[Chronic dementia in Parkinson disease treated by long-term administration of anticholinergic drug--evaluation of neuropsychological test, PET, and SPECT].

It is known that the anticholinergic drug causes acute psychosis and memory disturbance, which may be due to cholinergic dysfunction. But it has not been well described that the anticholinergic drug causes chronic dementia after long administration. We describe six cases of chronic dementia, which is thought to be induced by anticholinergic drug. We conducted detailed neuropsychological and neuroradiological examination in these six cases. All of them were Parkinson's disease, and had used anticholinergic drug for more than six months without any side effect, and then their initial symptom of dementia appeared, followed by chronic dementia. All cases recovered reversibly from dementia within a few weeks after stoppage of taking anticholinergic drug. And any of our cases had no possibility in the cause of chronic dementia other than the side effect of anticholinergic drug. Detailed neuropsychological examinations (WAIS, WMSR, and so on) were conducted in all cases, SPECT was in two cases, and PET was in one case, before and after stoppage of the anticholinergic drug. And in all cases, brain MRI was conducted. The indices of attention, verbal memory, visual memory, and delayed recall were significantly elevated after stoppage of drug. And both verbal IQ and performance IQ were increased after stoppage of drug, too. SPECT and PET revealed significant improvement, which showed diffuse and generalized change, not localized change.