Electromyography plus accurate neurological examination. The essence of motor neuron disease is the unexplained apoptosis of motor neurons or the necrosis of their conductive fibers. It is divided into many subtypes according to different situations. If you want to make an accurate diagnosis, you must do electromyography.
So, what will EMG show?
Typical EMG manifestations are muscles dominated by three or more segments (medulla oblongata, cervical spinal cord, thoracic spinal cord, lumbar spinal cord, etc. There are a large number of spontaneous potentials, the amplitude of which is widened by nerve compensation, and the strong recruitment shows neurogenic damage.
Of course, with the early and late development of the disease, its performance is also different. Only one or two segments may be damaged in the early stage, or only one or two segments may be damaged in the above three cases, but with the passage of time, there is a tendency to continue to increase. The most typical feature of motor neuron disease is that there is no platform period, no remission period, or continuous deterioration until death. The same is true of EMG.
Of course, the length of this process varies from subtype to subtype. Among them, the flail arm type and flail leg type are subtypes in which muscle atrophy and weakness at the proximal end of both upper limbs and distal end of both lower limbs are first found without other symptoms. Both of these developments are relatively slow. There is only one segment abnormality in EMG. Amyotrophic lateral sclerosis often progresses rapidly, often involving three segments within a few months, and gradually involving the medulla oblongata, which is characterized by poor speech, choking in drinking water, dyspnea and poor prognosis.
Therefore, in the early stage when motor neuron disease is found or suspected, EMG should be improved as soon as possible to determine whether it is motor neuron disease. What market segments are involved? What subtype will it be? What is the prognosis? The role of EMG in the diagnosis of motor neuron diseases is so important.