Sensitivity of a 256 channel EEG recording in temporal mesial sclerosis patients and temporal neocortical patients

Purpose: to describe the augmented sensitivity of a 256 channel EEGrecording in the epileptiform activity scalp localization by visual inspectionof patients affected by temporal mesial sclerosis and neocortical temporalepilepsy. Exploiting 20 left and 20 right electrodes covering facebetween orbitary floor and the upper margin jaw (anterior and posteriorzygomatic electrodes) we underlie the accuracy and non-invasivity ofthis method.Method: we recorded a rest 256 channel EEG in 14 patients (7 femaleand 7 male mean age 42 years) affected by temporal epilepsy. We consideredsix mesial temporal sclerosis patients and three neocortical temporalpatients. We then compared the scalp localization of epileptiform abnormalitiesby visual inspection through the standard 10–20 bipolar andmonopolar montages and later through the 256 Topo Plot Average ReferenceMap e.g. a projection of each electrode's activity on a scalp model.Result: in temporal mesial sclerosis patients, EEG abnormalitiesobserved in fronto temporal standard 10–20 montage are seen with thehighest negative peak in anterior zygomatic channels (Topo Plot Mapmontage), while temporal neocortical patients underling a large fieldpotential are seen in posterior zygomatic electrodes.Conclusion: since the basal temporal cortex is tangential to the lateralsurface of the skull and neocortical epilepsy underlies a large field potential,anterior and posterior zygomatic electrodes respectively could beconsidered at the same time as a non-invasive method and specific tool toincrease the maximum peak localization by visual inspection in patientsaffected by temporal mesial sclerosis and temporal neocortical epilepsypatients.