Effect of Acute Unilateral Middle Cerebral Artery Infarcts on Voluntary Cough and the Laryngeal Cough Reflex

Abstract

VC is of limited use in screening subjects for aspiration pneumonia risk. A normal laryngeal cough reflex indicated a neurologically protected airway.

Measuring voluntary and reflexive cough strength in healthy individuals

“…When a cough sequence is reflexively triggered, it is usually composed of a mixture of CRs and LERs (Stephens, Addington, & Widdicombe, 2003;Widdicombe & Fontana, 2006). It is difficult to distinguish a CR from an LER in a cough sequence without physiological measures, such as airflow or pressure.…”

“…For example, a study that investigated VC and RC in patients following stroke found that they were independent of each other and that VC was impaired in 79% of right-handed patients who had suffered acute left-sided middle cerebral artery (MCA) infarcts but CR remained unimpaired and no patients developed aspiration pneumonia (Stephens et al, 2003). A similar study investigating VC and RC in stroke patients found that 10% of patients had a weak or absent CR, whereas 20% of patients had an abnormal VC (Addington, Stephens, & Gilliland, 1999).…”

“…They hypothesized that this may be due to smaller lung volumes for RC compared to VC, where there is usually inspiration before the cough. It has already been suggested that reflexive airway protection status should not be determined from the assessment of VC (Addington et al, 2008;Stephens et al, 2003).…”

Associations Between Laryngeal and Cough Dysfunction in Motor Neuron Disease with Bulbar Involvement

“…A volitional cough is cortically mediated and can be initiated with or without laryngeal sensations or spoken requests. 49 Cough can also be suppressed volitionally. Conversely, a reflexive cough, i.e., "laryngeal cough reflex," is a brainstem mediated reflex triggered by sensations in the larynx, e.g., aspiration of food or liquid.…”

“…Conversely, a reflexive cough, i.e., "laryngeal cough reflex," is a brainstem mediated reflex triggered by sensations in the larynx, e.g., aspiration of food or liquid. 49 Finally, in contrast to the reflexive cough, the term "expiration reflex" refers to reflexive, forced expiration triggered by mechanical or chemical irritation of the vocal folds that occurs without a preceding inspiration. 50 Different patterns of motor activation of respiratory muscles have been observed in volitional versus reflexive cough.…”