David Lawi, Elise Dupuis-Lozeron,Gregory Berra, Gilles Allali, Thomas Similowski, Dan Adler
European Respiratory Journal 2020 56: 2000054; DOI: 10.1183/13993003.00054-2020
Background Chronic respiratory diseases are associated with cognitive dysfunction, but whether dyspnoea by itself negatively impacts on cognition has not been demonstrated. Cortical networks engaged in subjects experiencing dyspnoea are also activated during other tasks that require cognitive input and this may provoke a negative impact through interference with each other.
Methods This randomised, crossover trial investigated whether experimentally-induced dyspnoea would negatively impact on locomotion and cognitive function among 40 healthy adults. Crossover conditions were unloaded breathing or loaded breathing using an inspiratory threshold load. To evaluate locomotion, participants were assessed by the Timed Up and Go (TUG) test. Cognitive function was assessed by categorical and phonemic verbal fluency tests, the Trail Making Tests (TMTs) A and B (executive function), the CODE test from the Wechsler Adult Intelligence Scale (WAIS)-IV (processing speed) and by direct and indirect digit span (working memory).
Results The mean time difference to perform the TUG test between unloaded and loaded breathing was −0.752 s (95% CI −1.012 to −0.492 s) (p<0.001). Executive function, processing speed and working memory performed better during unloaded breathing, particularly for subjects starting first with the loaded breathing condition.
Conclusion Our data suggest that respiratory threshold loading to elicit dyspnoea had a major impact on locomotion and cognitive function in healthy adults.
Acute experimental dyspnoea can negatively impact on locomotion/cognition through shared neural substrates. There is a need for clinical interventions to improve non-respiratory symptoms of chronic respiratory diseases by focussing on alleviating dyspnoea. https://bit.ly/2wGHcjW
This article has an editorial commentary: https://doi.org/10.1183/13993003.01096-2020
This article has supplementary material available from erj.ersjournals.com
This study is registered as a clinical trial: Basec ID 2016-00807. The data that support the findings of this study are available from the corresponding author, Dan Adler, upon reasonable request.
Author contributions: D. Lawi: study conception and design, acquisition of data, analysis and interpretation of data, drafting of the manuscript. E. Dupuis-Lozeron: study conception and design, analysis and interpretation of data, critical manuscript revision. G. Berra: study conception and design, acquisition of data, critical manuscript revision. G. Allali: study conception and design, interpretation of data, critical manuscript revision. T. Similowski: study conception and design, interpretation of data, critical manuscript revision. D. Adler: study conception and design, analysis and interpretation of data, drafting and critical revision of the manuscript.
Conflict of interest: D. Lawi has nothing to disclose.
Conflict of interest: E. Dupuis-Lozeron has nothing to disclose.
Conflict of interest: G. Berra has nothing to disclose.
Conflict of interest: G. Allali has nothing to disclose.
Conflict of interest: T. Similowski reports personal fees and non-financial support from Novartis France; personal fees from AstraZeneca France, Boehringer Ingelheim France, GSK France, TEVA France, Chiesi France, Lungpacer Inc. and ADEP Assistance; and grants from Air Liquide Medical Systems, outside the submitted work.
Conflict of interest: D. Adler reports grants from The Geneva Pulmonary League (grant number 73732), during the conduct of the study.
Support statement: The study is funded by The Geneva Pulmonary League (grant number 73732). Funding information for this article has been deposited with the Crossref Funder Registry.