For each of the neuropsychological domains, composite Z-scores were computed by averaging Z-scores of the individual measures within each domain. Z-scores for the measures were computed based on standardized norms adjusted for age [Stroop (Golden, 1978), Short Categories (Wetzel et al., 1987), PASAT (Stuss et al., 1988), Block Design (Wechsler, 1997), and Rey (Denman, 1987)], age and years of education Symbol Digit Modalities [(Smith, 1982), MicroCog (Powell et al., 1993)] and age, gender, and years of education [(Trails A and B (Heaton et al., 1991), COWAT (Ruff et al., 1996)]. The Stroop, Symbol Digit Modalities, and the MicroCog test norms are not specific to gender, since gender did not significantly affect scores in the normative samples (Golden, 1978; Powell et al., 1993; Smith, 1982). The AMNART, which is used as a measure of premorbid intelligence (Grober et al., 1991), was adjusted for years of education (Schwartz et al., 1987), but did not have age norms because the test was designed to be resistant to the effects of normal aging. Grober and colleagues (1991) have reported that gender does not influence AMNART scores.
