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Refraction and motor functions
Orientation and lenght of lines
Motion perception and VField
Picture perception&recognition
&
OUR GOAL
to understand each child’s
visual functioning
Children with CVI
OUR GOAL: to understand - the quality of the image - the use of information in higher visual
functions
- the role of vision in development and education
The effect of visual impairment varies in different tasks. Visual disability is task dependent.
Visual Impairment
affects four main areas:• Communication
• Orientation & movement
• ADL, daily living skills
• Sustained near vision tasks
Four-leafed clover ofVISION
Visual Impairment
Basic questions:How does vision affect this function?
How is vision going to affect development of this function?
Does the child have compensatory techniques? How do I teach them?
Visual Impairment
Basic questions:How does vision affect this function?How is vision loss going to affect
development of this function?Does the child have compensatory
techniques? How do I teach them?How do I help the child to develop compensatory techniques?
Refraction and motor functions
Orientation and lenght of lines
Motion perception and VField
Picture perception&recognition
Visual cortex V1 & V2
Visual cortex V1 & V2
Visual cortices
posterior parietal
inferotemporal
frontal eye-hand coordination
spatial awareness
recognition
CVI Often a part of larger brain damage >>
thus
Cerebral visual impairmentor
Brain damage related
visual impairment
Brain damage related VI
Caused by:
- lesions in visual pathways
- cortical lesions, visual and other
- subcortical lesions
- leads to uneven profile of visual functions, some good, some poor
important in assessment of children with intellectual disabilities
CVI - Behaviours
- VARIATION in visual behaviour
- effect of basic disorder
- effect of medication, wakefulness
- misunderstanding the functions
easy to us, difficult to the child
CVI - Behaviours
- VARIATION in visual behaviour
- speech as compensatory function
CVI - Behaviours
- VARIATION in visual behaviour
- speech as compensatory function
- plays with adults, not with children
CVI - Behaviours
- VARIATION in visual behaviour
- speech as compensatory function
- plays with adults, not with children
- clings to parents in crowded places
CVI - Behaviours
- VARIATION in visual behaviour
- speech as compensatory function
- plays with adults, not with children
- clings to parents in crowded places
- uses colours for recognition
CVI - Behaviours
- VARIATION in visual behaviour
- speech as compensatory function
- plays with adults, not with children
- clings to parents in crowded places
- uses colours for recognition
- may learn letters early, only short words
CVI - Behaviours
- VARIATION in visual behaviour
- speech as compensatory function
- plays with adults, not with children
- clings to parents in crowded places
- uses colours for recognition
- may learn letters early, only short words
- starts drawing late or never
CVI – Behaviours 2
- stops at thresholds and shadows
- depth perception
- perception of surface qualities
CVI – Behaviours 2
- stops at thresholds and shadows
- does not look at, ”avoids eye-contact”
CVI – Behaviours 2
- stops at thresholds and shadows
- does not look at, ”avoids eye-contact”
- peripheral vision better, central scotoma
CVI – Behaviours 2
- stops at thresholds and shadows
- does not look at, ”avoids eye-contact”
- peripheral vision better, central scotoma
- gets lost in familiar places
CVI – Behaviours 2
- stops at thresholds and shadows - does not look at, ”avoids eye-contact” - peripheral vision better, central scotoma - gets lost in familiar places - gets angry if objects are moved
CVI – Behaviours 2
- stops at thresholds and shadows - does not look at, ”avoids eye-contact” - peripheral vision better, central scotoma - gets lost in familiar places - gets angry if objects are moved
- uses siblings and adults for help
CVI
A list
of
typical behaviours
does NOT
help us to understand a child.
When a child has an unusual behaviour,
describing it is not enough.
When a child has an unusual behaviour,
describing it is not enough.
Try to find out WHY the child has that behaviour.
Consider other impairments.
Consider the situation.
Fixation & accommodation
Length & parallel lines
Angle & cross
Pen and spasticity
Parallel v. crossing lines
Eye-hand coordination
Cognitive visual functions Discrimination of orientation of lines
Discrimination of size/length of lines
Detection & discrimination of movement
Perception of texture, surface qualities
Object / background, Depth
Recognition of faces, expressions
Recognition of geometric forms
Perception of pictures
Spatial awareness, eye-hand coordination
CVI
Diagnose and therapy: - team, transdisciplinary - tests are used by everyone - observation - structured play situations - repeated assessment
Transdisciplinary Diagnose
In the assessment of children withbrain damage related vision loss: - ophtalmologist: anatomy, refraction
- teacher, therapist: observations, testing
- neurologist: dg, neurologic impairements
- neuropsychologist: cognitive vision video documentation
Assessment of functional vision
- basic information from the eye hospital
structure of the pathways, refraction,
glasses (under- or overcorrection?)
VA, VF, CS, CV, VAd, motor functions
Assessment of functional vision
- basic information from the eye hospital structure of the pathways, refraction, glasses (under- or overcorrection?) VA, VF, CS, CV, VAd, motor functions - testing of all visual functions in play and teaching situations, effect of other impairments and disorders
Transdisciplinary assessment
School assistant
Assessment of functional vision
- basic information from the eye hospital structure of the pathways, refraction, glasses (under- or overcorrection?) VA, VF, CS, CV, motor functions - testing of all visual functions in play and teaching situations, other impairments
- effect of posture and facilitation in children with severe motor problems
Influencing factors
Four children
• Prematurely born girl with problems in recognition of faces + other impairments
• Boy with severe CP, poor head control and poor oculomotor functions, good VA, CS,VF
• Girl with extreme hypotonia, insufficient accommodation, slow hand movements
• Boy with deletion syndrome, central scotoma, hearing problems, delayed development
Recognition of faces
Re-cognition:
- the facial features are seen
- a template is formed in memory
- the face is seen again
- template is found and matched
Periventricular leukomalasiaNext to ventricle loss of white matter
PVL
Matching pictures
Recognising pictures of faces
Photophobiadue to optic atrophy
Glasses are tested both outside and inside
Photographic memory
Severe hypotoniano functions without good support
Spatial conceptseye-hand coordination good when supported
Correction of reading distanceaccommodation insufficiency
Early developmental level
Strabismus
Testing in play situations
Findings• A rare deletion in chromosome 2• MRI not yet possible, anesthesia dangerous• Optic discs greyish; hearing =? CAI?• Good orientation in space, explores• Reaches for and grasps• Notices grey on grey• Strabismus LE, does not seem to alternate• Seems to fixate at hair line > central scotoma• RE –3.0, LE –5.0 - -6.0 without cycloplegia• Vision for communication in lecture V.
Four children
• Prematurely born girl with problems in recognition of faces + other impairments
• Boy with severe CP, poor head control and poor oculomotor functions, good VA, CS,VF
• Girl with extreme hypotonia, insufficient accommodation, slow hand movements
• Boy with deletion syndrome, central scotoma, hearing problems, delayed development
Severe multihandicap
• Highly individual• Difficult to assess, formal tests may not function
- detection tests do not measure form perception
• Pleasure of seeing may be lacking- no drive to look, learning through vision does not occur
• Directing attention; comprehension; memory• No prior confirmation with mouth and hands• The child may be blind; hearing/ tactile/ haptic
- Try with very high contrast visuo-tactile toys, not too long.
”Levels” of CVI
• There are no general ”levels” of CVI• Each cognitive visual function needs to be
assessed individually
”Levels” of CVI
• Each cognitive visual function needs to be assessed individually
• We do not assess all functions during the first examination, repeated assessments needed
”Levels” of CVI
• Each cognitive visual function needs to be assessed individually
• We do not assess all functions during the first examination, repeated assessments needed
• Accept variation in results in CVI, try to find out the causes of variation
”Levels” of CVI
• Each cognitive visual function needs to be assessed individually
• We do not assess all functions during the first examination, repeated assessments needed
• Accept variation in results in CVI, try to find out the causes of variation
• Train to improve weak functions, find compensatory strategies, build on strong functions.
”Levels” of CVI• Each cognitive visual function needs to be assessed
individually• Do not believe that you have assessed all functions during
the first examination• Accept variation in results as a norm in CVI, try to find the
causes of variation• Train to improve weak functions, find compensatory
strategies, build on strong functions
• Never generalise, children with CVI are highly individual in their functions and experiences. Consider other impairments.
• Consider techniques of blind people.
CVI
• Impaired cognitive vision is most often part of brain damage related visual impairment that involves also motor functions and/or hearing.
• When CVI occurs without other neurologic problems, it is often wrongly diagnosed as ”autistic features” or the child is said to see ”when (s)he wants to see”.
OUR GOAL
to understand each child’s
visual functioning
Four-leafed clover ofVISION
Visual Impairment
Basic questions:How does vision affect this function?How is vision going to affect
development of this function?Does the child have compensatory
techniques? How do I teach them?How do I help the child to develop compensatory techniques?
Vision for Special Education
- consider ALL areas of functioning at preschool and school age
not only
- vision for academic subjects
Vision
is
a learned function
Learning to see
Hands (to midline and into mouth)
Mouth (a reliable source of information)
Tactile information, tasting, smell Vision (confirmed by other modalties)
Multimodal memory Recognition
Finding hands
Because
vision
is
a learned function
start early intervention early!
CVICerebral visual impairment
Brain damage related visual impairment