# Agreement Between a Pre-Markered T-Shirt and Manual Marker Placement for Opto-Electronic Plethysmography (OEP) Measures

## TL;DR

This study compares a pre-markered T-shirt to manual marker placement for measuring breathing patterns during exercise and finds them highly comparable.

## Contribution

The study introduces a pre-markered T-shirt as a time-efficient alternative to manual marker placement for OEP measurements.

## Key findings

- The pre-markered T-shirt showed strong agreement (ICC ≥ 0.9) with standard breath-by-breath gas analysis.
- Compartment contributions using the T-shirt had ICC values exceeding 0.8, indicating excellent agreement.
- Phase angles showed best agreement during moderate exercise (0.6 < ICC < 0.8).

## Abstract

Opto-electronic plethysmography (OEP) is used to measure chest wall compartment volumes and their synchronisation. Breathing pattern disorder (BPD) can be distinguished using the phase angles between these chest wall compartments during exercise. However, the time taken to manually place the standard OEP model involving 89 reflective markers is high during clinical application. The purpose of this study was to investigate the use of a pre-markered T-shirt instead of markers applied directly to the skin at rest, during different exercise intensities and recovery. Thirty-nine healthy participants (24 male, 15 female) aged 18–40 years performed an incremental cycling test with the skin-mounted OEP marker set. Participants then repeated the same cycling test with a pre-markered T-shirt. Across all test conditions, the T-shirt showed a strong level of agreement (Intraclass correlation coefficient (ICC) ≥ 0.9) with the standard breath-by-breath (BbB) gas analyser. Moreover, ICC values exceeded 0.8 for compartment contributions across all test conditions, indicating excellent agreement with the skin-mounted markers. The phase angles between compartments showed the best agreement during the moderate exercise level (0.6 < ICC < 0.8). In conclusion, the pre-markered T-shirt presents a viable solution for the quick monitoring of breathing patterns, as well as an effective tool in diagnosing BPD during exercise.