High-Frequency Anterior Thalamus Stimulation Interrupts Cortical Midline Theta Rhythm During Drowsiness in an Epileptic Patient

adjusted for a number of known confounders. Methods: We retrospectively reviewed video-EEG data of people with refractory temporal lobe epilepsy undergoing presurgical assessment and of ageand gender matched patients without known epilepsy presenting with PNES. One seizure per patient was analyzed. HR was assessed with the help of a one-channel ECG lead at different time points (2 min before, during the seizure where HR was highest, immediately after seizure cessation, and 1, 2, 3, 5 and 10 min postictally). Data are given as mean ± SD. Results: A total of 189 of patients and seizures were included in the study. Sixty TLES arising from wakefulness (20 men, 34 ± 12 years) and 129 PNES were analyzed. In the PNES group, 60 of the seizures had occurred spontaneously from wakefulness (PNES-S, 20 men, 37 ± 14 years), while 69 were induced by a provocation maneuver (verbal suggestion along with intravenous injection of vitamins; PNES-P, 23 men, 36 ± 14 years). In the PNES-P group, baseline HR was significantly higher as compared to the two other groups (p < 0.01). In the TLES group, relative HR changes were significantly higher during and shortly after seizure cessation, as compared to the PNES-S group (p 0.002). During seizures with major motor phenomena (generalized epileptic or psychogenic convulsions), relative HR changes during the seizures were not different (p = 0.165, convulsive TLES n = 11, convulsive PNES-S n = 36). However, in the first three minutes after seizure cessation, HR was higher in the major motor TLES group (p values < 0.01, 0.09 and 0.07). Furthermore, non-motor TLES displayed consistently higher relative HR changes during and shortly after seizure cessation up to 2 min postically as compared to the non-motor PNES-S. Conclusions: TLES display higher relative HR changes during non-motor seizures as well as shortly after major motor and non-motor seizures, as compared to PNES-S. The setting of a provocation maneuver itself appears to enhance baseline HR. Taken together, our results support the notion that analysis of periictal HR is helpful in the differential diagnosis of epileptic versus psychogenic, non-epileptic seizures.