Cerebral Visual Impairment - Lisa Flashcards
What is does CVI stand for ?
Cerebral visual impairment (also known as cortical visual impairment)
What do we test in clinics?
primary visual systems
What is CVI?
Occipital lobe damage
(Technical definition is visual dysfunction that cannot be attributed to disorders of anterior visual pathways or co-occurring ocular impairment)
Name some possible aetiologies of CVI
- hypoxic ishameic encephalopathy (HIE)
- pentriventricular leucomalacia (PVL)
- Traumatic brain injury
- Congenital anomalies
- Neurodevelopmental anomalies
- Idiopathic
- Meningitis
- TIA
- Shunted hydrocephalus
What is hypoxic ishameic encephalopathy (HIE)?
white matter damage Due to birth trauma
What is pentriventricular leucomalacia?(PVL)
white matter damage Due to prematurity
What is HIE and PVL both caused by?
Deprivation of blood and oxygen during birth
What an HIE and PVL lead to? (There are 6)
- Cerebral palsy
- Epilepsy
- Developmental delay
- Learning disabilities
- Motor disorder
- Speech disorders
Why is it difficult to predict symptoms and signs from an MRI scan of an child with CVI?
Due to neuroplasticity
What is neuroplasticity?
The brain creates new neural pathways and modifies existing ones in response to behavioral, environmental, and neural changes
Will an adult who has acquired CVI have more specific signs and symptoms?
YES
What is an example of an acquired way of getting CVI?
TIA
Have you watched Alfies’ video from the lecture?
No? Go watch it , it will help you understand what people with CVI can see/ cant see
What are 9 RF of CVI?
- Cerebral palsy
- Learning disability
- Low blood sugar after brith
-Premature birth - Traumatic birth
- Epilepsy
-Developmental delay - Motor disorders
- Speech disorders
If a child is born before 34 weeks, what % are likely to have a visual processing disorder?
> 30%
What % of children with cerebral palsy will have a visual processing disorder?
50%
What are 7 co-existing ocular conditions with CVI?
- Refractive error
- Squint & amb
- Nystagmus
- Cataract
- Glaucoma
- retinitis pigmentosa
- Keratoconous
Is it possible to recognise someones face when they are moving but not when they are static?
Yes- if there is damage to only the posterior occipital lobes only (green not red)
Which part of the brain stores our visual memories?
Temporal lobes (blue bit)
What part of the brain is responsible for motion planning and attention ?
Posterior parietal lobe (brown bit)
Which part of the brain is responsible for hand/eye coordination or if they are able to do direct visual guided movements?
Posterior parietal lobe (pink bit)
Which part of the brain is responsible for hand/eye coordination or if they are able to do direct visual guided movements?
Posterior parietal lobe (pink bit)
What is the bottom of the frontal lobes responsible for?
Executive planning for making choices
What does the motor cortex do?
Drives movement of the body and the frontal areas which drive fast movement of head and eyes
What is the ventral stream responsible for ?
Image storage and recognition system- conscious
What is the dorsal stream responsible for ?
Visual guidance, search and attentional system- unconscious
Does ventral or dorsal stream damage occur more frequently?
Dorsal
Should someone who is SSI have an eye test?
Of course! You need to check IOPs and everything to make sure it is still healthy (may show underlying issues)
What is the main intervention for CVI?
Refractive error intervention - you still want to stimulate the back of the eye even though they may not necessarily understand it due to occipital lobe damage
Can children with CVI be plano?
YES!
As there may be oculomotor abnormalities, what else tests should you do?
Saccades and smooth pursuits
(as they are not processing properly, they have not learned to control their eye movements well)
What may you see with a child with oculomotor abnormalities?
Nystagmus, inaccurate saccades, poor or absent pursuits
What VF defect is common with CVI?
Homonymous hemianopia
Can someone with CVI have colour vision issues and stereopsis issues?
Yes- their vision may be Plano but they may struggle with colour vision as they cannot communicate what they can see properly
What would someone with dorsal stream damage struggle to do?
Give attention to components in a crowded scene and use vision to guide movement
What would someone with ventral stream damage struggle to do?
Recognition of what is being looked at and recognition for route finding
If you have done your eye test and everything is healthy but you still think there is a problem with vision, what should you do?
Ask questions such as :
- Does this child recognise faces without making sounds (no auditory clues)
- Are they able to find a high contrast target with their eyes and follow it
- Do they have difficulty judging depth and distance?
- Do they have difficulty navigating familiar faces?
- Can they spot someone is a crowded scene ?
What test might help you detects whether a child is able to find a high contrast target with their eyes and follow it?
Bradford Visual Function box
Will you able to assess a child’s visual function in one sight test?
No- it is dependent on child’s behaviour and may alter depending on tiredness + may involve parents or teaching staff to be observing a child
Will you able to assess a child’s visual function in one sight test?
No- it is dependent on child’s behaviour and may alter depending on tiredness + may involve parents or teaching staff to be observing a child
How do we screen for CVI?
Using Gordon Button’s 5 screening questions
Using Gordon Button’s 5 screening questions, at what point would further investigation be required?
> 3 QStack are always/ often
Just for you’re info this is what Gordon’s buttons CVI questionnaire looks like
What are some day to day issues a child with CVI May face?
- Cannot reach out to pick up something
- Accessing information such as pictures or a letter box
- Walking confidently
- Recognising faces
- Understanding facial expressions
- Seeing a hand
If a px had dorsal stream impaired search would they able to look and listen simultaneously?
Probably not (so do not say look at me when i am talking to you)
What is simulanagnosia?
Only can describe objects without being able to perceive it
E.g they would not be able to say house , they would describe it as something we live in
What is optic ataxia?
They cannot use visuospatial information for guided arm movements
What is apraxia ?
Cannot produce accurate movements
How can you as an optometrist help someone with CVI?
Correct refractive error
What are the three B’s for visual impairment?
Bigger, bolder and brighter
What can a parent do to help their child with CVI in relation to clutter?
Keeping their house tidy and free of clutter so they do not get over stimulated by too much crowding + keeping things in the same place
Hemianopia is common with children with CVI, what advice could you give?
- CHP
- Supporters positioned standing to the side
- Training in scanning info
- Information displaced to the side
(Basc positioning everything to the sighted side)
What advice could you give to someone with lower VF loss? (4 things)
- Keep floors clear
- If you are helping them walk, hold their arm slightly backwards for height changes
- Chin in tilt
- Raised near objects
What are 7 dorsal stream dysfunction support strategies?
- Good storage
- Reduce clutter
- Minimise decor
- Not too much on a page + separation of words
- Serif font
- Limit distractions
- Wait for 8
What does wait for 8 mean?
Giving 8 seconds for them to process information
What kind of background would help a someone with CVI?
Calm quiet surroundings
What two things in particular would someone with ventral stream dysfunction struggles with?
Recognising objects and recognising faces
Why is ventral stream dysfunction less common?
It is more protected
What kind of saccades are 50% of Autistic people known to have?
Hypometric slow saccades
What is cortical blindness?
loss of vision without any ophthalmological causes
Can a person with cortical blindness move around a room with obstacles everywhere?
Yes because they are subconsciously aware but not consciously aware if them
Have a look at seeability website if you want some more info
Gogogogoogogo if u what
Why is TIA and HIE diffrent?
Neuroplasisity.
