Table 1

Unique variance in function explained by performance on the behavioural, cognitive, or motor measure after controlling for the variance accounted for by performance on both of the other two measures (R2change)

HD-ADL scale
MeasuresInstrumental activities: R2 change (95% CI)Physical activities: R2 change (95% CI)TFC scale: R2 change (95% CI)
*Apathy/executive score accounted for significantly more variance in the functional score than the cognitive variables.
†Apathy/executive score accounted for significantly more variance in functional score than the UHDRS motor score.
CANTAB-cognitive; cognitive component of the Cambridge neuropsychological test automated battery; CI, confidence intervals determined by a bootstrap procedure[14] employing 1000 resamples of the original data; HD-ADL, Huntington’s disease activities of daily living scale; TFC, Shoulson-Fahn total functional capacity scale; UHDRS, unified Huntington’s disease rating scale; UHDRS-cognitive, cognitive component of the UHDRS.
Apathy/executive36.0% (9% to 67%)*†22.0% (2% to 50%)13.0% (0.4% to 41%)
CANTAB-cognitive<1.0% (0% to 3%)*<1.0% (0% to 7%)<1.0% (0% to 6%)
UHDRS motor score3.0% (0% to 9%)†5.0% (0.2% to 17%)12.0% (0.4% to 26%)
Apathy/executive18.0% (5% to 38%)*12.0% (2% to 30%)6.0% (0.1% to 21%)
UHDRS-cognitive1.0% (0% to 3%)*1.0% (0% to 5%)<1.0% (0% to 5%)
Motor5.0% (1% to 13%)8.0% (1% to 17%)19.0% (4% to 32%)