Table 5.

Change in R² with the inclusion of diagnostic group × caudate volume interactions in regressions predicting executive function and attention measures

	Left Caudate Volume				Right Caudate Volume
	R2	ΔR2	%UV (ASD - BD)	%UV (ASD - TD)	R2	ΔR2	%UV (ASD - BD)	%UV (ASD - TD)
Category Test	.15	.03	1.0	2.2	.14	.03	1.4	2.2
Semantic Fluency	.21	.05	4.3	0.0	.18	.04	3.9	0.0
Phonetic Fluency	.06	.03	1.1	2.6	.05	.02	0.4	1.7
TMT-B	.16	.03	1.6	0.1	.17	.01	0.2	0.6
Stroop	.10	.02	1.7	0.2	.10	.03	2.2	0.0
WCST-P	.39	.00	0.2	0.1	.39	.00	0.0	0.1
WCST-C	.37	.00	0.0	0.4	.38	.00	0.0	0.2
CPT-Index	.07	.07	6.4	0.9	.07	.05	5.3	0.2
CPT-d'a	.17	.09	6.0d	4.6	.17	.08	6.2d	3.3
CPT-Riskb	.08	.14	5.5	11.2e	.08	.11	5.0	7.4d
CPT-Omitc	.11	.16	0.1	15.8f	.11	.11	0.6	11.4e

R²: associated with the main effects model (Table 4), ΔR²: the increment in R² with the addition of the interaction term, UV: % unique variance explained by diagnostic group differences, TMT-B: Children's version of Trail Making Test, Part B; PFT: Progressive Figures Test, Stroop: Stroop Color Word Page; WCST-P: Wisconsin Card Sorting Test, Perseveration errors; WCST-C: Wisconsin Card Sorting Test, Completed Categories; CPT: Continuous Performance Test, overall performance index score (Index), discriminant responding (d'), number of omission errors (Omit), and risk taking (Risk).

^aLCV × CPT-d' (F (7, 50) = 3.05, p < .01), RCV × CPT-d' (F (7, 50) = 2.69, p < .05).

^bLCV × CPT-risk (F (7, 50) = 4.64, p < .01), RCV × CPT-risk (F (7, 50) = 3.23, p < .01).

^cLCV × CPT-omit (F (7, 50) = 5.45, p < .01), RCV × CPT-omit (F (7, 50) = 3.66, p < .01).

^dp <.05.

^ep <.01.

^fp < .005.