{
  "abstract": "Introduction Respiratory muscle dysfunction leading to respiratory failure is a significant risk in both acute and chronic respiratory conditions. Developing non-invasive diagnostic indices of respiratory muscle weakness is crucial for improving access to such tools outside specialist clinical settings. While needle electromyography (EMG) enables the evaluation of individual motor unit activity, its invasive nature and limited clinical availability restrict its widespread application. High-density surface Electromyography (HD-sEMG) has shown considerable promise in assessing limb muscle activity, such as the tibialis anterior, where motor unit conduction velocity (MUCV) can be estimated and has been associated with recruitment thresholds and force production. 1 However, the potential of HD-sEMG in assessing respiratory muscles, particularly the diaphragm, remains largely unexplored. We aim to determine whether HD-sEMG can provide physiologically meaningful indices of diaphragm muscle activity, offering a novel and fully non-invasive approach to evaluating respiratory muscle function.Methods Bilateral 64-channel HD-sEMG signals were recorded from the lower intercostal spaces, anterolaterally, during quiet, resting breathing. Signals were segmented using 500 ms sliding windows and processed via spike-triggered averaging across five columns of electrodes aligned with presumed diaphragm muscle fibre orientation. Motor unit conduction velocity (MUCV) was computed from these columns and averaged over the full breathing cycle.Results In this ongoing study, signals recorded from five healthy adults (2 female, 3 male; median (IQR) age 24 (7) years, median (IQR) BMI 23.6 (0.3) kg/m 2) have been analysed to date. A representative HD-sEMG trace is presented in figure 1. Across the five participants, the median (IQR) MUCV was 2.5 (0.1) m/s.Abstract P263 Figure 1Conclusion The observed MUCV values fall within the expected physiological range, supporting the feasibility of using HD-sEMG to assess diaphragm function. Future analyses will include motor unit recruitment thresholds and discharge rates at rest and during graded inspiratory loading, aiming to correlate these neural drive markers with inspiratory flow and mouth pressure. These metrics may help differentiate healthy individuals from patients with respiratory muscle weakness in clinical practice.Reference Del Vecchio A, Negro F, Felici F, Farina D. Associations between motor unit action potential parameters and surface EMG features. Journal of Applied Physiology 2017;123(4),835–843.",
  "authors": [
    {
      "affiliations": [
        "Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK"
      ],
      "name": "X Ma"
    },
    {
      "affiliations": [
        "Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK"
      ],
      "name": "GF Rafferty"
    },
    {
      "affiliations": [
        "Centre for Robotic Research, Department of Engineering, King’s College London, London, UK"
      ],
      "name": "EN Kamavuako"
    },
    {
      "affiliations": [
        "Centre for Human and Applied Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King’s College London, London, UK",
        "King’s College London, London, UK"
      ],
      "name": "CJ Jolley"
    }
  ],
  "title": "P263 Assessment of diaphragm motor unit activity using high-density surface electromyography",
  "uid": "7ee8e51d-94fe-57ec-b562-6b2ae2a4f548"
}