A Prospective Study of Benign Fasciculation Syndrome (S45.007)

Objective: To further elucidate the natural history of BFS. Background: Benign fasciculations are common in the general population, occurring in about 70% of healthy individuals. They are almost never associated with a serious neuromuscular disorder. However, they appear to be a cause of anxiety, particularly among those in the medical field. To our knowledge, no prospective study has been conducted on BFS patients. Design/Methods: This is a two-year prospective study. Patients seen for fasciculations in the absence of weakness, atrophy, or other neurologic symptoms were eligible. Patients were diagnosed based on otherwise normal examinations and normal EMGs except for fasciculation potentials. To date, 34 patients have been enrolled. Interviews were conducted at diagnosis and months 1, 3, 6, 12, and 24. Results: 34.4% were female. 34.4% had a medical background. 29.4% had a diagnosed psychiatric disorder. However, only 8.8% were on an SSRI and 17.6% on a benzodiazepine. Subjective weakness was reported by 35.3%. Many patients reported sensory symptoms (47.1% numbness, 70.6% had tingling). Cramps were present in 64.7%. Based on the data we obtained over two years, we constructed Kaplan-Meier survival curves to predict the duration of each symptom. At 12 months, 95% of patients still had fasciculations, 25% still reported subjective weakness, 27.5% still had numbness, 57.9% still had tingling, and 62.6% still reported cramps. No patients developed motor neuron disease. Conclusions: Despite its benign natural history, BFS is a source of high morbidity for patients, both physically and psychologically. At two years, fasciculations resolved in only 5% of patients. Most still experienced subjective weakness, sensory symptoms, and cramps. Symptoms did not seem to resolve with reassurance. However, most of these patients were not treated for anxiety. It remains to be seen if BFS symptoms remit with treatment of anxiety. Disclosure: Dr. Filippakis has nothing to disclose. Dr. Jara has nothing to disclose. Dr. Ventura has nothing to disclose. Dr. Ruthazer has nothing to disclose. Dr. Russell has received royalty payments from McGraw Hill. Dr. Ho has nothing to disclose.