Claire Boswell-Ruys – Abstract

P33      Respiratory muscle reflex control and dysphagia in incomplete tetraplegia.

Boswell-Ruys CL[1,2,3], Peebles K[4], McNaughton K[4], Witherow J[4], Dupuche C[4], Elphick T[2], Mogg P[3], Barnhart M[3] and Butler JE[1,2,3].

  1. NeuRA, Sydney, Australia
  2. School of Medical Sciences, University of New South Wales, Sydney, Australia
  3. Allied Health Department, Prince of Wales Hospital, Sydney, Australia
  4. Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia

The short-latency reflex responses of respiratory muscles to muscle loading are inhibitory and act to protect the airway from obstruction (1). This protective reflex is mediated by inspiratory muscle receptors (1,2) and is absent in people with tetraplegia with complete sensory and motor loss (3). The aim of the study was to determine whether this protective reflex is present or absent in people with incomplete tetraplegia and determine if there is any relationship with dysphagia.

Electromyographic (EMG) signals from the diaphragm and scalene muscles, airflow, volume and mouth pressure were recorded in 10 participants with incomplete tetraplegia before and after 250ms inspiratory occlusions during quiet breathing. Non-invasive assessments of swallow included the eating assessment tool (EAT-10), timed water swallow test (TWST) and the test of mastication and swallowing of solids (TOMASs). Measures of lung function, tongue and respiratory muscle strength, and sleep apnoea severity were obtained.

Inhibitory reflex response was present in 60% participants. No relationship was found between any measures of swallow and the presence of the reflex. Compared with normative data participants had increased number of swallows, bites per cracker and masticatory cycle time in the TOMASS test.

The short-latency inhibitory reflex to airway occlusion is present in incomplete tetraplegia and has a higher incidence than in complete tetraplegia (similar to healthy control participants). The presence of the inhibitory reflex may be protective against aspiration.

  1. Butler JE et al (1995) J Physiol 487, 273-281
  2. Butler JE et al (1997) J Neurophysiol 78, 170-176
  3. McBain RA et al (2015) Exp Physiol 100, 216-225