# Impact of neonatal hyperbilirubinemia on peripheral neuromuscular development: evidence from muscle fiber conduction velocity measurements

## TL;DR

The study finds that high bilirubin levels in newborns may impair neuromuscular development, as shown by slower muscle fiber conduction velocities.

## Contribution

This work introduces sEMG-based MFCV as a noninvasive biomarker for detecting bilirubin-related neuromuscular impairment in neonates.

## Key findings

- Neonates with hyperbilirubinemia had significantly lower muscle fiber conduction velocity and Z-scores than controls.
- Control infants displayed normal MFCV patterns, which were absent in the hyperbilirubinemia group.
- Hyperbilirubinemia was associated with disorganized innervation zones and reduced conduction variability.

## Abstract

Neonatal hyperbilirubinemia is a common condition that may impair neurodevelopment, yet its impact on peripheral neuromuscular function remains underexplored.

This study aimed to assess the effects of hyperbilirubinemia on muscle fiber conduction velocity (MFCV) in neonates using surface electromyography (sEMG).

MFCV was estimated from tibialis anterior sEMG recordings during passive and isometric contractions in neonates with and without hyperbilirubinemia. Global and local time-delay strategies were applied. Z-score analysis and repeated-measures ANOVA were used to compare groups, while regression analysis examined MFCV temporal trends.

The hyperbilirubinemia group exhibited significantly lower MFCV and Z-score values than controls (p < 0.001). Control infants showed characteristic spatial and temporal MFCV patterns, including arch-shaped conduction profiles and time-dependent declines, which were absent in the hyperbilirubinemia group. Disorganized innervation zone (IZ) distributions and reduced conduction variability further indicated impaired neuromuscular development.

Neonatal hyperbilirubinemia may alter peripheral neuromuscular maturation. sEMG-based MFCV estimation may serve as a potential sensitive and noninvasive electrophysiological biomarker for detecting bilirubin-related neuromuscular impairment in early infancy.