AbstractThis is the first case report of a patient who received long-term (69-month) adjunctive vagus nerve stimulation (VNS) therapy for treatment-resistant depression (TRD) and reached VNS battery end-of-service (EOS).The patient is a 41-year-old female with depression who entered a study of adjunctive VNS therapy for TRD. Her Hamilton Rating Scale for Depression (HAM-D) scores dropped from a mean of 33.5 (pre-implantation baseline period) to 16 at the end of the 12-week acute-phase treatment period, and then fluctuated from <7 (normal range) to scores in the moderately depressed range (∼20) during long-term follow-up. Three and one-half years after VNS implantation, the patient's HAM-D scores began to increase from a score of 18 to a peak score of 27 ∼ 16 months later (5-years post-implantation). The patient subsequently reported that she could no longer feel stimulation from the device and device interrogation 2 weeks later indicated battery EOS. The patient was hospitalized due to worsened depression, the pulse generator was replaced, and medication adjusted. HAM-D scores through the subsequent 9 months of followup returned to a pattern of fluctuations within the range noted during the long-term follow-up period prior to VNS battery EOS.
Vagus nerve stimulation for medically refractory epilepsy: A long-term follow-up study