Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2006 Aug;61(8):699-705.
doi: 10.1136/thx.2005.057901. Epub 2006 Apr 6.

Differences in motor activation of voluntary and reflex cough in humans

D Lasserson  1 , K Mills, R Arunachalam, M Polkey, J Moxham, L Kalra
Affiliations

Differences in motor activation of voluntary and reflex cough in humans

D Lasserson et al. Thorax. 2006 Aug.

Abstract

Objectives: To study motor activation patterns of voluntary and reflex cough adjusted for cough flow rates.

Methods: Surface electromyography (EMG) and cough flow rate were measured in 10 healthy volunteers. Voluntary cough was assessed for 20 efforts in each quintile of increasing cough flow rate. Reflex cough was assessed for 25 efforts produced by nebulised l-tartaric acid. EMG was recorded over the expiratory (rectus abdominis, obliques, lower intercostals) and accessory (trapezius, pectoralis major, deltoid, latissimus dorsi) muscles. EMG activity, burst duration and onset were compared for each quintile of voluntary cough, and between voluntary and reflex cough matched for cough flow rate.

Results: EMG activity and burst duration of expiratory and accessory muscles during voluntary cough increased in proportion to cough flow. Expiratory muscles had longer EMG burst duration (difference 68 ms (95% CI 34 to 102), p<0.01) and earlier onset of EMG activity (difference 44 ms (95% CI 20 to 68), p<0.0001) compared with accessory muscles. EMG activity in all muscles was increased (mean 110.2% v 56.1%, p<0.001) and burst duration (mean 206 ms v 280 ms, p = 0.013) decreased in reflex cough compared with voluntary cough of equal flow rate. There were no differences in EMG onset (difference 8 ms (95% CI 25 to -9) or burst duration (difference 27 ms (95% CI 58 to -4) between expiratory and accessory muscles.

Conclusions: Functional organisation of motor activity differs between voluntary and reflex cough. Voluntary cough is characterised by sequential activation whereas reflex cough is associated with early and simultaneous activation of expiratory and accessory muscles.

PubMed Disclaimer

Conflict of interest statement

The authors have no financial, academic or personal conflicts of interest to report.

References

    1. Polkey M I, Lyall R A, Moxham J.et al Respiratory aspects of neurological disease. J Neurol Neurosurg Psychiatry 1999665–15. - PMC - PubMed
    1. Leith D E, Butler J P, Sneddon S L.et al Cough. In: Handbook of physiology: the respiratory system. Volume III, Part 1. Bethesda: American Physiological Society, 1990315–336.
    1. Korpas J, Widdicombe J G. Aspects of the cough reflex. Respir Med 199185(Suppl A)3–5. - PubMed
    1. Kobayashi H, Hosino M, Okayama K.et al Swallowing and cough reflexes after onset of stroke. Chest 19941051623 - PubMed
    1. Addington W R, Stephens R E, Gilliland K A. Assessing the laryngeal cough reflex and the risk of developing pneumonia after stroke: an interhospital comparison. Stroke 1999301203–1207. - PubMed

Publication types