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ORIGINAL ARTICLE
Development of a standardized occupational therapy screening tool
for visual perception in adults
DEIRDRE M. COOKE
1
, KRYSS MCKENNA
1
& JENNIFER FLEMING
12
From the
1
Division of Occupational Therapy, University of Queensland, Brisbane, Australia and
2
Occupational Therapy
Department, Princess Alexandra Hospital, Woolloongabba, Queensland
Abstract
Occupational therapy assessment and treatment of visual perceptual impairments are integral to the rehabilitation of clients
following stroke and other acquired brain injuries. Occupational therapists need to identify the nature of visual perceptual
performance impairments in order to choose rehabilitation intervention strategies appropriate for remediation of specific
problems or to compensate for limitations in daily function. This paper describes the variations in visual perception
terminology and occupational therapy approaches to visual perceptual assessment. Limitations of existing assessment tools
for visual perception are highlighted in terms of reliability, validity, normative information, length of time to administer, and
comprehensiveness in screening for visual perceptual impairment. In response to these limitations, a battery of items, called
the Occupational Therapy Adult Perceptual Screening Test (OT-APST) was selected to screen adults comprehensively for
impairments of agnosia, visuospatial skills including body scheme and neglect, constructional skills, apraxia, and acalculia.
It also includes a subtest to evaluate functional skills directly observed during screening. This new battery has established
reliability, validity and age-stratified normative data for adults 16 to 97 years of age. The OT-APST is recommended for use
in conjunction with observational assessment of activities of daily living for clients with stroke and acquired brain injury.
Key words: Acquired brain injury, apraxia, assessment, OT-APST, stroke, vision
Visual perception is the dynamic process of receiving
(perceiving) the environment through sensory im-
pulses and translating those impulses into meaning,
based on a previously developed view of the envir-
onment (1). Disorders of visual perception occur as
a result of acquired brain injury such as stroke,
traumatic brain injury, brain tumour (2), or disease
including dementia (3). The disorders may result in
difficulties organizing, processing, and interpreting
information perceived visually, and acting appropri-
ately on the basis of this information (4). Visual
perceptual impairments are related to reduced
independence and safety in self-care activities and
community living tasks (5,6), and subsequently
affect rehabilitation prognosis and discharge options
(2,7
/9).
Impaired function in such tasks as writing, perso-
nal grooming, dressing, and eating has been attrib-
uted to visual perceptual impairments and also to
apraxia (10). Apraxia is an impairment in the ability
to perform purposeful movement that is not due to a
primary motor or sensory impairment, nor attribu-
table to lack of comprehension, attention, or will-
ingness to perform the movement (11,12). Apraxia
also impacts on a person’s ability to interact ade-
quately and safely with the environment, and to
complete daily tasks. Assessment items tapping into
apraxia are commonly included in screening and
assessment batteries for visual perception (13
/18).
In view of this, both visual perception and apraxia
are considered together in this article.
Visual perceptual impairments vary in nature and
severity depending on the side, size, and location of
the lesion(s) in the brain (2,19). Incidence figures
vary according to the sensitivity and type of assess-
ment tool used, method of participant selection, type
of impairment measured and length of time since
onset of the injury. Visual perceptual impairments
Correspondence: Deirdre M. Cooke, MS BOccThy(Hons) OTR GradDipBus(Admin), PhD Candidate, Division of Occupational Therapy, University of
Queensland, Brisbane, Q 4072, Australia. E-mail: deecooke@powerup.com.au
Scandinavian Journal of Occupational Therapy. 2005; 12: 59/71
(Received 5 March 2004; accepted 18 June 2004)
ISSN 1103-8128 print/ISSN 1651-2014 online # 2005 Taylor & Francis Group Ltd
DOI: 10.1080/11038120410020683
are predominantly associated with lesions to the
non-dominant or right cerebral hemisphere,
although some perceptual impairments result from
left hemisphere damage (16). Apraxia is more
common following left hemisphere damage and
often occurs with aphasia, but may also be reported
following damage to the right cerebral hemisphere
(12,18). Specific perceptual impairments may occur
in isolation or in combination with other perceptual
impairments (6), and together with a range of motor,
language, sensory, and/or cognitive changes as a
result of a stroke. Hence each person has a unique
constellation of abilities and disabilities following
stroke or acquired brain injury (20). Perceptual
screening is indicated for people following either
right or left hemisphere lesions (21,22), and require
different treatment approaches depending on the
type or types of impairments present.
Visual perception terminology
Various definitions and classification systems for
visual perceptual impairments have been presented
in the literature (15,17,18,20,23
/26). Variations in
terminology and classifications make reading the
literature and comparing assessment processes and
intervention studies difficult (27). For the purpose of
this review, impairments of visual perception will be
described in terms of three broad categories outlined
by Benton and Tranel (24) including impairments in
visuoperceptual (agnosias), visuospatial, and visuo-
constructional skills. Apraxia and acalculia are
described in addition to these three categories of
visual perceptual impairment (see Table I).
The different areas of visual perceptual impair-
ment are summarized below.
1. Agnosia refers to the inability to recognize and
classify objects shapes, people, words, and
colour in a variety of settings.
2. Visuospatial skills involve the ability to relate
oneself to the position, direction or movement
of objects, or direction of points in space (17).
Disorders of body scheme are termed visuos-
patial skills as they relate to a defective under-
standing of body position and relation of body
parts to each other (13,26). Unilateral neglect
is a complex phenomenon described in the
literature that occurs as a result of visuospatial
impairment and impairment of attention (12).
Unilateral neglect may be described in terms of
the modality in which the neglect behaviour
becomes apparent including the descriptors of
sensory, motor, or representational neglect, or
by the spatial distribution of the abnormal
behaviour including personal or spatial neglect
(28). Behavioural manifestations of neglect
impact on an individual’s ability to perform
daily life tasks and are typically evaluated in
conjunction with visual perceptual abilities and
apraxia.
3. Visuoconstructional skills encompass the ability
to organize a number of parts into a whole
including two- and three-dimensional building
and assembly tasks (29), and drawing/written
tasks (graphomotor skills). Constructional dis-
orders are classified by some authors as aprax-
ias.
4. Apraxia is the inability to perform learned and
skilled purposeful movements in the absence of
loss of motor power, sensation, or coordination,
or language comprehension problems (26).
5. Acalculia or spatial dyscalculia refers to diffi-
culty calculating arithmetic problems as a result
of confusion in understanding the relative
position of numbers and the meaning of math-
ematical symbols (16).
Impairments of visual perception including unilat-
eral neglect and apraxia need to be differentiated to
enable appropriate interventions to be implemented.
Primary visual skills
Primary visual function can be affected by acquired
brain injury in areas of visual acuity, accommoda-
tion, visual fields, occulomotor range of motion,
fixation, saccades and pursuits, vergence, strabis-
mus, functional scanning, colour perception, and
stereopsis or depth of field (30
/32). The most
common primary visual changes after stroke are
visual field losses including homonymous hemiano-
pia or quadrantanopia. Approximately 20
/30% of
all people requiring rehabilitation following a stroke
experience homonymous hemianopia or quadranta-
nopia (33). Visual field impairments compromise
such tasks as reading and writing (20), independence
and safety in the use of kitchen appliances, and
mobility, particularly outdoors. They can also pro-
hibit driving (34). Primary visual skill impairment
must be differentiated from visual perceptual dis-
orders in order for these areas to be addressed
appropriately in treatment (34).
Impact of age, gender and education on visual
perceptual functioning
Performance on a variety of neuropsychological tests
including those for memory, learning, language,
praxis, and general cognition varies with age, gender
(35), and level of education (36). Males, older
people (70 years and older) and those who are less
60 D. M. Cooke et al.
educated generally perform more poorly on mea-
sures in these areas (36). Therefore age-appropriate
norms reflecting the performance of healthy people
are essential for screening and assessment tools used
to determine the presence and severity of problems
of visual perception (10,17,37).
Occupational therapy assessment of visual
perception
Occupational therapists use a range of assessment
tools and screening processes to measure visual
perceptual abilities and the impact of their impair-
ment on function after stroke and acquired brain
injury. Assessment processes range from the com-
pletion of brief tabletop tasks involving writing,
copying, and matching items, and behavioural ob-
servations of functional tasks such as the preparation
of a cup of tea, through to complex and lengthy
batteries of tabletop assessment items (2,14,26,38).
Through the use of clinical observations and occu-
pational analysis, occupational therapists also for-
mally and informally screen and assess perceptual
impairments in clients undergoing neurological re-
habilitation. Many of the early assessments for visual
perception used by occupational therapists were
adapted from the field of psychology, were not
standardized or reliable in their administration,
were not validated for the client group(s) for whom
they were used, and were descriptive and subjective
(39,40). The limitations of non-standardized assess-
ment approaches at both the tabletop or perfor-
mance component level and the occupational task
performance level are well recognized, including
difficulty defining, documenting, and communicat-
ing results, changes and outcomes (10,18,41).
Substantial progress has been made in the devel-
opment, standardization, and validation of tools
Table I. Classification of terminology for visual perceptual impairments and apraxia.
Areas of impairment* Specific impairments
1. Agnosias
(visual perceptual impairments,
visual discrimination *)
Visual object agnosia
Defective visual analysis and synthesis
/ Figure /ground discrimination
/ Simultanagnosia
/ Visual closure
Shape and size constancy (form constancy)
Facial agnosia (prosopagnosia)
/ Recognition of familiar and unfamiliar faces
Colour agnosia
Alexia
2. Visuospatial impairments
(spatial perception, spatial disorientation,
visuospatial agnosia or spatial relations syndromes*)
Judgement of direction, distance, position in space,
and the perception of depth
Topographical disorientation
Unilateral neglect
/ Sensory, motor, or representational neglect
/ Personal or spatial neglect (peripersonal or extrapersonal)
Body scheme disorders
/ Somatognosis
/ Finger agnosia
/ Left/right discrimination
/ Anosognosia
Line orientation
3. Constructional skill impairments
(visuoconstructional ability or
visuoconstructional praxis, visuomotor integration*)
Defective assembling performance on two- and three-dimensional tasks
/ Two-dimensional constructional impairments
/ Three-dimensional constructional impairments
Defective graphomotor performance (agraphia)
4. Apraxias (praxis*) Buccofacial/oral apraxia
Limb apraxias
(manual apraxia)
/ Ideational apraxia
/ Ideomotor apraxia
/ Gait apraxia
Dressing apraxia
5. Acalculia (spatial dyscalculia)
Adapted from Benton and Tranel (24).
*alternative terms included in parentheses.
Visual perceptual screening tool development 61
used by occupational therapists for the assessment
and documentation of visual perceptual and percep-
tual motor abilities using both tabletop and func-
tional task observation methods. Standardization of
a test implies uniform procedures for administration
and scoring of task responses in a manner specified
in a test administration manual, a large and appro-
priate healthy normative sample for test interpreta-
tion with age-stratified norms, and published
information on the psychometric properties of the
test including test reliability and validity (42).
A variety of standardized assessments batteries
measuring visual perceptual skills alone or in com-
bination with other cognitive and motor capacities
are available. They include:
. The Rivermead Perceptual Assessment Battery
(RPAB) (43);
. The Ontario Society of Occupational Thera-
pists Perceptual Evaluation (OSOT) (39);
. The Chessington Occupational Therapy Neu-
rological Assessment Battery (COTNAB) (44);
. The Cerebral Vascular Accident (CVA) evalua-
tion battery of St. Marys Hospital (45);
. The Loewenstein Occupational Therapy Cog-
nitive Assessment (LOTCA) (46,47);
. The LOTCA-G
TM
(Geriatric version of the
LOTCA) (48);
. The Baylor Adult Visual Perceptual Assessment
(49).
Non-standardized, non-validated perceptual and
apraxia assessment tools, behavioural checklists,
and facility-specific non-standardized assessments
are also used in clinical practice. However, the use
of standardized, reliable, quantifiable, and valid
assessments are more effectively able to determine
the level of function or impairment of clients, and to
measure the efficiency and effectiveness of treatment
(10,50
/52).
Top-down versus bottom-up assessment
approaches
In the early 1990s, several occupational therapy
researchers changed the focus of the perceptual
assessment process from one of evaluating specific
component skills (such as figure
/ground perception,
neglect, shape constancy, and visual closure) typi-
cally measured using tabletop tests, to evaluating
perceptual skills during occupational performance of
real-life tasks (13,53
/55). Four standardized occu-
pational therapy assessments utilizing clinical obser-
vation of functional task performance have been
developed. These include the A
´
rnado´ttir Occupa-
tional Therapy Neurobehavioral Evaluation (A-
ONE) (13), the Perceive, Recall, Plan and Perform
Model (PRPP) (56), the Assessment of Motor and
Process Skills (AMPS) (54), and the Structured
Observational Test of Function (SOTOF) (53).
The approach used in these four observational
assessments is often described in the occupational
therapy literature as a ‘‘top-down’’ or occupation-
based approach to assessment as opposed to the
earlier ‘‘bottom-up’’ or component approach, focus-
ing on assessment of skills through tabletop tests
(57). Top-down assessment processes provide a
profile of cognitive/perceptual strengths and weak-
nesses, and describe the impact on performance of
functional tasks (58). These can be useful for
describing the functional ability and level of inde-
pendence of a person in daily task performance,
potential safety issues, and need for cues or assis-
tance (58). Top-down assessments are methods of
screening the impact of perceptual and cognitive
changes on the performance of daily life tasks
following stroke. They also allow evaluation of the
effectiveness of interventions such as compensatory
strategies or new ways of completing daily life tasks.
When used alone, however, top-down assessments
may not enable clear delineation of specific impair-
ments that can then be targeted in treatment. For
example, a client might have difficulty putting a shirt
on the correct way, due to visual perceptual, visual
field or acuity, sensory, praxis, or fine motor
coordination problems. While functional observa-
tion assessment would objectively describe the
person’s functional ability and level of assistance
needed to complete the task, assessment of the
component skills of cognition, perception, praxis,
sensibility, and primary visual skills would enable
appropriate treatment to be implemented to address
the underlying cause of the functional problem.
Bottom-up assessments provide scores that deter-
mine the type and level of specific perceptual
impairments. Bottom-up assessments identify speci-
fic perceptual strengths and weaknesses; they enable
specific impairments to be identified following
comparison with normative data, and a common
language for communication of results. They also
facilitate communication with a client and his or her
family members regarding the type of underlying
impairment that is impacting on daily task comple-
tion. They do not generally define a level of
independence or safety in activities of daily living
(ADL) or domestic tasks as top-down assessments
do.
Toglia’s ‘‘Dynamic Investigative Approach’’
(59,60) is an approach to assessment observation
that analyses the person’s responses to cues and
task changes in order to understand his or her level
of insight, use of feedback, error detection, and
62 D. M. Cooke et al.
potential for learning (58). Golisz (58) advocated
use of a dynamic investigative approach in addition
to conventional bottom-up occupational therapy
assessments of perception and cognition. Top-
down approaches use some elements of the dynamic
investigative approach. It has been further suggested
that occupational therapy assessment methods
should enable a client’s ability to make use of
alternative strategies or behaviours for task comple-
tion to be examined. They should also determine a
client’s response to cueing or environmental fea-
tures, and they should gauge his or her awareness of
impairments and learning ability (58,61).
Both the top-down and bottom-up standardized
assessments may be used in combination to delineate
specific perceptual problems and understand their
functional manifestations (62). Recognizing the im-
portance of both top-down and bottom-up assess-
ments, the remainder of this paper concentrates on
the evaluation of existing bottom-up assessments
and the development of a new bottom-up assess-
ment.
Evaluation of existing assessment tools
Many existing perceptual assessments are designed
to test only one construct area of visual perception,
most typically left neglect (for example, the Beha-
vioural Inattention Test [BIT] (63), the Schenken-
berg Line Bisection Test (64), and Albert’s Test
(65)). These tests are not suitable for use as
comprehensive screening tools for visual perception.
Several paediatric assessments of visual perception
have been standardized and have had norms devel-
oped for the adult population including the Beery
Developmental Test of Visual Motor Integration
(VMI) (66) with adult norms reported in 1986
(67), the Motor-Free Visual Perception Test
(MVPT) (68) with adult norms reported in 1980
(69), the Test of Visual Perceptual Skills (TVPS)
(70) with adult norms reported in 1995 (71), and
the MVPT with items presented in vertical format to
reduce the influence of hemianopia or inattention on
visual perceptual performance (72). These tools
measure just one or two visual perceptual skills
areas, and lack documentation of test reliability
and validity for adult clients, hence restricting their
suitability for use as a comprehensive screening tool
for visual perception with adults.
Screening is an initial process of identifying
potential problems. A screening test enables broad
categorizations to be made as a first step in a
selection decision or diagnostic processes (16,73).
If impairment is detected on screening, a more in-
depth assessment to determine a diagnosis and
formulate a treatment plan is indicated (16). Many
of the existing perceptual assessment batteries were
not intended to be used as screening tests, but rather
as in-depth assessments. In the absence of more
appropriate screening methods, sections of these
batteries have been used clinically for perceptual
screening where time does not allow for completion
of the whole battery. This has reduced the validity of
result interpretation.
A comparison of the existing standardized com-
ponent or bottom-up assessments that evaluate a
range of perceptual skill is presented in Table II. In
this table, the skill areas assessed, details of the
psychometric properties of reliability, validity, and
norms where available, and administration time are
provided. This table summarizes the limitations of
each tool for use as a screening test for visual
perceptual assessment. A screening tool for visual
perception for use with adults following stroke and
other forms of acquired brain injury was evaluated in
terms of the following characteristics:
1. comprehensive assessment of the major con-
structs of visual perception including agnosias,
visuospatial skills including body scheme and
unilateral neglect, constructional skills, and
apraxia;
2. demonstrated psychometric properties of test
reliability including inter-rater, intra-rater,
test
/retest reliability, and test internal consis-
tency;
3. demonstrated psychometric properties of test
validity including forms of content validity,
construct validity, criterion validity, and face
validity;
4. normative data available for clients 65 years and
over;
5. administration time less than 30 minutes.
Each assessment battery presented in Table II has
limitations in one or more of these criteria for use as
a standardized screening tool for visual perception.
Following a review of the literature, the need
emerged for a brief but comprehensive, standar-
dized, valid, and reliable screening tool for visual
perception that systematically screened the major
constructs of visual perception, was clinically useful,
of acceptable length, and that had available norma-
tive data to assist result interpretation.
Development of the Occupational Therapy
Adult Perceptual Screening Test (OT-APST)
The Occupational Therapy Adult Perceptual
Screening Test (OT-APST) was developed by the
first author in 1992 (74). Test design and develop-
ment involved a literature review, survey of current
Visual perceptual screening tool development 63
Table II. Psychometric properties of standardized assessment batteries for assessment of visual perception in adults.
Assessment Skill areas assessed
Norms
age range
Norms
sample size
Time to
administer
Type/s of
reliability
reported
Type/s of validity
reported
Limitations for use
as a screening
Rivermead Perceptual Assessment Battery
(RPAB)
16 performance tests in areas of 16
/69 69 60 to 120
minutes
Inter-rater Content criterion
(including concurrent)
/ Too lengthy for use as
a screening tool
/ Form constancy 65 /97 100 Test /retest Construct (including
discriminative)
/ Does not evaluate all
major constructs
/ Colour constancy
/ Sequencing
/ Object completion
/ Figure /ground discrimination
/ Body image
/ Inattention
/ Spartial awareness
Loewenstein Occupational Therapy Cognitive
Assessment (LOTCA)
26 subtests in six areas
/ Orientation 20 /70 55 45 minutes Inter-rater
Internal
consistency
Construct Criterion
(including predictive)
/ Too lengthy for use as
a screening tool
/ Visual perception
Ecological
/ Spatial perception
/ Praxis
Cross cultural/ Visuomotor organ zation
/ Thinking operations
Loewenstein 23 subtests in six areas 70 /91 43 30 to 45
minutes
Inter-rater Construct (including
discriminative)
/ Too lengthy for use as
a screening tool
Occupational / Orientation Criterion
Therapy / Perception
Cognitive
/ Praxis
Assessment, Geriatric / Visuomotor organization
Version (LOTCA-G) / Thinking operations
/ Memory
Ontario Society of Occupational Therapy
Perceptual Evaluation (OSOT)
28 subtests under 6 functional areas: 40
/69 70 Not stated Inter-rater
Internal
consistency
Construct Face / Too lengthy for use as
a screening tool
/ Sensation
/ Limited validity
documentation
/ Scanning
/ No normative data
available beyond 69
years of age
/ Apraxia
/ Does not evaluate all
major constructs
/ Body awareness
/ Spatial relations
/ Visual agnosia
64 D. M. Cooke et al.
Table II. (Continued)
Assessment Skill areas assessed
Norms
age range
Norms
sample size
Time to
administer
Type/s of
reliability
reported
Type/s of validity
reported
Limitations for use
as a screening
The CVA Evaluation battery of St. Marys
Hospital
33 items Not
stated
No
normative
group
Not stated No Construct
/ Very limited reliability
and validity
documentation
/ Self care
/ No normative group
/ Left-side function
/ Does not evaluate all
major constructs
/ Recovery stage
/ Perception
/ Strength
Chessington Occupational Therapy
Neurological Assessment Battery
(COTNAB)
12 tests in 4 sections 16
/65 150 60 to 80
minutes
No No / Too lengthy for use as
a screening tool
/ Visual perception
/ Constructional ability 65 /87 47 / No reliability or
validity
documentation
/ Sensory motor ability
/ Does not evaluate all
major constructs
/ Ability to follow instructions
Baylor*
/Adult Visual Perceptual Assessment / Figure ground 20 /80 58 Not stated No Construct / Limited validity
documentation
/ Form constancy
/ No reliability
documentation
/ Position in space
/ Depth perception
/ Visual body scheme
/ Spatial relations
Visual perceptual screening tool development 65
practice, instrument development, piloting, and
preliminary reliability evaluation. Clinical piloting
by a large number of occupational therapists working
in a variety of settings throughout Queensland
occurred between 1995 and 2001. A further revision
of the OT-APST was completed in 2001 after a
survey and expert panel discussions were conducted
with occupational therapists to review various as-
pects of clinical usefulness of the original OT-APST,
and to determine the face validity, content validity,
and clinical utility of the revised OT-APST.
The OT-APST has 25 items in 7 subtest areas
including: agnosias (5 items); visuospatial relations,
including unilateral neglect (5 items) and body
scheme (4 items); constructional skills (3 items);
apraxia (6 items); acalculia (1 item); and functional
skills (5 items). Several of the OT-APST items
contribute to assessment of more than one area.
The OT-APST items screen for visual perceptual
impairments across each of the major constructs of
visual perception including those most frequently
occurring after stroke. The OT-APST includes a
number of previously published tests in a compre-
hensive battery format. It also measures functional
skill level in areas commonly impacted by visual
perceptual impairments such as reading, writing,
arithmetic, and the ability to tell the time and to hold
and manipulate a common object (stapler).
All test items are administered and scored accord-
ing to standard directions provided in a manual. The
design of the OT-APST requires test completion
using only simple verbal or motor responses, and the
use of just one hand for written and manipulative
items. It provides alternate methods of administra-
tion of several items for clients with expressive
language problems. Alternate methods of assessing
written items except for handwriting enable the
spatial abilities of clients to be evaluated even if
they are not able to hold a pen sufficiently well to
write or draw. The OT-APST can be administered
within 20 to 25 minutes.
Completion of the OT-APST requires adequate
comprehension of simple verbal instructions. It is
not suitable for people with severe auditory compre-
hension problems, for those unable to use either
hand for task completion, or for those whose level of
arousal or attentional capacity prohibits participa-
tion for the time required for tasks to be undertaken.
Screening of primary visual skills including visual
acuity, visual tracking, visual fields, and visual
history is completed prior to OT-APST administra-
tion. If a visual field impairment such as an homon-
ymous hemianopia is identified on visual screening,
the OT-APST test procedure is modified to include
moving all test materials into the person’s intact
visual field as recommended by Chaikin (20).
The OT-APST is designed to be able to be
completed by a healthy adult with little difficulty
regardless of age or level of education. This enables
it to be used in the clinical setting with adults from a
range of backgrounds. The OT-APST is not in-
tended to assess the upper limits of the range of
visual perceptual skills in the healthy adult popula-
tion. Achievement of a score of ‘‘intact’’ or ‘‘within
normal limits’’ on each subtest of the OT-APST
reflects the completion of visual perceptual tasks
Table III. Occupational Therapy Adults Perceptual Screening
Test subtests and items.
OT-APST subtests
(subtest total score)
OT-APST items
(item scores)
Agnosias (26)
Colour agnosia (6)
Object agnosia (1)
Figure
/ground (5)
Shape constancy (10)
Reading *
/alexia (4)
Visuospatial
relations
Unilateral neglect
Unilateral neglect (13)
/ Clock (3)
Body scheme (22)
/ House (4)
/ Writing (1)
/ Reading (4)
/ Telling time (1)
Body scheme
/ Body parts self (8)
/ Body parts therapist (4)
/ Left/right discrimination (4)
/ Directions/position in space (6)
Constructional skills
(53)
Graphic construction
/ Clock (3)
/ House (4)
Two-dimensional construction (26)
Three-dimensional construction (20)
Apraxia (10) Smile command and copy (2)
Wave right hand *
/command and copy
(2)
Wave left hand
/command and copy (2)
Stapler hold command and copy (2)
Pen use for writing (1)
Writing (1)
Acalculia (4) Calculations *
/addition and subtraction
(4)
Functional skills (11) Reading (4)
Writing (1)
Calculations (4)
Telling time (1)
Use of stapler (1)
Behavioural
observations
Comments only
Insight Comments only
Time for OT-APST
completion
Recorded in minutes
66 D. M. Cooke et al.
within two standard deviations of the healthy nor-
mative sample of a comparable age.
Comparison of subtest scores with normative
sample data and the overall profile of subtest scores
are used to interpret results. An overall or total score
for the OT-APST is not recorded. The OT-APST
should be completed in its entirety to maintain its
sensitivity as a screening tool, and for the reliability
and validity of result interpretation.
OT-APST item descriptions
Agnosia
Agnosias. After determining the existence of known
colour blindness, the client is requested to name or
identify six colours in an array to evaluate colour
recognition skills. Object recognition and naming are
evaluated through presentation of a stapler that the
client is asked to name and describe in terms of its
use. The ability to name or point on command to
four common shapes in the shape constancy item
evaluates shape recognition ability.
Figure
/ground. Figure/ground/perceptual closure
skills are evaluated through recognition of five items
in an overlapping array.
Shape constancy. The ability to identify four common
shapes in a mixed array of 10 shapes of varying sizes
and positioned at differing angles is evaluated by
asking the client to point to the shapes. The array is
presented in a vertical alignment (portrait form) in
front of the client to elicit primarily shape constancy
skills, and to a lesser degree visual scanning accu-
racy.
Reading. Alexia or the inability to read words is
evaluated through reading aloud a passage of in-
dented text described in more detail under assess-
ment of unilateral neglect.
Visuospatial relations
Unilateral neglect. Five items on the OT-APST
including writing ability, telling the time, drawing a
clock, copying a house diagram, and reading a
paragraph screen for the presence of unilateral
neglect. An alternate method of assessing these items
is included for clients unable to hold a pen in either
hand to draw. A handwriting sample involving the
client writing his or her name and address is
completed to evaluate neglect through examination
of the use of space on the page, and to screen for the
presence of agraphia.
Reading. A reading paragraph is included in the OT-
APST to evaluate the functional skill of reading and
visual scanning accuracy, to detect the presence of
neglect and the impact of a visual field loss on
reading, and to screen for alexia. The text is
presented in ‘‘landscape form’’, and has an equal
number of words right and left of the centre of the
page. The reading paragraph has indentations of
random lengths on both sides of the page in order to
be sensitive to attention/neglect changes to both the
left and the right side of space. It is printed in size
20-point Times New Roman Font and is at a grade
five/six (age 10 and 11 years) reading level as
measured by the Flesch Reading Formula (75).
The examiner observes and records omissions and
repetitions during this task. Reading performance in
the presence of spatial problems generally deterio-
rates as a person continues to read a passage (20),
hence a passage of just 12 lines is included in the OT-
APST. Reading comprehension is not evaluated.
Occupational therapists should be alert to asymme-
tries of performance when observing all OT-APST
items, not just those specifically included to test for
neglect such as the drawing and copying tasks (20).
Body scheme. Knowledge of body scheme and left
right discrimination ability are tested by requesting
the person to differentiate sides (left and right), and
identify his or her own body parts and those of the
examiner through pointing to or moving the body
part as requested. Information may also be elicited
about elements of personal and extrapersonal ne-
glect on the body scheme items.
Directions/position in space. Knowledge and use of
directions such as ‘‘on top of’’ and ‘‘behind’’ are
evaluated by requiring the person to move coloured
blocks to different positions in relation to each other,
or to describe the colour or point to the block that is
‘‘furthest away’’ from and ‘‘nearest’’ to him or her on
the tabletop.
Constructional skills
It has been suggested that skills underlying graphic,
two-dimensional, and three-dimensional construc-
tion may be separately affected by acquired brain
injury and hence each of these skills should be
examined in screening (17). The following items
are included in the OT-APST to screen all three
areas of constructional skills.
Visual perceptual screening tool development 67
Graphic constructional skills. Drawing a clock and
placing its hands at a designated time, and copying a
house are included in the OT-APST to evaluate
graphic constructional skills.
Two- and three-dimensional constructional skills. Two-
dimensional and three-dimensional constructional
skills are evaluated on the OT-APST through a series
of items organized hierarchically from simple to
more complex. The client is asked to reproduce
coloured block patterns in two-dimensional (2 by 2
block and 3 by 3 block designs) and three-dimen-
sional (3, 7, and 9 block designs) planes by copying a
model provided. If performance on the two simplest
tasks for testing two- and three-dimensional con-
structional skills is poor, the more complex items are
not administered. These cut-offs for poor perfor-
mance are incorporated to improve efficiency in test
administration time and to reduce client frustration.
To evaluate three-dimensional constructional
skills, three-dimensional models rather than pictures
of these models are copied to use and incorporate
real life three-dimensional environmental cues, and
to use blocks in the model that are the same size as
those used to create the copy.
Apraxia
Several items are included to screen for praxis skills
related to facial gesture, expressive use of the upper
limbs, and object use (stapler and pen). They are
presented in a hierarchical order from performing
gestures on command, to imitation and performance
with actual use of an object as recommended by
authors in the area of praxis assessment (12,76).
Screening questions to prompt the occupational
therapist to consider motor planning problems
observed during interactions with the client prior
to OT-APST assessment are included in the praxis
screening section of the test.
Acalculia
Several simple one- and two-digit addition and
subtraction calculations are included to screen for
the presence of acalculia. Calculations included in
the OT-APST are at a grade two level (age 7 years) of
schooling ability, and are suitable to determine an
adult’s ability to recognize and utilize mathematic
symbols for acalculia screening.
Functional skills
Functional skills measured include reading and
writing, and the ability to complete simple mathe-
matical calculations, tell the time, and use a stapler.
Further observations of the client’s performance of
other activities of daily living such as dressing and
grooming as well as a kitchen task are recommended
(but not formally included in the OT-APST) to
interpret the functional implications of perceptual
and motor planning strengths or impairments de-
tected using the OT-APST. These observations also
enable examination of praxis or motor planning
ability of the person’s whole body rather than just
the upper limbs as are observed when doing a
tabletop assessment.
Behavioural observations
No formal measure of attention/arousal is included
in the OT-APST; however, the examiner is
prompted to comment on the client’s general level
of cooperation, distractibility, attention, need for
repetition of instructions, perseveration, fatigue,
anxiety, pain or discomfort, and preoccupation
with other thoughts during assessment completion.
The impact of these behaviours on assessment
interpretation and daily living task performance
should also be considered.
Insight
Accurate perceptual processing is dependent on
awareness of the ability or inability to process and
act on perceptual information (14), and to partici-
pate in rehabilitation of cognitive/perceptual pro-
blems (61). Unawareness of impairments and their
impact on performance of functional tasks are
common following acquired brain injury (42). The
client is asked at the completion of the OT-APST to
indicate which, if any, of the items he or she found
more difficult than others in order to gain a general
impression of his or her level of insight into
difficulties noted on assessment.
Time for OT-APST completion
The length of time taken for OT-APST completion is
recorded on the assessment form as a general
indicator of the information-processing speed of
the client and to reflect the perceptual processing
ability of the individual. These figures can be
compared with age-matched normative data for the
OT-APST.
OT-APST result interpretation
Scores for items in each construct or subtest area are
added to allow interpretation of patterns of impair-
ments and to compare with normative data, but not
to produce a total score for the OT-APST. Specific
perceptual impairments may occur in isolation or
68 D. M. Cooke et al.
together with a range of other perceptual impair-
ments, hence a summed score of unrelated areas of
perceptual skills would not be meaningful. Results
are used to determine the need for more detailed
assessment of problem areas, to educate the client
and family about changes that are present, and to
guide treatment, rehabilitation, and discharge plan-
ning for that individual. Observation of the client’s
performance of personal and domestic activities of
daily living tasks is recommended to determine the
impact of perceptual changes identified during
screening on his or her level of independence and
safety for discharge. OT-APST result interpretation
beyond comparison with the normative cut-off
scores and the implication of results for treatment
planning is dependent on the occupational thera-
pist’s clinical reasoning, understanding of neurology,
and occupational analysis and observational skills.
Psychometric properties of the OT-APST
Research results detailing the psychometric proper-
ties of the OT-APST including test reliability,
validity, and normative data are outlined briefly but
reported elsewhere (77). Reliability studies for the
OT-APST included 18 people following stroke and
10 occupational therapy raters. A high level of inter-
rater, intra-rater, and test-retest reliability has been
demonstrated for all items. Internal consistency
measures of the subtests were examined in the
validity study of the OT-APST scale design. The
OT-APST has established features of content valid-
ity; construct validity including scale design, separa-
tion of known groups, on a convergent validity,
concurrent criterion validity including sensitivity
and specificity analysis; ecological validity and face
validity. Validity studies were completed comparing
the performance of 208 participants following stroke
on the OT-APST and the LOTCA or LOTCA-G.
Normative data for 356 healthy people between the
ages of 16 and 97 are available in age-stratified
format with cut-off scores for intact/impaired for
each of the OT-APST subtests based on the perfor-
mance of the healthy normative sample.
Conclusion and future directions
Occupational therapists should use assessments that
are standardized, reliable, quantifiable, and valid to
determine the level of function or impairment of
clients, and to measure the efficiency and effective-
ness of treatment (10,50,52). Perceptual screening
in the acute hospital and rehabilitation settings is an
important process, particularly for clients whose age
and goals include return to driving, work, active
daily lifestyle pursuits, and living alone. Effective
screening allows for identification of those clients
who need more detailed assessment and therapy
intervention to maximize recovery, and to provide
education on changes to the client and family
members. Methods of assessing visual perception
and apraxia following acquired brain injury and the
development of a new standardized screening tool
for use with adults have been described. This new
tool is both reliable and valid, and has relevant age-
stratified normative data for comparison. The OT-
APST is designed for use in combination with skilled
occupational analysis of daily life tasks using top-
down assessments. Bottom-up assessment is neces-
sary to determine the separate contributions of visual
perceptual impairments and apraxia to target treat-
ment appropriately. It will be beneficial for future
research to examine the psychometric properties of
test responsiveness and predictive criterion validity
of the OT-APST, and to examine the use of this tool
with the different diagnostic groups for whom it is
intended.
Acknowledgements
The first author would like to express appreciation to
the many occupational therapists who have contrib-
uted tremendous clinical insights and encourage-
ment throughout the process of clinical trialling,
survey feedback, and expert panel discussions. This
paper was written while in receipt of an Australian
Postgraduate Award Scholarship.
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