a1 University of Edinburgh Division of Psychiatry, The Royal Edinburgh Hospital, Edinburgh, UK
a2 University of Oxford Department of Psychiatry, Warneford Hospital, Oxford, UK
a3 University of Stirling Department of Psychology, University of Stirling, Stirling, UK
Background The dual task paradigm (Baddeley et al. 1986; Della Sala et al. 1995) has been proposed as a sensitive measure of Alzheimer's dementia, early in the disease process.
Method We 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.
Results There 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.
Conclusions The dual task paradigm lacks sensitivity for use in the early differential diagnosis of Alzheimer's disease.
(Received June 18 2007)
(Revised December 12 2007)
(Accepted February 28 2008)
(Online publication April 15 2008)