Thoracic Excursion Is a Biomarker for Evaluating Respiratory Function in Amyotrophic Lateral Sclerosis.

Area of Science:

• Neurology
• Pulmonology
• Biomarker Discovery

Background:

• Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting motor neurons.
• Assessing respiratory function is crucial for managing ALS progression and patient outcomes.
• Current biomarkers may not fully capture the multifaceted decline seen in ALS patients.

Purpose of the Study:

• To evaluate the clinical utility of thoracic excursion as a biomarker in patients diagnosed with ALS.
• To determine the test-retest reliability of thoracic excursion measurements in this population.

Main Methods:

• Measurements included forced vital capacity (FVC), thoracic excursion, diaphragmatic compound muscle action potential (DCMAP) amplitude, and diaphragm thickness (DTfi).
• Muscle strength (MRC sum score) and respiratory status (ALSFRS-R, mMRC Dyspnea Scale) were also assessed.
• Test-retest reliability of thoracic excursion was specifically analyzed.

Main Results:

• Thoracic excursion demonstrated excellent test-retest reliability (ICC: 0.974).
• It showed strong correlations with FVC (r=0.678), ALSFRS-R (r=0.610), and MRC sum score (r=0.470).
• Thoracic excursion was more sensitive to changes than DCMAP amplitude and diaphragm thickness, decreasing with FVC decline across all disease stages.

Conclusions:

• Thoracic excursion is a reliable and sensitive biomarker for assessing respiratory function in ALS.
• It effectively predicts respiratory and general dysfunction, proving useful across early and late disease stages.
• This measurement offers valuable insights into disease progression and patient status in ALS.