To evaluate the correlation between peripheral neurofilament levels and clinical subtypes of amyotrophic lateral sclerosis and the severity of peripheral motor axonal involvement.

Amyotrophic lateral sclerosis (ALS) is a kind of neurodegenerative disease that affects upper and lower motor neurons. In animal model studies have shown that peripheral nerve degeneration in ALS motor function decline, tip peripheral nerve degeneration is of great significance for early progress of ALS may be, at the same time analysis showed that the motor neuron involvement severity and the prognosis of patients with ALS show obvious negative correlation, so finding biomarkers can reflect the motor neuron axonal degeneration is of great significance. Neurofilaments is an intermediate fiber specifically expressed in central and peripheral neurons and can serve as a biomarker for axonal injury, but there is no evidence now that peripheral neurofilament levels have been associated with severity of motor axonal involvement in ALS.

Inclusion Criteria:

• Patients with lower motor neuron involvement (LMND-ALS), who have visited the Department of Neurology of the Third Hospital of Beijing Medical University since August 2017, meet the diagnostic criteria for ALS in 1998. The main clinical manifestations were muscle weakness with atrophy and bundle fibrillation, the pyramidal tract sign was relatively mild, and extensive neurogenic damage with CMAP amplitude decreased could be seen in patients with electromyography.

  • LMND-ALS CMAP amplitude < median array: in line with LMND -ALS inclusion criteria, and CMAP amplitude of peripheral motor nerves (CMAP amplitude of the 10 peripheral motor nerves with the most obvious CMAP amplitude decline was selected as the CMAP amplitude for grouping of the patients) was less than the median of CMAP amplitude of LMND -ALS group.
  • LMND -ALS CMAP amplitude ≥ median array: meeting LMND -ALS inclusion criteria, and CMAP amplitude of peripheral motor nerves (CMAP amplitude of 10 peripheral motor nerves with the most obvious CMAP amplitude decline was selected as the CMAP amplitude for grouping of the patients) was greater than or equal to the median of CMAP amplitude of LMND -ALS group.

• Patients with upper motor neuron involvement (UMND-ALS): patients with ALS who visited the Department of Neurology of the Third Hospital of Beijing Medical University since August 2017 and met the diagnostic criteria for ALS in 1998. The main clinical manifestations were limb stiffness and spasm, obvious pyramidal tract signs, relatively mild muscle atrophy and fasciculation, and no significant decrease in amplitude of electromyography CMAP.

• Patients with ALS with flail arm syndrome (FAS) and flail leg syndrome (FLS): patients with ALS who met the diagnostic criteria for ALS in 1998 and visited the Department of Neurology of the Third Hospital of Beijing Medical University since August 2017. The clinical symptoms were confined to upper limbs (FAS) or lower limbs (FLS) for more than 12 months, and the main manifestations were lower motor neuron involvement signs such as muscle weakness and atrophy.

Exclusion Criteria:

• Merging other nervous system degenerative diseases (Alzheimer's disease, Parkinson's disease, multiple system atrophy, etc.) to take off the sheath, central nervous system disease, multiple sclerosis, optic myelitis spectrum disorders), peripheral neuropathy (GBS, chronic inflammatory more nerve root sheath sex mental derangement, hereditary peripheral neuropathy, diabetic peripheral neuropathy, vice tumor peripheral neuropathy, secondary to autoimmune diseases ), into the group within a month before the cerebrovascular disease or cerebral or spinal surgery patients.

Patients with lower motor neuron involvement (LMND-ALS), who have visited the Department of Neurology of the Third Hospital of Beijing Medical University since August 2017, meet the diagnostic criteria for ALS in 1998.