Depression is a major co-morbid condition with epilepsy, and has been found to be the single largest determinant of health-related quality of life in patients with epilepsy, even greater than seizure frequency and severity. Several studies have looked at the changes in symptoms of depression in patient treated with Vagus Nerve Stimulation for epilepsy. However, these studies have had some major limitations, including that they relied on scales designed to measure severity of depression in a population of clinically depressed patients instead of a scale that measures depressive symptoms in a community population, and that they measured changes in symptoms after only six months of VNS, even though research suggest that the benefit of VNS, in terms of reducing both seizure frequency and depression, strengths over a longer time period than six months. Our study aims to demonstrate an improvement in depression symptoms measured by the Center for Epidemiologic Study of Depression scale (CES-D) after one year or more of VNS. Methods: Seven adults with epilepsy treated with VNS were asked to fill out two sets of scales, one in reference to how they felt the month prior to VNS implantation and the other for how they felt after at least one year of VNS. Results: Scores on the CES-D improved from an average of 24.3 before VNS to an average of 19.8 at least one year after insertion, however, this change was not statistically significant (p=0.327). Overall functioning, as measured by the Darthmouth COOP scale, improved from an average score of 29 before VNS to an average of 2.2 at least one year after VNS (lower score indicates higher functioning), which was statistically significant (p=0.012). Seizure severity, as determined by a continuous 0-10 scale, improved from an average of 6.64 prior to VNS insertion to 2.98 after at least one year of VNS, which approached statistical significance (p=0.06). Conclusion: Our results suggest that there is an improvement in symptoms of depression and overall functioning in patient with epilepsy after one year or more of VNS, and that the change in functioning is directly related to a reduction in seizure severity.
Enright, Leah; Sarah McGinn; and Alya Reeve. "Pilot Study: Evaluation of Changes in Depressive Symptoms After One Year in Patients with Refractory Epilepsy Treated with Vagus Nerve Stimulation." (2008). http://digitalrepository.unm.edu/ume-research-papers/51