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


METHODS
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.
Lonie
J A
JA
University of Edinburgh Division of Psychiatry, The Royal Edinburgh Hospital, Edinburgh, UK.
Tierney
K M
KM
Herrmann
L L
LL
Donaghey
C
C
O'Carroll
R E
RE
Lee
A
A
Ebmeier
K P
KP
D000368:Aged; D000544:Alzheimer Disease / Q000150:complications / Q000175:diagnosis / Q000523:psychology*; D000648:Amnesia, Retrograde / Q000150:complications / Q000523:psychology*; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000150:complications / Q000523:psychology*; D003866:Depressive Disorder / Q000150:complications / Q000523:psychology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D013647:Task Performance and Analysis; D014145:Trail Making Test / Q000706:statistics & numerical data