Background

Cognitive deficits are presumed to be the primary driver of functional impairment in Alzheimer's disease (AD); however, functional impairment is likely multifactorially determined.

Objective

Our objective was to determine the relative contribution of neuropsychiatric symptoms in predicting ratings of functional status.

Methods

A total of 223 patients received routine neurological and neuropsychological evaluations and met criteria of probable AD dementia based on the McKhann criteria. Demographic, cognitive, and neuropsychiatric variables were entered in a hierarchical linear regression analysis to predict functional status as measured by the Functional Activities Questionnaire (FAQ).

Results

The total model explained 29.7% of the variance (p <  0.001) in FAQ. Importantly, neuropsychiatric variables explained 12.7% of the unique variance, with apathy and sleep as significant contributors.

Conclusion

Two neuropsychiatric variables, apathy and changes in sleep/nighttime behaviors, predicted ratings of functional status in AD patients independent of age, global cognition, memory and executive function measures, and depressive symptoms. These results highlight the importance of neuropsychiatric symptoms in understanding and potentially treating the functional limitations so prevalent in AD.

Background

We investigated the viability of psychometrically robust executive function measures as markers for premanifest Huntington's disease (HD).

Methods

Fifteen premanifest HD subjects and 42 controls were compared on the NIH EXAMINER executive function battery. This battery yields an overall executive composite score, plus working memory, cognitive control, and fluency scores that are measured on psychometrically matched scales. The scores were correlated with two disease markers, disease burden and striatal volumes, in the premanifest HD subjects.

Results

The premanifest HD subjects scored significantly lower on the working memory score. The executive composite positively correlated with striatal volumes, and the working memory score negatively correlated with disease burden. The cognitive control and fluency scores did not differ between the groups or correlate significantly with the disease markers.

Conclusions

The NIH EXAMINER executive composite and working memory scores are sensitive markers of cognitive dysfunction, striatal volume, and disease burden in premanifest HD.

Background

We investigated the viability of psychometrically robust executive function measures as markers for premanifest Huntington's disease (HD).

Methods

Fifteen premanifest HD subjects and 42 controls were compared on the NIH EXAMINER executive function battery. This battery yields an overall executive composite score, plus working memory, cognitive control, and fluency scores that are measured on psychometrically matched scales. The scores were correlated with two disease markers, disease burden and striatal volumes, in the premanifest HD subjects.

Results

The premanifest HD subjects scored significantly lower on the working memory score. The executive composite positively correlated with striatal volumes, and the working memory score negatively correlated with disease burden. The cognitive control and fluency scores did not differ between the groups or correlate significantly with the disease markers.

Conclusions

The NIH EXAMINER executive composite and working memory scores are sensitive markers of cognitive dysfunction, striatal volume, and disease burden in premanifest HD.