Electroclinical analysis of postictal noserubbing

Background: Postictal noserubbing (PIN) has been identified as a good, albe it imperfect, lateralizing and localizing sign in human partial epilepsy, p ossibly related to ictal autonomic activation. Methods: PIN was studied pro spectively in a group of consecutive patients admitted for video-EEC monito ring, with the laterality of noserubbing correlated with electrographic sit es of seizure onset, intra- and interhemispheric spread, and sites of seizu re termination. Results: PIN was significantly more frequent in temporal th an extratemporal epilepsy (p<0.001; 23/41 (56%) patients and 41/197 (21%) s eizures in temporal lobe epilepsy compared with 4/34 (12%) patients and 12/ 167 (7%) seizures in extratemporal epilepsy). The hand used to rub the nose was ipsilateral to the side of seizure onset in 83% of both temporal and e xtratemporal seizures. Seizures with contralateral PIN correlated with spre ad to the contralateral temporal lobe on scalp EEG (p<0.04). All extratempo ral seizures with PIN showed spread to temporal lobe structures. One patien t investigated with intracranial electrodes showed PIN only when ictal acti vity spread to involve the amygdala: seizures confined to the hippocampus w ere not associated with PIN. PIN was not observed in 63 nonepileptic events in 17 patients. Unexpectedly, one patient with primary generalized epileps y showed typical PIN after 1/3 recorded absence seizures. Conclusions: This study confirms PIN as a good indicator of ipsilateral temporal lobe seizur e onset. Instances of false lateralization and localization appear to refle ct seizure spread to contralateral or ipsilateral temporal lobe structures, respectively. Involvement of the amygdala appears to be of prime importanc e for induction of PIN.