This was a cross-sectional study in which patients were divided into 20 patients with amyotrophic lateral sclerosis, 20 patients with peroneal muscular dystrophy, 20 patients with Kennedy's disease and 30 healthy controls, in which patients with amyotrophic lateral sclerosis continued to be followed up for 1 year and the results of 4 cross-sectional examinations were taken.

Background Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that usually starts in middle age and manifests mainly as progressive atrophy and weakness of skeletal muscles throughout the body, with death from respiratory muscle involvement after 3 to 5 years. There are no biomarkers for early diagnosis and no effective treatments. Because of the rapid progression of amyotrophic lateral sclerosis, it is important to find indicators that can objectively reflect early changes in the disease. The motor unit number index (MUNIX) is a non-invasive, rapid and objective method to assess the number of motor units, which reflects the loss of motor neurons and has its theoretical basis in monitoring early disease progression.

Objective To explore the diagnostic value of MUNIX in motor neuron disease and other related disorders.

To investigate the role of the 1-year rate of change of MUNIX in monitoring the disease progression in patients with amyotrophic lateral sclerosis.

To investigate the role of MUNIX in predicting survival analysis of ALS patients

[Design] This was a cross-sectional study in which patients were divided into 20 patients with amyotrophic lateral sclerosis, 20 patients with peroneal muscular dystrophy, 20 patients with Kennedy's disease and 30 healthy controls, in which patients with amyotrophic lateral sclerosis continued to be followed up for 1 year and the results of 4 cross-sectional examinations were taken.

Inclusion Criteria:

• ALS patient group: 20 patients with confirmed or proposed ALS meeting the 1998 revised El Escorial diagnostic criteria for limb onset ALS.

• CMT group: 20 patients with peroneal muscular dystrophy meeting the genetically confirmed diagnosis, who signed an informed consent form.

• KD group: 20 patients with genetically confirmed Kennedy's disease consistent with genetic diagnosis, signed informed consent.

• healthy controls:

  1. age-matched healthy adults who volunteered to participate;
  2. definite exclusion of tremor, tonicity, and prior brain disease;
  3. exclusion of common disorders affecting peripheral nerves such as entrapment peripheral neuropathy, diabetic peripheral neuropathy, and alcoholic peripheral neuropathy;
  4. signed informed consent.

Exclusion Criteria:

1. signs of sensory impairment;
2. significant sphincter dysfunction;
3. visual and oculomotor impairment;
4. autonomic dysfunction;
5. signs of extravertebral symptoms;
6. severe cortical dysfunction;
7. ALS-like syndrome.

ALS is a degenerative disease of the nervous system, with an incidence of 2-3 in 100,000. It usually begins in middle age and mainly presents with progressive atrophy and weakness of skeletal muscles throughout the body. After 3 to 5 years, it dies of respiratory muscle involvement. At present, there are no biomarkers for early diagnosis and no effective treatment.