Table 2.

Neuropsychological test scores at 6- and 24- month assessments (N = 902).

	6 months	24 months	P-value*
Raw Scores (mean, SD)
HVLT-R total †	19.8 (5.7)	19.9 (6.7)	0.645
HVLT-R delayed†	6.7 (2.8)	6.7 (2.8)	0.865
WAIS-R Digit Symbol†	41.7 (12.5)	41.9 (12.6)	0.574
Trail A‡	43.4 (20.4)	40.0 (17.6)	<0.001
Trail B ‡§	109.3 (58.5)	100.3 (50.0)	<0.001
T-Scores (mean, SD)
HVLT-R total †	35.0 (10.8)	35.2 (11.5)	0.551
HVLT-R delayed†	37.5 (11.4)	37.6 (11.4)	0.675
WAIS-R Digit Symbol†	43.7 (10.0)	44.2 (10.0)	0.018
Trail A‡	39.8 (12.0)	42.4 (11.8)	<0.001
Trail B ‡§	42.0 (11.6)	44.0 (11.9)	<0.001
Global Deficit Scores
Score (median, IQR)	1.0 (0.4–1.8)	0.8 (0.4–1.6)
Any impairment ≥0.5 (%)	628 (69.6%)	602 (66.7%)	0.089
Severe impairment ≥1.0(%)	483 (53.6%)	438 (48.9%)	0.002

HVLT-R, Hopkins Verbal Learning Test-Revised; SD, Standard Deviation; WAIS-R, Wechsler Adult Intelligence Scale–Revised.

*Paired t tests (2-tailed).

^†Number of correct responses.

^‡Time in seconds.

^§Missing values at 24 months (n = 69) were replaced with imputed values.

Bold-faced p-values indicate statistical significance at the 0.01 level.