Table 1.

Source	Task	Patient sample	Result
Beatty & Monson, 1990	California Card Sort Task (Delis et al., 1989)	16 PD; Stages 1–4; M = 2.6	PD= NC (d =.57)
Channon, 1997	Unidimensional classification learning	20 PD	PD < NC (d =.41)
Dimitrov, Grafman, Soares & Clark, 1999	California Card Sort Task	8 PD; Stages 1–4; M=3.0	PD = NC (d =.93)
Farina et al., 1994	Picture sorting task (Incisa della Rocchetta, 1986)	22 PD Stages 1–2	PD < NC
Hanes, Andrewes & Pantelis, 1995	Verbal solutions task (Reitan, 1972)	25 PD Stages 1–4; M = 2.76	PD < NC (d =.41)
Price, 2006	Multi-dimension classification learning	16 PD; Stages 1–3; M = 2.2	PD < NC (d = 1.0)
Swainson et al., 2006	Five Dimension Task (Swainson & Robbins, 2001)	11 mild PDOFF 27 mild PDON 14 severe PDON	mild PDOFF = NC; mild PDON < NC severe PDON = NC

Summary of studies examining rule generation in PD

Note. Stages refers to Hoehn & Yahr (1967) ratings of PD severity; M = mean level of PD severity; d = Cohen’s d measure of effect size