FORCE REGULATION IS DEFICIENT IN PATIENTS WITH PARIETAL LESIONS - A SYSTEM-ANALYTIC APPROACH

By means of a quantitative system-analytic investigation strategy, the postural motor control of the fingers was evaluated, to characterise the possible deficit of force regulation in patients with parietal les ions. In spite of a normal response to short torque pulses, the pariet al-lesion patients had difficulties in returning to the preload level after the application of an additional step torque load to fingers II- IV of their left or right hands. The control offset (measured 500 ms a fter step torque application) was significantly larger in the patient group. This deficit in the investigated patients with parietal lesions to compensate for step torque loads was not due to a paresis, but rat her resulted from a disturbance in the generation of a sufficient coun terforce against the applied step torque within an adequate time windo w and motor pattern. This distinct force-regulation deficit was found in patients with left- and right-sided parietal lesions. (C) 1998 Else vier Science Ireland Ltd. All rights reserved.