11 - Stroke,TBI, VF loss Flashcards
Stroke: the ____ most common cause of death world-wide
-What’s the most common stroke type in the elderly?
2nd
-ischemic (2’ to atherosclerosis or embolism)
Which lobe controls: higher mental fxns, personality, Broca’s area, motor control, FEFs?
FRONTAL lobe
recall: broca: (difficulty comprehending, no problem swearing/speaking)
Which lobe controls: pressure/touch SENSORY info, visual spacing processing, PLANNING of a motor task?
PARIETAL lobe (parietal = planning)
Which lobe controls/contains: auditory complex, Wernicke’s area, smell, inferior optical radiations (Meyer’s loop)
TEMPORAL lobe
Which lobe controls: vision, visual recognition, LGN/calcarine fissure, primary visual cortex?
OCCIPITAL lobe
What part of the brain is a MODERATOR of fxns of the motor system, including eye movements?
basal ganglia (cluster of nuclei temporal to the thalamus)
Name the “sensory hub” containing the thalamus, hypothalamus, epi & subthalami?
diencephalon
Which part of the brain: plays a role in CONTROL of eye movements (thru a fdbk loop), MOTOR control/posture, integrates all fdbk to motor systems, and is important in the VOR reflex?
cerebellum
-lesion: ataxia, jerk nystagmus, interruption of VOR, under/overshooting saccades
Ischemic injury in WHICH stroke syndrome may produce the following deficits?
- complex physical/cognitive defects
- contralateral hemiplegia
- contralateral hemianopsia
- if FEF lesioned: eye deviation IPSI
- if LGN lesioned: pupil SPARING
AChA syndrome - anterior choroidal stroke (uncommon-3%)
-pt may have slow response to questions (psychomotor bradykinesia), impulsive actions, aphasia
Ischemic injury in WHICH stroke syndrome may produce the following deficits? (be specific)
- cortical infarct of FRONTAL lobe
- contra hemiplegia (hand>leg)
- transient head/eye dev. toward lesion
- VF sparing
- dominant affected: broca’s aphasia, inability to repeat
- non-dom affected: mild hemi-neglect
SUPERIOR MCA infarct
-LESS intense than inferior
Ischemic injury in WHICH stroke syndrome may produce the following deficits? (be specific)
- intense infarct to the parietal, occipital AND temporal lobes
- NO motor/somatosensory defects
- dominant affected: Wernicke’s aphasia - poor comprehension
- non-dominant: hemi-neglect
INFERIOR MCA infarct
-MORE intense than superior
Ischemic injury in WHICH stroke syndrome may produce the following deficits?
- CONTRA sensory syndrome, hypoesthesia
- CONTRA hemiaNOPia
- amnesia
- if directly to left occip: alexia w/o agraphia (can write, CAN’T read)
- blindness if embolism obstructs both PCS branches
Posterior Cerebral artery syndrome
What type of stroke usually has infarcts
LACUNAR stroke “little lake”
Which type of stroke affects the brainstem, cerebellum, diencephalon, and spinal cord, and may possibly affect the EW nuclei.
-Common result: palsies
Infratentorial stroke (contains the brainstem area/structures)
Irreversible injury in stroke occurs when blood flow falls under __mL/100g/min
- what area is a focus of research as it may not be permanently damaged w/ ischemic tissue?
- TPA is indicated how soon after stroke occurs?
10
- penumbric area
- 3.5-4 hours after onset to minimize damage (CI: >80Y/O, anticoagulants)
Approximately what percent of stroke admits have hemianopia, hemi-inattention, or VF neglect?
~30% (up to 50% have visual manifestations)
What’s the most common visually debilitating complication of stroke, 70% of which result from a stroke?
-prognosis?
Homonymous hemianopia
- if any recovery, will be w/i 6 wks, deff by 6 mos
- 70% of all HH cases have central VF (macular) sparing of 5 deg or less!
What is the Riddoch phenomenon?
Preservation of MOTION perception in an otherwise complete scotoma (d/t originally an occipital lesion)
Reading fluently left to right, one needs about ___ characters on left and about __-__ characters on right - RIGHT hemianopia affects reading more than left
3-4 left, 7-11 (5 degrees) right
hemianopic alexia = difficulty reading in the presence of a right hemianopia
Give 5 rehab approaches
1) traditional approaches for hemianopic alexia - low mag as possible, lighting & contrast enhancement
2) reading related training methods
3) eye mvmt/saccade training
4) visual search training
5) prismatic spectacle desigs
Three steps to visual search training?
1) LARGE amplitude eye mvmts into blind field
2) systematic (Z-movement) training
3) Strategy transfer to natural situation
Must beware of what phenomenon that is bound to occur any time prism is used in rehab mgmt?
To rx yoked prism for HH defects, what direction do you order the base in?
What type of prisms are used to attempt to eliminate the above prismatically-induced phenomenon?
APICAL SCOTOMA
-Base IN THE DIRECTION of the field defect (ie right homo hemi, base right will shift the entire image LEFT into seeing field)
EP (peripheral) prisms - placed 6mm above & below LOS/pupil center - pt must learn what’s real and prism-induced. Ensure adequate B frame size; can use fresnel; determine minimum inter-prism distance.
Note: in fitting EP (peripheral) prisms, does the LOCATION of the prisms determine the amt of shifted field?
-where is diplopia experienced w/ EP prisms?
NO - the STRENGTH of the prism does - still want to place 6 above/below and encroach as much as possible
-PERIPHERAL visual field
Are EP prisms placed uni or bilaterally? What’s the difference?
UNILATERALLY! will EXPAND FOV; while if placed bilaterally they would only EXCHANGE that field of view (would gain no expansion)
Lesions to the (right/left) hemisphere more commonly result in visual neglect, specifically if to the ___ ___ ___ lobe
-must detect if neglect is occurring in the ___ or ___ space
right: right INFERIOR PARIETAL lobe (planning, processing of visual spacing, sensory info)
- peripersonal: affects near activities (food on one half, shaving half their face)
- extrapersonal: O&M problems
Name five types of pencil and paper neglect testing:
-What CAN/CAN’T move when neglect testing? why?
1) line bisection- right bias = LEFT-sided neglect
2) clock drawing - half o clock
3) figure copying - a disaster
4) Gautheir’s bells (circle bells on one half)
5) Letter cancellation (circle all e; cross out all r) - on one half only
-HEAD can move - PAPER/OBJECT CAN’T (that’s how you differentiate neglect
What phenomenon is being described?
-Pt shows awareness to the presentation of a stimulus in the affected VF area, but when two identical stimuli are presented on either side of the VF (intact and non), the pt has no idea the stimulus in the affected VF area is present
extinction phenomenon
-considered (+)extinction when they fail to recognize stimulus in affected VF area at least once out of 6 times
What type of pencil and paper tests are the MOST sensitive?
- What’s even MORE sensitive than paper and pencil testing?
- What’s the MOST sensitive neglect test?
cancellation tests
observation tests
COMBO of cancellation (a paper and pencil test) AND observation
What’s an excellent rehab strategy for neglect that’s NOT useful in the case of VF loss?
-must repeat adaptation testing at least ___ times to gain an effect
YOKED PRISM!
10 - but it’s unknown whether prism should continue to be worn everyday or only during training sessions
Stroke may result in what visual findings?
tons.
- Ocular misalignment/CNIII palsy, diplopia (PCA stroke - constant fall risk), dorsal midbrain presents w/ INO, reading impairments
- other disorders: saccadic and/or accom dysfxn, convergence palsy/insufficiency, oculomotor dysfxn w/ or w/o fixational stability
Mgmt of a nerve palsy: try ___ prisms first - may undercorrect to encourage recovery…if this doesn’t work, what type of filter should you use?
fresnel
bangerter filters if fresnel fails
Rehab strategies for saccadic/oculomotor dysfxn: what types of tests?
- repetitive saccade/pursuit training
- DEM/King Devick to track progress
- word/letter searches
Rehab strategies for accommodative dysfxn: what types of tests?
pencil pushups, lens rock, flippers, bifocals
Rehab strategies for convergence palsy/CI dysfxn: what types of tests?
pencil pushups, brock string, prism vergence, prism @ N w/ near add (LAST RESORT)
Which two tests may be useful to assess cognitive impairment? (Old material, but cumulative)?
Mini-mental (MMSE)
MoCA (montreal cog assessment)
Describe:
- Prosopagnosia: Can’t recognize ____
- Simultagnosia: Can’t describe ___ picture/scene, rather only ____ aspect of it
- Optic ataxia: what’s “gone”?
proso: no FACE recognition
simult: can’t describe SCENE - only one aspect (dishes)
optic ataxia: SPATIAL MAPPING gone
What’s the leading cause of VF loss? Other causes?
GLAUCOMA - then stroke, RP, proliferative DR
Which two main oc disease cause CONCENTRIC and ARCUATE field loss?
-Common concerns?
Glaucoma, RP
-Concerns: contrast, lighting needs, mobility concerns, acuity loss (late), night blindness in RP
What are the four patterns of VF loss in RP progression?
I - progressive CONCENTRIC loss
I - VF loss beginning SUPERIORLY, developed ARCUATE scotoma (C-shape!)
III - complete/incomplete RING SCOTOMA breaking into periphery
IV/End Stage - residual central VF, possibly w/ small peripheral island
**Regardless of VF abilities, if the MD on a VF machine is -__dB , the pt is considered legally blind
-22dB - KNOW.
Rehab strategies for READING:
1) keep mag as low as possible/as VA permits
2) consider good lighting & contrast
3) line guides/typoscopes to reduce omission errors
Concentric VF loss Rehab strategies - can encourage what SAME four concepts for mgmt?
1) eye scanning/training
2) optical minification
3) prism “substitution” or VF enhancement
4) O&M training
What’s the advantage of an amorphic lens?
providies MERIDIONAL minification - in only the HORIZONTAL direction - few still produced…induced astig/head tilt
Recall: what are the THREE MOST POWERFUL VISUAL PREDICTORS of the likelihood of falling?
1) VF loss (-5dB)
2) CS loss
3) VA loss
