Table 1.
A summary of published studies comparing head growth in children with autism vs. controlsa
| Study | n ASDa | Dev. period of measurement (months) | Mean IQ of subjects | Control group | Method of measurement | 1st year of life principle findings | 12–36 month significant findings | Analytic methodb |
|---|---|---|---|---|---|---|---|---|
| 1. Courchesne et al. 2003 | 48 | Birth—14 | 75 | CDC Norms/FELS longitudinal sample study | OFC and MRI | Birth-14 month (acceleration) | Cross-sectional | |
| 2. Torrey et al. 2004 | 15 | Birth—14 | 56.8 | NCPP (1959–1965 birth cohorts) | OFC | Difference at birth but no difference in growth trajectory | [no difference] | Cross-sectional, growth curve |
| 3. Hazlett et al. 2005 | 113 | Birth—36 | 54.1 | Contemporaneous controls with TYP (n = 178) or DD (n = 11) | OFC and MRI | [no difference] | 12–24 months (acceleration) | Cross- sectional, growth curve analysis |
| 4. Fukumoto et al. 2008 | 85 | Birth—12 | 75.5 | JMHLW 2000 infant physical growth survey | OFC | 1–12 month (acceleration) | Cross-sectional | |
| 5. Elder et al. 2008 (Study of 77 high- risk sibs) | Not Reported | Birth—24 | Not Reported | 2002 CDC Norms | OFC | Birth-12 month (acceleration) | 12–24 months (deceleration) | Cross-sectional, multilevel modeling |
| 6. Dawson et al. 2007 (deceleration) | 28 | Birth—36 | 61.5 (Mullen Composite) | 2002 CDC Norms | OFC | Birth-12 month (acceleration) | 12—36 months (relative deceleration) | Cross-sectional, growth curve |
| 7. Webb et al. 2007 | 28 | Birth—36 | Not Reported | 2000 CDC Norms | OFC | 7–10 month (acceleration) | Cross-sectional | |
| 8. van Daalen et al. 2007 | 53 | Birth—64 | <70: 33 70–85:6 | 1996, 1997 NOASR | OFC | [no difference] | [no difference] | Cross-sectional |
| >85: 14 | ||||||||
| 9. Constantino et al. [Current Study] | 48 | Birth—36 | 92 | Unaffected sibs and contemporaneous control sib pairs | OFC | Birth—15 month (trend, acceleration) | Cross-sectional, growth curve |
aNumber of ASD-affected subjects from unique families
bP-Values for principal differences between ASD subjects and controls
1. Comparison of 22 ASD infants vs. 31 controls with birth—14 month data indicated a significantly greater increase in HC, p < .001
2. At 4 months, the HC of the ASD subjects was not significantly larger than the HC of the controls (p = .07)
3. The growth curves for subjects with autism vs. controls were significantly different; p < .001 for all three parameters comprising the curves
4. In the low functioning ASD boys, HC differed from the controls at 1 month (p = .0008), 3 months (p = .025), and 6 months (p = .0001). The high functioning ASD boys differed from the controls at 6 months (p = .02)
5. Whole group cross-sectional differences between high risk siblings and CDC norms are significantly different at 6–12 months, p < .05 at each time point; birth—12 month slopes are greater than CDC norms, p < .001. Subset with significant ASD symptoms (Early Developmental Interview, EDI or Modified Checklist for Autism in Toddlers, M-CHAT) vs. those without differed in 12–24 month HC slope (EDI, p = .05), and exhibited a larger 12 month intercept (M-CHAT, p = .02)
6. The orbitofrontal circumference (OFC) z-score for the ASD subjects at 12 months was significantly larger than the control group’s (p < .001). Although the rate of change of HC decreases from 12–36 months (p = .001), the rate of change does not significantly differ from that of the norms (p = .409)
7. The mean OFC z-scores in the ASD group did not significantly differ from the controls from 0–7 months and from 10–13 months, but they were significantly larger than the controls from 7–10 (p < .001) and 13–36 (p < .007) months
8. No significant difference between ASD subjects and controls were found
9. Growth curve trajectory for ASD subjects mildly accelerated in comparison controls for age range birth—15 months, p=.07. The magnitude of difference was on the order of 0.03 cm/month