What is visual perception ?
The ability to use vision to adapt to the environment
which requires the integration of vision within the
CNS to turn the raw data supplied by the retina into
cognitive concepts of the perception of space and
objects that can be manipulated and used for
decision making .
The process by which this occurs is known as visual
How it works ?
It occurs through visual processes
Visual input from environment to eye
Pathway from retina to geniculate nucleus to primary visual
Input travel from primary visual cortex to preforntal lobe
for complete visual processing
Visual processing within the CNS
RETINA : RODS AND CONES
, BIPOLAR CELLS , GANGLION
FROM OPTIC CHAISMA
FROM OPTIC TRACT TO
VIA GENICULO CALCARINE
TRACTS TO VISUAL
PATHWAY FROM RETINA TO LGN AND TO VISUAL
The visual cortex is the part of the cerebral cortex responsible for
processing visual information, and is located in the occipital lobe.
The term visual cortex refers to the primary visual cortex (also
known as striate cortex or V1) and extra striate visual cortical areas
such as V2, V3, V4, and V5.
Primary cortex transmits information to two
primary pathways –
The dorsal stream and The ventral stream.
Visual input ventral stream is responsible for through parietal object
The travels from the visual cortex form recognition, and posterior
The dorsal stream is associated with motion, the position
temporal circuitry to the prefrontal lobe to of environment andvisual
representation, conscious perception complete cortical is
of objects in the world, engagement with the environment
associated with Long term memory storage
and control of the eyes/arms (especially when visual
information is used to guide saccades).
COMPONENTS OF VISUAL PERCEPTUAL
visual perceptual processing can be defined in a
It consist of process of visual cognition , visual
memory, pattern recognition, visual scanning and
visual attention .
Hierarchical model of visual perceptual
Visual memory and
Visual scanning and
Visual acuity, visual field and
The highest order visual perceptual process in the
hierarchy is visual cognition.
These perceptual processes are supported by three
basic visual function that forms the foundation of the
hierarchy : Oculomotor Control,Visual Fields ,Visual
Visual cognition : It is a ability to manipulate and
integrate visual inputs with other sensory information
to gain knowledge, solve problems, formulate plans
, and make decisions.( For the complete cognitive
Adult standing at a
Visual memory : visual cognition cannot occur without
the presence of visual memory.
The mental manipulation of visual stimuli requires the
ability to create and retain a picture of the object in the
mind’s eye while the visual analysis is being
Before the visual image can be stored in memory , and
individual must recognize the pattern making up the
Pattern recognition, which sub-serves visual memory
in the hierarchy , it involves identifying the object
from the surroundings.
A salient feature is one that distinguishes a particular
object from another .
Green apple and red apple
To see its general shape, contour and features like
color, shading, and texture .
Pattern recognition can not be accomplished without
the next process in the hierarchy :
visual scanning : It is accomplished through the use of
saccadic eye movements . A saccade is a movement of
the eye towards an object of interest in the
Visual scanning is actually a product of visual
Visual search occurs on two levels :
An automatic or reflexive level- (controlled by brain
stem) Any novel object moving or sudden appearing in
the peripheral visual field, such as a flash of light. This
response serves to protect an individual from
unexpected intrusions in the environment.
A voluntary level- (directed by the cortex), is complete
for the explicit purpose of gathering information .
Visual attention is a critical prerequisite for visual
If and how a person attends to an object or
information determines if and how that visual input is
analyzed by the CNS, which becomes the basis for
decision making .
People who do not attend to visual information do not
initiate a search for visual information , do not
complete pattern recognition , do not lay down a visual
memory and cannot use this visual input for decision
Engagement of visual attention and the other higher
level processes in the hierarchy cannot occur unless
the CNS is receiving clear, concise visual information
from the environment .
Visual input is provided through the visual functions
of oculomotor control, visual fields and visual acuity.
Oculomotor control : It enables eye movement to be
completed quickly and accurately and ensures
perceptual stability .
Visual fields : Which lets the brain know what's going
on in the environment .
Visual acuity : Ensures that the visual information sent
to brain is accurate.
DYSFUNCTIONS AND ASSESSMENT
Disorders of visual perception are
found in :
Intracranial compressing masses
Neurodevelopmental conditions (eg, autism)
Schizophrenia and depression.
Purpose of the assessment
To identify the limitation in activity or occupation.
To link that limitation to presence of a visual
To develop an appropriate intervention plan based on
the results of the assessment .
Occupational therapy assessment of specific
visual –perceptual impairments
Visual acuity : It is commonly measured by Snellen
Normally :( 20/20) it means that a person can see the
letter that a person with normal vision can see at 20
The common Defects of visual acuity are :
3. Astigmatism- It is an optical defect in which vision is
blurred due to the inability of the optics of the eye to
focus a point object into a sharp focused image on the
Assessed by :
LeaNumbers low vision test chart and
warren text card
Visual field defect is caused due to damage to the receptor
cells in the retina optic pathway that relays retinal
information to CNS for processing results in a visual field
Conditions occuring in VFD are :
Heminanopsia : There has been loss of vision in one half of
the visual fields in the eyes.
Homonymous : it means deficit is same in both the eyes.
The assessment of the VF is know as perimetry test these
ranges from simple confrontation test to more precise
imaging of a scanning laser opthalmoscope (SLO).
Visual field defects
Screening of visual field deficits
Equipments: eye patch or patches
Set up : patient seated directly opposite to
examiner, approx 20 inches eye to eye .
Background behind examiner should be dark and
Procedure : patch the patient left eye and close or patch
your own right eye
Instruct patient to look at your left eye and tell him or her
you will be moving a target in from the side and the patient
is to indicate when the target is first seen.
Move target in from all angles
Compare the patient response with yours.
Position hands at 3 and 9 clock so that you can just see
your fingers . Ask the patient how many fingers you are
holding up .
A problem is indicated if the patient cannot see the
target when you do or does not see both fingers
Visual skills for reading test provides an effective way
to measure the interference of the VFD on reading
Perimetry devices such as the Damato 30 – point
multifixation campimeter ( biVABA).
Visual attention and scanning
Condition which occurs due to defect of VA and scanning
Hemi- inattention : Instead of initiating from left to right
visual search pattern, clients with right hemisphere injuries
often begin and confine search to right side .
Visual neglect : it is a combination of hemi- inattention
and left visual field defect (VFD).clients with this condition
show exaggerated inattention towards the left half of the
visual space surrounding the body and often do not move
the eye past midline towards the left or turn head towards
the left side .
hemiagnosia, hemineglect, unilateral neglect, spatial
neglect, unilateral visual inattention, hemiinattention
neuropsychological condition in which, after damage to
one hemisphere of the brain is sustained, a deficit in
attention to and awareness of one side of space is observed.
It is defined by the inability of a person to process and
perceive stimuli on one side of the body or environment
that is not due to a lack of sensation.
Unsworth, C. A. (2007). Cognitive and Perceptual Dysfunction. In T. J. Schmitz & S. B. O’Sullivan (Eds.), Physical
Rehabilitation (pp. 1149-1185). Philadelphia, F.A: Davis Company.
Spatial neglect may result from lesions of the dominant
parietal, temporal, or frontal cortex.
There are different types of unilateral neglect:(Eskes &
Brain Imaging Studies
Assessment of lower level visual functions ( visual
acuity , oculomotor function and visual field).
Letter cancellation test
Brain injury visual assessment battery for
adults.(Other specific scales are to be discussed later
Scan board test
Described by warren
Consist of large 20 by 30 inch board with a
series of 10 numbers displayed in an
unstructured pattern .
The board is placed at the eye level and
centered at the client’s midline .
The client is asked to scan the board
Point out all of the numbers that are seen.
The examiner records the pattern the client
Comparision of search pattern : person with visual field
defect vs hemi- inattention
Visual field defect
Search pattern is abbreviated
toward blind fields
Search pattern is asymmetrical:
initiated/confined to the right
Attempts to direct search
towards blind side
No attempt to direct search
toward left side
Search pattern is organized and
Search pattern is random and
Clients rescans to check
accuracy of performance
Client does not rescan to check
accuracy of performance
Time spend on task is
appropriate to level of difficulty
Client completes task quickly;
level of efforts applied is not
consistent with difficulty of task
From Warren M:Brain injury visual Assessment battery
Occulomotor function deficit
Deficit in oculomotor control following brain injury
generally results from either of two types of disruption
Specific cranial nerve
Disruption of central neural control of the extra ocular
muscles affecting the coordination of eye movements .
Oculo motor function
The defects is associated with cranial nerve injury .
Oculomotor nerve (3): impaired vertical eye
movements , lateral diplopia for near vision
tasks, dilation of pupil and impaired accomodation
, ptosis of eyelid.
Trochlear nerve (4) : impaired downward and lateral
eye movements, vertical diplopia for near vision tasks
Abducence nerve (6) : impaired lateral eye
movements, lateral diplopia for far vision tasks.
Assessment of oculomotor
Ask the client about the expercience of diplopia :
o Look for the diplopia disappering when eye closed
o Which side lateral or vertical
o Far or near
o The next part of the assessment is observing the client
eye and eye movement for deficiencies
1. The eye are observed for asymmetries in pupil size
, eyelid function and eye position as the client
focuses on a distance object .
Look for ptosis
Tracking of the moving object : in figure of H or X
Note the point of convergence ( normally approx 3
inches from the bridge of nose ).
Eye ball movement
Assessment of specific visual
Visual object Agnosia : caused due to lesion to the right occipital lobe .
In this the person is unable to recognize and identify an item using
Assessment is performed by asking the individual to identify five
common objects by sight.
Color agnosia : Refers to inability to remember and recognize the
specific colors for common objects in the environment. Also know as
Assessment : present the client with two common objects that are
accurately colored and two objects that are not accurately colored . Ask
the patient to pick the object that are not accurately colored.
Color Anomia: refers to the client’s inability to name the color of the
object. while the client understand the differences between the
different colors of objects, they are unable to name the color of the
object accurately .
Color anomia : ask the client to name the color of
various objects in their environment .
Metamorphopsia : refers to visual distortion of
objects, such as the physical properties of size and
weight .Assessment includes presenting the client with
various objects of different weights and sizes.
Prosopagnosia : refers to an inability to recognize and
identify familiar faces caused due to lesion of the right
posterior hemisphere .
Non standardized test : to identify the names of the
people in photographs, with family members
Simultanognosia : refers to the inability to recognize
and interpret a visual array as a whole and is caused by
lesion to the right hemisphere of the brain .
The person is able to identify the individuals
components of a visual scene , but are unable to
recognize and interpret the gestalt of the scene .
Assessment : presenting the client a photograph of a
detailed visual array .
Right – left discrimination :
It is the inability to identify the right and left sides of
one’s own body or of that of the examiner .
The person with right and left discrimination cannot
tell the therapist which is the right arm and which is
the left .
It is caused due to lesion at the parietal lobe of either
Testing : ask the person to point to body part on
command, such as : right ear, left foot, right arm.
Visual-spatial perception Disorders
It refers to appreciate the spatial arrangement of one’s
body, objects in relationship to oneself, and relationship between
objects in space.
Figure-ground discrimination: it is a inability to visually
disctinguish a figure from the backgroung in which it is
The patient cannot locate items in a pocketbook or
drawer, locate buttons on a shirt.
It is caused due to parieto-occipital lesion of the right
hemisphere and less frequently the left hemisphere commonly
produce this disorder.
It can be assessed functionally in a variety of contexts . During
a dressing activity, or by asking in the client to pick one utensil
out of many utensils .
The Ayres Figure-ground Test( subtest of the southern
California sensory integration tests)
Form discrimination : It is inability to perceive or
attend to subtle difference in form and shape . The
patient is likely to confuse objects of similar shape or
not to recognize an object placed in a unusual
It is caused due to lesion at the parieto-temporooccipital region of the non-dominant lobe.
Testing : A number of items similar in shape and
different in size are gathered. The patient is asked to
identify them. Visual agnosia must be ruled out first.
Spatial disorientation, is the inability to perceive the
relationship of one object in space to another object, or
It is caused due to lesion to the inferior parietal lobe
Testing : The patient may be unable to tell the time
from a clock because of difficulty in perceiving the
relative positions of the hands. Before testing
unilateral neglect and hemianopsia should be ruled
Rivermead perceptual assessment battery(RPAB)
The Arnadottir OT-ADL Neurobehavioural Evaluation
In this the person experiences inaccurate judgment of
direction, distance, and depth.
Caused due to lesion in the posterior right hemisphere
in the superior visual association cortices.
To test the person is asked to fill a glass of water.
Position in space
It is inability to perceive and to interpret spatial
concepts such as up, down, under, over, in, out, in
front of, and behind.
The lesion is usually located in the non-dominant
Testing : to test function, two objects are used, such as
a shoe and a shoebox. The patient is asked to place the
shoe in different position in relation to shoebox; for
example, in the box, on top of box or next to box.
Vertical disorientation: it is the distorted perception of
what is vertical . Caused due to lesion in the nondominant parietal lobe.
Test by asking the person to place the cane vertically
when it is placed horizontally .
Topographic disorientation: difficulty in
understanding and remembering relationship of one
location to another .
Caused due to lesion inferior parietal lobe or occipital
association cortex and occipito temporal cortex.
Test by asking to describe or to draw a familiar root
such as the block in which he lives .
Standardized assessment tools
Toglia’s dynamic object search test : assess the visual
processing , visual scanning , and visual attention
AMPS( assessment of motor and process skills ): it
evaluates the performance skills necessary for engagment
in areas of occupation by assessing 16 motor skills and
processing skills ( eg. Temporal oraganization , organizing
space and objects )
Loewenstein occupational therapy cognitive assessment (
LOTCA) and Rivermead perceptual assessment battery
provide a comprehensive profile of visual perceptual and
motor skills and involve both motor free and
A variety of other assessment tools require either a
verbal or a simple pointing response .
Motor-Free Visual perceptual Test –revised ( MVPT-R)
Assess basic visual perceptual abilities
And an alternative version of the test present the
multiple choice in a vertical format to reduce the
interference of hemianopsia or visual inattention
The Test of Visual perceptual skills – upper level
Hooper visual organization test
Minnesota paper Form Board Test
1. Motor-Free Visual Perception Test, Third Edition
By Ronald P. Colarusso, EdD, and Donald D. Hammill, EdD
The Motor-Free Visual Perception Test (MVPT) is a widely
used, standardized test of visual perception. This measure
is meant to assess visual perception independent of motor
ability. It was originally developed for use with children
, however it has been used extensively with adults.
Contains 36 items.
Contains 40 items. Since the MVPT-R includes children up
to 12 years old, four items were added to the items of
the original MVPT to accommodate the increased agerange covered by the norms of the MVPT-R.
Contains 65 items.
Original MVPT and MVPT-R.
The test takes 10-15 minutes to administer, and 5 minutes to
score (Brown et al., 2003).
Original MVPT and MVPT-R.
One point is given for each correct response. Raw scores are
then converted to age and perceptual equivalents to allow
for a comparison of the patient's performance to that of a
normative group of same-aged peers.
The Developmental Test of Visual Perception: Second
Purpose: Measures both visual perception and visual- motor
Ages: 4 to 10 years
Administration Time: 45 minutes
Visual-Motor Speed, Position in Space, Eye-Hand
Coordination, Copying Spatial Relations, FigureGround, Visual Closure, Form Constancy.
The subtests are grouped into two categories:
Motor-Reduced Visual Perception and
Scoring is recorded as quotients in these areas. A General
Visual Perception Quotient is also generated. The Complete
Set includes Manual, Picture Book, 25 Profile/Examiner
Record Forms, and 25 Response Booklets, all in a storage box.
The Test of Visual-Perceptual Skills, Third
The TVPS-3 includes the following subtests:
Visual Sequential Memory
It Assess to determine the visual perceptual strengths
and weaknesses of students.
Items are presented in a multiple-choice format, and
responses can be made vocally (by letter of the
response choice) or by pointing to the answer choice.
This format can be used with students who may have
impairments in motor, speech, hearing, neurological
and cognitive functions.
It is untimed and takes about 25 minutes. Scoring is
quick and uncomplicated. Raw scores are reported as
scaled scores and percentile ranks for each subtest; the
overall total score is reported as a standard score and
percentile rank. Age-equivalents are also provided for
the subtest and overall scores.
Specific test Scales for Unilateral Spatial
Albert's Test Unilateral spatial neglect (USN)
Behavioral Inattention Test Unilateral spatial neglect
Bells TestVisual neglect - extrapersonal space
Catherine Bergego Scale (CBS)Visual neglect extrapersonal space
Clock Drawing Test (CDT)Visuospatial and praxis
abilities, may determine attention and executive
Comb and Razor Test Unilateral spatial neglect (USN) personal space
Double Letter Cancellation Test (DLCT) Unilateral
spatial neglect (USN) in the near extrapersonal space
Draw-A-Man Test-Unilateral spatial neglect (USN) in
the personal and extrapersonal space (as well as the
presence of anosagnosia). Other constructs:
intellectual ability/cognitive function/body image
Line Bisection Test-Unilateral spatial neglect (USN)
Semi-Structured Scale for the Functional
Evaluation of Hemi-Inattention-Unilateral spatial
neglect (USN) - personal and extrapersonal space
Single Letter Cancellation Test (SLCT)-Unilateral
spatial neglect (USN) - extrapersonal space
Star Cancellation Test-Unilateral spatial neglect
(USN) - extrapersonal space
The test sheet is presented to the patient at their
midline. Some of the lines are pointed out to
him/her, including those to the extreme right and
extreme left. The examiner asks the patient to
cross out all of the lines, and demonstrates what is
required by crossing out the 5 central lines
him/herself. The patient is encouraged to cross out
all the lines until he/she is satisfied that they have
all been crossed.
Time to administer
Less than 5 minutes
11x 8.5-inch page of paper with 41 lines 2 cm in length
each and pencil.
Draw a man test evaluation
Using a blank piece of paper
and a pencil, the seated
patient must draw an entire
man. The picture is scored by
giving one point for the
presence of each of the
following body parts:
head, trunk, right arm, left
arm, right hand, left
hand, right leg, left leg, right
foot, and left foot. The total
score of this version of the
test is 10
Impact of Motor, Cognitive, and Perceptual Disorders on
Ability to Perform Activities of Daily Living After Stroke
by Louisette Mercier, MA et al . In (Stroke. 2001;32:2602-2608)
Background and Purpose—This study evaluates the relative
impact of motor, cognitive, and perceptual deficits on
functional autonomy with 100 elderly (aged 55 to 79 years)
victims of stroke.
Methods—Two different approaches were used for
measuring functional autonomy: the Functional Autonomy
Measurement System (Système de Mesure de l’Autonomie
Fonctionnelle [SMAF]) and the Assessment of Motor and
Process Skills (AMPS).
The Functional Autonomy Measurement System (Système
de Mesure de l’Autonomie Fonctionnelle [SMAF]) is an
instrument for evaluating autonomy that was developed on
the basis of the theoretical framework of the World Health
Organization’s international classification of
impairments, disabilities, and handicaps.
It evaluates 29 functions covering activities of daily living
(7 items), mobility (6 items), communication (3
items), mental functions (5items), and instrumental
activities of daily living (8 items). Each function is scored
on a 5-point scale (0, 0.5, 1, 2, and 3).
The Assessment of Motor and Process Skills (AMPS)
provides a measure of the quality of motor and process
skills when the subject carries out an activity of daily living
or a domestic activity.
Evaluated byUpper extremity functional hemiplegia
Most of the various tests chosen to evaluate cognitive
functions were taken from a neuropsychology battery
called Protocole d’Évaluation Neuropsychologique Optimal
Evaluation by MVPT-V
The Motor Free Visual Perception Test-Vertical (MVPT-V) evaluates
visual discrimination, figure-ground differentiation, consistency of
form, visual memory, and visual synthesis.
A cancellation task using bells was developed by Gauthier et al and
gives a more refined evaluation of the degree of unilateral visual
neglect than previous cancellation tests).
Spatial relation deficits were measured with the line orientation
judgment test, which was considered by Beaumont and Davidoff to be
a test of visuospatial functions.
Three subtests were taken from the Ontario Society of Occupational
Therapy perceptual evaluation battery to measure visuoconstructional
Rey figure test
Visuoconstructional deficits/apraxia were also measured with the
complete detailed scoring system for the copy of Rey’s complex figure.
Norms have been established for neurologically healthy people and for
various groups of stroke patients.
Results:show that motor, cognitive, and perceptual
factors all make a significant contribution to the
variation in functional autonomy and confirm the
accuracy of the model (93% of the variance is
explained when the SMAF is used to measure
functional autonomy, and 64% of the variance is
explained when the AMPS is used).
Conclusions—The factors that make the greatest
contribution in explaining the variance in
functional autonomy are, in order of importance,
the motor factor, the perceptual factor, and the
Seeing The Gaps: A Systematic Review Of Visual Perception Tools
For Children With Hemiplegia. MEGAN AULD, et al In 2011
disability and rehabilitation.
Aim – visual perception difficulties are common in
children with cerebral palsy – hemiplegia, however it is
not known which assessment tool is the best for this
Method: Databases were searched for assessments
that: (i) measured visual perception; (ii) were reported
in studies with children with hemiplegia and (iii) had
clinimetric data available to assessors.
Results: Three assessments met criteria: the Test of Visual
Perceptual Skills (TVPS), Motor-Free Visual Perceptual
Test (MVPT) and Developmental Test of Visual Perception
All three assessments demonstrate variable construct and
criterion validity with other clinical assessments.
The DTVP, MVPT and TVPS demonstrate high test-retest
reliability for total scores, but individual TVPS subtests are
There is considerable overlap in content between the
subtests of the examined assessments. There
is, however, substantial variation in the manner in which
these subtests are applied.
The MVPT is a discriminative and evaluative assessment
tool used in children aged 4–11 years. The MVPT displayed
excellent inter-rater reliability.
Clinical utility- All three assessments have high
clinical utility – they are of a similar cost, do not
require training to implement and are relatively easy to
administer and score.
Conclusions: The TVPS is the most rigorously
investigated of the three assessments; however, this
systematic review has uncovered significant flaws in
both its validity and its reliability. The TVPS has some
significant flaws in its test design, impacting both the
validity and reliability of the test. At present the DTVP
and MVPT demonstrate the strongest clinimetric
properties and would, thus, be recommended for
Test-Retest Reliability of the Motor-Free Visual
Perception Test Revised (MVPT-R) in Children with and
Without Learning Disabilities
Patricia A et al in 2002, Vol. 22, No. 3-4 , Pages 23-36
Aim and objective :The Motor-Free Visual Perceptual
Test Revised (MVPT-R) is an updated edition of the original test
with the addition of four items and normative data for 9-11-yearold children. Test-retest reliability studies on the MVPT-R are
not reported. The purpose of this paper is to report the testretest reliability of the MVPT-R in children with and without
learning disabilities. The MVPT-R was administered to 38
children with identified learning disabilities and 37 control
children (aged 7-10 years) on two separate occasions within a 2.5
week window of time.
Results suggest moderate test-retest reliability for the MVPT-R
with more stability in visual perceptual scores for children with
learning disabilities. This information will be helpful for
therapists using the MVPT-R as a descriptive measure for
Text book of physical rehabilitation sullivan.
Pedretti 6th edition
Unsworth, C. A. (2007). Cognitive and Perceptual
Dysfunction. In T. J. Schmitz & S. B. O’Sullivan
(Eds.), Physical Rehabilitation (pp. 1149-1185).
Philadelphia, F.A: Davis Company