Table 3.
Continuous electroencephalographic monitoring characteristics with a comparison of the features in patients with electrographic seizures to those without, when appropriate
| Category | Total population (with and without electrographic seizures) | No electrographic seizures |
Electrographic seizures |
Difference | |
|---|---|---|---|---|---|
| cEEG indication^ | Encephalopathy with possible electrographic seizures | 55 | 41 | 14 | |
| Management of refractory status epilepticus @ | 42 | 19 | 23 | ||
| Event characterization | 31 | 26 | 5 | ||
| Management of intracranial pressure | 1 | 1 | 0 | ||
| Unknown indication | 1 | 0 | 1 | ||
| EEG monitoring duration* (N=98) | <12 hours | 13 (13.3%) | 11 (16.7%) | 2 (6.3%) | Pearson chisquare= 23.6043 p<0.0005 |
| >12–24 hours | 37 (37.8%) | 31 (47%) | 6 (18.8%) | ||
| >24–48 hours | 22 (22.5%) | 14 (21.2%) | 8 (25%) | ||
| >48–72 hours | 5 (5.1%) | 4 (6.1%) | 1 (3.1%) | ||
| >72 hours | 20 (20.4%) | 5 (7.6%) | 15 (46.9%) | ||
| Unknown | 1 (1%) | 1 (1.5%) | 0 (0%) | ||
| Mental status at start of cEEG (N=98) | Lethargic/obtunded/abnormal | 63 (64.3%) | 42 (63.6%) | 21 (65.6%) | Pearson chi-square= 1.7267 p= 0.422 |
| Comatose | 27 (27.6%) | 17 (25.8%) | 10 (31.3%) | ||
| Normal | 8 (8.2%) | 7 (10.6%) | 1 (3.1%) | ||
| Initial cEEG background (N=98) | Normal sleep | 11 (11.2%) | 9 (13.6%) | 2 (6.3%) | Pearson chi-square= 4.5092 p= 0.341 |
| Slow disorganized | 68 (69.4%) | 47 (71.2%) | 21 (65.6%) | ||
| Discontinuous | 6 (6.1%) | 4 (6.1%) | 2 (6.3%) | ||
| Burst suppression | 8 (8.2%) | 3 (4.6%) | 5 (15.6%) | ||
| Attenuated and featureless | 5 (5.1%) | 3 (4.6%) | 2 (6.3%) | ||
| Typical cEEG background (N=98) | Normal sleep | 12 (12.2%) | 12 (18.2%) | 0 (0%) | Pearson chi-square= 15.1228 p= 0.004 |
| Slow disorganized | 63 (64.3%) | 44 (66.7%) | 19 (59.4%) | ||
| Discontinuous | 10 (10.2%) | 6 (9.1%) | 4 (12.5%) | ||
| Burst suppression | 9 (9.2%) | 2 (3%) | 7 (21.9%) | ||
| Attenuated | 4 (4.1%) | 2 (3%) | 2 (6.3%) | ||
| End cEEG background (N=98) | Normal sleep | 18 (18.4%) | 17 (25.8%) | 1 (3.1%) | Pearson chi-square= 7.882 p= 0.096 |
| Slow disorganized | 64 (65.3%) | 39 (59.1%) | 25 (78.1%) | ||
| Discontinuous | 9 (9.2%) | 5 (7.6%) | 4 (12.5%) | ||
| Burst suppression | 4 (4.1%) | 3 (4.6%) | 1 (3.1%) | ||
| Attenuated | 3 (3.1%) | 2 (3%) | 1 (3.1%) | ||
| Interictal epileptiform discharges (N=98) | Present | 59 (60.2%) | 31 (47%) | 28 (88%) | Pearson chi-square= 14.7762 p< 0.0005 |
| Absent | 39 (39.8%) | 35 (53%) | 4 (12.5%) | ||
| Patterns in the cEEG^ | Periodic discharges | 20 | 7 | 13 | |
| Lateralized | 7 | 4 | 3 | ||
| Generalized | 9 | 2 | 7 | ||
| Bilaterally independent | 3 | 1 | 2 | ||
| Multifocal | 0 | 0 | 0 | ||
| Unknown | 2 | 0 | 2 | ||
| Rhythmic pattern | 8 | 3 | 5 | ||
| Lateralized | 3 | 2 | 1 | ||
| Generalized | 5 | 1 | 4 | ||
| Bilaterally independent | 1 | 0 | 1 | ||
| Multifocal | 0 | 0 | 0 | ||
| Unknown | 0 | 0 | 0 | ||
| Spike/sharp-wave | 29 | 13 | 16 | ||
| Lateralized | 5 | 3 | 2 | ||
| Generalized | 10 | 4 | 6 | ||
| Bilaterally independent | 8 | 5 | 3 | ||
| Multifocal | 14 | 4 | 10 | ||
| Unknown | 0 | 0 | 0 | ||
*
EEG monitoring interruptions <12 hours are considered the same session
^
Numbers do not sum up to 98 as one patient may have had more than one indication for performing a cEEG
@
cEEG was performed in patients with refractory SE when it was clinically unclear that the SE had stopped (such as because of diminished or absent reactivity to stimuli).
Legend: cEEG: Continuous EEG. SE: Status epilepticus.