Visually directed reaching of children with motor impairments.

Impaired postural fixation affects the efficiency and flexibility of impending movements. 38 children aged between four and 11 years with abnormal postural fixation associated with slight neurological disturbances were studied, together with a matched control group, when reaching for a moving object. 298 reaches from each group were analysed by a technique which took into account the three-dimensional properties of the reaches. Acceleration profiles were analysed and used to divide reaches into movement elements. The aiming of those elements were calculated and compared with an optimal value. The test indicated the following: the relative lengths of approach paths was greater for the children in the clinical group than for the controls; the neurologically impaired children were less apt than the controls to increase the efficiency of their reaching patterns; but they took their less efficient motor performance into account when planning the reach and aimed further ahead of the target than the controls.