Abstracts

RATIONALE: Mania infrequently occurs after anterior temporal lobectomy (ATL). Whether this is related to epilepsy or epilepsy surgery is unknown. Study of transient mania following epilepsy surgery may help delineate brain systems involved in suppressing abnormally elevated mood. METHODS: 15 patients with post-ATL transient mania were matched for age, sex, and side of surgery with 15 patients who did not have mania. Preoperative data from MRI, PET or SPECT, neuropsychological tests, scalp and intracranial EEG, and Wada were compared. Data were scored as incongruent when lateralized to the non-surgical side. Patients were also compared for seizure type, seizure frequency, preexisting psychiatric diagnosis, psychotropic drug treatment, aura type, early risk for seizure, pathology findings,and seizure outcome using categorical analyses. RESULTS: Abnormalities in the hemisphere contralateral to the ATL were present more often (29/75=39%) in mania patients than in controls (8/75=11%,p=.002). This was due to bilateral EEG findings (interictal spikes or seizure onset) in mania patients (11/15=73%) versus controls (1/15=7%,p=.002). There was a higher prevalence of preoperative generalized tonic-clonic seizures in the mania group (9) than controls (3)(p=.026). Mania tended to occur more often after right ATL (11) than left ATL (4) when compared with all other ATL done at our center (400) (p=.06). Patients with mania tended (p=.08) to have postoperative seizures more often than controls. All other presurgical tests and comparisons did not differ between patients and controls. Four people in each group had preoperative psychiatric diagnoses, but none had preoperative mania. CONCLUSIONS: The presence of greater bilateral limbic and diencephalic dysfunction appear to be risk factors for mania after ATL. The tendency for mania to occur more often after right ATL is consistent with the valence model of mood that associates positive emotional states with relative left hemispheric hyperfunction.