Does sleep disordered breathing in amyotrophic lateral sclerosis influence acute intermittent hypoxia-induced respiratory facilitation?


Clinical Trials

Poster Number: 62


Juliette Clavier, BS, University of Florida, Barbara Smith, PT, PhD, University of Florida

Degeneration of phrenic motor units in amyotrophic lateral sclerosis (ALS) leads to progressive hypoventilation and sleep-disordered breathing (SDB), necessitating the validation of approaches that may help preserve independent breathing ability. Acute intermittent hypoxia (AIH) consists of modest fluctuations in the inspired oxygen content. AIH is a well-established means to induce phrenic motor plasticity in rodents, and it augments rehabilitation in patients with other neurologic conditions susceptible to SDB. We recently reported that a single AIH session subsequently led to increased tidal volume and respiratory muscle activity in adults with ALS. The objective of this project was to evaluate whether SDB-related chronic intermittent hypoxia may facilitate breathing ability following single AIH exposures. Adults with ALS and vital capacity >60% predicted (n=8) wore a home sleep monitor, and the Apnea Hypopnea Index from sleep reports sorted patients into groups of no-mild versus moderate SDB. Additionally, participants underwent single sessions of AIH and sham hypoxia, in random order, separated by one week. Changes in ventilation were calculated at 60 minutes post-intervention. The data distribution was measured with Shapiro-Wilks and Mann-Whitney or unpaired T-tests to evaluate differences between SDB groups. Tidal volume and minute ventilation responses to AIH trended larger in the moderate SDB group, compared to no-mild SDB. Respiratory rate responses to AIH did not differ based on SDB. The distinctions in breath volume and minute ventilation between SDB groups suggest that the moderate SDB may have preconditioned these participants for more robust respiratory plasticity following a single AIH exposure. These preliminary findings indicate the presence of SDB must be considered when interpreting respiratory motor facilitation, in response to AIH. Further subject recruitment is ongoing and necessary to validate these results.