Ictal singing due to right mesial temporal lobe epilepsy involving a bihemispheric network☆

Singing is a rare ictal symptom of focal epilepsy. Here, we report a case of a right-handed patient who demonstrated ictal singing due to right mesial temporal lobe epilepsy. Subtraction ictal SPECT coregistered to MRI (SISCOM) performed during ictal singing demonstrated areas of hyperperfusion in the bilateral frontal regions (more prominent in the left frontal lobe), bilateral subcortical regions, insular cortices, and bilateral cerebellum in addition to the right temporal area. An intracranial EEG revealed that an ictal singing episode commenced after an ictal rhythm from the right temporal area was propagated to the contralateral side of the left hemisphere. These findings suggest that the symptomatogenic zone for ictal singing includes neural networks from the frontal and temporal regions of both hemispheres rather than specific cortical areas even when the epileptogenic zone is located in the right mesial temporal area, as evidenced in this patient.