Three Japanese patients with Joseph disease from different families developed sleep disturbance, followed by delirium at the middle to end stage. Brain CT scans of the three patients showed brainstem tegmental atrophy. EEG revealed slowing of background activity. Two necropsy cases showed degeneration of the reticular formation, raphe nuclei and locus ceruleus in the brainstem tegmentum in addition to the common pathological findings of Joseph disease. The clinicopathological correlation between the delirium and the brainstem tegmental atrophy in Joseph disease is discussed.