Somatomotor Manifestations in Temporal Lobe Seizures

Abstract

Somatomotor manifestations (SMM) sometimes are included among the clinical features of temporal lobe seizures in man. The data are limited and conflicting. Seizures (101) recorded during stereo-EEG explorations in 50 patients, selected on the basis of the demonstration of onset in temporal lobe structures (stereo-EEG) and the presence of lateralized SMM and/or secondary generalization (SG) are described. SMM and SG were present in .apprx. 20% of our population of patients with temporal seizures explored with stereo-EEG, and were only rarely observed during the 1st 10 s (early SMM) of the seizures (< 10%). Seizures characterized by early SMM were generally induced by electrical stimulation or chemical activation and only exceptionally spontaneous. In all cases the ictal electrical discharge also involved at an early stage extratemporal structures such as the rolandic operculum, the parietal lobe or contralateral temporal structures. In most cases (> 90%) SMM represented a late (> 10 s) event in the ictal symptomatology. The face and the upper limb were by far the most frequently involved segments. Of the seizures 38% ended up in SG. The associated ictal symptomatology was rather poor and differed from previous findings in temporal lobe seizures: oroalimentary automatisms were relatively rare, whereas an impairment of consciousness was observed in > 50% of seizures. The critical electrical discharge had a long duration and always involved extratemporal structures in one or both hemispheres. The involvement of the central region could be demonstrated in all patients with deep electrodes in that region. SMM are not characteristic of temporal lobe seizures, and their presence indicates spreading of the critical discharge beyond the temporal lobe.