All seizure babies (n=75) | Moderate HIE (n=27) | Severe HIE (n=17) | Metabolic/genetic disorder (n=16) | Stroke (n=10) | Other* (n=5) | P values† | |
Median (IQR) | Median (IQR) | Median (IQR) | Median (IQR) | Median (IQR) | Median (IQR) | ||
Seizure period (hours)‡ | 15.9 (4.4 to 42.1) | 8.7 (2.0 to 21.2) | 33.5 (11.9 to 58.0) | 25.0 (1.1 to 77.6) | 22.1 (6.6 to 55.1) | 14.1 (4.0 to 65.6) | 0.068 |
Age (hours after birth) at first recorded seizure | 19.4 (12.8 to 48.8) | 16.5 (8.7 to 35.5) | 15.2 (11.0 to 20.7) | 56.6 (42.7 to 99.3) | 25.4 (14.2 to 44.9) | 31.8 (18.1 to 74.4) | 0.001§ |
Total seizure burden (min) | 68.5 (27.5 to 166.8) | 48.5 (23.2 to 79.6) | 112.8 (32.7 to 223.6) | 39.9 (14.6 to 210.6) | 149.6 (54.2 to 289.6) | 117.3 (2.9 to 283.6) | 0.060 |
Number of seizures | 24.0 (9.0 to 51.0) | 10.0 (4.0 to 32.0) | 31.0 (21.0 to 57.5) | 30.5 (7.0 to 56.8) | 50.0 (15.0 to 166.5) | 12.0 (2.0 to 210.0) | 0.005¶ |
Median seizure duration (s) | 109.0 (65.0 to 225.5) | 143.0 (96.0 to 696.0) | 109.0 (66.5 to 205.8) | 93.8 (44.1 to 162.6) | 104.0 (63.1 to 158.0) | 70.0 (42.0 to 243.0) | 0.069 |
Maximum hourly seizure burden (MSB) (min/hour) | 21.3 (11.3 to 32.3) | 18.0 (14.4 to 28.3) | 24.7 (14.2 to 40.1) | 13.4 (7.9 to 24.2) | 30.3 (18.3 to 42.9) | 20.7 (1.3 to 30.2) | 0.063 |
Hour after birth in which MSB occurred | 31.0 (17.0 to 61.0) | 17.0 (12.0 to 43.0) | 27.0 (18.5 to 49.0) | 57.0 (43.8 to 145.5) | 29.5 (20.8 to 65.0) | 56.0 (29.5 to 102.0) | 0.002** |
Age (hours after birth) at last recorded seizure | 55.2 (28.5 to 86.1) | 34.4 (16.6 to 59.9) | 54.3 (28.1 to 80.3) | 71.9 (47.9 to 304.9) | 58.4 (31.5 to 122.0) | 56.6 (30.2 to 126.5) | 0.008†† |
*n=2 for seizures of unknown origin; n=2 for sepsis/meningitis; n=1 for postnatal cardiorespiratory arrest (and severe HIE).
†From Kruskall-Wallis test, with ‘other’ excluded from the analysis.
‡Time from start of first EEG seizure to end of last EEG seizure.
§Pairwise comparisons revealed significant differences between the metabolic/genetic disorder group and both the moderate HIE (adjusted p=0.002) and the severe HIE (adjusted p=0.002) groups.
¶Pairwise comparisons revealed significant differences between the moderate HIE group and both the severe HIE (adjusted p=0.034) and the stroke (adjusted p=0.019) groups.
**Pairwise comparisons revealed significant differences between the metabolic/genetic disorder group and the moderate HIE group (adjusted p=0.001).
††Pairwise comparisons revealed significant differences between the metabolic/genetic disorder group and the moderate HIE group (adjusted p=0.005).
EEG, electroencephalography; HIE, hypoxic-ischaemic encephalopathy.