Motor-evoked responses in primary lateral sclerosis

Muscle Nerve. 1992 May;15(5):626-9. doi: 10.1002/mus.880150515.


Primary lateral sclerosis (PLS) may be distinguished on the basis of clinical and pathological features from amyotrophic lateral sclerosis (ALS). The former is featured by a much longer clinical course, exclusively upper motor neuron findings, losses of precentral pyramidal neurons, and preservation of anterior horn cells. Electrophysiological studies of 7 PLS cases have shown normal peripheral motor conduction, absent or very delayed motor-evoked potentials, the occasional late development of denervation activity in distal muscles, and normal somatosensory-evoked potentials.

MeSH terms

  • Aged
  • Amyotrophic Lateral Sclerosis / diagnosis*
  • Amyotrophic Lateral Sclerosis / physiopathology
  • Diagnosis, Differential
  • Electromyography
  • Evoked Potentials / physiology
  • Evoked Potentials, Somatosensory / physiology
  • Humans
  • Middle Aged
  • Motor Neurons / physiology*
  • Muscles / innervation
  • Neural Conduction / physiology