Transcript CVI-Dr Lea
Orientation and lenght of lines Refraction and motor functions 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 of VISION 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? Orientation and lenght of lines Refraction and motor functions Motion perception and VField Picture perception&recognition Visual cortex V1 & V2 Visual cortex V1 & V2 Visual cortices posterior parietal eye-hand coordination spatial awareness frontal recognition inferotemporal CVI Often a part of larger brain damage >> thus Cerebral visual impairment or 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 with brain 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 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 leukomalasia Next to ventricle loss of white matter PVL Matching pictures Recognising pictures of faces Photophobia due to optic atrophy Glasses are tested both outside and inside Photographic memory Severe hypotonia no functions without good support Spatial concepts eye-hand coordination good when supported Correction of reading distance accommodation 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 of VISION 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! CVI Cerebral visual impairment Brain damage related visual impairment