Somatomotor Manifestations in Temporal Lobe Seizures

Abstract

Some authors include somatomotor manifestations (SMM) among the clinical features of temporal lobe seizures in man; however, data are limited and conflicting. This study describes 101 seizures 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). SMM and SG were present in about 20% of our population of patients with temporal seizures explored with stereo-EEG, and were only rarely observed during the first 10 s (early SMM) of the seizures (less than 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 (greater than 90%) SMM represented a late (greater than 10 s) event in the ictal symptomatology. The face and the upper limb were by far the most frequently involved segments. Thirty-eight percent of seizures ended up in SG. The associated ictal symptomatology was rather poor and differed from our previous findings in temporal lobe seizures: oroalimentary automatisms were relatively rare, whereas an impairment of consciousness was observed in more than 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. In conclusion, SMM are not characteristic of temporal lobe seizures, and their presence indicates spreading of the critical discharge beyond the temporal lobe.

Analysis of dynamics and propagation of parietal cingulate seizures with secondary mesial temporal involvement

“…The posterior cingulate cortex is known to project to the hippocampus via the entorhinal cortex [17] and to receive connections from the hippocampus, possibly via the thalamus [18]. In a report of 36 patients with TLE who were monitored with stereo-EEG, ictal propagation to the cingulate gyrus was frequent [19]. …”

Hemifacial motor and crying seizures of temporal lobe onset: case report and review of electro-clinical localisation

“…In the context of TLE, past investigators have considered the amygdala as the most likely medial temporal region structure to send projections to the extratemporal structures responsible for associated motor signs, including both dystonic posturing 4 and somato-motor signs. 3 However, investigators disagree about the pathways of propagation from the amygdala that causes the motor symptoms. 5 Gloor reported that there are no direct projections from the amygdala to the motor cortex, and that any behavioural response initiated by amygdaloid activity reflected involvement of the motor system indirectly.…”

“…Such a mechanism of symptoms is consistent with the conclusion by Bossi et al that motor symptoms in TLE are related to activation of extratemporal structures. 3 …”

The amygdalo-motor pathways and the control of facial expressions

“…Monkeys and humans with bilateral lesions of the amygdala appear less reserved when encountering strangers and produce more affiliative displays (Meunier et al, 1999; Emery et al, 2001; Adolphs, 2010; Bliss-Moreau et al, 2013). In light of these findings, it is not surprising that electrical stimulation of the amygdala, and seizures originating therein, cause facial movements in both humans and monkeys (Baldwin et al, 1954; Feindel and Penfield, 1954; Feindel, 1961; van Buren, 1961; Gloor, 1975; Bossi et al, 1984; Hausser-Hauw and Bancaud, 1987; Fish et al, 1993). The output of the amygdala might influence the choice of facial expressions because it signals the identity, facial expression, and gaze direction of others (Leonard et al, 1985; Gothard et al, 2007; Hoffman et al, 2007; Gamer and Büchel, 2009) or the subjective impression elicited by face stimuli (Wang et al, 2013).…”