6. VISUAL IMPAIRMENT WITH MOTOR IMPAIRMENT
Visual impairment caused by damage to the anterior visual pathways (eyes to lateral geniculate nucleus) may occur in children who also have impairment of movement. The cause of the motor impairment is often peripheral but it may be caused by brain damage which does not, however, involve visual function or attentive functions related to vision. Such children have two impairments but there is less cumulative effect in these cases than when both impairments are caused by brain damage (see Chapter 7).
Depending on the type of the motor impairment, the child's techniques in moving, in activities of daily life (ADL) and in sustained near vision tasks need to be modified to fit the motor abilities. On the other hand, in teaching compensation for the motor handicap, limitations in the use of vision must be kept in mind. For example, when using a wheel chair, the child's ability to see the environment to plan the route requires specific assessment of vision. A wheel chair user may need to investigate the route for a longer distance ahead by using a telescope than a visually impaired child who is able to walk.
A visually impaired child who does not have arms or has poor or no function in the arms has specific ergonomic needs and may need to learn to use feet instead. This causes an unusually long working distance for a visually impaired child. We are usually unaccustomed to design near working situations when the child uses toes to manipulate the computer or to bake and cook. One has to see it happen to believe that children can become highly skilled in the use of their feet instead of the hands. The long working distance requires either telescopic spectacles or closed circuit television or the camera coupled with a computer for seeing the keyboard. The picture of the keyboard can be in the lower or upper part of the screen and the text written by the child in the other part of the screen. The text is placed where it is easiest to read. The keyboard needs to be looked at because children's toe movements are seldom so exact that the child can write without visual control. Even those who use their fingers often have so poor control of movements that they must guide writing with constant visual feed- back. Use of synthetic speech to provide supporting information is often necessary.
Both for this group of children and for children whose motor impairment and vision impairment are caused by brain damage (Chapter 7) the development of optimal ergonomics is an important task for their physiotherapists/occupational therapists and teachers. There needs to be a wide range of adjustability in the tables and supporting devices. Also the difficulties in the use of vision should be considered when modifying them for a particular child.
Supporting devices for heads warrant serious consideration especially for progressive muscle diseases and for stable conditions where head control is a problem. Head support should be smoothly adjustable to allow fine-tuning of the head position when identifying the best position for looking at books or CCTV. Ideally it should be possible for the child to change the angle but this can become too expensive. Many children are irritated by the surface quality of the straps on their forehead so this detail also needs to be considered.
Land mine victims are a new problematic group of children with a combined loss of their extremities and vision. In most places where these children live, neither visual aids nor special educational aids are available and the children are dependent on auditory information for their learning (if they did not lose their hearing). If they come to schools with advanced technical aids, they can learn to use computer-aided writing with a modified key board or Morse code. Some of these children have lost much of their hearing in the explosion but may hear or feel the rhythm of the Morse code and may have enough function in one limb to move a modified Morse key. Some of them can bite the Morse key and use head movements for writing.
Morse code is a convenient way to communicate because in its simplest form it does not require any devices; it is possible to tap the code directly on the body of a person. This requires that persons communicating with the child are familiar with the Morse code. If a computer is available it can be used to translate the child's message in Morse code to printed text.
A child who has lost a considerable amount of vision and motor functions, possibly also has impaired hearing, is in a demanding situation. The background of normal visual and motor development prior to injury often seems to help them to develop ingenious techniques using the few motor functions that they still have left.