Auditory Object Recognition: Evidence from Aphasia
1. AUDITORY OBJECT
COGNITION IN
DEMENTIA
Johanna C. Golla, Lois G. Kimb, Julia C.
Hailstonea, Manja Lehmanna, Aisling Buckleya,
Sebastian J. Crutcha, Jason D. Warrena (2011)
Presented by
Diana Cordeiro
and
Laura
Gwilliams
2. BACKGROUND
Deficits people with dementia face have been widely
studied
Visual object processing deficits are well established
But the cognition of nonverbal sounds (i.e., auditory
objects) in dementia has been relatively little
explored
Similarities exist between the two domains, but a
‘visual object’ is much more concrete and easily
defined than an ‘auditory object’
3. AUDITORY OBJECT?
Auditory objects are made up of acoustic properties
which are processed by the hearer
Recognise sound characteristics
And, properties of the object that created the sound
Unclear how the brain processes an object in the
auditory domain, especially for people with dementia
syndromes
4. WHY STUDY THE AUDITORY DOMAIN?
1) Clinical Perspective
Disorders of auditory processing gives rise to a diverse host of
symptoms and deficits
2) Cognitive Neuropsychological Perspective
Determine cognitive components required to process an
auditory object
Relation between these essential components and the study of
damaged brains
5. AIMS
Build upon previous study:
1) Extend investigation to include patients diagnosed with
Alzheimer’s disease (AD) and Primary Progressive
Aphasias (PPA)
2) Assess auditory object cognition while taking working
memory into consideration
3) Extend analysis of auditory object cognition to include
a wider range of processes including early perceptual
mechanisms
Goll, J. C., Crutch, S. J., Loo, J. H., Rohrer, J. D., Frost, C., Bamiou, D. E., et al. (2010). Non-verbal sound
processing in the primary progressive aphasias. Brain, 133, 272–285.
9. RESULTS
Comparisons between syndromes and control
AD PNFA LPA GAA
Pitch change detection Preserved Preserved
Pitch change direction Deficit Deficit
Timbre Preserved Deficit Deficit Preserved
Size familiar Preserved Preserved Preserved Preserved
Size unfamiliar Preserved Preserved Preserved Preserved
Apperceptive Deficit Preserved Deficit
Semantic Preserved Deficit Preserved
After adjusting for non-verbal working memory performance
10. CONCLUSIONS
Dementia syndromes are associated with impaired
processing of auditory objects
Separable stages of auditory object analysis
Separable profiles of impaired auditory object cognition in
dif ferent dementia syndromes
Working memory was an important aspect of auditory
recognition
Taken together, results suggest dementia syndromes
are associated with distinctive profiles of auditory
object processing
11. LIMITATIONS
Small case numbers
Deficits occurred in context of general auditory
dysfunction and widespread cognitive impairment
Cannot make direct anatomical and pathological link to
deficits observed
None of the deficits were restricted to a
particular dementia syndrome
12. FUTURE RESEARCH
Larger patient cohorts and additional
neurodegenerative diseases
Clinical perspective:
Core symptoms of disorders could be better understood with
further study into auditory dysfunction
Cognitive Neuropsychological perspective:
Establish relationship between different elements of auditory
object perception
Explore processes for object segregation in embedded complex
auditory scenes
Compare mechanisms of object analysis across different
modalities, using appropriate matched tasks in each modality
dianaPrior study into PNFA and SDPrevious study was into Primarynonfluent aphasia.. Previous study didn’t take WM into consideration
DianaPrimary progressive aphasia
dianaEarly stage of perceptual coding at the subcortical level, pitch and pitch change
Laura - experimental design was forced choice, uni-modal and single auditory object at a time to reduce STM demands - 7 elements to investigate the three levels of cognitive auditory processing - early perceptual was studied through sub-object sounds which corresponded to a single sound characteristic - perceptual representations investigated through apperceptive task where the sound was computationally degraded and the participants were asked to say wherther the sound was created by a particular object category, in this instance ‘tool’ or ‘animal’ - semantic recognition of objects looked at a further level where the participants had to say whether the particular function that the object served was outside or inside.Subcortical // perceptual (combo of sub-object) // semantic, the meaning of these objectsVisual diagrams: Familiarise subjects with each testPitch and timbre tests – directional arrowsAuditory size test – words ‘big’ and ‘small’Apperceptive test – canonical examples of tools and animalsSemantic test – photographs of interior and exterior scenes
diana
diana
Laura - small case nubers, especially in the granulin gene mutation who had one participant, but this is inherent in studies of this kind - cannot make correlational claims to link the audiotry deficits to the anatomical and pathological observations because general auditory dysfunction was found as well as widespread cognitive impairment - none of the deficits were completely restricted to a particular syndrome, suggesting there is a level of overlap between the auditory processing of these elements
Laura – make within and across dementia generalisations - study auditory dysfunction further to better understand the core symptoms of the disorder - relationship between different elements of auditory object perception - object segregation within context; maybe context helps some people not others - look at cross-modal perception because the combination of domains is how the world is experieneed in reality, so should look at how they interact