Peduncular hallucinations in brainstem encephalitis drawn by a patient.

A 74-year-old man presented with acute cerebellar ataxia, ophthalmoplegia, left facial dysesthesia and weakness, dysarthria, dysphasia, and hyperreflexia. Episodic evening hallucinations occurred, triggered by eye closing, and lasted minutes; they were unaccompanied by paranoia, delusions, or REM sleep behavior disorder. We diagnosed brainstem encephalitis, apparently immune-mediated because IV immunoglobulin and corticosteroid therapy improved his symptoms. MRI excluded infection, tumor, or infarction of brainstem; the CSF was normal except for protein of 59 mg/dL. After recovery, he sketched vivid, colorful pictures (figure) of the hallucinations. Peduncular hallucinations are vivid, with colorful people, animals, or scenes, triggered by eye closure without disturbance of consciousness or psychotic symptoms,1 as in this case.