Table 2. Sleep schedules and patterns in developmental delay group and comparison groups.
aComparisons between the DD-only group and the DD plus neurological diseases group. bComparisons between the DD-only group and the DD plus psychobehavioral diseases group. cBetween all groups’ comparison P-value. *P-value < 0.05 was considered statistically significant.
IQR, interquartile range; DD, developmental delay
| Outcome | Overall | DD-only | DD plus neurological diseases | P-valuea | DD plus psychobehavioral diseases | P-valueb | P-valuec |
| Median (IQR)/Number (%) | Median (IQR)/Number (%) | Median (IQR)/Number (%) | Median (IQR)/Number (%) | ||||
| Weekday | |||||||
| Bedtime | 22:00 (21:30-22:30) | 22:00 (21:30-22:30) | 21:45 (21:00-22:30) | 0.696 | 22:10 (21:30-23:00) | 0.016* | 0.002* |
| Wake time | 07:45 (07:00-08:00) | 07:40 (07:00-08:00) | 07:00 (06:30-07:47) | 0.006* | 08:00 (07:15-08:30) | 0.211 | 0.001* |
| Nocturnal sleep duration (hours) | 9.8 (9.0-10.5) | 10.0 (9.3-10.5) | 9.5 (8.9-10.0) | - | 9.6 (9.0-10.3) | - | 0.124 |
| Sleep insufficiency - Preschooler | 243 (88.0%) | 114 (90.5%) | 17 (70.8%) | - | 112 (88.9%) | - | 0.812 |
| Sleep insufficiency - School-aged | 33 (12.0%) | 12 (9.5%) | 7 (29.2%) | 14 (11.1%) | |||
| Napping - Average duration (hours) | 2.0 (1.3-2.0) | 2.0 (1.5-2.0) | 1.5 (1.0-2.0) | - | 2 (1.0-2.0) | - | 0.255 |
| Need for napping - Preschooler | 309 (89.3%) | 150 (88.8%) | 22 (95.7%) | - | 137 (89.0%) | - | 0.924 |
| Need for napping - School-aged | 31 (37.3%) | 8 (27.6%) | 12 (63.2%) | 11 (31.4%) | |||
| Weekend | |||||||
| Bedtime | 22:30 (22:00-23:00) | 22:30 (22:00-23:00) | 22:30 (21:30-23:00) | - | 22:30 (22:00-23:00) | - | 0.131 |
| Wake time | 08:30 (08:00-09:17) | 08:30 (08:00-09:00) | 08:00 (07:00-09:00) | - | 08:30 (08:00-09:30) | - | 0.092 |
| Nocturnal sleep duration (hours) | 10.0 (9.5-10.5) | 10.0 (9.5-10.5) | 10.0 (9.4-10.5) | - | 10.0 (9.5-10.5) | - | 0.121 |
| Sleep insufficiency - Preschooler | 187 (95.9%) | 84 (94.4%) | 14 (87.5%) | - | 89 (98.9%) | - | 0.749 |
| Sleep insufficiency - School-aged | 8 (4.1%) | 5 (5.6%) | 2 (12.5%) | 1 (1.1%) | |||
| Napping - Average duration (hours) | 2.0 (1.5-2.0) | 2.0 (1.5-2.0) | 2.0 (1.0-2.0) | - | 2.0 (1.0-2.5) | - | 0.233 |
| Need for napping - Preschooler | 247 (78.4%) | 120 (80.5%) | 19 (90.5%) | - | 108 (74.5%) | - | 0.136 |
| Need for napping – School-aged | 32 (38.1%) | 10 (34.5%) | 12 (63.2%) | 10 (27.8%) | |||
| Sleep onset latency | |||||||
| Less than 20 minutes | 283 (53.7%) | 136 (56.0%) | 30 (61.2%) | - | 117 (49.8%) | - | 0.163 |
| 20-60 minutes | 224 (42.5%) | 102 (42.0%) | 17 (34.7%) | 105 (44.7%) | |||
| >60 minutes | 20 (3.8%) | 5 (2.1%) | 2 (4.1%) | 13 (5.5%) | |||