Psychometric Properties of a Decisional Capacity Screening Tool for Individuals Contemplating Participation in Alzheimer's Disease Research.

BACKGROUND

With the growing population of individuals affected by Alzheimer's disease (AD) and related disorders, there is a pressing demand for research on late-life cognitive disorders. However, this population's high risk for decisional incapacity necessitates evaluation of capacity to consent to research participation, adding cost and complexity to the research process. The University of California, San Diego Brief Assessment of Capacity to Consent (UBACC) was initially validated in a sample of persons with schizophrenia and healthy controls.

OBJECTIVE

To assess the psychometric properties of the UBACC when used in a sample of individuals contemplating participation in AD research.

METHODS

The UBACC was administered to a convenience sample (n = 132) consisting of individuals with mild to moderate cognitive impairment (n = 52), their study partners (n = 52), and healthy older adults control subjects (n = 30), as part of a broader study to evaluate perceived burden of research participation. Reliability tests, correlational analyses, and exploratory factor analytic methods were used to examine the psychometric properties of the instrument.

RESULTS

UBACC scores were significantly associated with both global cognition (rs= 0.564, p <  0.001) and verbal fluency (rs = 0.511, p <  0.001), indicating concurrent validity with related constructs. The resulting factor structure differed from that reported by the developers in their initial testing. Items clustered almost entirely on one factor; items reflecting the construct of understanding accounted for 32.12% of total variance, with no evidence for distinct reasoning or appreciation scales.

CONCLUSION

The UBACC shows promise when used to screen for decisional capacity among those considering participation in AD research.