How Vision impacts Memory:

The visual connection in the adult neurological population

Alicia M. Reiser, MS OTR/L

Physical Therapy at St. Luke’s

Vision and Visual Perception

• Rowe et al (2009) up to 92% stroke survivors had some visual impairment

• Visual Deficits can be mistaken as cognitive or physical deficits• Vision

– Primary way we acquire information

Alerts us to danger, pleasure

Enables anticipatory actions

Plans for situations and reactions• Visual Perception

– “Applying cognitive concepts of space and form to understand the visual world by transforming raw data form the retina into cognitive concepts”

Eye Sight vs. Vision: What’s the Difference?

Mary Warren’s visual hierarchy and the 4 circles of vision

Magnacellular ParvocellularAmbient (peripheral) vision Focal

visionDoesn’t go to occipital lobe occipital/temporal lobes

Visual language processing visual spatial processing

Directs motor movement of eyes/hands object identification

Gross Motor fine motor

Centering: Where is it?

Identify:What is it?

Antigravity:Where am I?

Speech/auditory:What do I

know about it?

VISION

Visual cognitionVisual memory

Pattern recognitionScanning

Visual attentionOculomotor control, visual fields, visual

acuity

(Hillier and Kawar, 2013)

(Warren, 1993)

What does the hierarchy mean?• Visual cognition: ability to mentally manipulate visual info and

integrate it with other sensory info to solve problems, form plans and make decisions (executive functioning)

• Visual memory: store and retrieve a mental image of object in the mind’s eye, apply new patterns to solve problems by comparison

• Pattern recognition: identify the salient features of an object in order to visually remember it (shape, color, texture). This determines if the memory is laid down. Frontal Lobe looks for as many attractors as possible- what makes an object different. CVA and TBIs tend to use more generic attractors.

• Scanning: the ability of the fovea to fixate and take in the environment in a sequential pattern by using saccades automatically by the brain stem and voluntarily by the frontal lobes. Reading is usually linear, non structured shape is circular.

• Visual attention: 3 step cognitive process (disengage, move and compare). Critical step in visual processing using both global and focal attentions

• Oculomotor control, visual fields, visual acuity: together allows for efficient conjugate movement, registering the entire scene and eyesight, including contrast. Oculomotor control provides perceptual stability, acuity provides clarity of detail and color, and field allows for awareness of objects in environment (Warren, 1993)

• Hierarchy: works together at all levels- think developmentally• Following brain injury:

– Visual field, acuity, control and visual attention impacted– OT screens for this deficits and identifies limitations in occupational performance (Warren, 2014)

• Oculomotor control affected by disruption of CN function or disruption of CNS control– Exotropia, high exophoria, accommodative dysfunction (Blurry vision), convergence insufficiency (diploplia),

low blink rate, spatial disorientation (the inability of a person to determine his true body position, motion, and altitude relative to his surroundings), poor fixation, irregular eye pursuit movements and unstable ambient vision

• Diploplia, illusion that objects are moving in the environment, poor concentration and attention, staring, poor visual memory, eye pain, neuromotor deficits including balance, coordination and postural control (Kane)

Team Introduction

• Neuro opthomologist: diagnose and prognose- what caused the impairment?

• Neuro or behavioral optomotrist: diagnose, prognose and interventions to improve

• Certified Vision Rehab Therapist: if vision is significantly impaired to teach blind tech

• Occupational Therapist: screen and identify strategies to improve occupational performance

Primary changes after brain injury:

Visual field, visual acuity,

oculomotor control, visual attention

ADL performance affected

• Reading

• Writing

• Employment

• Role of parent, child, spouse, worker

• Functional Directional Skills– Driving– Topographical orientation – Personal space

Vision Screen Performed by OT

Screen for Acuity

• Deficits due to optic nerve damage or bilateral damage to the occipital lobe

• High Contrast Acuity: distance and near, low contrast– Distance Snellen Chart– Reading acuity chart– Mars Chart, LeaNumbers Chart or Glass Test

Treating acuity dysfunction• Clean glasses• Check med side effects: seizure, spasticity• Refer to optometrist/opthomologist for refraction update• Improve accommodation• Use contrast on stairs, with meals, in bathroom,

minimize patterns and clutter, increase lighting, LED lighting, enlarged adaptive equipment, organize environment, simplify tasks, manage glare

• Electronic Magnifiers

Visual pathway to the brain

Left honomonous hemianopsia

Right hemianopsia

Binasal occlusion

Tunnel vision

Screen for Visual Field

• Deficits due to MCA, PCA (75% result in homonymous hemianopsia) or occipital lobe brain injury

• Diagnosed by opthamologist or optometrist, usually after 5 months• Perimetry testing: central and peripheral, manual or computerized • Confrontation test: shown unreliable• Tangent Screen: results given in isopter, absolute scale or gray

scale diagrams

• Visual Skills for Reading Test (Pepper), Telephone number copy• Trail making test, clock drawing test, single letter cancellation test,

line bisection test

Behaviors seen with HH

• Don’t cross visual midline therefore filling in the blanks with previous visual memories, safety imparied

• Scan slowly to affected side impacting rate of ADL completion• Miss detail on blind side with reading, small detail tasks• Reduced hand monitoring with function• Decreased mobility: slowed, looks down, stops to search, gets lost• Writing: drifts• ADLS: driving, shopping, yard work, meal prep, money mgmt,

communication, homemaking, self-care• Reading: word recognition due to limited fovea previously 19

characters, unable to preplan saccade– Right: affects saccade, can’t preplan next word– Left: omits words, skips lines

Treating Hemianopsia• Recovery rare after 6 months (Zhang, et al, 2006): Compensation is Key• Computerized Light boards: Dynavision, Wii• Laser pointer: flashlight tag• Reading: Pre-Reading tasks to increase saccade length, large print familiar text,

occupation based text. Maybe not bifocals• Writing: illumination, contrast, bold lines and black pen• “Scan the environment” tasks

– Wider head turns– Increased head movement for scanning– Faster rate of head movement– Improved search pattern– Wide scanning tasks

• Approach from the affected side during divided attention tasks• Modify the environment• Prisms from neuro optomotrist

Visual Attention

• Skills to attend: filter out, balance all perceptions, become salient, termination

• Monitor central field (cones- what is it?) and peripheral field (rods-where am I?)

• Constant communication through cortex, brainstem and cerebellum orchestrated by the frontal lobe

• Mass practice , experience and context can all improve recovery

Types of Attention

• Focused attention: responding to specific element

• Sustained attention: maintaining response over period of time

• Selective attention: free from distraction of environment

• Alternating attention: shift from one task to another

• Divided attention: simultaneous engagement in more than one task, multitasking

Neglect

• Due to deviation in normal search pattern• Disorder in:

– spatial cognition• No concept of space….no insight

– spatial orientation• Left sided space doesn’t exist

– spatial exploration• Difficulty crossing visual midline• Difficult disengaging search pattern from right

• 80% result from damage in right parieto-temporal-frontal circuitry (Warren)

• If vestibular cortex: pusher syndrome

Behaviors

• Decreased ADLS: reading, WC mobs, driving

• Limited insight

• Decreased task initiation

• Decreased sustained attention

• Decreased working memory

• Perseverates

• Decreased alternating attention

Evaluation for Visual Attention

• Why is there inattention?– Spatial bias– Impaired conceptualization– Non lateralized inattention

• Tests: Cancellation tests (assesses search pattern), Telephone number copy, Reading performance, Design Copy, Scan Board, ScanCourse, Dynavision, ADL observation

Search Patterns (Warren)

Left Hemianopsia

• Abbreviated search pattern- omissions on left

• Pattern is organized• Re-scanning to check

accuracy• Sustained attention

measured by completion time appropriate

• Improves with cuing

Hemi- inattention

• Abbreviated search pattern- omissions on left

• Pattern is random• Revisitng on right• Reduced sustained

attention, shorter completion time

• Cue meaningless

Interventions for Visual Attention

• Modify Environment to support participation– Decrease pattern, increase contrast, reduce

glare, lighting

• Improve attention through language to assess performance, activity based

• Visual Scanning Training– Focus on: Left to right, symmetrical scanning,

completing search to left, observe detail, anticipate, rapidly shifting R v L

Treating Visual Attention

• Multimatrix tasks: categorization, spelling

• Shapes and grid tasks

• Pencil and Marsden ball tasks with patch

• Cognitive load tasks– Go-no-go: flash pen light a number of times,

hold fingers up how many seconds to wait, then pt taps table equal to amount of flashes

Treatment

• Meaningful occupations

• Salient tasks: babies, pets, family

• Multimatrix Game, Tracking Tube

• Refer to developmental or neuro optometrist for prisms, lenses

• Sensory Input: Incorporate auditory, visual (prisms or partial occlusion) and vestibular treatment with cognitive load

Oculomotor Impairment

• Caused by closed head injury, facial trauma, Cranial nerve trauma or Brainstem injury; damage to cortical areas that use eye movements to shift attention (Warren), PD, MS

• Saccades: bring taret to fovea after activated by attention, uses scan and search with quick movements

• Smooth pursuits: triggered by movement and hold a moving image on the fovea

• Cervical VOR

Accomodative dysfunction

• Convergence insufficiency• Treated by optometrist• OT uses larger print or magnifiers

• Binocular insufficiency• Convergence excess• Divergence excess• Divergence insufficiency

• 23 kinds of nystagmus• Ocular dysmetria: over/under shoots with saccades,

slows down identification

• 3 steps to accommodate– Converge to target and stimulate

photoreceptors– Lens thickens to refract light– Pupils constrict to reduce scatter of light

Behaviors

• Difficulty focusing, altered perception, disruption of balance

• OT cannot fix oculomotor dysfunction – Modify and Adapt– Manage condition until resolves– Eliminate stress for improved ADLS

• Most clears up within 6 months (Park, Hwang, Yu, 2008)

Altered Perception

• Diploplia– Doubled images– Blurred images– Ghosting images– Distorted images

• Acquired paralytic strabismus– Due to paralysis or weakness of CN 3,4,6

Cranial Nerve Review:

• CN 3 (Oculomotor nerve) lesion: exotropia, vertical or medial movements difficult, lateral diploplia, ptosis, dilated pupil, due to severe TBI

• CN 4 (Trochlear Nerve) lesion: bilateral lesions common, vertical diploplia near vision, head tilt contralateral side

• CN 5 (Abducens Nerve) lesion: esotropia, lateral diploplia for far vision

Screening for binocularity

• Unilateral Cover test: phorias near and far

• Broch string: convergence, suppression near vs far, alignment, accommodation

• Red/Green Fusion test: suppression right vs left eye

• Near point of convergence

• Behaviors with phorias: headache, blurred vision

• Convergence insufficiency: poor recall of what read, decreased reading, look out window

• Convergence excess: love to read, get close to notes to write

• Suppression: poor sports skills

• Accommodative infacility: poor concentration, poor sustained attention

What and how to screen: What does it mean?

Screen for diploplia• Screen if binocular or monocular

diploplia– Only when both eyes open:

binocular diploplia– Patching can be useful– Even when one eye shut:

Monocular diploplia– patching doesn’t help: requires

sx, vision rehab or prisms• Screen where the diploplia is?

– Move eyes around from 12 to 6 to 12

– Where is the double vision worse? Better?

– Tilt head right, left. Worse, better?

• Patching: complete occlusion

– Can lead to monocular vision, eye fatigue and strain

– Must alternate patch- poor pt compliance

– Decreased depth perception / increase fall risk

– Strengthen the oculomotor deficit

• Occlusion:

– Binasal occlusion forcing peripheral vision

– Nasal portion of dominant eye

– Need MD consent

Diploplia cont….

• Prisms from optomotrist when peripheral or central nerve injury (Hilliar, 2014) Used with phorias to achieve fusion.

• Multimatrix games• Fusion tasks with scanning• Convergence activities

– Reading– Broch string– Pencil push ups– Add an auditory component with a metronome

– Add a cognitive load by converging on every 3rd beat

Other Disturbances in Visual Perception

• Visual discrimination: ability to discriminate one thing from another allowing for pattern recognition

• Pattern recognition: spatial patterns (shape of the letter), sequential patterns (q is a spatial pattern in a sequence of letters to form a word) and movement patterns (magnocellular through gestures, expression)

• Behaviors include not recognizing patterns, sequences, difficulty with symbolic literacy, difficulty organizing space and time

Visual Memory

• Semantic Declarative Memory: info heard or read

• Episodic Declarative Memory: remembering what did or what happened

• Implicit Procedural Memory: long term memory for motor learning task (tying shoe, handwriting)

• Working Memory: metacognition…think while we are thinking! Reading, writing, lecture

Visual Imagery

• Manipulating images in minds eye

Perceptual Midline Shift

• Perceived midline of body is not the actual midline of the body– Auditory– Visual– Vestibular

– Due to dysynchrony of sensory integration at midbrain with major contributions from ambient visual pathway causing poor sports performance, social insecurity and difficulty driving (Hillier and Kawar)

– Benefit from yoked prisms

Treating Tunnel Vision

• Bimanual circles

• Mimicking gross motor movements while fixated straight ahead

• Flashlight tag

• Scarf juggling

Therapeutic strategies after trauma

• Adapt: make plastic changes in the cerebellum and brainstem neuronal responses to head movement– Decrease retinal slip/oscillopsia– Improve postural control and gaze– Decrease vertigo– Use for those with unilateral lesions with high velocity head movement

or central lesion

• Habituate: minimize sensitivity to aggravating stimuli• Use for those with unilateral lesions causing asymmetry and visual

vestibular mismatch

• Substitute: enhance visual and somatosensory cues to compensate• Use for those with bilateral lesions and high velocity unilateral lesions

with gaze stability and somatosensory training

References• Hillier, Carl and Kawar, Mary. (continuing education PDP, 2013). Eyesight

to Insight: Visual/Vestibular Assessment and Treatment. Pittsburgh, PA.

• Hillier, Rita and Tarbutton, Natalie. Vision Deficits following Stroke: Implications for Occupational Therapy Practice. OT Practice, 19 (21), 13-16

• Lane, Kenneth (2012). Visual Attention in Children: Theories and Activities. SLACK Publishers, New York.

• Park, UC; Kim S. J.; Hwang, J. M. & Yu, Y. S. (2008). Clinical features and natural history of acquired third, fourth, and sixth cranial nerve palsy. Eye (Lond). 2008 May;22(5):691-6. Epub 2007 Feb 9.

• Rowe, F., Brand, D., Jackson, C. A., Price, A., ….Freeman, C. (2009). Visual impairment following stroke: Do stroke patients require visual assessments? Age and Ageing, 38, 188-193.

• Rummell, Errol. (2012, September 17). Vision Rehab for Hemianopsia: How VRT can improve vision loss from a neurological origin. Advance for Occupational Therapy Practitioners

• Warren, Mary. (1993). A Hierarchical Model for Evaluation and Treatment of visual Perceptual Dysfunction in Adult Acquired Brain Injury, Part 1. AJOT, 47, 42-54.

• Warren, Mary. (continuing education vis ABILITIES Rehab Services, inc. 2014). Visual Processing Impairment I: Evaluation and Intervention for Adult Acquired Brain Injury. JFK Johnson Rehabilitation Institute, Edison, New Jersey.

• Zhang, X., Kadar, S., Lynn, M. J., Newman, N. J. & Bouisse, V. (2006). Homonymous he,ianopsia in strole. Journal of Neuro-opthomology, 26, 180-183.

Appendix

Eye Terms

• Mobility: the ability to move eyes full range• Motility: skill with which the eyes move (smooth,

slightly jerky, jerky)• Pursuits: tracking of moving object with body

still or stationary object with body moving• Steady fixation: ability to keep eyes from moving

off moving target• Saccades: quick eye movement for scanning

environment, reading (visual memory, comprehension based here)

Eye Terms• Binocularity (teaming or alignment)

– Phoria “the tendency to” or weakness• Orthophoria: tendency to stay in alignment• Exophoria: tendency to drift out, therefore a shift

inward when contralateral eye occluded• Esophoria: tendency to drift in, therefore a shift

outward when contralateral eye occluded• Hyperphoria: tendency to drift upward, therefore a

shift downward when contralateral eye occluded• Results in intermittent diploplia• REFERRAL to Dev/Neuro Optomotrist if eso or

hyperphoric

• Binocularity– Tropia “is out of alignment” or

paralyzed/ Strabismus• Exotropia: eye is turned out• Esotropia: eye turned in• Hypertropia: eye turned up• Cyclotropia: eye is rotated• Results in constant diploplia of gaze

• Strabismus is acquired from TBI or developmental