Study sample characteristics
| Boys (n = 26) | Girls (n = 25) | Total (n = 51) | ||||
|---|---|---|---|---|---|---|
| Mean | SD | Mean | SD | Mean | SD | |
| Age (yr) | 12.0 | 3.9 | 12.6 | 3.3 | 12.3 | 3.6 |
| SES | 45.9 | 11.3 | 42.9 | 13.3 | 44.5 | 12.2 |
| Estimated IQ | 139 | 31 | 142 | 27 | 141 | 29 |
| Neuropsychological test scores | ||||||
| Purdue Pegboard RH | 12.7 | 2.1 | 13.3 | 2.3 | 13.0 | 2.2 |
| Purdue Pegboard LH | 11.9 | 2.5 | 13.3 | 2.6 | 12.6 | 2.6 |
| SB-IV “Bead Memory” | 22.8 | 4.9 | 24.4 | 5.4 | 23.6 | 5.2 |
| WJ-III “Auditory Working Memory” | 21.1 | 9.1 | 22.5 | 6.1 | 21.8 | 7.8 |
| WJ-III “Retrieval Fluency” | 56.1 | 15.1 | 67.4* | 17.1 | 61.9 | 16.9 |
| NAA/Cr | ||||||
| Frontal GM | R 2.1 | 0.5 | 2.1 | 0.4 | 2.1 | 0.5 |
| L 2.2 | 0.4 | 2.0 | 0.3 | 2.1 | 0.3 | |
| Frontal WM | R 2.5 | 0.3 | 2.5 | 0.3 | 2.5 | 0.3 |
| L 2.4 | 0.3 | 2.4 | 0.3 | 2.4 | 0.3 | |
| Parietal GM | R 2.1 | 0.2 | 2.1 | 0.2 | 2.1 | 0.2 |
| L 2.1 | 0.2 | 2.1 | 0.2 | 2.1 | 0.2 | |
| Parietal WM | R 2.5 | 0.4 | 2.6 | 0.3 | 2.5 | 0.4 |
| L 2.3 | 0.3 | 2.5 | 0.2 | 2.4 | 0.3 | |
Note:—R indicates right; L, left;LH, left hand; RH, right hand; WM, white matter; GM, gray matter; SES, socioeconomic status; NAA/Cr, N-acetylaspartate/creatine ratio.
* Girls had higher scores on the WJ-III “Retrieval Fluency” test (P < .05).