ELECTROPHYSIOLOGY OF BIMANUAL-BIPEDAL AUTOMATISMS

To determine the localizing value and electrophysiology of bimanual-bi pedal automatisms (BBAs), we studied these behaviors in 54 seizures of 8 patients with temporal or frontal lobe seizure onset. BBAs occurred with a frequency of 27% in frontal lobe epilepsy (FLE) and of 7% in t emporal lobe epilepsy (TLE). The distribution of electrode sites showi ng ictal activity during these automatisms was significantly different in the two patient groups (0.0001 Chi-square). Mesio- and/or laterote mporal plus orbital frontal areas were involved areas when the behavio rs appeared in patients with TLE; dorsolateral and mesiofrontal region s were the most commonly involved when the behaviors occurred during t he course of frontal lobe seizures. We concluded that BBAs represent a ctivation of frontal lobe circuitry but are not unique to seizures of frontal lobe origin. Eyelid flutter and repetitive body movements in e ither the axial or sagittal plane were significantly associated with t he frontal lobe group whereas oral-alimentary automatisms were associa ted with the temporal lobe group. Thus, these associated behaviors may help indicate whether a frontal or temporal lobe seizure onset has oc curred when BBAs are observed. A new concept of ictal expression is pr oposed to conform with the results as well as with other apparently di sparate ictal behaviors that may have localizing value.