Epileptic discharges in a mammillary body of a patient with refractory epilepsy

Objectives.  To document epileptiform discharges recorded within a mammillary body (MB) of a patient with chronic refractory epilepsy (CRE). Materials and Methods.  A 37-year-old man, whose epilepsy was not controlled by medication or vagus nerve stimulation, was enrolled in a study of the effects of deep brain stimulation of the MB and mammillothalamic tract (MTT) in CRE. Surface and deep EEG recordings were obtained for 3 days before implantation of the macroelectrodes and for 4 days after implantation of the macroelectrodes but before implantation of the stimulator battery. Results.  Paroxysmal epileptiform discharges were recorded in the right MB while other surface and deep recordings, in particular from the right MTT, were silent. When these discharges were longer than 100 sec, they spread to the right MTT area and then to the left MB and MTT area. Simultaneously, the patient became agitated and confused. Conclusions.  This original observation indicates that subcortical neuronal structures, such as the MB, may sustain epileptiform discharges in humans.