Awakenings from persistent vegetative state: report of three cases with parkinsonism and brain stem lesions on MRI.

Three patients with a persistent vegetative state after severe head injury are reported. They recovered from a prolonged disturbance of consciousness after the administration of levodopa. These patients all had parkinsonian features. On magnetic resonance imaging, the distribution of lesions implied a diffuse axonal injury involving the substantia nigra or ventral tegmental area. The existence of patients whose dopaminergic systems may have been selectively damaged by a severe head injury should be recognised because such individuals may respond to levodopa treatment.