Table 1. Perinatal and demographic characteristics of all included children, categorised by hand preference.
| Total | NRH | RH | p* | Cramér's V | ||
|---|---|---|---|---|---|---|
| (n = 179) | (n = 41) | (n = 138) | ||||
| Demographic and perinatal measures | ||||||
| NRH | n (%) | 41 (22.9) | NA | NA | NA | |
| Left-handedness | n (%) | 35 (19.6) | 35 (85.4) | NA | NA | |
| Mixed-handedness | n (%) | 6 (3.4) | 6 (14.6) | NA | NA | |
| Sex | Male, n (%) | 87 (48.6) | 23 (56.1) | 64 (46.4) | 0.274 | |
| Gestational age (weeks) | Mean (SD) | 26.5 (1.0) | 26.4 (0.9) | 26.5 (1.0) | 0.262 | |
| Birth weight (g) | Mean (SD) | 886 (163) | 842 (142) | 899 (167) | 0.350 | |
| Plurality | Singleton, n (%) | 119 (66.5) | 31 (75.6) | 88 (63.8) | 0.158 | |
| Birth season | Winter, n (%) | 51 (28.5) | 13 (31.7) | 38 (27.5) | 0.492 | |
| Spring, n (%) | 38 (21.2) | 6 (14.6) | 32 (23.2) | |||
| Summer, n (%) | 45 (25.1) | 13 (31.7) | 32 (23.2) | |||
| Autumn, n (%) | 45 (25.1) | 9 (22.0) | 36 (26.1) | |||
| Apgar score at 1 minute1 | Median (IQR) | 5 (2) | 4.5 (3) | 5 (3) | 0.600 | |
| Apgar score at 5 minutes1 | Median (IQR) | 7 (2) | 7 (2) | 7 (2) | 0.961 | |
| Apgar score at 10 minutes2 | Median (IQR) | 8 (1) | 9 (2) | 8 (1) | 0.690 | |
| Post-menstrual age in days at MRI scan at term equivalent age3 | Median (IQR) | 41.1 (0.6) | 41.3 (0.5) | 41.1 (0.8) | 0.105 | |
| Age in months at MABC-2-NL | Median (IQR) | 70.1 (1.8) | 70.1 (2.5) | 70.1 (1.6) | 0.130 | |
| Scanning data | ||||||
| MRI at term equivalent age available | n (%) | 171 (95.5) | 40 (97.6) | 131 (94.9) | 0.684 | |
| Kidokoro score available | n (%) | 167 (93.3) | 40 (97.6) | 127 (92.0) | 0.301 | |
| DTI usability | n (%) | 95 (53.1) | 27 (65.9) | 68 (49.3) | 0.062 | |
| Parental measures | ||||||
| Hand preference mother4 | NRH, n (%) | 28 (17.4) | 8 (20.0) | 20 (16.5) | 0.616 | |
| Hand preference father5 | NRH, n (%) | 29 (18.4) | 12 (31.6) | 17 (14.2) | 0.016 | 0.192 |
| Parental NRH5 | At least one parent NRH, n (%) | 52 (32.9) | 18 (47.4) | 34 (28.3) | 0.030 | 0.173 |
| Maternal education level6 | Low, n (%) | 40 (22.9) | 9 (22.0) | 31 (23.1) | 0.801 | |
| Middle, n (%) | 65 (37.1) | 17 (41.5) | 48 (35.8) | |||
| High, n (%) | 39.1 (40.0) | 15 (36.6) | 55 (41.0) | |||
| Paternal education level7 | Low, n (%) | 27 (25.2) | 6 (25.0) | 21 (25.3) | 0.444 | |
| Middle, n (%) | 34 (31.8) | 10 (41.7) | 24 (28.9) | |||
| High, n (%) | 46 (43.0) | 8 (33.3) | 38 (45.8) | |||
| Brain inury measures | ||||||
| Combined brain injury8 | n (%) | 81 (47.4) | 15 (37.5) | 66 (50.4) | 0.153 | |
| Focal lesions total9 | n (%) | 75 (43.6) | 15 (37.5) | 60 (45.5) | 0.374 | |
| IVH | n (%) | 72 (40.2) | 15 (36.6) | 57 (41.3) | 0.588 | |
| CBH8 | n (%) | 11 (6.4) | 3 (7.5) | 8 (6.1) | 0.720 | |
| Global lesions total10 | n (%) | 25 (15.0) | 4 (10.0) | 21 (16.5) | 0.312 | |
| PHVD | Surgical intervention n (%) | 9 (5.0) | 2 (4.9) | 7 (5.1) | 1.000 | |
| Kidokoro global score10 | Moderate or severe, n (%) | 21 (12.6) | 4 (10.0) | 17 (13.4) | 0.573 | |
| Kidokoro white matter score10 | Moderate or severe, n (%) | 30 (18.0) | 5 (12.5) | 25 (19.7) | 0.302 | |
| Kidokoro gray matter score10 | Moderate or severe, n (%) | 36 (21.6) | 13 (32.5) | 23 (18.1) | 0.054 | |
| Kidokoro deep gray matter score10 | Moderate or severe, n (%) | 2 (1.2) | 1 (2.5) | 1 (0.8) | 0.423 | |
| Kidokoro cerebellar score10 | Moderate or severe, n (%) | 19 (11.4) | 2 (5.0) | 17 (13.4) | 0.251 |
Abbreviations: NRH, non-right-handedness; RH, right-handedness; NA, not applicable; SD, standard deviation; IQR, interquartile range; MABC-2-NL, Movement Assessment Battery for Children second edition, Dutch version; MRI, magnetic resonance imaging; DTI, diffusion tensor imaging; IVH, intraventriculair haemorrhage; CBH, cerebellar haemorrhage; PHVD, post-haemorrhagic ventricular dilatation.
For some variables, the total sample size is smaller than the reported original sample due to missing values: 1 n = 177, 2 n = 95, 3 n = 171, 4 n = 161, 5 n = 158, 6 n = 175, 7 n = 107, 8 n = 171, 9 n = 172, 10 n = 167.
*Independent samples t-test for continuous variables; Pearson Chi-Square (χ2) for categorical variables; Fisher's Exact Test for dichotomous variables with expected cell counts <5.