Donepezil in parkinson hallucinosis and in atypical parkinsonisms

Background: Involvement of cholinergic pathways may explain visual hallucinations in patients with Parkinson's disease (PD) and diffuse lewy body disease (DLBD), and may account for cognitive dysfunctions characterizing these disorders and progressive supranuclear palsy (PSP). Methods: We studied the effects of 3 months of therapy with donepezil (5 mg/day) on cognition, hallucinosis, and extrapyramidal symptoms in 5 patients with PD and hallucinosis, 5 patients with DLBD and in 5 patients with PSP, following an open design and using specific rating scales (UPDRS, Parkinson psychosis rating scale, GDS, caregiver assessment, MMSE, and cognitive tests for frontal disturbances). Results: No changes in cognition, burden for caregivers and severity of extrapyramidal symptoms were observed in patients with PSP. Visual hallucinosis improved in DLBD with no changes in severity of extrapyramidal symptoms. In 3 out of 5 PD patients donepezil induced an improvement in visual hallucinations, but in 2 of them motor symptoms significantly worsened. Conclusions: Central acting acetylcholinesterase inhibitors may be useful in the treatment of visual hallucinations in DLBD and PD. However, a careful follow-up of PD patients is mandatory given the possibility of a decisive worsening of motor symptoms. Further studies are needed to evaluate the usefulness of these drugs in PSP.