Typical unfamiliar face discrimination ability in anterior temporal lobe epilepsy
Résumé
Compared to patients with prosopagnosia, other animal species, infants or children, neurotypical human adults are experts at individuating pictures of unfamiliar faces, but the neural basis of this function remains largely unknown. Since an increasing number of studies rely on intracranial recordings in anterior temporal epileptic patients (aTLE) to investigate the neural mechanisms of face recognition, it is important to assess aTLE patients’ ability to discriminate and match unfamiliar individual faces. Here, we tested 42 patients with left (n=17) or right (n=25) aTLE, and 42 healthy matched controls. Seven computerized neuropsychological tests were administered: the Benton Face Recognition Test (BFRT), the Cambridge Face Memory Test (CFMT), delayed matching of upright pictures of faces and objects, the Mooney Face Test, famous face recognition and naming, unfamiliar face and object learning. Relative to controls, we found that (1) both left and right aTLE patients were impaired (−10.5% and −8.2% in accuracy, respectively) in learning unfamiliar faces, but without any specificity (i.e. impairment also for nonface objects); (2) on average, right aTLE patients had significantly slower response times at all tasks, but this included the WAIS’ Code subtest assessing processing speed, showing that this effect is not specific to visual tasks and (3) importantly, there was no difference between aTLE patients and matched controls on all the tasks assessing individual face discrimination (mean BFRT scores at 42.3/54 and 42.6/54 and CFMT scores at 47.2/72 and 47.1/72 for left and right aTLE respectively, significant inversion effect for matching individual faces but not cars). Overall, our study shows that left and right aTLE patients do not differ quantitatively and qualitatively at unfamiliar face discrimination tasks relative to healthy controls.