Table 1.
Characteristics of participants by diagnostic group.
| Measure | Fragile X syndrome | Down syndrome | ||||
|---|---|---|---|---|---|---|
| M | SD | Range | M | SD | Range | |
| Chronological age | 15.77 | 4.19 | 6.84 to 23.76 | 16.86 | 4.56 | 7.60 to 23.72 |
| NVIQa | 47.13c (49.62) | 6.45 (13.34) | 42–68 (13.72 to 76.31) | 48.84f. (52.66) | 6.89 (11.43) | 42–66 (25.96 to 77.10) |
| VIQa | 49.06d (50.06) | 7.53 (13.49) | 42–78 (17.50 to 83.85) | 46.12g (42.48) | 5.77 (13.30) | 43–72 (7.43 to 73.03) |
| Full scale IQa | 45.68e (49.92) | 6.88 (12.43) | 40–66 (19.06 to 74.64) | 45.03h (47.62) | 6.02 (11.89) | 40–67 (23.93 to 75.07) |
| ADOS severityb | 5.46e | 2.58 | 1 to 10 | 3.19g | 2.18 | 1–9 |
For FXS, n = 80 unless indicated otherwise. For DS, n = 78 unless indicated otherwise.
aStanford-Binet, 5th edition standard scores. Values in parentheses are the Sansone et al. deviation IQs. bSeverity Score from Autism Diagnostic Observation Schedule, 2nd edition; cn = 78; dn = 79; en = 78; fn = 73; gn = 74; hn = 73.