What is the role of motor evoked potentials (MEPs) in the diagnosis of motor neuron disease?

Updated: Aug 20, 2019
  • Author: Jasvinder Chawla, MD, MBA; Chief Editor: Selim R Benbadis, MD  more...
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Answer

Answer

Reported MEP abnormalities in motor neuron disease include absence of response, prolongation of latency, enhanced cortical threshold and, most commonly, low-amplitude polyphasic responses. The degeneration of spinal motor neurons explains the tendency of MEPs to be of short duration.

The average survival duration of patients with a normal CMCT is not significantly different from those with an abnormal CMCT. MEP studies have limited use in the diagnosis of amyotrophic lateral sclerosis; they do not provide significant prognostic information.


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