Magnetic stimulation of motor cortex in relation to fastest voluntary motor activity in neurologically asymptomatic HIV-positive patients.

Forty-two HIV-positive patients of various CDC stages without clinically evident neurological deficits were examined with transcranial magnetoelectrical stimulation (TMS). Cortical as well as cervical and lumbar root stimulation was performed after excluding peripheral neuropathies in comparison to an age- and sex-matched control group. Whereas central conduction times were normal, conduction between cervical or lumbar roots and muscle was prolonged. Results were correlated to those of a motor test battery, which revealed slowing of fast alternating movements similar to findings in extrapyramidal disorders. Data indicate that proximal parts of the peripheral nervous system and extrapyramidal structures are subclinically involved in early HIV infection whereas the fastest corticospinal projections remain intact.