most noticeable difficulty was on the
acorn item, for which Australian-educated controls consistently chose the distractor.
Percent
accuracy
3:34
Item
number
Given
item Target Distractor
14 40 acorn pig donkey
86 16 windmill tulip daffodil
89 4 thimble needle cotton
92 31 puddle cloud sun
92 32 rocket moon star
94 12 pyramid palm tree pine tree
94 14 ticket bus car
94 26 nun church house
Table 3:3. Most frequently incorrect items on PPT for controls.
Only items that were incorrect for at least two different control participants are included.
3. Object decision: Perhaps the most concerning test result was for the object recognition
task from BORB (Riddoch Humphreys, 1993). The performance of the control group on
this task varied so greatly that it effectively had very little capacity for detecting
impairments, with the worst-performing control scoring just 20/32 (chance is 16/32). The
mean of 25.93 was also noticeably lower than that of the original normative sample (M =
27.0, SD = 2.2). Fortunately, the lack of sensitivity of this test did not matter for the
aphasic participants, for whom the lowest score was 26/32.
Although an English advantage might again be predicted, given that many of the animals
represented in the test might be unfamiliar to people raised and educated in Australia, this
was certainly not the case – three of the Australian-educated controls outperformed their
England-educated peers. However, the clearest outcome of error analysis was the obvious
response bias towards real objects (M = 95%, SD = 5%; for unreal objects, M = 67%, SD =
13%). This lack of ability for unimpaired controls to reliably identify made-up pictures
suggests possible problems with the materials. Feedback from the controls who found the

test difficult indicated that the drawings were not clear enough, and it is important to note
that the lowest scoring control did not report any diagnosed visual problems (aside from
the need to wear glasses). A qualitative observation was that participants appeared to
improve as the test proceeded, suggesting that practice items or coaching might improve
reliability, validity and sensitivity.
4. Nonword repetition: Lastly, it was noted in Chapter 2 that several control participants
had minor hearing difficulties which were considered age appropriate and were not
obvious in conversation. These difficulties seemed irrelevant on all of the tasks with the
exception of nonword repetition. As can be seen in Figure 3:1, those with minor hearing
loss performed considerably worse on this task (for the 4 hearing impaired controls, out of
24, M = 16.75, SD = 2.87, for the 11 unimpaired controls M = 23.55, SD = 0.69). This is in
contrast to word repetition, on which the score out of a possible 80 differed only slightly
(hearing impaired M = 78.25, SD = 1.26; for unimpaired M = 79.55, SD = 0.82). A two-way
analysis of variance revealed a significant effect of hearing on the tests (F(1, 13) =
3:35
55.67, p 0.01).
The inclusion of these participants was justified on the grounds that they were considered
representative of the general population. The advantage of this decision is that allowances
can be made for aphasic participants with mild hearing difficulties (to the extent that it
seems relatively ‘normal’ for this age group). The disadvantage is the lack of sensitivity in
detecting impairments of nonword repetition in participants with good hearing. Although
the outcome of nonword repetition is therefore somewhat less transparent, the results are
nevertheless useful. Obviously, a good score on this task (22/24 or higher) is indicative of
intact abilities (within the confines of the basic model, which means intact auditory input,
phoneme input and output buffers, and speech/motor output). Scores below this point were
interpreted within the context of the basic model (which in this instance complies with
most mainstream language models), and are examined more closely in the relevant
chapters.

3:36
100
80
60
40
20
0
Words Nonwords Words Nonwords
Hearing impaired Normal hearing
Percent correct
Figure 3:1. Control group performance on repetition tasks.
Mean scores in percent for word and nonword repetition for the 4 members of the control group with
minor hearing loss and the 11 without.

Patterns of Reading Impairments in Cases of Anomia - Dr Christopher Williams

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