Ictal dystonia and secondary generalization in temporal lobe seizures: A video-EEG study

The aim of this study was to determine whether the occurrence of unilateral ictal limb dystonia (ID) during complex partial seizures (CPS) reduces the possibility of contralateral propagation (CP) and secondary generalization (SG) in patients with temporal lobe epilepsy (TLE). We assessed 216 seizures recorded in 33 patients with pharmacoresistant TLE. All patients underwent video-EEG telemetry prior to surgical treatment with good postoperative outcomes (Engel I). Ictal limb dystonia was observed in 16 of the 33 patients (48%) and 58 of the 216 seizures (26.8%). We found highly significant differences in the frequency of SG between seizures with ID and seizures without ID (2/58 vs. 41/158; 3.45% vs. 25.95%; p < 0.001). Contralateral propagation was seen in 13 of the 57 analyzed seizures with ID compared to 85 of the 158 seizures without ID (22.8% vs. 53.8%; p < 0.001). Among the CPS without SG, we found that the mean duration of seizures with ID was significantly longer than the duration of seizures without ID (81.66 ± 40.10 vs. 68.88 ± 25.01 s; p = 0.011). Our findings that CP and SG occur less often in patients with ID, yet the duration of CPS without SG is longer in patients with ID, suggest that the basal ganglia might inhibit propagation to the contralateral hemisphere but not ictal activity within the unilateral epileptic network.

► Frequency of secondary generalization is lower in seizures with ictal dystonia (ID). ► Contralateral propagation is rarer in seizures with ID compared to those without ID. ► Duration of complex partial seizures with ID is longer than in seizures without ID. ► Basal ganglia have an inhibitory role on seizure propagation.