Recognition memory impairment in Parkinson's disease: Power and meta-analyses

Contrary findings notwithstanding, the prevailing notion is that recognitio n memory is little affected by Parkinson's disease (PD). Both a power analy sis and a meta-analysis were conducted to help clarify the degree of recogn ition memory deficit associated with PD. The power analysis confirmed that, in general, memory studies of PD participants have been underpowered. This analysis indicated the need to pool study results in a subsequent meta-ana lysis, the main finding of which was that recognition memory deficits do oc cur with PD. The largest deficit occurs in PD participants with dementia. N evertheless, deficits also occur in PD participants without dementia on med ication, but nondopaminergic central nervous system abnormalities are more likely to underlie this deficit than PD medication itself. Future developme nt of a theory of cognitive dysfunction in PD should take into account thes e recognition memory deficits, which may increase with disease progression.