EFFECT OF UNILATERAL SENSORY IMPAIRMENT OF THE SOLE OF THE FOOT ON POSTURAL CONTROL IN MAN - IMPLICATIONS FOR THE ROLE OF MECHANORECEPTION IN POSTURAL CONTROL

Body sway was measured in normal subjects and in patients with impaired mechanical sensitivity in limited areas of one or the other sole due to microvascular free flap reconstruction for a traumatic defect. This approach was used for evaluating the role of mechanoreception of the soles in postural control, and for determining the extent to which the sensitivity decrement affected the ability of these patients to control their posture. Mechanical sensibility was determined with vibratory stimuli of different frequencies which preferentially activate receptors of different types in the skin. Body sway was measured with a force platform technique with the eyes open and also closed. In both controls and patients the total extent of sway was larger when the eyes were kept closed. With the eyes open, the patients showed a normal extent of sway, but with the eves closed the sway increased more than in the controls. The amount of sway increased both with the severity of the sensory impairment, and with the size of the affected skin region.