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Abstract
Damage to the hemispheric white matter is observed both in multiple sclerosis (MS) and normal aging, causing neuropsychological deficits in tasks of executive function, working memory (WM), and speed of information processing (SPEED). In this study two main hypotheses were investigated: (a) that SPEED may constitute a determining factor of WM impairment in MS patients and in aging individuals; (b) that self-reported depressive symptoms may aggravate cognitive deficits in MS patients. The study investigated 31 elderly MS patients without depression, 36 depressed ones, 108 demographically comparable controls and 100 community recruited senior participants. Performance of the groups was compared on a self-report measure of depression and on a WM test battery. Results showed that WM performance depends on SPEED, depressive symptoms, age, and schooling - variables which interact in complex ways.