Abstracts

Rationale: Epileptic aura associated with a particular emotion are well known and have been previously demonstrated to arise from the limbic system. Stereotypical emotional expressions for which the patient has no recollection - so called mimetic automatisms - can be seen during gelastic seizures. However, spontaneous mimetic automatisms of fear or sadness without preceding emotional aura have not been well characterized and provide insight into an efferent pathway for emotional expression. We describe the clinical and video-electrographic features of three patients with temporal lobe epilepsy who demonstrate mimetic automatisms of negative emotions; to our knowledge, video electroencephalography (vEEG) of spontaneous ictal negative emotional expressions of which the patient is unaware has not been previoulsy published. Methods: Out of 557 patients admitted for vEEG monitoring between 7/2006 and 5/2008, 3 patients (0.5%) were identified who had mimetic automatisms as their predominant semiology. Data was reviewed from the patients' charts, including vEEG, magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), fluorodeoxyglucose positron emission tomography (FDG-PET), and neuro-psychological testing. Results: Patient 1 was a 70 yo man with 18 stereotypic events captured on vEEG, during which his face would appear as if it was full of grief; his consciousness was not impaired during the event, but his stated mood during the spell was not congruent with his displayed affect. His EEG with sphenoidal electrodes revealed intermittent interictal left temporal sharp waves, and ictally demonstrated rhythmic delta slowing evolving over the left temporal area. His FDG-PET and ictal SPECT showed an area of increased signal over the left mesial temporal region (see figure 1). Patient 2 was a 60 yo woman with 8 stereotypic events all associated with repetitive vocalization and frightened appearance, during which time she was not reactive to commands and after which she was amnestic. EEG revealed frequent intermittent left anterior temporal spikes, and corresponding ictal patterns from the same region. Her FDG-PET during the period of frequent seizures revealed mild hypermetabolism in the left mesial temporal region, which resolved on follow-up imaging during a seizure-free period. Patient 3 was a 64 yo female with noninvasive and invasive recordings, who had 7 seizures associated with a repetitive frightened appearance, during which time she was not reactive and after which she was briefly aphasic and then amnestic. MRI showed a lesion in the left mesial temporal region, and invasive EEG confirmed an ictal onset zone in the left amygdala and posterior hippocampus. She became seizure-free after a limited lesionectomy. Conclusions: The mesial temporal structures often present as the anatomical substrate for the generation of an aura associated with fear or sadness. However, seizures with extremely stereotypical expressions may occur without the patient's awareness, and argue for a subconscious efferent pathway for emotional expression also involving these structures.