Differential diagnosis of amyotrophic lateral sclerosis and similar syndromes.

The aim of this investigation was to re-evaluate the electromyographic findings in patients with ALS and with localised lesions of the spinal cord and to find some clues for differentiation. Two hundred and sixteen patients took part in this investigation. They were subdivided into two groups. The first group consisted of 168 patients with data for amyotrophic lateral sclerosis. The second group consisted of 48 patients with syndrome of amyotrophic lateral sclerosis caused by cervical myelopathy. Detailed neurological and electromyographic examinations were performed to all patients. In conclusion the electromyographic findings in patients with ALS are not different than the abnormalities in muscles innervated by the affected segments in patients with localised lesions which compress the anterior portion of the spinal cord. The only clues for differentiation are the clinical signs and the distribution of electromyographic abnormalities.