Visual perceptual difficulties in hemiplegia

Pat Kennedy is a Paediatric Occupational Therapist with a special interest in visual perceptual difficulties and particular insight into the problems experienced by children and young people with hemiplegia. Here she talks about the visual perceptual problems that children with hemiplegia may experience.

Organising information in the brain

All of our brains are responsible for organising information that enters them. The development of visual perception relates to how the brain organises material that enters it specifically through the eyes. The visual cortex, located at the back of the brain, must decide what to respond to and how to make sense of the information very quickly.

There are two stages: Stage 1 is the organisation of incoming information and Stage 2 relates that information to things the brain has already experienced.

The visual field and hemianopia

Although most children have their visual acuity (what they can directly see) and ability to read from a chart assessed, most do not have their visual field (what they can see around them) tested.

A visual field defect may mean a child cannot see what happens on one or both sides of them. Hemianopia, the loss of half the visual field, can affect the skills required for reading when letters need to be scanned across to make words and sentences. For example, a child with left hemianopia will lose the beginning of every word and a child with right hemianopia will lose the end of every word.

Deciding what to discard

People make cognitive maps all the time to decide what visual information to keep and what to discard; otherwise they would overload the brain. Children and young people with hemiplegia seem to have difficulty deciding what to keep or discard.

Sometimes they attend to minute peripheral details, i.e., fail to discard irrelevant information, and then miss the main points. Some children and young people with hemiplegia may experience visual neglect, which can cause them to ignore what happens on the affected side, unless they use another means of drawing attention to it. They may also stumble easily and be less prepared for movement.

Making things easier

What becomes clear from this, albeit brief, introduction to the mechanics of visual perception is that perceptual problems can lead to emotional problems, because children tend to avoid the things they cannot do.

However, there are ways of making tasks easier. For example, clipboards are better than 'Blu-Tac' for holding paper because the position of the page can be changed, allowing the child to make the 'work' work for them. There are also computer programmes to help with sequencing work and to train the eye to track a moving object.

Fundamentally disorganised

Many children and young people with hemiplegia with visual perceptual problems are fundamentally disorganised. For example, they can do picture matching but are spatially disorganised so that puzzles, whether in a frame or not, are often virtually impossible for them to do. (There are several tests that occupational therapists and psychologists use to discover the extent and type of spatial difficulties).

Constantly thinking

Teachers and parents need to be aware how tiring problem-solving is for children and young people with hemiplegia. Indeed some children may need to start from scratch ever single time they encounter the same problem. children and young people with hemiplegia constantly need to think about what they are doing and how they are going to do it.

Practical solutions in the classroom

• sitting square on to the board or face to face, not having to turn to attend to visual and verbal stimuli
• computer screens should be at eye level
• for writing instruction and other practical organisational learning, the teacher/LSA should sit alongside the child to enable them to have the same angle of vision.
• for children who are visually inattentive, it is helpful to work face to face so that the child can see facial expressions, check eye gaze and eye movements.
• display boards should be in the child's direct line of vision with the minimum opportunity for distraction, or adjusted for the child's restricted vision/field defects.
• in group work, the child should be seated in the front or the middle of the group.
• ensure that the child has enough space on the desk or tabletop to work effectively (don't seat a left hander next to a right hander and vice versa)
• pre-schoolers learn to write better on a well-stabilised vertical surface. Later on an angled surface might be better.
• surfaces need a clear background for writing drawing etc. White boards are better than black or green.
• plain tabletops might be more effective covered in off-white paper.

Problems with maths

Children and young people with hemiplegia often cannot plot corners to make a square and find spacing/drawing of lines hard.

Also peculiar to maths are problems in early arithmetic,

e.g. 1+2=3 (set out horizontally) is a verbal skill, whereas

14
+16

(set out in columns) is a visual spatial skill, requiring the ability to carry numbers across the columns.

Making maths and science easier

• with younger children use sticky labels to construct bar charts
• when comparing blocks or bar charts, lining up etc use a line drawn on an acetate to divide blocks
• use a black fineliner pen for stencils and maths drawings as it gives a clearer outline.
• at 16+ young people should be allowed to use photocopies for scientific drawings, rather than attempt them freehand.