Table 2.
Participants’ demographics, single-nucleotide polymorphisms, neuropsychological scores, and baseline neurophysiological measures.
| All (N = 63) | NT (n = 44) | ASD (n = 19) | p | NT Met− (n = 23)‡ | ASD Met− (n = 8)‡ | p | NT Met+ (n = 16)‡ | ASD Met+ (n = 9)‡ | p | NT ε4− (n = 26)§ | ASD ε4− (n = 10)§ | p | NT ε4+ (n = 13)§ | ASD ε4+ (n = 6)§ | p | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Age (yr, mean ± SD) | 34.57 ± 12.77 | 33.05 ± 13.15 | 38.11 ± 11.38 | 0.150 | 33.96 ± 13.69 | 39.88 ± 13.96 | 0.303 | 32.94 ± 3.31 | 35.67 ± 3.02 | 0.589 | 31.74 ± 2.14 | 36.50 ± 3.21 | 0.246 | 37.69 ± 4.57 | 36.17 ± 4.92 | 0.843 |
| Sex (M : F) | 51 : 12 | 34 : 10 | 17 : 2 | 0.318 | 19 : 4 | 6 : 2 | 0.634 | 13 : 3 | 9 : 0 | 0.280 | 22 : 4 | 10 : 0 | 0.559 | 10 : 3 | 5 : 1 | 1.000 |
| Race (White : non-White) | 37 : 26 | 22 : 22 | 15 : 4 | 0.050 | 13 : 10 | 6 : 2 | 0.433 | 8 : 8 | 7 : 2 | 0.229 | 16 : 10 | 7 : 3 | 0.716 | 5 : 8 | 5 : 1 | 0.141 |
| Education (yr, mean ± SD) † | 16.52 ± 2.1 | 16.79 ± 2.09 | 15.81 ± 3.06 | 0.171 | 16.76 ± 2.07 | 16.60 ± 3.13 | 0.888 | 16.94 ± 1.95 | 16.22 ± 2.86 | 0.465 | 16.63 ± 1.56 | 14.89 ± 2.15 | 0.015 | 17.23 ± 2.65 | 19.75 ± 0.96 | 0.087 |
| BDNF (Met− : Met+) ‡ | 31 : 25 | 23 : 16 | 8 : 9 | 0.560 | 23 : 0 | 8 : 0 | N/A | 16 : 0 | 9 : 0 | N/A | 16 : 10 | 3 : 7 | 0.139 | 7 : 6 | 4 : 2 | 1.000 |
| APOE (ε4− : ε4+) § | 36 : 19 | 26 : 13 | 10 : 6 | 0.765 | 16 : 7 | 3 : 4 | 0.372 | 10 : 6 | 7 : 2 | 0.661 | 26 : 0 | 10 : 0 | N/A | 13 : 0 | 6 : 0 | N/A |
| Handedness (Right : Left) | 59 : 4 | 42 : 2 | 17 : 2 | 0.578 | 24 : 0 | 6 : 2 | 0.056 | 14 : 2 | 9 : 0 | 0.520 | 27 : 0 | 10 : 0 | 1.000 | 11 : 2 | 4 : 2 | 0.557 |
| IQ (mean ± SD) | 107.29 ± 13.03 | 108.18 ± 11.12 | 105.21 ± 16.82 | 0.411 | 107.63 ± 12.13 | 104.13 ± 17.56 | 0.533 | 109.19 ± 10.30 | 110.67 ± 13.17 | 0.758 | 108.11 ± 12.02 | 102.70 ± 17.00 | 0.286 | 108.54 ± 10.16 | 113.50 ± 9.99 | 0.334 |
| AQ (mean ± SD) ¶ | 18.42 ± 8.67 | 14.75 ± 5.13 | 29.20 ± 7.98 | < 0.001 | 14.91 ± 5.58 | 36.50 ± 4.65 | < 0.001 | 15.81 ± 4.34 | 26.67 ± 6.48 | < 0.001 | 14.88 ± 4.59 | 27.13 ± 5.96 | < 0.001 | 16.08 ± 6.03 | 33.25 ± 9.60 | 0.001 |
| RMT (% MSO, mean ± SD) | 35.65 ± 7.42 | 36.00 ± 8.29 | 34.84 ± 4.97 | 0.574 | 35.04 ± 7.28 | 34.88 ± 6.49 | 0.954 | 36.69 ± 10.21 | 34.22 ± 3.99 | 0.497 | 34.88 ± 8.89 | 33.40 ± 5.19 | 0.625 | 37.38 ± 7.77 | 34.67 ± 3.44 | 0.429 |
| AMT (% MSO, mean ± SD) | 26.52 ± 5.32 | 26.09 ± 5.61 | 27.52 ± 4.55 | 0.329 | 25.35 ± 4.60 | 28.00 ± 6.04 | 0.206 | 26.56 ± 6.81 | 26.33 ± 3.12 | 0.925 | 26.15 ± 5.94 | 26.40 ± 4.40 | 0.906 | 25.23 ± 4.90 | 26.67 ± 3.67 | 0.533 |
| Baseline MEP amplitude (mV, mean ± SD) | 1.34 ± 1.33 | 1.27 ± 1.31 | 1.51 ± 1.39 | 0.523 | 1.45 ± 1.58 | 1.54 ± 1.71 | 0.885 | 1.19 ± 1.03 | 1.57 ± 1.29 | 0.422 | 1.37 ± 1.58 | 1.86 ± 1.69 | 0.418 | 1.28 ± 0.88 | 0.83 ± 0.68 | 0.287 |
Racial categories were defined according to the National Institutes of Health guidelines (NIH Office of Extramural Research, 2001). Comparisons of proportions were conducted with Fisher’s exact test. Education and single-nucleotide polymorphisms were not statistically compared between the subgroups because the data were not available for the total sample. N/A indicates that a statistical comparison between the two subgroups was not applicable because the measure of interest itself was the basis for subdividing the sample. Significant p-values are in bold font. The p-values were not adjusted for multiple comparisons. AMT, active motor threshold; APOE, apolipoprotein E; APOE ε4+, ε2/ε4 or ε3/ε4 genotype; APOE ε4−, ε2/ε3 or ε3/ε3; AQ, autism-spectrum quotient; BDNF, brain-derived neurotrophic factor; BDNF Met−, Val66Val; BDNF Met+, Val66Met; IQ, intelligence quotient; MEP, motor evoked potential; Met, metionine; MSO, maximum stimulator output; N/A, not applicable; RMT, resting motor threshold; SD, standard deviation; Val, valine.
Education data were available for 16 and 42 participants in the ASD and NT groups, respectively.
BDNF data were available for 17 and 39 participants in the ASD and NT groups, respectively.
APOE data were available for 16 and 39 participants in the ASD and NT groups, respectively.
AQ scores were available for 15 and 44 participants in the ASD and NT groups, respectively.