LATERALIZING SIGNS IN INTRACTABLE PARTIAL EPILEPSY - BLINDED MULTIPLE-OBSERVER ANALYSIS

We evaluated the accuracy and interobserver variability of selected ic tal and postictal behavioral changes. Three observers, blinded to clin ical history, EEG, and side of surgical resection, analyzed videotapes of 166 seizures in 38 patients, looking for lateralizing signs. Twent y-seven patients with temporal lobe resections were seizure-free for g reater-than-or-equal-to 1 year postoperatively, and 11 with extratempo ral resections had at least 90% reduction in seizures greater-than-or- equal-to 1 year postsurgery. The epileptogenic region (ER) was lateral ized by analyzing lateralizing signs in 78% of patients; positive pred ictive value (PPV) was 94% (90% CI = 87% to 100%). Overall kappa was 0 .68. Signs were considered present if seen by two or more observers. F orty-five percent had version, ie, forced and sustained head deviation (kappa = 0.76, PPV = 94%); 37% had dystonic posturing of the upper ex tremity (kappa = 0.47, PPV = 93%); and 34% had unilateral mouth deviat ion (kappa = 0.83, PPV = 92%). These signs indicated a contralateral E R. Twenty-one percent had unilateral upper extremity automatisms, all ipsilateral to the ER (kappa = 0.65, PPV = 100%); 21% had postictal dy snomia, indicating a dominant-hemisphere ER (kappa = 0.89, PPV = 100%) ; and 16% had ictal speech, usually indicating a nondominant-hemispher e ER (kappa = 0.75, PPV = 83%). Dystonic posturing, postictal dysnomia , ictal speech, and unilateral upper extremity automatisms may indicat e a higher probability of temporal lobe epilepsy. Analysis of laterali zing signs shows good interobserver agreement and provides useful clin ical information.