Working memory in healthy aging and in Parkinson's disease: Evidence of interference effects

Focusing on the relevant information while suppressing the irrelevant one are two critical abilities necessary for complex cognitive processes such as reasoning, problem solving, and decision-making. Research on working memory (WM) refers to these top-down components as “executive attention” and “inhibition”, respectively. The present research aimed to study the functioning of these two WM components employing a new experimental paradigm. Furthermore, we also investigated if, and to what extent, these two components decline in healthy aging and are impaired in Parkinson’s disease (PD), two conditions in which WM deficits were always reported mainly through span measures. Three groups of healthy participants were tested: young adults, older adults, and elderly subjects. A group of PD patients under dopaminergic medication was also tested. Results show that the transient storing of an irrelevant information in WM causes interference effects on both response latency and response accuracy, and that these effects are remarkable in elderly individuals (over-70). Interestingly, results also show that PD patients had a better performance in terms of response latency and a normal performance in terms of accuracy, when tested with the new paradigm and compared with a matched control group. These findings suggest the existence of similar mechanisms for orienting of attention inwards to the contents of WM, or outwards to perceptually available stimuli. Furthermore, the results suggest that our new paradigm may represent a valid measure to highlight age-related decline in top-down WM components, and to evaluate different aspects of WM functioning in PD patients