# Multiparametric Analysis of Nasal Inspiratory Pressure (SNIP) in Duchenne Muscular Dystrophy: A Case‐Control Study With Healthy Subjects

## TL;DR

This study shows that sniff nasal inspiratory pressure measurements can detect early muscle weakness in Duchenne Muscular Dystrophy patients compared to healthy controls.

## Contribution

The study introduces SNIP-derived parameters as a non-invasive method to detect early inspiratory muscle dysfunction in DMD.

## Key findings

- DMD subjects had significantly lower maximum relaxation rate (MRR) and maximum rate of pressure development (MRPD) compared to healthy controls.
- SNIP parameters effectively distinguished DMD from healthy subjects with high accuracy (AUC 0.94 for SNIP).

## Abstract

Individuals with Duchenne Muscular Dystrophy (DMD) exhibit respiratory muscle changes leading to fatigue and weakness, and assessing relaxation rates and contractile properties may help detect early fatigue.

To non‐invasively assess inspiratory muscle relaxation and contractile rates using sniff nasal inspiratory pressure (SNIP) parameters in DMD subjects and compare them with matched healthy controls.

A case‐control study of 32 DMD male subjects and 32 age‐matched healthy controls (12.7 ± 5.1 years). All subjects underwent spirometry, maximal respiratory pressures, and SNIP test. We calculated the maximum relaxation rate (MRR), decay constant (τ), and maximum rate of pressure development (MRPD) from the SNIP curve.

The DMD group had significantly lower MRR (5.9 [5.1–6.9] vs. 8 [6.9–10.3] %/ms, p = 0.001), lower MRPD (−0.38 [−0.47 to −0.26] vs. −0.62 [−0.52 to −0.80] cmH2O/ms−1, p = 0.001), and higher τ (65.7 [50.7–78.1] vs. 40.5 [30.2–48.7] ms, p = 0.001). ROC curves showed that SNIP parameters effectively distinguish DMD from healthy subjects (SNIP [AUC 0.94, p < 0.001], MRR [AUC 0.86, p < 0.001], τ [AUC 0.92, p < 0.001], and MRPD [AUC 0.89, p < 0.001]).

DMD subjects show impaired inspiratory muscle contraction and relaxation, indicating early muscle weakness or fatigue. SNIP‐derived parameters may help in the early identification of inspiratory muscle dysfunction in DMD, potentially contributing to clinical detection and intervention.