UNILATERAL BLINKING - A LATERALIZING SIGN IN PARTIAL SEIZURES

Background: Despite lateralizing signs, clinical lateralization of par tial seizures may be difficult. We evaluated the usefulness of ictal u nilateral blinking as a new lateralizing sign. Methods: We retrospecti vely searched our seizure database over a 30-month period and collecte d videotapes of patients with ictal unilateral blinking. After initial review, we excluded patients in whom blinking was not clearly unilate ral and those in whom it was accompanied by simultaneous facial clonic activity or mouth deviation. All patients underwent prolonged EEG-vid eo monitoring. Results: We identified 14 patients who met the above cr iteria, for a frequency of 1.5%. Age ranged from 18 months to 50 years (mean, 21.6). There were 11 males and 3 females. Unilateral blinking occurred 0 to 37 seconds (mean, 10) after clinical onset and was visib le for 1 to 37 seconds (mean, 17). In 10 patients, other:Lateralizing signs were present. All patients had partial epilepsy, localized by su rface EEG in 10 and by additional invasive EEG in four-nine were left hemisphere (four temporal, four frontal, one not further localized), t hree right hemisphere (two temporal, one frontal), and two undetermine d. Of the 12 patients whose epileptogenic zone was lateralized, blinki ng was ipsilateral in 10 and contralateral in two. The predictive valu e of unilateral blinking was 83% against EEG localization. Conclusion: Unilateral blinking is a relatively uncommon but reliable lateralizin g sign in partial seizures, usually indicating an ipsilateral epilepto genic zone.