Working memory in medicated patients with Parkinson's disease: the central executive seems to work.

OBJECTIVE: To determine whether a deficit of the central executive can explain the attentional deficits of patients with Parkinson's disease. METHODS: Fifteen patients with idiopathic Parkinson's disease and 15 controls were given a dual task paradigm minimising motor demands and combining verbal, visual, or spatial span with two conditions of articulatory suppression. RESULTS: Although the spans were systematically lower in medicated parkinsonian patients than in controls, suggesting a decrease of central processing resources, there was no direct evidence for a deficit of the central executive. CONCLUSIONS: A deficit of the central executive either is not an inevitable feature of the disease, or is dependent on the nature of task (visuomotor v cognitive), or is corrected by dopaminergic medication.