The contribution of conventional EMG to the diagnosis of amyotrophic lateral sclerosis with bulbar symptoms

INTRODUCTION: We presented here the results of quantitative electromyographic (EMG) study from 61 patients affected by Amyotrophic Lateral Sclerosis (ALS) with bulbar symptomatology at the time of study. MATERIAL AND METHODS: Patients were divided into two groups depending on whether the illness started with bulbar manifestations alone or with predominant neuromuscular weakness. RESULTS: Electromyography was performed on the abductor pollicis brevis, deltoideus or biceps brachii and tibialis anterior muscles (target muscles). In the first study the EMG was abnormal in more than 90% of the patients regardless to the duration of the illness and muscular weakness distribution. In the follow-up study the EMG was abnormal in all the patients lacking significant differences between the two groups. CONCLUSIONS: Quantitative EMG appeared as a very useful tool for the early diagnosis of ALS with bulbar manifestations. We found a correlation between the alterations of the different EMG parameters with the natural evolution of the illness.