Table 1.
Descriptive statistics of demographic and neuropsychological variables.
| Children with DD (n = 22) | Typical Readers (n = 22) | Χ2 | df | p | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sex (Male/Female) | 16/6 | 15/7 | 0.11 | 1 | 0.741 | |||||||||
| Handedness | Right-handed | 18 | 17 | 0.31 | 2 | 0.856 | ||||||||
| Left-handed | 3 | 3 | ||||||||||||
| Ambidextrous | 1 | 2 | ||||||||||||
| Min | Max | Mean (SD) | Skewness | Kurtosis | Min | Max | Mean (SD) | Skewness | Kurtosis | t-Test | df | p | ||
| Age | 10.92 | 16.5 | 14.10 (1.48) | −0.40 | −0.22 | 11 | 16.25 | 13.18 (1.65) | 0.47 | −1.31 | −1.94 | 42 | 0.059 | |
| IQ † | 7.0 | 13.5 | 10.59 (1.78) | −0.10 | −0.61 | 7.5 | 18.5 | 13.70 (2.82) | −0.67 | 0.23 | 4.38 | 42 | <0.001 | |
| IQ, Vocabulary | 5.0 | 16.0 | 9.73 (2.75) | 0.25 | −0.24 | 8.0 | 18.0 | 13.23 (3.09) | −0.27 | −0.95 | 3.98 | 42 | <0.001 | |
| IQ, Block Design | 8.0 | 18.0 | 11.82 (2.04) | 1.16 | 3.10 | 7.0 | 19.0 | 14.18 (3.65) | −0.47 | −0.49 | 2.65 | 42 | 0.012 | |
| TR, accuracy | −10.43 | 0.74 | −3.34 (2.42) | −1.30 | 2.52 | −0.13 | 1.42 | 0.61 (0.34) | 0.10 | 0.88 | 7.61 | 42 | <0.001 | |
| TR, speed | −4.21 | −0.09 | −2.55 (1.01) | 0.44 | −0.11 | −1.00 | 1.18 | 0.16 (0.65) | 0.02 | −1.00 | 10.55 | 42 | <0.001 | |
| SWR, accuracy | −10.00 | 0.33 | −3.41 (2.63) | −0.74 | 0.22 | −0.67 | 1.00 | 0.27 (0.56) | −0.04 | −1.16 | 6.42 | 42 | <0.001 | |
| SWR, speed | −10.12 | −0.41 | −3.66 (2.16) | −1.49 | 2.77 | −1.11 | 0.87 | 0.04 (0.57) | −0.19 | −0.96 | 7.75 | 42 | <0.001 | |
| SPWR, accuracy | −8.50 | 0.33 | −2.28 (1.91) | −1.57 | 4.33 | −0.67 | 1.33 | 0.50 (0.46) | −0.47 | 0.60 | 6.61 | 42 | <0.001 | |
| SPWR, speed | −9.42 | −0.67 | −3.38 (2.42) | −1.43 | 1.36 | −1.03 | 1.40 | 0.26 (0.64) | −0.26 | −0.65 | 6.82 | 42 | <0.001 | |
| SLFS | −2.30 | 0.65 | −1.15 (0.72) | 0.46 | 0.61 | −1.35 | 1.35 | 0.14 (0.76) | −0.69 | −0.28 | 5.72 | 41 | <0.001 | |
| SLBS | −2.20 | 1.35 | −0.71 (0.75) | 0.93 | 2.25 | −1.35 | 1.60 | −0.07 (0.89) | 0.73 | −0.41 | 2.53 | 41 | 0.015 | |
| SDFS | −2.20 | 0.00 | −1.38 (0.62) | 0.49 | −0.08 | −2.00 | 1.00 | −0.61 (0.74) | 0.18 | −0.21 | 3.68 | 41 | 0.001 | |
| SDBS | −1.35 | 0.65 | −0.56 (0.47) | 0.56 | 1.01 | −1.40 | 2.00 | 0.10 (0.96) | 0.91 | −0.20 | 2.84 | 41 | 0.007 | |
| SNWR | −7.00 | 3.53 | −1.66 (2.71) | −0.1 | −0.41 | −2.79 | 3 | 1.18 (1.40) | −1.45 | 2.26 | 4.38 | 42 | <0.001 | |
| ADHD | DSM-IV-I ‡ | 41 | 82 | 60.09 (10.73) | 0.33 | −0.32 | 39 | 59 | 46.11 (5.49) | 0.94 | 0.34 | −5.43 | 42 | <0.001 |
| DSM-IV-HI § | 38 | 71 | 49.20 (7.96) | 1.13 | 1.57 | 38 | 65 | 47.36 (7.63) | 1.099 | 0.377 | −0.76 | 40 | 0.450 | |
| SES ¶ | 20 | 90 | 58.84 (19.16) | −0.08 | −0.37 | 30 | 90 | 60.23 (19.42) | 0.19 | −1.04 | 0.56 | 39 | 0.579 | |
TR: Text reading; SWR: single words reading; SPWR: single pseudo-words reading; SLFS: single letters forward span; SLBS: single letters backward span; SDFS: single digits forward span; SDBS: single digits backward span; SNWR: single non-word repetition. † Mean score of vocabulary and block design subtests of the WISC-III [108]. ‡ The DSM-IV-Inattention (DSM-IV-I) subscale of the CPRS-R:L [116,117,118]. § The DSM-IV-hyperactivity/impulsivity (DSM-IV-HI) subscale of the CPRS-R:L [116,117,118]. ¶ As estimated by father’s/mother’s employment [124].