Central motor conduction in Hirayama disease

Electroencephalogr Clin Neurophysiol. 1995 Apr;97(2):73-6. doi: 10.1016/0924-980x(94)00246-4.


The pathogenesis of Hirayama disease is usually attributed to microcirculatory disturbances in the anterior spinal artery territory, leading to segmental anterior horn cell loss and occasional lower limb hyperreflexia. In 7 patients with Hirayama disease, central motor conduction to upper (CMCT-ADM) and lower limbs (CMCT-TA) was evaluated. CMCT-TA was normal in all, but CMCT-ADM was marginally prolonged (8.4 msec, amplitude 0.8 mV) on one side only. Peripheral delay in the upper limbs was found in 2 patients (1 side each) which might be due to fall-out of anterior horn cells. In 2 patients with lower limb hyperreflexia, HM ratio, vibratory inhibition and reciprocal inhibition of soleus H reflex were also normal, suggesting lack of pyramidal dysfunction. Our results do not suggest any pyramidal dysfunction as a cause of lower limb hyperreflexia in Hirayama disease.

MeSH terms

  • Adolescent
  • Adult
  • Electromyography
  • Extremities / innervation
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Muscular Atrophy, Spinal / pathology
  • Muscular Atrophy, Spinal / physiopathology*
  • Neural Conduction / physiology*
  • Reaction Time / physiology
  • Spinal Cord / pathology