Performance of people with mild cognitive impairment or early Alzheimer's disease on the behavioural assessment of the dysexecutive syndrome test battery
Aim: Decline in executive functioning in Mild Cognitive Impairment has only been investigated with single tests to date. A battery of executive function tasks (BADS: Behavioural Assessment of the Dysexecutive Syndrome) was used to investigate and compare the extent of executive function difficulties in people with Mild Cognitive Impairment and early Alzheimer Disease. Degree and prevalence of decline were examined for each of the groups, and performance patterns compared between the two groups. Participants: 37 Participants (19 MCI, 18 early AD) were recruited from one urban, one suburban and one rural centre. Participants were selected on the basis of clinical judgments made by local psychiatrists, and for the MCI group checked against Petersen criteria (1999) as far as information was accessible to the main researcher. Probable Alzheimer's disease had been diagnosed either according to ICD- 10 criteria (centres I and 3) or NINCDS-ADRDA criteria (centre 2). Groups did not differ significantly on socio-demographic variables. Design: A mixed cross-sectional exploratory design was employed, examining performance on executive function tasks within each of two clinical groups separately, and comparing performance between the two clinical groups. Effects of confounding variables were examined, and subsequently effects of 'age' were controlled for. Main results: Both groups showed decline on executive functioning tasks, but this was mild in the MCI group compared to normative data, whereas significantly poorer performance was observed in the early AD group. Impairment was not ubiquitous in either group. Whereas patterns of performance across subtests were similar for both groups, performance levels for different subtests differed. Hence different tasks might be differentially suited to assess executive function deficits in each group.