Concomitants of visual hallucinations in Alzheimer's disease

Visual hallucinations (VH) are the most common hallucinations in Alzheimer's disease (AD), but their relationships with other behavioral symptoms and measures of cognitive performance are unclear. Using the BE-HAVE/AD, a semistructured behavioral inventory, we identified 20/160 AD patients (13%) who were currently having VH. Patients with VH performed worse on the Mini-Mental State Examination and had more behavioral symptoms than patients without VH. Symptoms particularly associated with VH included auditory hallucinations, verbal outbursts, delusions, and paranoid ideation. Principal factor analysis of the BEHAVE/AD yielded four factors accounting for 47% of the total variance. VH loaded on two factors involving symptoms of "paranoia" and "agitation/hallucinations." Our findings suggest that VH in AD patients are common, often occur in the presence of specific behavioral disturbances, and may have management implications.