Dynamic features of standing and their correlation with neurological disorders.

Standing posture is a result of complex activity of the human control system. Irregularities of postural control may be expected to result in deviations from normal standing. In the present study a ballistic monitoring technique was employed to establish criteria for assessment of postural disorders. Two "Kistler" force plate dynamometers were used to measure changes in the weight bearing components of each foot and displacement of the center of pressure of each foot. The patterns were analysed separately, and it was found that each of the monitored parameters demonstrated three modes of oscillation--termed Tremor, Ataxia and Sway. Statistical analysis conducted on three groups of subjects (normals, post-C.V.A. hemiplegics and brain injured) revealed significant intergroup differences in movement patterns. Good agreement was found between the interpretation of the ballistic features and the clinical diagnosis.