Table 3.
Seizure outcomes and associated factors
| MEG slowing | No MEG slowing | p value | ||
|---|---|---|---|---|
| A) Patient demographics | ||||
| Age | years | 20.0 ± 3.3 | 28.2 ± 1.4 | < 0.01* |
| Gender | Male | 14 (19.2) | 59 (80.8) | 0.34 |
| Female | 7 (11.9) | 52 (88.1) | ||
| Handedness | Right | 13 (13.4) | 84 (86.6) | 0.06 |
| Left | 2 (11.1) | 16 (88.9) | ||
| Ambidextrous/unknown | 6 (35.3) | 11 (64.7) | ||
| B) Epilepsy characteristics | ||||
| Duration epilepsy | years | 8.0 ± 1.5 | 15.2 ± 1.1 | < 0.01* |
| Seizure frequency | no. per week | 13.1 ± 3.8 | 10.7 ± 2.2 | 0.65 |
| AEDs tried | no. | 5.7 ± 0.5 | 4.7 ± 0.3 | 0.13 |
| Lobe involved | Temporal | 7 (9.3) | 68 (90.7) | 0.03* |
| Extratemporal/multilobe | 14 (24.6) | 43 (75.4) | ||
| Primary Pathology | Gliosis only | 5 (11.9) | 37 (88.1) | 0.12 |
| MCD | 10 (30.3) | 23 (69.7) | ||
| MTS | 4 (16.0) | 21 (84.0) | ||
| Tumor | 1 (4.5) | 21 (95.5) | ||
| Ischemia/infarct | 1 (20.0) | 4 (80.0) | ||
| Other | 0 (0.0) | 5 (100.0) | ||
| History of generalized seizures | Yes | 13 (16.7) | 65 (83.3) | 0.81 |
| No | 8 (14.8) | 46 (85.2) | ||
| Side of surgery | Right | 9 (26.4) | 46 (83.6) | 0.99 |
| Left | 12 (15.6) | 65 (84.4) | ||
| Previous resection | No | 18 (16.1) | 94 (83.9) | 0.99 |
| Yes | 3 (15.0) | 17 (85.0) | ||
| C) Pre-operative diagnostics | ||||
| MEG spike activity | Specific to EZ | 12 (17.6) | 56 (82.4) | 0.85 |
| Non-specific or discordant | 5 (14.3) | 30 (85.7) | ||
| No spikes modelled | 4 (13.8) | 25 (86.2) | ||
| MRI | Abnormal | 18 (16.5) | 91 (83.5) | 0.48 |
| Normal | 3 (13.0) | 20 (87.0) | ||
| Ictal scalp EEG | Localized | 13 (16.5) | 66 (83.5) | 0.99 |
| Not localized | 8 (16.0) | 42 (84.0) | ||
| PET (when performed) | Abnormal | 4 (15.4) | 22 (84.6) | 0.99 |
| Normal | 2 (15.4) | 11 (84.6) | ||
| TOTAL | 21 (15.9) | 111 (84.1) | ||
Data are N (%) for categorical variables or mean ± SEM for continuous variables.
*
Statistically significant value (p < 0.05) from χ2 test (categorical) or t-test (continuous) comparing patients with or without asymmetric slowing on MEG.
AED: anti-epileptic drug; EEG: electroencephalography; EZ: epileptogenic zone; MCD: malformation of cortical development; MEG: magnetoencephalography; MRI: magnetic resonance imaging; MTS: mesial temporal sclerosis; PET: positron emission tomography.