Tolerability of Vagus Nerve Stimulation for the Treatment of Epilepsy
Abstract number :
3.213
Submission category :
Year :
2000
Submission ID :
2478
Source :
www.aesnet.org
Presentation date :
12/2/2000 12:00:00 AM
Published date :
Dec 1, 2000, 06:00 AM
Authors :
Jorge J Asconape, Jill M Gerardot, Robert M Worth, Hema Patel, Deborah K Sokol, Joel C Boaz, Vicenta Salanova, Omkar N Markand, Indiana Univ Sch of Medicine, Indianapolis, IN; Indiana Univ, Indianapolis, IN.
RATIONALE: An advantage of vagus nerve stimulation (VNS) appears to be the relatively low incidence of adverse events compared to conventional antiepileptic drug (AED) therapy. We reviewed our experience at Indiana University with the tolerability of VNS. METHODS: The records of 50 patients undergoing VNS from November 1997 through April 2000 were reviewed for reported side-effects. A survey to rate the severity and degree of functional impairment caused by the VNS-induced dysphonia was given to 33 patients. They were also asked to compare VNS to AED therapy in terms of tolerability. RESULTS: Twelve patients (24%) were children (< 16 years) and 38 (76%)adults. The mean duration of VNS was 14.2 months (range: 3 weeks to 30 months). Dysphonia at the time of VNS activation or during increments of the output current was reported by 31 (93.9%) of 33 patients in whom it could evaluated. During chronic therapy it was reported by 24 (66.6%) of 36 patients. Of 33 patients answering the survey, 22 (66.6%)graded the discomfort associated with the dysphonia as none, 6 (18.2%) as mild, and 5 (15.2%) as moderate. When asked about the degree of functional impairment, 17 (51.5%)answered none, 10 (30.3%) mild, 5 (15.2%) moderate, and 1 (3%) severe. Coughing was reported during initial activation or immediately after adjusting the output current in 23 (59%) of 39 patients. It was not reported during chronic stimulation. An increased level of alertness was reported in 28 (59.6%) of 47 patients in whom the information was available. Less common side effects, possibly due to collateral stimulation of neighboring nerves, included hiccups (2 patients), rhythmic contracture of the diaphragm (2 cases), contracture of left shoulder muscles (1 case), left occipital tingling (1 case), left facial tingling (1 case), bilateral tingling of the upper extremities (1 case). When asked how VNS compared to AED therapy, of 33 patients surveyed, 27 (81.8%) considered VNS superior, 6 (18.2%) considered it equivalent, and none rated VNS as worse. CONCLUSIONS: VNS appears to be well tolerated with a high index of patient satisfaction. Dysphonia, the most frequent side-effect, is of little significance in most cases.