Table 3

Seizure characteristics by aetiology, n=75

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 seizure19.4 (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 seizures24.0 (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 occurred31.0 (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 seizure55.2 (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.