Table 1.

Comparison of clinical features of PDD, DLB, and AD.

Disease	Clinical features
PDD	Dementia appears after 1 year in the diagnosis of PD. Apathy, depression, and anxiety appear more commonly than in DLB patients.
DLB	Fluctuating cognitive dysfunction visual, hallucinations, and Parkinson's syndrome. It progresses faster than PDD, with irritability and unstable mood.
AD	AD behaves multiple cognitive domains disturbance mainly including memory, visual spatial ability, language, and executive function. The impairment of visual spatial ability and executive function was less than that of PD.

PDD: Parkinson's disease dementia; DLB: dementia with Lewy bodies; AD: Alzheimer's disease.