The goals of this study are to describe the results obtained in seizure control as well as the side effects in a cohort of patients who are ≥50 years of age, implanted with vagus nerve stimulation for therapy resistant epilepsy.

Side effects related to antiseizure medications are much more common in patients older than 50, as they may have other medical comorbidities. However, many patients in the older spectrum are therapy resistant to antiseizure medications and other co-adjuvant treatments are required. Currently, there are no publications addressing this issue.

We interrogated the database of the Western University Epilepsy Program in London, Ontario. We selected patients who were ≥50 years of age and previously implanted with VNS due to therapy resistant epilepsy.

A total of 12(10.5%) patients were ≥50 years of age. The median age was 55.8 years old(IQR=53.5-61.7) and the median age of implantation was 48.5(IQR=42.8-53.3). 75%(N=9) of patients were female. All patients had some type of comorbidity. The median number of antiseizure medications was 2.5(IQR=2-3) and the most frequent EEG finding was generalized epileptiform discharges in 50%(n=6). The median follow-up period was 44.5(IQR=34.3-63.8) months after the VNS implantation.  Seizure freedom was achieved for several months in 33.3%(n=4) and 41.7%(n=5) had at least a 50% seizure reduction.  Complications related to the implantation were not found in any of these patients, however, 75%(n=9) developed some type of side effect. The most common were hoarseness in 41%(n=5) and sore throat in 25%(n=3). The maximum output current was 1.5 mA(IQR=1-2).

VNS is a relatively safe therapy in patients older than 50 years of age, with therapy resistant epilepsy. The rate of side effects is slightly higher and the output used is lower than in other groups. More data is required to establish the utility and safety of VNS in the elderly.