A patient with a variant of akinetic mutism had responded to Sinemet and had been maintained at a functional level on this medication. We report follow-up studies of his speech and language skills, blink rate, and cerebrospinal fluid amine metabolites while on Sinemet and following its withdrawal. On Sinemet, cerebrospinal dopamine metabolites were normal at 90 min postdose. Off Sinemet, the patient experienced no clinical deterioration and some improvement in his speech and language skills. Although the cerebrospinal dopamine metabolites fell to markedly subnormal levels, his blink rate remained abnormally high (85–100/min) for 5 weeks. An antibody to dopaminergic neurons was present in the cerebrospinal fluid. The data suggest that the patient had sustained damage to the substantia nigra, with a resultant deficit in endogenous dopamine production. Remodeling appears to have occurred in the striatal system despite Sinemet-induced normal levels of dopamine available for release by striatal neurons.