Table 4.
Comparisons of RD, MD, RD/MD, and No LD groups on IQ, achievement, and neuropsychological measures for children with verbal and nonverbal IQ > 70 with complete data (N = 603).
| RD n = 37 |
MD n = 100 |
RD/MD n = 48 |
No LD n = 418 |
|
|---|---|---|---|---|
| IQ | ||||
| Verbal IQ mean (SD) | 88.7 (11.8) | 93.2 (11.1) | 87.2 (10.6) | 100.9 (12.7) |
| Adjusted mean | 90.0 | 94.2 | 89.6 | 100.2 |
| Scheffe p group vs. No LD* | 0.001 | 0.001 | 0.001 | --- |
| Nonverbal IQ mean (SD) | 91.4 (10.2) | 88.2 (8.9) | 86.6 (10.0) | 98.3 (12.6) |
| Adjusted mean | 92.3 | 88.8 | 88.0 | 98.2 |
| Scheffe p group vs. No LD | 0.030 | 0.001 | 0.001 | --- |
| WIAT-III | ||||
| Word Reading mean (SD) | 78.6 (5.7) | 97.4 (9.6) | 76.2 (6.4) | 104.4 (11.5) |
| Adjusted mean | 79.3 | 98.0 | 77.5 | 104.1 |
| Scheffe p group vs. No LD* | 0.001 | 0.001 | 0.001 | --- |
| Numerical Operations mean (SD) | 94.1 (8.7) | 78.4 (4.7) | 75.1 (6.3) | 101.3 (10.2) |
| Adjusted mean | 94.5 | 78.6 | 75.6 | 101.1 |
| Scheffe p group vs. No LD | 0.030 | 0.001 | 0.001 | --- |
| Neuropsychological Tests | ||||
| Language Composite mean (SD) | 85.8 (11.0) | 88.4 (11.1) | 84.2 (9.8) | 95.5 (12.5) |
| Adjusted mean | 85.7 | 89.7 | 86.4 | 95.0 |
| Scheffe p group vs. No LD | 0.001 | 0.001 | 0.001 | --- |
| Working Memory Composite mean (SD) | 88.4 (9.3) | 89.5 (12.1) | 84.5 (11.5) | 98.1 (12.3) |
| Adjusted mean | 89.4 | 89.9 | 85.7 | 97.8 |
| Scheffe p group vs. No LD | 0.001 | 0.001 | 0.001 | --- |
| Attention Composite mean (SD) | 8.4 (3.0) | 8.0 (2.7) | 7.4 (2.8) | 9.3 (2.5) |
| Adjusted mean | 8.4 | 8.2 | 7.4 | 9.3 |
| Scheffe p group vs. No LD | 0.252 | 0.002 | 0.001 | --- |
| Inhibition Composite mean (SD) | 6.6 (2.8) | 6.8 (2.7) | 5.7 (2.5) | 8.3 (2.9) |
| Adjusted mean | 6.7 | 6.9 | 5.9 | 8.3 |
| Scheffe p group vs. No LD | 0.016 | 0.001 | 0.001 | --- |
| Naming mean (SD) | 6.4 (3.3) | 7.8 (3.7) | 6.7 (3.8) | 8.7 (3.8) |
| Adjusted mean | 6.6 | 8.0 | 6.7 | 8.8 |
| Scheffe p group vs. No LD | 0.009 | 0.343 | 0.004 | --- |
| Visual Perception Composite mean (SD) | 8.0 (2.4) | 7.1 (2.3) | 7.0 (2.5) | 9.1 (2.5) |
| Adjusted mean | 8.2 | 7.4 | 7.1 | 9.1 |
| Scheffe p group vs. No LD | 0.170 | 0.001 | 0.001 | --- |
| Visuomotor Precision mean (SD) | 7.5 (3.3) | 7.6 (3.1) | 6.8 (3.7) | 8.5 (3.4) |
| Adjusted mean | 7.4 | 7.6 | 6.5 | 8.5 |
| Scheffe p group vs. No LD | 0.343 | 0.144 | 0.003 | --- |
*
None of the between LD group comparisons were significant with Scheffe adjustment. Adjusted means (ANCOVAs), controlling for maternal education, and adjusted p-values with Scheffe correction for multiple comparisons.