Added clinical value of the inferior temporal EEG electrode chain

Abstract Objective To investigate the diagnostic added value of supplementing the 10–20 EEG array with six electrodes in the inferior temporal chain. Methods EEGs were recorded with 25 electrodes: 19 positions of the 10–20 system, and six additional electrodes in the inferior temporal chain (F9/10, T9/10, P9/10). Five-hundred consecutive standard and sleep EEG recordings were reviewed using the 10–20 array and the extended array. We identified the recordings with EEG abnormalities that had peak negativities at the inferior temporal electrodes, and those that only were visible at the inferior temporal electrodes. Results From the 286 abnormal recordings, the peak negativity was at the inferior temporal electrodes in 81 cases (28.3%) and only visible at the inferior temporal electrodes in eight cases (2.8%). In the sub-group of patients with temporal abnormalities ( n  = 134), these represented 59% (peak in the inferior chain) and 6% (only seen at the inferior chain). Conclusions Adding six electrodes in the inferior temporal electrode chain to the 10–20 array improves the localization and identification of EEG abnormalities, especially those located in the temporal region. Significance Our results suggest that inferior temporal electrodes should be added to the EEG array, to increase the diagnostic yield of the recordings.