The Generalized Tonic-Clonic Seizure in Partial Versus Generalized Epilepsy: Semiologic Differences

Summary: Purpose: To study differences in the clinical manifestations of generalized tonic-clonic seizures (GTCS) of partial versus generalized onset.

Methods: We studied 10 GTCSs in nine patients with idio-pathic generalized epilepsy (IGE) and 10 GTCSs in 10 patients with temporal lobe epilepsy (TLE). Videotaped seizures were reviewed for all clinical features, focusing on asymmetries during different phases of each seizure.

Results: In the IGE group, focal features were seen before generalized motor activity in seven seizures. The most common was adversive head turn (six seizures). One patient had opposite direction of head turning in two recorded seizures. The tonic phase was always symmetric. In the last generalized clonic phase, asymmetry or asynchrony of motor activity was seen transiently in three seizures. The TLE group showed focal features before generalization in all seizures. Adversive head turning occurred in nine patients and was always contralateral to the focus. Focal clonic activity occurred before generalization in three and was always contralateral to the focus. The generalized tonic phase was usually asymmetric, and in the last clonic phase, motor activity was asymmetric or asynchronous in eight seizures (p > 0.05, IGE vs. TLE).

Conclusions: Brief focal features or asymmetry at onset are common in the GTCSs of IGE. However, asymmetry or asynchrony during the last clonic phase are uncommon in IGE, in contrast to TLE.