Clinical progression of benign fasciculation syndrome: a systematic literature review

Objectives: Benign fasciculation syndrome (BFS) is a challenging clinical condition that causes great concern to patients, as the sudden onset of fasciculations often raises suspicion of the presence or future development of motor neuron diseases. This article hence aims to provide a systematic literature review of clinical studies that investigated the clinical progression of BFS over time. Methods: We conducted an electronic search of PubMed, Scopus, and Web of Science using the keyword "benign fasciculation syndrome" in article title, abstract, and keywords, with no time or language restrictions, to identify all possible studies with a minimum number of 10 patients that examined the clinical progression of BFS over time. Results: Three articles with 180 patients, predominantly men (140/180; 78%), could be included in our analysis. In 98.3% of all patients fasciculations persisted over a period of 8 months to several years after the initial diagnosis of BFS, but no patient developed motor neuron dysfunction at follow-up. In the two studies providing details on clinical evolution of symptoms, fasciculations improved in 51.7% of patients and worsened in 4.1%. These results confirm the almost benign nature of BFS, with progression to overt motor neuron disease described only in specific case reports. Conclusion: Despite its benign nature, BFS does not appear to resolve over time, as fasciculations persist in the vast majority of BFS cases, albeit with some improvements in more than half of patients.