Visual processing
...... is the end product of the integration of visual attention, visual scanning, pattern recognition and memory.
Visual cognition
(DYNAMIC INVESTIGATIVE METHOD) Investigative Questioning
"How do you know this is a ......?"
If correct responses can be facilitated through cues or task grading, a ........... approach may be indicated. If correct responses cannot be facilitated, ........... or ............ may be indicated
-cognitive rehabilitative -a sensory motor (affolter method), functional approach
Bicycle drawings tend to reflect the drawing distortions characteristic of lateral damage. Right hemisphere patients tend to have very good .... with ....; left hemisphere patients tend to have good ......with very simplified drawings that lack ......
-detail; poor structure -structure; detail
Bicycle drawings tend to reflect the drawing distortions characteristic of ...... Right hemisphere patients tend to have very good .... with ....; left hemisphere patients tend to have good ......with very simplified drawings that lack ......
-lateral damage -detail; poor structure -structure; detail
Difficulty or inability to recognize or match colors or to sort different shades of the same color. In severe cases all objects are seen as shades of gray and white. Results from occipital temporal lesions.
ACHROMATOPSIA
Lack of awareness of a paralyzed extremity. The individual may deny that the extremity belongs to him/her. Lesion may be in the frontal lobe.
ANOSAGNOSIA
The inability to recognize familiar sounds or distinguish between sounds. Individuals may not be able to distinguish between a baby crying and a telephone ringing. Most common with temporal lobe lesions, particularly bilateral lesions.
AUDITORY AGNOSIA
SELF-MONITORING STRATEGIES - - - -
Anticipation Accurate anticipation of difficulty leads to the ability to plan and initiate the use of strategies. Checking Double checking. Looking at objects or scenes from more than one Outcomes perspective. Pacing Learning to slow down or speed your response to visual information based on specific conditions. Stimulus Speed and accuracy of visual processing may be increased by reducing the Reduction amount of visual information to be processed.
brain damage is primarily posterior, affecting the occipital lobes and surrounding regions. Damage tends to be diffuse and widespread rather than focal. There is a relative preservation of the most elementary dimensions of visual perception, with striking impairment in the ability to recognize, copy, or match simple shapes as well as more complex objects. Many patients can trace shapes they cannot recognize by vision alone (using hand or head motion) and tracing may be used as a means to facilitate recognition. The patient may appear blind to casual observers. Recognition of real objects may be better than simple stimuli due to a wider set of available cues. Patients may "recognize" objects by adding up their visual impressions.
Apperceptive Agnosia (narrow sense) -
any failure of object recognition in which perceptual impairments seem clearly at fault, despite relatively preserved elementary visual functions such as acuity, brightness and color vision. Name the 3 Types....
Apperceptive Agnosias - -Apperceptive Agnosia (narrow sense) -Dorsal Simultanagnosia -Ventral Simultanagnosis
graphomotor task examples 1 2 3 4 5
Ask the patient to draw and copy simple shapes and pictures (house, clock, flower, person) Test of Visual Motor Integration (VMI) Rey's Complex Figure Drawing Taylor Complex Figure Drawing Draw a Bicycle Test
failure to recognize objects despite apparently intact visual perception of them. Name the 3.....
Associative Agnosias - -Associative visual object agnosia (narrow sense) -Prosopagnosia -Pure Alexia
The 3 criteria for this category are: 1. Difficulty recognizing visually presented objects as determined by the inability to name the object, gesture its use or place it in a semantic category. 2. The ability to recognize the object through another sense. 3. Visual perception that seems adequate to the task of recognition - tested by having patients copy pictures they cannot identify, or match objects as being the same or different. (however there most likely is some sort of perceptual difficulty relating to visual organization). Localizing information is not clear. Many cases have been reported with bilateral occipital-temporal damage, but there are cases of unilateral damage. There may be different perceptual difficulties with different types of associative agnosia.
Associative visual object agnosia (narrow sense) -
(COMPLEX VISUAL PROCESSING) Possible underlying characteristics may include:
Attentional bias - unequal attention to all parts with a tendency to overfocus on irrelevant details Slow processing time
The individual is unable to name colors or point to colors named. Objects may no longer be associated with their distinctive color (i.e. a red apple). The individual is able to demonstrate the perception of color through appropriate color matching and sorting tasks. Lesion may be in the angular gyrus)
COLOR AGNOSIA
Used to identify conditions that facilitate object recognition. It involves the analysis of task parameters, task grading and the use of systematic cueing and investigative questioning. DO VISUAL SCREENING FIRST!
DYNAMIC INVESTIGATIVE METHOD -
generally occurs after bilateral parieto-occipital damage. Although these patients are able to recognize most objects, they generally cannot see more than one at a time. Visual fields may be full but they may have a constricted "effective" field. Sometimes more than one small object in central vision can be perceived. Patients are often described as acting like blind people, walking into furniture and groping for things. The impairment is clearly one of visual attention rather than blindness or field deficits. Patients will not react to a visual threat (a hand coming toward their face). They are unable to count objects and are unable to read. Since many objects have parts that can be seen as objects (i.e. the stars on a flag) these patients may seem to have difficulty recognizing objects, however it may be more accurate to say that they have difficulty "seeing" them at the correct level of the hierarchy of whole/part analysis. Whatever they can see, they can recognize. Moving objects may be particularly difficult to maintain perception of, but even stationary objects in view may spontaneously "disappear". Dorsal simultanagnosics have difficulty localizing objects in space.
Dorsal Simultanagnosia -
(DYNAMIC INVESTIGATIVE METHOD) Task Parameters - - - - -
Environment - context Familiarity Directions (structure/visual exploration requirements) Amount (number of objects presented at one time) Spatial arrangement (positioning of objects)
Prefrontal part of the brain in the motor association area. Responsible for voluntary visual search based on anticipation of where information is to be found in the environment. Severe injury results in the inability to....
Frontal Eye Fields voluntarily direct eye movements toward the contralateral side.
(DYNAMIC INVESTIGATIVE METHOD) Task grading Headers..... Draw diagram....
Grading Environment Familiarity of Objects Directions # of Objects Spatial Measurements
Provides information as to the ability to integrate and organize visual information. Standardized for ages 13-69. The test requires naming ability
Hooper Visual Organization Test (HVOT)
SIMPLE VISUAL PROCESSING IMPAIRMENTS - VISUAL AGNOSIA VS. COMPLEX VISUAL PROCESSING (Toglia, 1990)
Impairment in the higher visual processes necessary for object recognition, with relative preservation of elementary visual functions. The inability to detect subtle differences in shapes, objects, size and position. Breakdown occurs in visually confusing environments (i.e. crowded stores) and with detailed, abstract or unfamiliar information.
the central nervous system is aware of objects but may not be able to accurately identify them.
Left hemisphere damage -
Attaches emotional meaning to what we see. We are more likely to attend to an object that triggers an emotional response. Injury may result in ....... to the environment.
Limbic System' indifference
PROTOCOL FOR ADMINISTRATION OF REY'S COMPLEX FIGURE
Materials - Rey's Complex Figure, blank 8.5 X 11 paper, 5-6 colored pens or pencils, stop watch, scoring sheet The patient is instructed to copy the drawing which has been set out so that its length runs along the patient's horizontal plane with the vertical cross to the left. Watch the patient's performance closely. Start timing the patient when he begins drawing. Each time the patient begins a section of the drawing, hand him a different colored pencil. Note the order of their colors at the bottom of the sheet. The use of colored pencils and accurate recording of their order of use will help you determine the patient's procedural type. Stop timing when the patient indicates he is finished drawing. Cueing is not to be provided. After the patient has finished his drawing, take away both the Rey's figure and his drawing. Then ask the patient to draw the figure from memory. You may encourage the patient to put anything he can remember on the paper, even if he isn't quite sure of its accuracy, as partial credit is given for distorted, incomplete or improperly placed items. Use the scoring sheet to record: Procedural type, drawing time for copy trial and the content score for both the copy and recall trials. Use the same procedure for the Taylor Complex Figure
Originally designed and standardized for children 4-8. Occupational Therapist Mary Jane Bouska standardized the test on normal and brain injured adults ages 18-80. Provides a measurement of overall perceptual ability.
Motor Free Visual Perception Test (MVPT)
Name the 3 non-motor visual perception tests 1 2 3
Motor Free Visual Perception Test (MVPT) The Test of Visual Perceptual Skills (TVPS) Hooper Visual Organization Test (HVOT)
Constructional tasks 1 2 3 4
Parquetry designs Two dimensional block designs Three dimensional block designs Benton's Constructional Praxis Test
Visual information is combined with other sensory input to create a "map" of the contralateral side of the body. Information is processed for spatial relationships regarding the location of objects in space and their juxtaposition to the person's body and to each other. Lesions result in ...
Posterior parietal lobe (superior route) unilateral inattention
The inability to recognize faces despite intact intellectual functioning and even apparently intact visual recognition of most other stimuli. In some cases it is possible to separate impaired awareness of recognition from impaired recognition (the guilty knowledge test). It appears that the neurology of this deficit may involve the parieto-occipital area of the right hemisphere (or perhaps both hemispheres).
Prosopagnosia -
patients cannot read normally despite visual capabilities that appear normal on testing and despite their ability to understand spoken language and write. These patients are unable to read something that they have just written. It is essentially a visual agnosia for verbal material. May result from a lesion in the dominant angular gyrus)
Pure Alexia -
(DYNAMIC INVESTIGATIVE METHOD) Systematic cueing 1 2 3 4
Repetition cue-"look again" Analysis cue-ask patient to describe misperceived object Perceptual cue-therapist emphasizes critical feature-pointing, repositioning Semantic cue-choice of 3 categories, give the patient the category
Responsible for the control of global attention. Visual input into the reticular formation results in increased arousal and engagement of attention.
Reticular Formation (brainstem)
Hemispheric differences ....... - directs attention toward both the right and left hemifields. Processes items by breaking them down into blocks of information enabling simultaneous processing of several items which allows for more configural processing. ....... - directs attention only toward the right hemifield. Processes information sequentially. This allows for more discrimination of details and allows for object identification.
Right Left
The central nervous system will not be alerted to the presence of objects and the focal attention of the left hemisphere cannot be adequately engaged.
Right hemisphere damage-
From the occipital cortex, visual information branches out in two directions as it travels toward the frontal lobes.
SCANNING/SELECTIVE ATTENTION
The inability to recognize one's own body parts and their relationship to each other. Lesion may be in the dominant parietal lobe.
SOMATOAGNOSIA (AUTOPAGNOSIA)
SITUATIONAL STRATEGIES
Scanning Organized scanning - left/right Visual Imagery Imagining what you are looking for facilitates recognition Visual Analysis A more "active" approach to visual processing. Silently verbalizing characteristics/verbal mediation Organization Consistency, spacing, grouping
Responsible for the involuntary visual capture of visual stimuli occurring in the peripheral fields. The action is automatic and reflexive. Injury results in decreased monitoring of the peripheral fields and zombie-like behavior.
Superior Colliculi (midbrain)
The inability to recognize objects by touch despite intact sensation. Lesion may be in the somatosensory areas posterior to the postcentral gyrus.
TACTILE AGNOSIA (ASTEREOGNOSIS)
Visual information is processed for object identification- pattern recognition, detail, color, form, size, quantity. Lesions result in diminished....
Temporal Lobe (inferior route) object recognition
The third version is normed to age 18 years 11 months. Contains seven subtests.
The Test of Visual Perceptual Skills (TVPS)
COMPLEX VISUAL PROCESSING
The ability to detect subtle differences in shapes, objects, size and position. Breakdown occurs in visually confusing environments (i.e. crowded stores) and with detailed, abstract or unfamiliar information. Possible underlying characteristics may include: (know 1-2 reasons for breakdown)
ADMINISTRATION of VMI
Use pencil-no erasing allowed Booklet must be centered and squared Say "You are to copy what you see at the top of each page. Make your drawing of each shape in the space below it." Do not trace the form with your finger or pencil as the motions provide cues. Do not let the patient trace the form. Avoid calling the form by its name or a descriptive term. The shapes are to be copied in order, starting with #1. Only one try on each form is allowed with no erasures. Have the patient complete all shapes The patient is not timed or pressured
TESTING THE LIMITS - INVESTIGATING THE REASONS FOR POOR PERFORMANCE on the VMI 1 2 3
VISUAL PERCEPTION - After completion of all forms ask the patient to compare his drawings to the forms. "Does your drawing look the same?" "How is it different?" If the patient perceives the differences the difficulty is not likely to be perceptual. MOTOR CONTROL - After completion of all the forms ask the patient to trace the forms. If tracing is difficult, motor control is contributory. INTEGRATION - After completion of all forms ask the patient to copy the form again on a blank paper and/or have him watch you copy it. See if performance improves. If the problem is integrative, performance may improve with practice or imitation. You can also try motor guidance and verbalization.
seen with lesions in the left inferior temporo-occipital region. Patients are generally able to recognize a single object, but do poorly with more than one and have difficulty with complex pictures. Although they cannot recognize, unlike dorsal simultanagnosics, they can see multiple objects. They may be able to read, but do so a letter at a time - spelling words in order to recognize them. They will describe different aspects of a complex picture, often with no understanding of the picture as a whole.
Ventral Simultanagnosis -
...... is dependent on accurate pattern recognition. It is difficult to recall visual input that has no meaning for us.
Visual memory
DEVELOPMENTAL TEST OF VISUAL MOTOR INTEGRATION (VMI): The VMI supports a ...... for the development of .... & ....... Higher level cognitive skills and functional performance requires integration of ...... and ....... The VMI presents a sequence of forms from simple to complex that reflects ..... Research indicates that the forms are virtually ..... The test can be administered in ...... minutes and can be used with ...... children through ....years.
a sensory-motor basis intelligence and achievement sensory inputs and motor output normal development culture-free 10-15, pre-school,19
Dysfunction in graphomotor or constructional tasks as been termed ......
constructional apraxia
What do non motor visual perception test help the therapist with? They do not provide therapist with....
to help the therapist objectively identify the presence and severity of complex visual processing dysfunction the underlying factors that may be contributing to breakdown
Graphomotor tasks Vs. Constructional tasks
two dimensional tasks that require the individual to draw parts to form a single structure. Accurate perception of spatial relationships is necessary. They require more motor control than constructional tasks. two or three dimensional. They require the patient to join or assemble parts to form a single structure. Accurate perception of spatial relationships is required. More depth perception is required than for graphomotor tasks.
Visual scanning is the motor expression of .......
visual attention
