Temporal Lobe Epilepsy Onset After Age Five Does Not Alter Facial Emotion Recognition Following Curative Nondominant Temporal Lobectomy
Shearwood McClelland III M.D.1, Rebeca E. Garcia B.Sc.2, Daniel M. Peraza B.A.3, Tina T. Shih M.D.4, Lawrence J. Hirsch M.D.5, Joy Hirsch Ph.D.3, Robert R. Goodman M.D., Ph.D.2
1Department of Neurosurgery, University of Minnesota Medical School, Minneapolis, MN; Departments of 2Neurological Surgery, 3Radiology, and 5Neurology, Columbia University, College of Physicians and Surgeons, New York, NY; Department of 4Neurology, University of California at San Francisco, San Francisco, CA
The nondominant amygdala is crucial for processing facial expression and emotional recognition (ER) of visual stimuli, particularly in facial fear recognition. Patients with temporal lobe epilepsy (TLE) associated with mesial temporal sclerosis (MTS) often incur amygdalar and hippocampal damage. Previous studies have shown that patients with right-sided (nondominant) MTS experience impaired ER if TLE onset occurred before age six. This finding has resulted in the hypothesis that early right mesiotemporal insult impairs plasticity, resulting in ER deficits, while damage later in life (seizure onset after age five) results in no deficit. However, this hypothesis has not been tested in a uniformly seizure-free postsurgical population. This study was performed to examine this issue in late-onset postsurgical patients.
Controls (n=10) and late-onset patients (n=5) were recruited. All patients underwent nondominant anteromedial temporal lobectomy (AMTL), had TLE onset after age five, Wada-confirmed left-hemisphere language dominance and memory support, MTS on both pre-operative MRI and biopsy, and were Engel class I five years after surgery. Using a standardized (Ekman and Friesen) human face series depicting neutrality and the six basic emotions conveyed by facial expression (happiness, sadness, fear, disgust, anger and surprise), subjects were asked to match the affect of one of two faces to that of a simultaneously presented target face. Target faces expressed fear, anger, or happiness.
Statistical analysis (t-test) revealed that the late-onset group had ER (as measured by percentage of faces correct and reaction time) for fear (P=0.871), anger (P=0.256), and happiness (P=0.608) comparable to controls. All 95% confidence intervals included zero.
Following curative AMTL in nondominant MTS patients, TLE onset after age five does not predict significant ER impairment for facial expressions. Future studies are needed to examine whether early TLE onset continues to impair ER following AMTL.