Table 4.

Associations among age and cognitive variables in 122 adults with HD and group differences co-varying for premorbid IQ (WRAT-4 word reading)

		β (SE)	t	p
WCST-128	Total errors	0.09 (0.09)	1.05	0.298
D-KEFS verbal fluency	Letter fluency	0.01 (0.03)	0.09	0.927
	Category fluency	−0.02 (0.04)	−0.18	0.861
	Category switching	0.04 (0.04)	0.45	0.651
D-KEFS Trail Making	Number–Letter Switching*	0.04 (0.02)	2.01	0.047
D-KEFS Tower	Total achievement	−0.19 (0.03)	−2.09	0.039
D-KEFS	Inhibition	−0.03 (0.03)	−0.31	0.755
Color–Word Interference	Inhibition/switching	−0.13 (0.03)	−1.40	0.163
WAIS-IV	Letter–Number Sequencing	−0.26 (0.03)	−2.95	0.004
	Coding	−0.17 (0.03)	−1.83	0.070
	Digit span	−0.14 (0.02)	−1.67	0.098
IGT	Net total	0.13 (0.11)	1.28	0.205
UPSA	Total	−0.41 (0.06)	−3.98	<0.001

WCST-128, Wisconsin Card Sorting Test—128 items version (age-matched and education-matched T-scores); D-KEFS, Delis–Kaplan Executive Function System (age-matched scaled scores); WAIS-IV, Wechsler Adult Intelligence Scale-Fourth Edition (age-matched scaled scores); IGT, Iowa Gambling Task (age-, education-, and gender-matched T-score); WRAT-4, Wide Range Achievement Test, Fourth Edition (raw scores); UPSA, UCSD Performance-Based Skills Assessment (raw scores).

^*Robust regression was used to adjust for skew in the distribution.