Page 107 - Handbook of Electronic Assistive Technology

94 HANDBOOK OF ELECTRONIC ASSISTIVE TECHNOLOGY

Crossing midline: The ability to move hands from one side of the body across a line
running from a child’s nose to the pelvis that divides the body into left and right sides.
Hand and finger strength: An ability to exert force against resistance using the hands
and fingers that allows the necessary muscle power for controlled movement.
Hand/eye coordination: The ability to process information received from the eyes to
control, guide and direct the hands in the performance of a task such as handwriting.
Hand dominance: The consistent use of one (usually the same) hand for task
performance, which allows refined skills to develop.
Hand division: Using just the thumb, index and middle finger for manipulation.
Object manipulation: The facility to skilfully manipulate tools such as the ability
to hold and move pencils, handle scissors with control and the controlled use of
everyday tools such as a toothbrush, hairbrush and cutlery.
Body awareness (proprioception): This ability enables us to know where our limbs are
in space without having to look.

What is also important to observe is the ‘quality’ of the movement. The statement ‘cli-
ent can lift and lower their head’ or detail of the degrees of movement achievable is mean-
ingless if it takes prompting (i.e., physical or verbal from another) to achieve this or if it
takes significant time for the person to respond to the request to raise or lower their head.

Sensory Skills

Vision and Hearing. There is a whole range of sensory aids (vision and hearing, electronic
and otherwise) which is outside the remit of this book. However, for the types of technol-
ogy included, knowledge of the client’s vision and hearing is of specific interest.
Understanding what the client can see may be difficult. Ophthalmology reports give
insight; however, if a client has multiple complex disabilities establishing what they can
see may not be accurately defined. Where this becomes even more complex is when the
problem is not purely physiological, for example, in the case of cerebral vision impairment.
Here we may be left to rely on others’ interpretation of functional vision. Observation of
the client in different settings can help to determine what is the primary sense used. For
example, noting whether they are most responsive when a person enters the room or only
when someone speaks.
Information about visual acuity (Snellen tests) report on how well detail is seen with
central vision. This will impact on the size of a target that a client can see on a screen and
so may limit the number of symbols/options that can be available at one time, impact on
the size of screen required and limit where the device needs to be mounted.
Knowing whether the client can visually scan and track is also important, i.e., whether
they can move their gaze easily from one image to the next across a screen when looking
at a set of options presented to them. Also, whether they can track and follow a mov-
ing target is important when considering powered mobility control and following cursor
movement.