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Cognitive Processing Impairments of Sleep Deprivation: Visual Search and Brown-
Peterson Task Performance Analysis
Guzzetti, J.R.
Department of Neuroscience, Hiram College, Hiram, Ohio
ABSTRACT
With a surge in cultural prevalence, the operational impairments of sleep deprivation (SD) have
been well documented in recent decades. Previous research exploring the influence of SD on
functional memory and visual sensory impairments has uncovered one which is detrimental. The
present research aimed to investigate the specific visual sensory systematic impairments endured
during total SD, in addition to the impairments on short-term memory. Fourteen college
undergraduates completed two cognitive assays, the Brown-Peterson Task and Visual Search
following a night of total SD, and on another occasion following a solid night sleep. The results
herein assist in the affirmation of a number of previous findings in the field of sleep deprivation
research. The findings herein imply that total SD has a detrimental effect on the filtering
efficiency of vision and on the encryption of information to short-term memory. Implications of
the findings and possible directions for future research are explored in the discussion.
INTRODUCTION
The occurrence of total sleep deprivation, or
one whole night with absolutely no sleep,
has become an occurrence in a frequency on
the rise in a number of cultures around the
world, for a variety of purposes. For many
individuals, there are occasions when total
SD is electively endured—with the apparent
view of a sleeping period as a necessary
tradeoff for the time-consuming, punctual
completion of a task. Of course, there are
numerous, unfortunate instances of total SD,
brought about from a number of reasons,
such as emotional restlessness in any of its
many forms, the unmanageable anxiety
toward a future event, or any other various
reasons. The general impairments of SD
have previously been extensively explored
in a number of scientific disciplines.
Additionally, the impact of SD on neural
circulatory control has been documented.
Kato (2000) sought to record blood pressure,
heart rate (HR), as well as muscle
sympathetic nerve activity in total SD
individuals. He and colleagues found that
SD induced increased resting blood
pressure, decreased muscle sympathetic
nerve activity; however, it had little
influence on HR.[5] Pilcher and Huffcutt
(1996) carried out a meta-analysis outlining
the cognitive and motor impairments of SD,
as well as the negative influence of SD on
mood, which seems to be the most robust. [7]
Durmer and Dinges (2005) carried out an
investigation of the specific regions of
cognition that are hindered by SD, beyond
mood and motor impairments. Their
findings suggest that the cognitive deficits
endured through SD are highly subjective,
and most typically area of working memory,
executive attention, and higher cognitive
functioning are distinctly vulnerable. [2] The
present research deals with instances of

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planned SD in order to complete one or
many time-consuming tasks. Arguably, the
most chronically sleep-deprived age groups
in most societies are young adults, the
student population, in particular. Often
times, the degree of the workload taken on
at a college level may lead a student to
resort to total SD in order to satisfy their
goals. It is young adults belonging to this
population that comprise the sample herein.
Understanding the exact nature of the
cognitive impairments of SD may aid these
individuals by providing them with
knowledge of the adverse consequences of
their actions. This education may be a
resolving factor when facing indecision on
proceeding with potentially dangerous tasks
such as driving a motor vehicle or intense
physical activity.
The purpose of this study was to
explore the potential impairments of short-
term memory and visual attention and
discrimination induced by SD.
Undergraduate students whom intended to
sacrifice a night of sleep, typically in order
to address academic obligations, performed
two cognitive assays. The assays
administered here in were Visual Search, to
examine visual discrimination/attention and
the Brown-Peterson task, to analyze
functional short-term memory. Common
Visual Search assays impart the test-taker
with the responsibility of distinguishing
targeted from untargeted/distractor stimuli
and as quickly as possible report whether or
not (Y/N-typically by keystroke) the
consistent target stimulus is present. For
instance, a trial of Visual Search may
present an image with numerous red
triangles and blue squares, with only a
single target item (e.g. blue triangle) either
singularly present or absent on the screen
with the various distractor stimuli. The
Brown-Peterson Task, developed in the
latter half of the 1950s, was developed in
order to record the limits of, and influential
factors on short-term memory. The task
explores the influence of interference on
short-term memory. The task itself is
composed of a series of trials which initially
present the test-taker with a randomized
consonant trigram (e.g. TQW, PZC).
Trigrams employed by the Brown-Peterson
Task are generated through evasion of
common acronyms, arrangements
representative of small words, and
arrangements which can easily be
committed to a mnemonic device, as use of
such tactics by the test-taker are
discouraged. After which, the test-taker is
prompted with simple computation
instructions (e.g. Count backwards by 4’s
from 345), for thirty seconds, which is spent
by the test-taker performing the counting
aloud. The count backwards was varied
across trials, starting and ending numbers
were inconsistent (always started in the
hundreds), and the counting increment was
slightly and randomly varied (by 3’s – by
5’s). Finally, following the thirty second
period, the test-taker’s counting is
interrupted and they are asked to recall the
most recent trigram presented. [9] Herein, a
cross-over repeated-measure experimental
design was incorporated, in which the
participants were assigned to either the
control, or randomly to one of the two cross-
over experimental conditions. Participants in
Condition 1 completed the assays following
SD first, and then a second time when well-
rested (FSD). Condition 2 completed the
assays first when well-rested, then second
when SD (FWR). Participants in these two
conditions had deprived themselves of sleep
for between 18-30 h, in many cases, to
address academic responsibilities. Those
assigned to the control completed the tasks
twice, well-rested each occasion in order to
inspect the significance of potential
improvement upon practice of the tasks
(CWR).

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In light of the prevalence of SD
occurrence as an intertwined, recurrent
aspect of numerous modern lifestyles, SD
has become a popular division of research in
a wide ray of biological fields. Prior
research has indicated that SD is a condition
which can occur under multiple,
distinguishable instances with somewhat
differing impacts. The impairments of total
SD have been shown to vary considerably,
as discovered by Raidy and Scharff (2005).
Raidy and Scharff discovered that no
significant deficits are experienced in visual
memory processing until the SD has reached
an approximate length of 18-20 h. [8] These
findings offer a highly important quantified
estimate of when the impact of SD becomes
apparent and detrimental. Kong, Soon, and
Chee (2011) found decreased activation of
visual processing brain regions in SD
subjects, suggesting componential
impairment of visual processing under this
condition. [6] In recent years, Drummond
(2012) conducted an experiment exploring
visual working memory system
impairments, focusing on both total SD, and
partial SD (inadequate sleep over the course
of several nights). Drummond’s findings
suggest that partial and total SD have no
considerable adverse effects on the capacity
of visual working memory; however, total
SD can weaken filtering efficiency, or the
ability to quickly discriminate targeted from
untargeted stimuli. [1] Collectively, a
broadening range of research has indicated
the presence of visual sensory system
impairments, when SD.
The deficits of short-term memory
experienced when SD, additionally, have
been extensively examined. Forest and
Godbout (2000) found increased
vulnerability to distraction during
performance on the Brown-Peterson task in
SD subjects. [3] Similarly, Harrison and
Horne (2000) discovered SD impairments
affecting temporal memory, or recollection
of the chronological order of recent
happenings. [4] These findings carry the
implication that SD can impair short-term
memory mediation and efficiency. Much of
prior SD literature has aimed to investigate
the specific SD impairments of long-term
memory, as well. Findings by Vecsay (2009)
indicated that SD has negative effects on
short-term memory maintenance and
encoding (to long-term memory), as SD
impairs neuronal signaling to the
hippocampus, a region of the brain known to
be the center of learning and long term
memory storage/retrieval. [9] Therefore, the
assumption can be made that short-term
memory function is hindered by SD.
Extensive prior research suggests that SD
may yield short-term memory and visual
sensory systematic impairments.
The present research further
investigated the nature of the known deficits
of SD. I hypothesized that poorer
performance would be exhibited on the
cognitive assays following SD, compared to
being well-rested; as SD should, to some
degree negatively impact the cognitive
processing required for short-term memory
and visual information distinction.
MATERIALS AND METHOD
Participants
Twelve males and eight females, ages 19-22
years (M age=20.1) were recruited through
personal encounter to participate in the
present research. Participants were college
undergraduates who admitted to having
little-to-no familiarity with sleep deprivation
research. Only prospects that planned to
endure one night of total SD by their own
accord were asked to participate in an
experimental group of the study. Participants
were advised to use to the night of total SD
to address academic obligations. If not using
the time to handle academic responsibilities,

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participants were simply advised to keep
themselves occupied. Many sleep-deprived
participants underwent the deprivation in
groups. Use of medication, stimulant or
otherwise was not suggested. Participants
undergoing SD were instructed to moderate
their caffeine intake, if choosing to do so.
Additionally, they were advised to avoid
caffeine consumption altogether in the 1.5
hour period before assay completion. All
participants gave written informed consent
before admittance in the study. The study
was approved by the Institutional Review
Board of Hiram College, United States.
Design and Procedure
In a randomized, repeated-measure, cross
over design, participants completed two
cognitive assays on two separate occasions:
when sleep-deprived and when well-rested.
Participants were randomly assigned to
either of the two experimental groups of the
control. Condition 1 (FSD, n=7) performed
the assays first when sleep-deprived, and
then second when well-rested. Condition 2
(FWR, n=7) performed the assays first when
well-rested, and then second when sleep-
deprived. The control (CWR, n=6)
completed the tasks twice, well-rested on
each occasion in order to investigate the
potential for improvement upon practice of
the tasks. The gap between testing sessions
for participants in all groups stretched from
several days, to weeks. Subjects were
politely greeted upon their scheduled arrival
to the laboratory for completion of the
cognitive assays. Prior to arrival for post-SD
testing, participants resided in lecture or
residence halls within the campus where of
which they were addressing academic
obligation, or occupying themselves
otherwise. All data from SD testing sessions
were collected between 8-11 A.M. on any
given day. Administration of caffeine was
inspected through verbal self-report prior to
testing.
Cognitive Assays
The cognitive assays, Visual Search, and the
Brown-Peterson task were performed in that
order at the time of testing sessions. The
Visual Search assay was completed on a
Dell OptiPlex 360 desktop computer. The
Brown-Peterson Task was carried out at the
experimenter’s control via Microsoft Office
Power Point on a Dell OptiPlex 360 desktop
computer with the aid of a stopwatch.
Measures
Participant trial completion time and/or
correctness were analyzed and compared
from the WR and SD sessions in order to
examine the specific short-term memory and
visual working memory impairments.
Reaction times (RT) were averaged from
sixty-four Visual Search trials in order to
compute mean RT. Incorrectly-answered
trials were discarded from the calculation of
the mean RT. Additional analysis was
conducted through record of the number of
mistakes made by participants in WR and
SD sessions. The percent correctly-recalled
for the fourteen Brown-Peterson Task trials
was calculated for each participant in each
session.
RESULTS
Figures 1a & 1b comparatively display the
scores of CWR on the first and second
testing sessions for both cognitive assays.
There was no consistent trend of
improvement for either task in the control
group, some improved the second time
around whereas some did worse. Figure 2
displays the scores on the Brown-Peterson
Task for all participants in FSD as well as
FWR. Analysis of solely RTs from the
Visual Search trials failed to express
significantly improved performance when
WR as opposed to SD. Figure 3 displays the

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number of errors made of the sixty-four
trials (per session) by participants when SD
and WR. All but one SD participant, made at
least one mistake during at least one of their
testing sessions, removing the option of an
analysis of SD vs. WR scores for strictly
participants correctly answering all trials
sixty-four trials.
(A) Brown Peterson Task
(B) Visual Search
Figure 1. Results of Brown-Peterson Task
for the first and second testing sessions of
the control are graphed (A) Results of the
Visual Search for the first and second testing
sessions of the control are graphed (B).
Brown-Peterson Task
Figure 2. Results of Brown-Peterson Task
for all SD participants. Almost all
participants exhibited better performance
when WR (M score=74.25%) as opposed to
SD (M score=61.3%).
Visual Search
Figure 3. Mean number of errors committed
by SD participants. More errors occurred on
average when SD (M nerror=4.1) than when
WR (M nerror=2.8).
Implications of the findings in terms of the
support within for the hypothesis are
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discussed in the forthcoming section, in
addition to directions for future studies.
Discussion
The hypothesis that a poorer performance
would be exhibited on the Brown-Peterson
Task when participants were SD was
supported. The hypothesis that a poorer
performance would be exhibited on the
Visual Search was not strongly supported
through analysis of RT, but supported to
some degree through analysis of trial error
frequency. The results of the present study
are directly in line with what much of
previous research has indicated, regarding
the cognitive deficits of SD. As Durmer and
Dinges (2005) had suggested, subjectivity in
this type of research is nearly an
unmanageable factor when experimentally
exploring the deficits of SD. [2] This was
seen herein as many individuals performed
considerably more poorly than others when
both SD and/or WR. The differences seen in
error frequency on the Visual Search trials
reaffirm a recent study conducted by
Drummond (2012). Also using visual
search, Drummond has asserted that SD
does not so much limit our capacity for
visual sensory information as much as it
hinders filtering efficiency, or the ability to
distinguish targeted from untargeted visual
stimuli. [1] Filtering efficiency is effectively
examined through Visual Search
administration. Additionally, the
aforementioned findings of Harrison and
Horne (2000), made through the exploration
of the impact of SD on short-term memory
mediation as well as temporal memory were
reaffirmed herein. [4] Although not
graphically depicted in the results, hindrance
of temporal memory was directly observed.
This was seen with SD participants in the
midst of Brown-Peterson Task
administration. On numerous occasions,
when asked to report the most recent
trigram, SD participants would confidently
report trigrams from several trials prior,
clearly indicative of some minor distortion
of time due to SD. I speculate that it may be
fruitful to experimentally explore the
potential of SD-induced strategic neural
signaling inhibition from particular external
information mediums. That is, STM system
maintenance may understandably be more
negligible than visual sensory maintenance,
as the latter is arguable more critical to
survival.
Much of what can be drawn from the
findings herein is supplemental to a large
body of existing research focusing on the
impairments of SD. Evidently the properties
of the visual sensory system and working
short-term memory function are negatively
affected in the absence of sufficient sleep.
Alarmingly, countless individuals frequently
suffer from SD, yet that does not cause them
to refrain from daily activities such as
working and driving while experiencing the
impairments. Performance of simple tasks
such as driving immediately qualifies the
detriments of SD as dangerous, to not only
the SD individual but those crossing in close
proximity. The present findings suggest that
one’s driving ability is considerably
impaired by SD, likely as well as
performance at work. Perhaps those who
need to be most cognoscente of their subpar
SD performance are individuals whose work
involves the operation of heavy machinery
(construction worker, crane op, factory
workers, etc.) for palpable reasons. Also,
students undergoing higher learning should
recognize the importance of understanding
that their [typical] SD performance is not
optimal, and that they are not maximizing
their abilities when suffering from SD. This
is of pivotal importance as numerous
students may be doing more harm than good
when depriving themselves of sleep in order
to address academic obligations. For
instance, completely depriving one’s self of
sleep in order to complete a ten page term

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paper would likely prove to be a more
efficient and effective strategy than doing so
in order to study extensive material for a
midterm exam. Individuals may benefit from
analyzing the negative impacts of SD prior
to selectively and strategically undergoing
total SD, in order to understand how they
will be affected.
The most outstanding limitations of
the research herein are undoubtedly the
sample size, and the 12-week max
timeframe allocated for the research.
Limited manpower was also problematic for
the demand of data collection. Additionally,
inability to actually limit participants
caffeine intake was problematic, as many
failed to adhere to the advisory of limiting
their intake. Considering the subjective
variety of general neurocognitive
impairments brought about during SD, it
may be a stretch to apply the findings herein
to the general population.
Future research investigating the
cognitive processing impairments of SD
should take care to incorporate the
administration of additional cognitive
assays, such as change blindness, and
operation span, in order to further
investigate the extent of the impairments.
Additionally, future research addressing
similar domains of cognition should
compose experiments using the same assays,
however, with the employment of auditory
and visual distractors during assay
completion in order to examine the impact
of SD on distraction susceptibility.
Administration of the assays used herein and
possibly others should be carried out
experimentally with a variety of age groups
in order to examine the potential for
increased impairment susceptibility with
aging. Additionally an experiment should be
designed which accurately explores the
potential for recruitment of compensatory
mechanisms in individuals who frequently
electively endure total SD, compared to
those who rarely or have never undergone
total SD. Conclusively, future SD research
should seek to unveil the reaches of the
deficits of SD and also address the potential
health issues presented by chronic SD in
order to effectively educate a considerable
portion of the population on what their
bodies are enduring when undergoing SD.
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