# Airflow Features Obtained From Voluntary Throat Clearing Compared to Voluntary Cough and Induced Reflexive Cough in a Healthy Population

## TL;DR

This study compares airflow features of throat clearing, voluntary cough, and reflexive cough in healthy people, finding throat clearing produces significantly less airflow.

## Contribution

The study is the first to report quantitative airflow metrics for voluntary throat clearing and shows its aerodynamic differences from coughing.

## Key findings

- Voluntary throat clearing had significantly lower peak expiratory flow and expired volume compared to cough types.
- Airflow features of throat clearing differ physiologically from voluntary and reflexive coughs.
- Instrumental assessment of throat clearing could improve clinical evaluations for dysphagia.

## Abstract

Coughing and throat clearing are different airway protective manoeuvres elicited in the framework of dysphagia. However, coughing and throat clearing may be auditorily confused during a clinical swallowing evaluation. In addition, literature reporting comparisons between coughing and throat clearing via gold standard airflow metrics is lacking.

To report quantitative airflow data for voluntary throat clearing, and to examine in a healthy population the aerodynamical differences between voluntary throat clearing, voluntary cough and induced reflexive cough.

Forty healthy participants were included in the study. Airflow measurements were obtained from single voluntary throat clearings, single voluntary coughs and the first two induced reflexive coughs of the reflexive cough epoch. The measurements included the peak expiratory flow rate in litres/s and the cough expired volume in litres of each single manoeuvre.

Results showed that voluntary throat clearing displayed lower airflow feature values compared to voluntary cough and induced reflexive cough (p < 0.001).

Voluntary throat clearings were aerodynamically significantly different from voluntary and reflexive coughs. Future studies should determine whether these differences reflect distinct impacts on airway protection. In dysphagic populations, instrumental assessment of throat clearing may enhance clinical swallowing evaluations.

What is already known on this subject
A large body of literature has emphasized airflow differences between voluntary coughs and induced reflexive coughs, supporting physiological differences between both types of manoeuvres and complementary roles with regard to airway protection. Throat clearing is another airway protective manoeuvre anecdotally considered during a clinical swallowing evaluation and in literature. In addition, throat clearing is confused with coughing, and little is known regarding its ability to protect the airways.

A large body of literature has emphasized airflow differences between voluntary coughs and induced reflexive coughs, supporting physiological differences between both types of manoeuvres and complementary roles with regard to airway protection. Throat clearing is another airway protective manoeuvre anecdotally considered during a clinical swallowing evaluation and in literature. In addition, throat clearing is confused with coughing, and little is known regarding its ability to protect the airways.

What this study adds to existing knowledge
This exploratory study is the first to report quantitative airflow metrics for voluntary throat clearings, and to demonstrate significantly lower airflow features for voluntary throat clearing compared to voluntary cough and induced reflexive cough, in a healthy population. The combination of airflow features obtained in this study with anatomical observations and acoustical features increases insight into the physiological differences between throat clearing and coughing.

This exploratory study is the first to report quantitative airflow metrics for voluntary throat clearings, and to demonstrate significantly lower airflow features for voluntary throat clearing compared to voluntary cough and induced reflexive cough, in a healthy population. The combination of airflow features obtained in this study with anatomical observations and acoustical features increases insight into the physiological differences between throat clearing and coughing.

What are the potential or actual clinical implications of this work?
The study demonstrates that the instrumental assessment of throat clearing as a distinctive airway protective manoeuvre would be of value to enable more accurate clinical swallowing evaluation and management of dysphagic patients. Further investigation and consideration of throat clearing are warranted.

The study demonstrates that the instrumental assessment of throat clearing as a distinctive airway protective manoeuvre would be of value to enable more accurate clinical swallowing evaluation and management of dysphagic patients. Further investigation and consideration of throat clearing are warranted.