Teaching Video NeuroImages: Tongue myokymia in hypoglossal neuropathy

Summary

  • 50yo F
  • c/c
    • painless dysphagia
    • dysarthria
  • PEx
    • involuntary tongue movements
    • reduced bulk
    • deviation to Rt on protrusion
  • Ex
    • U/S
  • Dx
    • chronic idiopathic hypoglossal neuropathy

Further

Terminology

Original

A 50-year-old woman presented with painless dysphagia and dysarthria. There was no radiation exposure. Examination revealed involuntary tongue movements and reduced bulk with deviation to the right on protrusion. The remaining neurologic examination was normal. MRI brain/skull base with contrast was normal.

Ultrasound examination before EMG demonstrated abnormal tongue movement along with the sonographic anatomy of the submental muscles and tongue (video 1).1 Ultrasound allows for dynamic assessment of the tongue, which is otherwise impossible with other imaging techniques.2 Right genioglossus EMG confirmed myokymia and sparse fasciculations with background chronic neurogenic motor unit rearrangement and reduced recruitment.

Video

Video 1.
Ultrasound examination of the genioglossus showed abnormal echotexture of the right tongue associated with myokymia and fasciculations of the tongue, characterized by repeated and sustained twisting motions of small portions of the tongue, more prominent on the right side of the tongue (left side of the screen).

The diagnosis was chronic idiopathic hypoglossal neuropathy with clinical remission but subsequent deterioration due to the development of nerve hyperexcitability.

  1. Van Den Engel-Hoek L, Van Alfen N, De Swart BJ, De Groot IJ, Pillen S. Quantitative ultrasound of the tongue and submental muscles in children and young adults. Muscle Nerve 2012;46:31–37.
  2. Simon NG. Dynamic muscle ultrasound: another extension of the clinical examination. Clin Neurophysiol 2015;126:1466–1467.