Table 1.

Demographics of study participants ^*Full scale IQ was estimated based on four sub-scales of the WISC/WAIS [Wechsler Intelligence Scale for Children (WISC-III or IV UK), (Wechsler, 2004) and Wechsler Adult Intelligence Scale (WAIS-III), (Wechsler, 1997)].

	Control	ASD	p-value
Number	22	22
Gender	Male (22)	Male (22)
Age mean (SD, Range)	17.51 (2.76, 13.6–21.3)	17.56 (2.91, 13.0–21.8)	0.76
Full scale IQ* Mean (SD, Range)	110.50 (16.97, 84–147)	105.95 (13.46, 84–127)	0.25
Verbal IQ∧ Mean (SD, Range)	117.60 (12.69, 93–134)	105.60 (18.48, 79–134)	0.11
Performance IQ~ Mean (SD, Range)	120.80 (26.39, 91–155)	124.35 (17.46, 99–155)	0.73
Handedness	Right (22)	Right (22)
Medication	None	None
Ethnicity	Irish (22)	Irish (22)

^∧Verbal IQ was estimated using the Information and Vocabulary subtests of the WISC III for n = 10 participants with ASD and n = 10 matched controls, using Sattler's method (Sattler, 1992). It was not possible to produce a Verbal IQ for n = 12 participants with ASD and n = 12 controls, as the WISC IV was used to estimate full scale IQ for these participants. ~Performance IQ was estimated using the Picture Completion and Block Design subtests of the WISC III for n = 10 participants with ASD and n = 10 for controls, using Sattler's method (Sattler, 1992). It was not possible to produce a Performance IQ for n = 12 participants with ASD and n = 12 controls, as the WISC-IV was used to estimate full scale IQ for these participants. Subtests of the WISC-IV that were used to calculate full scale IQ included Similarities, Block Design, Digit Span, and Coding. Subtests of the WAIS that were used to calculate full scale IQ included Similarities, Block Design, Digit Span and Matrix Reasoning.