Abstracts

RATIONALE: Vagus nerve stimulation (VNS) has proven effective in a variety of seizure disorders in children and adults. However, its efficacy and side effects in the elderly remain uncertain. Antiepileptic drugs are often associated with more side effects and drug interactions in this population and alternative therapies are desirable. At the end of this activity, the participants should be able to discuss the efficacy and tolerability of vagus nerve stimulation in patients older than age 60.
METHODS: Medical records of all 152 patients treated with VNS at the three Mayo Clinic sites (Rochester, Scottsdale, and Jacksonville) were reviewed. Patients older than age 60 who were receiving VNS were selected and their clinical course including duration of epilepsy, seizure type, etiology, and adverse effects were evaluated. Patients were contacted to ascertain the efficacy and tolerability of VNS. The seizure frequency at last visit was compared to pre-implantation seizure frequency.
RESULTS: Nine patients receiving VNS at the three Mayo Clinic sites older than 60 were identified. There were five women and four men with a mean age of 65 at implantation (range 57-82). Six patients had partial, two had partial and secondary generalized, and one had primary generalized seizures. The etiologies were prior head trauma (3), encephalitis (3), idiopathic (2), and tuberous sclerosis (1). The duration of epilepsy prior to initiation of VNS ranged from 2 to 61 years. The duration of follow-up ranged from 12 to 40 months (mean = 25 months).
At the last follow-up, two patients (22%) had a 100%, two (22%) had a 60-80%, and one (11%) had a 30% reduction in seizure frequency. One patient who benefited initially with an 80% reduction in seizures died 14 months after implantation during a seizure. Three patients had no significant benefit, and one patient had an increase in seizure frequency (44% non-responders). Six patients had a reduction in the frequency and duration of seizure clusters. There were no incidents of intraoperative asystole, device failure, or wound complications. One patient experienced vocal cord paresis post-operatively, which resolved several months later. Medications were reduced in two patients. Side effects related to VNS occurred in five patients (55%), including dyspnea, hoarseness, dysphonia, and dysphagia, but these side effects did not result in discontinuation of treatment in any patient.
CONCLUSIONS: VNS resulted in a significant improvement in seizure frequency in 44% of this elderly epilepsy population. VNS was well-tolerated in this age group.