Force matching by patients with unilateral focal cerebral lesions.

The performance of patients with unilateral frontal-, temporal- or fronto-temporal excisions was examined on an isometric force-matching task involving the coordination of forces generated by flexing the fingers. Patients with excisions from the right fronto-temporal cortex were significantly slower with both hands when performing this task using either two or three fingers, whereas the other patient groups tested were not impaired. This deficit in force coordination may result from an impairment in monitoring proprioceptive feedback or an inefficiency in programming the appropriate amount of force output.