Working memory profiles of patients with multiple sclerosis: Where does the impairment lie?

Introduction: Previous studies have mostly provided general estimations regarding Working Memory impairment in patients with Multiple Sclerosis. The aim of the present study was to investigate the relative degree of impairment in the four Working Memory components in Multiple Sclerosis. Method: Thirty-eight patients diagnosed with MS and 27 matched controls were assessed using 12 different cognitive tasks of the four components, i.e. phonological loop, visuospatial sketchpad, central executive and episodic buffer. More precisely, Greek translated and adapted versions of the following tasks were administered: Digit recall, Word recall, Non-word recall, Block recall, Mazes recall, Visual Patterns recall, Backward Digit recall, Backward Block recall, Listening recall, Logical Memory I-Immediate Story recall and Greek Verbal Learning Test, which is based on the California Verbal Learning Test. Results: The phonological loop, the central executive and the spatial subcomponent of the visuospatial sketchpad were found to be equally disrupted in MS patients. The episodic buffer was found to be more heavily affected. On the other hand, the visual subcomponent of the visuospatial sketchpad proved to be preserved. Conclusions: WM subcomponents are differentially affected in patients with MS. This novel finding is discussed within the framework of existing knowledge regarding WM impairment in MS.