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Open Access Research article

Clinical utility of the cogstate brief battery in identifying cognitive impairment in mild cognitive impairment and Alzheimer’s disease

Paul Maruff12*, Yen Ying Lim1, David Darby1, Kathryn A Ellis134, Robert H Pietrzak5, Peter J Snyder6, Ashley I Bush1, Cassandra Szoeke147, Adrian Schembri2, David Ames34, Colin L Masters1 and for the AIBL Research Group

Author Affiliations

1 The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia

2 CogState Ltd., Melbourne, Victoria, Australia

3 Academic Unit for Psychiatry of Old Age, Department of Psychiatry, The University of Melbourne, Kew, Victoria, Australia

4 National Ageing Research Institute, Parkville, Victoria, Australia

5 Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA

6 Lifespan Hospital System & Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI, USA

7 CSIRO Preventative Health Flagship, Parkville, Victoria, Australia

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BMC Psychology 2013, 1:30  doi:10.1186/2050-7283-1-30

Published: 23 December 2013

Abstract

Background

Previous studies have demonstrated the utility and sensitivity of the CogState Brief Battery (CBB) in detecting cognitive impairment in Alzheimer’s disease (AD) and mild cognitive impairment (MCI) and in assessing cognitive changes in the preclinical stages of AD. Thus, the CBB may be a useful screening tool to assist in the management of cognitive function in clinical settings. In this study, we aimed to determine the utility of the CBB in identifying the nature and magnitude of cognitive impairments in MCI and AD.

Methods

Healthy adults (n = 653) adults with amnestic MCI (n = 107), and adults with AD (n = 44) who completed the CBB participated in this study. Composite Psychomotor/Attention and Learning/Working Memory scores were computed from the individual CBB tests. Differences in composite scores were then examined between the three groups; and sensitivity and specificity analyses were conducted to determine cut scores for the composite scores that were optimal in identifying MCI- and AD-related cognitive impairment.

Results

Large magnitude impairments in MCI (g = 2.2) and AD (g = 3.3) were identified for the learning/working memory composite, and smaller impairments were observed for the attention/psychomotor composite (g’s = 0.5 and 1, respectively). The cut-score associated with optimal sensitivity and specificity in identifying MCI-related cognitive impairment on the learning/working memory composite was -1SD, and in the AD group, this optimal value was -1.7SD. Both composite scores showed high test-retest reliability (r = 0.95) over four months. Poorer performance on the memory composite was also associated with worse performance on the Mini Mental State Exam and increasing severity on the Clinical Dementia Rating Scale sum of boxes score.

Conclusions

Results of this study suggest that the CogState learning/working memory composite score is reduced significantly in CI and AD, correlate well with measures of disease classification and are useful in identifying memory impairment related to MCI- and AD.