Role of working memory components in planning performance of individuals with Parkinson's disease.

The current study investigated the involvement of all four components of Baddeley's [Baddeley, A. D. (2000). The episodic buffer: A new component of working memory? Trends in Cognitive Sciences, 4, 417-423] revised working memory model in deficits of planning accompanying Parkinson's disease (PD). PD resulted in poorer formulation and execution of plans, as measured by the Tower of London task. PD also reduced the efficiency of the episodic buffer and central executive components of working memory, but did not influence storage of verbal or visuospatial information. Planning deficits in PD were particularly linked to problems in integrating multimodal short-term information with long-term memory (episodic buffer). These results emphasize the importance of integrative and executive processing in cognitive problems in PD, rather than simple memory deficits.