NUCOG10: The development and validation of a short form of the NUCOG cognitive assessment tool

Abstract

Objective:

The Neuropsychiatry Unit Cognitive Assessment is a valid and reliable screening tool used in detecting cognitive deficits in a range of neurological and psychiatric conditions. We aimed to develop abbreviated versions of the Neuropsychiatry Unit Cognitive Assessment tool using retrospective data, and to assess their psychometric performance in distinguishing between healthy cognition and dementia.

Methods:

Healthy controls (n = 132, 41%) and those with dementia (n = 191, 59%) were randomised into a ‘training’ cohort (n = 226, 70%) for the development and a ‘testing’ cohort (n = 97, 30%) for validation of the short-form versions. Receiver-operating characteristic curves were first computed for each of the 24 original Neuropsychiatry Unit Cognitive Assessment items. Items were ranked according to area under the curve values to create five-, 10- and 15-item short-form versions, which were subsequently validated.

Results:

The psychometric properties of the Neuropsychiatry Unit Cognitive Assessment short-form versions were comparable with the original, with all maintaining high convergent validity and reliability. Of the three versions, the 10-item version strikes the ideal balance of breadth and brevity. With a cut-off score of 42/54, the 10-item version generated similar sensitivity, specificity and predictive values for dementia as the original Neuropsychiatry Unit Cognitive Assessment, with a sensitivity of 0.98, specificity of 0.95, and positive and negative predictive values of 0.97.

Conclusions:

The 10-item Neuropsychiatry Unit Cognitive Assessment has strengths in its shorter administration time, of approximately 10 minutes, high reliability and validity, and retention of items from each cognitive domain from the original Neuropsychiatry Unit Cognitive Assessment. Future research may involve testing these short forms in non-tertiary settings, across dementia subtypes and in non-dementia groups.