Psychometric properties and responsiveness of Neuro-QoL Cognitive Function in persons with Huntington disease (HD)

Individuals with Huntington disease (HD) experience progressive cognitive decline that may appear years before motor manifestations of the disease. These declines have a profound effect on health-related quality of life (HRQOL) over the disease course, and thus it is important that self-report measures of cognitive function are validated for use in longitudinal studies.

359 individuals with premanifest or manifest HD completed baseline and at least one follow-up (12- and 24-month) assessment. Neuro-QoL™ Cognitive Function was administered at each time-point. Participants completed a self-reported global rating of cognitive change, as well as performance-based cognitive changes (using the Symbol Digit Modalities Test). Standardized response means (SRMs) and general linear models evaluated whether Neuro-QoL™ Cognitive Function was responsive to change over time with respect to self-reported and performance-based anchors. Test-retest reliability and known-group validity were also examined.

Responsiveness was supported by effect sizes that were small in magnitude, but in the expected direction relative to self-reported and performance-based change. General linear models generally supported 12- and 24-month responsiveness relative to self-reported cognitive change and 12-month responsiveness relative to performance-based change. Test-retest reliability was excellent, and the measure exhibited known-group validity.

Longitudinal analyses generally indicate that the Neuro-QoL™ Cognitive Function measure is sensitive to change over time in individuals with HD. Neuro-QoL Cognitive Function changes reflect self-reported cognitive change at 12 and 24 months and performance-based change at 12 months. This measure may be useful in clinical trials or longitudinal observation studies.