Dual task performance in early Alzheimer's disease, amnestic mild cognitive impairment and depression

Abstract

BackgroundThe dual task paradigm (Baddeleyet al.1986; Della Salaet al.1995) has been proposed as a sensitive measure of Alzheimer's dementia, early in the disease process.MethodWe investigated this claim by administering the modified dual task paradigm (utilising a pencil-and-paper version of a tracking task) to 33 patients with amnestic mild cognitive impairment (aMCI) and 10 with very early Alzheimer's disease, as well as 21 healthy elderly subjects and 17 controls with depressive symptoms. All groups were closely matched for age and pre-morbid intellectual ability.ResultsThere were no group differences in dual task performance, despite poor performance in episodic memory tests of the aMCI and early Alzheimer's disease groups. In contrast, the Alzheimer patients were specifically impaired in the trail-making test B, another commonly used test of divided attention.ConclusionsThe dual task paradigm lacks sensitivity for use in the early differential diagnosis of Alzheimer's disease.