Autism Attenuates Sex Differences in Brain Structure: A Combined Voxel-Based Morphometry and Diffusion Tensor Imaging Study

Article Figures & Data

Download figure
Open in new tab
Download powerpoint
Fig 1.
Example of positioning of ROIs for FA measurement on a representative participant.
Download figure
Open in new tab
Download powerpoint
Fig 2.
A, Bar graph of total white matter volume. B, Gray matter VBM statistical map demonstrating a sex × diagnosis interaction in the right inferior parietal lobe and rolandic operculum (peak coordinates [49, −14, 19]). C, Bar graph of gray matter volume for the cluster shown in B demonstrates attenuated male-female difference in AS patients compared with controls. Please see Table for statistical results.

Table 1:

Statistics for structural measurements^a

Statistics
Gross brain volume
Total gray matter volume
Sex: males 780 ± 65 mL vs females 700 ± 40 mL; F(1,53) = 33.4, P < .001, η_p² = 0.40
Diagnosis: n.s; sex × diagnosis: n.s.
Total white matter volume
Sex: males 540 ± 45 mL vs females 470 ± 35 mL; F(1,53) = 43.3, P < .001, η_p² = 0.45
Diagnosis: n.s.; sex × diagnosis: F(1,53) = 7.1, P = .01, η_p² = 0.12
1) Control males 550 ± 50 mL vs control females 460 ± 35 mL; F(1,27) = 37.8, P < .001^b
2) AS males 530 ± 40 mL vs AS females 490 ± 30 mL; F(1,25) = 9.1, P = .006^b
3) Control males 550 ± 50 mL vs AS males 530 ± 40 mL; n.s.
4) Control females 460 ± 35 mL vs AS females 490 ± 30 mL; F(1,25) = 6.8, P = .02
Right inferior parietal lobe and rolandic operculum
Regional gray matter volume
Sex: males 0.63 ± 0.09 vs females 0.59 ± 0.07; F(1,53) = 4.6, P = .04, η_p² = 0.08
Diagnosis: controls 0.63 ± 0.09 vs AS 0.58 ± 0.07; F(1,53) = 4.8, P = .03, η_p² = 0.08
Sex × diagnosis: F(1,53) = 23.3, P < .001, η_p² = 0.31
1) Control males 0.69 ± 0.06 vs control females 0.57 ± 0.07; F(1,27) = 24.2, P < .001^b
2) AS males 0.56 ± 0.06 vs AS females 0.61 ± 0.07; n.s.
3) Control males 0.69 ± 0.06 vs AS males 0.56 ± 0.06; F(1,27) = 27.1, P < .001^b
4) Control females 0.57 ± 0.07 vs AS females 0.61 ± 0.07; n.s.

Note:—n.s. indicates not significant.
↵a All tests include the NART as a covariate. According to the Bonferroni correction, we set α = .013 for post hoc comparisons. All values are given as means ± standard deviation. The values reported after “Sex” correspond to males and females, irrespective of diagnosis; the values reported after “Diagnosis” correspond to control and AS participants, irrespective of sex. Separate values for each group are given only in the presence of a significant interaction.
↵b Statistically significant post hoc comparison at the corrected threshold.