Single-fiber electromyography in amyotrophic lateral sclerosis and cervical spondylosis.

INTRODUCTION

Cervical spondylosis (CS) is a common disease in adults and may coexist with amyotrophic lateral sclerosis (ALS). It is important to detect ALS coexisting with CS (ALS-cs) at an early stage, especially when surgical treatment of CS is planned.

METHODS

Single-fiber electromyography was performed in 26 patients with ALS, 19 with ALS-cs, and 22 with CS.

RESULTS

Mean jitter, percentage of jitter >55 μs, and percentage of impulse blocking were not statistically different between ALS and ALS-cs cases, but they were significantly lower in CS. Mean fiber density was not statistically different among the 3 groups. The percentage of pairs with jitter >55 μs exceeding 40% and mean jitter exceeding 55 μs had high sensitivity and specificity in the diagnosis of ALS.

CONCLUSIONS

Single-fiber electromyography can supply valuable information in helping to differentiate ALS from CS.