Emotional facial paresis in temporal lobe epilepsy: its prevalence and lateralizing value

The selection of patients with medically refractory temporal lobe epilepsy (TLE) for surgery depends on the concordance of data from clinical, imaging and electroencephalographic evaluation. Though clinical examination is often normal, emotional facial paresis has been described in patients with TLE. Utilizing a well-characterized group of mesial TLE (MTLE) patients, who have achieved excellent seizure outcome following anterior temporal lobectomy with amygdalohippocampectomy (ATL), we investigated the prevalence, predictive value and associations of emotional facial paresis. When compared to 8 out of 50 control subjects (16%), 36 out of 50 MTLE patients (72%) exhibited unilateral emotional facial paresis; the difference was highly significant (P<0.0001). The presence of contralateral emotional facial paresis correctly predicted the side of ATL in 86.1% patients. The occurrence of emotional facial paresis was significantly associated with longer duration of epilepsy prior to ATL and left ATL. Our observations confirm that emotional facial parersis contralateral to the side of mesial temporal sclerosis (MTS) is a valuable localizing sign in correctly predicting the epileptogenic temporal lobe. We hypothesize that the presence of an intact right hemisphere and pathological changes more extensive than MTS may be required for emotional facial paresis to readily manifest.