Brain damage due to lack of oxygen and nutrients to the brain
as a result of burst blood vessels or a blood clot. (The World
Health Organisation WHO) CLINICAL DEFINITION A rapidly developing
episode of focal or global dysfunction, lasting longer than 24
hours or leading to death, and of presumed vascular origin.
(Macintosh, C; 2003)
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Leslie Ritter and Bruce Coull, 2011 (The University of
Arizona)
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85% ischaemic: Cerebral artery blockage (cerebral thrombosis)
Cerebral Infarction Atheroma build up in intra and extracranial
arteries Embolus travelling blockage 15% intracerebral or arachnoid
haemorrhage
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75% 10% 15% Cerebral Infarctions }
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Most common cause of disability Third most common cause of
death 150,000 sufferers per year on average Age 65+ Effects
dependent on area of brain affected All different in and of
variable severity Effects short and long term
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Walking Speech and or language Mental processes cognition
Swallowing Paralysis Eyesight
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Visual field loss Blurring of vision Reduced vision Nystagmus
Diplopia Moving images oscillopsia Visual Neglect Difficulty
judging depth and movement Photosensitivity Hallucinations Agnosia
recognition difficulties
All ocular muscles Glossopharyngeal nerve (for swallowing)
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Damage to cortical control of eye movements Severe stroke
difficulty looking away from lesion Can have deviation of eyes
towards lesion site. Gaze palsies poor prognosis
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Common effect of stroke Oxford Audit 55% of patients VAs
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Demonstrate vision test Speak slow Repeat yourself where
necessary Uniocular VAs Assess reading ability can identify
problems e.g. field loss, neglect, impaired eye movements
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Slide 19
Type of field loss dependent on location of stroke Can affect
patients in daily life activities and driving Many patients unaware
of field loss Right sided defects most common
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Incongruous right homonymous inferior quadrantinopia Bitemporal
hemianopia Complete Left visual field loss Binasal hemianopia Right
homonymous hemianopia with macular sparing Right homonymous
superior quadrantinopia Right homonymous hemianopia
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Homonymous hemianopia (most common) Stroke of middle cerebral
artery or posterior cerebral artery Affects optic radiations or
visual cortex Post stroke often homonymous and congruous Macula
sparing = occipital cortex Riddoch phenomenon: Complete homonymous
hemianopia to immobile objects but detection of moving objects
maintained.
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Can be associated with visual neglect Lesion optic radiation
damage usually in right hemisphere.
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Most disruptive and common visuo-spatial problem after right
sided stroke Ignoring everything in a particular region of space
More common in right sided stroke Limits rehab. Associated with
poor functional recovery Can affect all distances. Examples: - only
eating from one side of plate - shaving one side of the face - only
drawing half a picture Can be associated with visual field
defect
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Field DefectNeglect Make effort to achieve full pursuit
movements Poor and incomplete pursuit Searching saccades after
target disappears No effort to find target
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Albert test Neglect Lines missed on one side of the page. Tests
for neglect invikve cancellation, copying and drawing to prove that
patients miss half of the picture and or the text
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Balloon Test Test A look for and cross through 22 balloons
amongst 202 balloons and circles (targets popping out) Test B
finding and crossing through 10 circles within 3 minutes (serial
searching) Serial search more impaired than parallel search in
visual neglect Test B requires more attention missing more on test
B eliminates possibility of field defect
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Bilateral vision loss Damage to striate cortex Posterior
cerebral artery infarction due to embolism Not all patients
aware
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Charles Bonnet syndrome Lack of sensory impulses to visual
cortex Differentiate hallucinations from diplopia
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Cognitive Poor recognition No problems with vision and
perception 3 types: - Visual Object Agnosia - Prosopagnosia -
Colour Agnosia
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Ensure patient has correct glasses and wearing correct glasses
for viewing distance Ensure prescription up to date Re-refraction
may be necessary Low vision aid magnifiers etc Compensatory head
postures
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Coloured markers on one side of page Underlining text Typoscope
(strip of card with a section removed to imitate a window)
Following text with the finger Turning the page to read vertically
or upside down depending on type of field loss
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Fresnel prisms Place prism on half of lens on side of
hemianopia facing in direction of field defect: Base out prism on
left half of left lens in left sided hemianopia Displacing image in
missing area to one side to make patient aware of it Increase
scanning skills Prism adaptation training (Keane et al 2006) Visual
stimulation of the visual field border area (Bergsma and Van der
Wildt 2009)
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Scanning training Limb activated treatment Sustained attention
training Fresnel prisms base away from neglected side to encourage
patient to look in neglected area Monocular occlusion of eye on
side of lesion patient forced to look in neglected area of
vision
Slide 34
Visual Field Loss Following Stroke or Head Injury (BIOS)
Bergsma DP, Van Der Wildt G. Visual Training of Cerebral Blindness
Patients Gradually Enlarges the Visual Field. British Journal of
Ophthalmology 2010; 94: 88-96 Keane S, Turner C, Sherrington C,
Beard JR. Use of Fresnel Prism Glasses to Treat Stroke Patients
with Hemispatial Neglect. Archives of Physical Medical
Rehabilitation 2006; 87: 1668-1672 Lee AW, Daly A, Chen CS. Visual
Field Defects after Stroke. Australian Family Physician 2010;
39(7): 499-503 Macintosh C. Stroke re-visited: visual problems
following stroke and their effect on rehabilitation. British
Orthoptic Journal 2003; 60: 10 14 Op de Beeck H, Haushofer J,
Kanwisher NG. Interpreting fMRI data: maps, modules and dimensions.
Nature Reviews Neuroscience 2008; 9: 123-135 Townend BS, Sturm JW,
Petsoglou C, OLeary B, Whyte S, Crimmins D. Perimetric Homonymous
Visual Field Loss Post Stroke. Journal of Clinical Neuroscience
2007; 14(8): 754-756 www.RNIB.org.uk
