Apomorphine and levodopa challenge in patients with a focal midbrain lesion

Three patients who presented with parkinsonian signs resulting from a focal midbrain lesion are reported. In all patients parkinsonian features occurr ed acutely and improved following acute challenge with apomorphine but not with levodopa. Remission of parkinsonian signs occurred spontaneously to a different degree. Inconsistent clinical response following administration o f levodopa has been well documented in patients with focal midbrain lesions associated with parkinsonian signs; however, the efficacy of apomorphine h as not been tested before. Anatomic or etiologic features do not allow us t o predict in which cases parkinsonian signs secondary to a midbrain lesion would respond to levodopa or to dopamine agonists. A trial with apomorphine is warranted in all such cases.