Neuropsychiatric Symptoms of Epilepsy

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S. Meletti
epilepsy or not. This is a highly relevant issue in the analysis of neuropsychological
outcomes. Longitudinal, prospective studies are needed to shed light on this issue.
Finally, another important issue concerns the ER ability of ATL patients seen at
long follow-up intervals. Since several factors can contribute to the interpretations
of neuropsychological findings in TLE and in ATL patients (i.e., etiology, side of
focus/surgery, age of epilepsy onset, post-operative seizure freedom), we recently
evaluated ER in an homogenous cohort of ATL patients (undergone to surgery at
around 40 years of age) with: (a) more than 5 years of follow-up and (b) complete
seizure-freedom status. We found that deficits in the evaluation of facial expressions
were still present at long follow-up intervals in seizure-free patients [ 74 ]. This finding
should prompt researchers to investigate in future studies whether this picture
changes in relation to the age of ATL surgery, especially if the patients operated
earlier can better compensate or implement plasticity mechanisms leading to recover
the deficit.
Facial Expression Processing in TLE: Evidences from FMRI
Beyond neuropsychological and behavioral tasks, functional magnetic resonance
imaging (fMRI) has been used to evaluate the brain processing of emotional stimuli
in patients with TLE/ATL. Experiments have been performed to understand the
consequences of pathological amygdala tissue (in the case of chronic medial TLE),
or of the absence of the amygdala (in the case of ATL), on the processing of emotional
material. Knowledge from fMRI experiments in healthy subjects consistently
demonstrated that facial expressions, and particularly fearful faces, induce a robust
response in the amygdala [ 75 , 76 ]. The amygdala response to facial expression can
be modulated by different variables (type of stimulus, type of response, type of task)
but is highly reproducible. Moreover, the perception of emotional faces induces a
higher fMRI response over the extra-striate visual cortical areas (such as the fusiform
face area) with respect to the vision of neutral faces [ 77 ]. This means that the
perception of emotional stimuli enhances cortical activity in associative areas. This
is one of the ways through which emotions affect and enhance cognition. In the case
of chronic medial TLE, different authors have reported two main results. First, the
medial temporal lobe region ipsilateral to the epileptogenic zone does not show a
reproducible response to facial expression, and especially to fearful ones; this result
is the direct consequence of the pathological tissue affecting the amygdala/temporal
pole region. This effect, or loss of fMRI responses to fearful faces, has also been
used in chronic TLE to obtain information at single-subject level to lateralize the
side of the epileptogenic focus [ 78 – 81 ]. Moreover, activation of the right amygdala
preoperatively was predictive of emotional disturbances following right anterior
temporal lobectomy [ 79 ].
Second, and probably most importantly, it has been demonstrated that amygdala
pathology prevents the increased response in distant cortical areas as instead has
been observed in healthy subject while viewing emotional facial expressions [ 44 ,