Visual hallucinations (VHs) are common in Lewy body disease (LBD) with dementia, including dementia with Lewy bodies and Parkinsons disease with dementia, while auditory hallucinations are quite rare.Recent neuropsychologicai studies on LBD have shown an association between visual cognitive impairments and VHs, and radionuclear studies have demonstrated decreased blood flow in the posterior lobe.These findings suggest that selective impairments in visual information processing functions contribute to the pathophysiology of VHs.