We performed motor tests (most rapid alternating movements [MRAMs] of index fingers and most rapid contractions [MRCs] of voluntary isometric index finger extensions) in HIV-positive patients with (group 1) and without (group 2) AZT treatment over a 6-month period. Whereas MRAMs remained uninfluenced, MRCs showed a clear improvement in the treated group and a decline in the nontreated group, according to the T helper cell counts. MRCs were not only a sensitive test procedure for detecting subclinical lesions in HIV-positive patients, but also a reliable therapy control measurement.