International Journal of Epilepsy 2016; 03(01): 42-62
DOI: 10.1016/j.ijep.2015.12.027
Thieme Medical and Scientific Publishers Private Ltd. 2017

Extra-temporal seizure semiology – Central

John Stern
1   Professor, Dept of Neurology, UCLA, Los Angeles, USA
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Publication Date:
12 May 2018 (online)

The localization of seizures is evident in the transient functional changes that occur during seizures, as can be assessed through several diagnostic tests. Beyond the electro-physiologic and imaging modalities, the patient's subjective experience and objective behavior during seizures are critical tests, and each of the other diagnostic tests must be validated as plausible in the context of the seizure manifestation (semiology). A critical facet to semiology is that the seizure manifestation does not necessarily indicate the epileptogenic region. More accurately, it indicates the symptomatogenic zone, that is, the zone where the seizure first becomes behaviorally evident. This may be the epileptogenic zone or the first eloquent cortex to become involved in the seizure as it spreads. Semiology may be approached by parcellating each cerebral hemisphere into 16 regions that differ in their associated seizure manifestation. Of these regions, primary motor, supplementary motor, primary sensory, and parietal association are collectively the central region. Each of these four regions may produce motor and sensory abnormalities, but the motor regions are, of course, more likely to produce motor and more likely to have a larger motor component when both motor and sensory activity are present. The complexity of the activity is differentiating and helps localize the region to either primary or supplementary/association. Simple and spreading jerks or sensations are more likely to be primary cortex. Complex and asymmetric movements are more likely to be supplementary motor, and cognitively complex somatosensory perception are more likely to be parietal association cortex.