Evaluation of the diagnostic performance of brachial plexus ultrasound in amyotrophic lateral sclerosis.

OBJECTIVE

This study aimed to assess the diagnostic performance of brachial plexus cross-sectional area (BP-CSA) measured by nerve ultrasound (NUS) for differentiating amyotrophic lateral sclerosis (ALS) from controls.

METHODS

A retrospective, cross-sectional study was conducted including patients with ALS and control patients who underwent NUS evaluation of the BP-CSA and the cervical nerve root CSA (C-CSA). Reference values for BP-CSA were built using reference cohort. Receiver operating characteristic curve analysis was performed in independent discovery and validation cohorts to assess the diagnostic performance of BP-CSA.

RESULTS

A total of 244 patients (114 ALS and 130 controls) were included. BP-CSA significantly correlated with body weight (coefficient = 0.50, p < 0.001). After adjusting for body weight, BP-CSA values were significantly lower in patients with ALS than controls (p < 0.001). Adjusted BP-CSA showed superior diagnostic performance compared to C-CSA, with area under the curve values of 0.75 (95 % CI: 0.64-0.86) and 0.78 (95 % CI: 0.68-0.88) in the discovery and validation cohorts, respectively.

CONCLUSIONS

BP-CSA, when adjusted for body weight, shows reliable performance in diagnosing ALS.

SIGNIFICANCE: This study highlights the clinical value of BP-CSA as a potential ALS diagnostic biomarker and underscores its superiority over cervical nerve root measurements.