Voluntary Cough Assessment

Why assess cough?

Cough 🗣️💨 is important for ejecting foods and liquids from the lungs 🫁 to prevent asphyxiation and aspiration pneumonia. In this tutorial, we will discuss why and how to assess voluntary cough as a way to enhance your clinical swallow evaluation.


Evaluating cough is important three reasons:

  1. First, impaired cough (dystussia), characterized by either blunted reflex cough sensation or a weak/ineffective cough motor response, is associated with dysphagia and aspiration in many patient populations. Therefore, assessing cough can improve the accuracy of identifying and predicting someone with dysphagia, making it a useful addition to your battery of dysphagia screening tasks.

  2. Second, assessing cough provides a more holistic understanding of airway protection. In other words, we should try to understand how well a patient with dysphagia can clear aspirate material from the airway, in addition to understanding how frequently/severely they aspirate. People who aspirate but are able to clear the lower airway of foods and liquids through effective coughing should be managed clinically much differently than people who aspirate and are unable to clear the lower airway of aspirate material because of their ineffective coughs.

  3. Third, if voluntary cough is assessed and found to be impaired, then it may also be an important and clinically feasible therapy target to include in a one's rehabilitation plan. For example, including exercises such as Expiratory Muscle Strength Training (EMST) or Voluntary Cough Skill Training (VCST) may be warranted if attempting to improve reflex and voluntary cough behaviors - see tutorials on these exercises.

How do you assess cough?

Two types of voluntary coughs can be assessed clinically: “single” 🗣️💨 and “sequential” 🗣️💨💨💨 voluntary coughs. For each, provide a verbal instruction and an audio-visual model (see below). The patient should complete a minimum of three trials of each for both the single and sequential voluntary coughs so that you can assess average cough strength and variability in cough strength.

Single Voluntary Cough

  1. Verbal instruction: “Cough hard once, like this.”

  2. Audio-visual model: Take a deep breath in and then cough hard once.

Single Cough.mov

Sequential Voluntary Cough

  1. Verbal instruction: “Cough as if something went down the wrong pipe. It might look something like this.”

  2. Audio-visual model: Take a deep breath in, then perform a three-cough epoch (i.e., one breath in followed by three coughs).

Sequential Cough.mov

Coughs can then be assessed using audio-perceptual and instrumental methods

Audio-Perceptual Assessment of Cough

Subjective, audio-perceptual assessment of cough involves listening 🗣️💨👂 for and documenting impressions related to perceived cough strength (weak/strong), quality (normal, breathy, strained, effortful, discoordinated, throat clear), and effectiveness (effective/ineffective).

Cough Examples.mov

Instrumental Assessment of Cough using a Peak Flow Meter

Objective methods for assessing cough involve using instruments capable of measuring cough airflow 🗣️💨📏👩‍🔬. Handheld peak flow meters are on such instrument. Peak flow meters measure how fast air can be exhaled in liters of air per minute (L/min), and are typically used for conditions like Asthma. They are relatively cheap, portable, and commercially available - making them feasible to use for clinical practice.


Below is an example of assessing single and sequential voluntary cough peak expiratory flow rate (PEFR) using the Lung Performance peak flow meter.

Single and Sequential.mov

Lastly, compare cough PEFR to healthy norms and values associated with dysphagia & aspiration. More comprehensive norms need to be developed, but I consider PEFR <300 L/min to be abnormal. See my below slide for some references and my general (informal) interpretation guide.

References:

  • Borders, J. C., Brandimore, A. E., & Troche, M. S. (2020). Variability of Voluntary Cough Airflow in Healthy Adults and Parkinson’s Disease. Dysphagia, 1-7.

  • Sakai, Y., Ohira, M., & Yokokawa, Y. (2020). Cough Strength Is an Indicator of Aspiration Risk When Restarting Food Intake in Elderly Subjects With Community-Acquired Pneumonia. Respiratory Care, 65(2), 169-176.

  • Sohn, D., Park, G. Y., Koo, H., Jang, Y., Han, Y., & Im, S. (2018). Determining peak cough flow cutoff values to predict aspiration pneumonia among patients with dysphagia using the citric acid reflexive cough test. Archives of physical medicine and rehabilitation, 99(12), 2532-2539.

  • Kulnik, S. T., Birring, S. S., Hodsoll, J., Moxham, J., Rafferty, G. F., & Kalra, L. (2016). Higher cough flow is associated with lower risk of pneumonia in acute stroke. Thorax, 71(5), 474-475.

  • Curtis, J. A., & Troche, M. S. (2020). Handheld Cough Testing: A Novel Tool for Cough Assessment and Dysphagia Screening. Dysphagia, 1-8.

  • Min, S. W., Oh, S. H., Kim, G. C., Sim, Y. J., Kim, D. K., & Jeong, H. J. (2018). Clinical Importance of Peak Cough Flow in Dysphagia Evaluation of Patients Diagnosed With Ischemic Stroke. Annals of Rehabilitation Medicine, 42(6), 798.

  • Laciuga, H., Brandimore, A. E., Troche, M. S., & Hegland, K. W. (2016). Analysis of clinicians’ perceptual cough evaluation. Dysphagia, 31(4), 521-530.

  • Plowman, E. K., Watts, S. A., Robison, R., Tabor, L., Dion, C., Gaziano, J., ... & Gooch, C. (2016). Voluntary cough airflow differentiates safe versus unsafe swallowing in amyotrophic lateral sclerosis. Dysphagia, 31(3), 383-390.

  • Hegland, K. W., Okun, M. S., & Troche, M. S. (2014). Sequential voluntary cough and aspiration or aspiration risk in Parkinson’s disease. Lung, 192(4), 601-608.

  • Kimura, Y., Takahashi, M., Wada, F., & Hachisuka, K. (2013). Differences in the peak cough flow among stroke patients with and without dysphagia. Journal of UOEH, 35(1), 9-16.

  • Bianchi, C., Baiardi, P., Khirani, S., & Cantarella, G. (2012). Cough peak flow as a predictor of pulmonary morbidity in patients with dysphagia. American journal of physical medicine & rehabilitation, 91(9), 783-788.

  • Pitts, T., Troche, M., Mann, G., Rosenbek, J., Okun, M. S., & Sapienza, C. (2010). Using voluntary cough to detect penetration and aspiration during oropharyngeal swallowing in patients with Parkinson disease. Chest, 138(6), 1426-1431

  • Hammond, C. A. S., Goldstein, L. B., Horner, R. D., Ying, J., Gray, L., Gonzalez-Rothi, L., & Bolser, D. C. (2009). Predicting aspiration in patients with ischemic stroke: comparison of clinical signs and aerodynamic measures of voluntary cough. Chest, 135(3), 769-777.

  • Pitts, T., Bolser, D., Rosenbek, J., Troche, M., & Sapienza, C. (2008). Voluntary cough production and swallow dysfunction in Parkinson’s disease. Dysphagia, 23(3), 297-301.

  • Ebihara, S., Saito, H., Kanda, A., Nakajoh, M., Takahashi, H., Arai, H., & Sasaki, H. (2003). Impaired efficacy of cough in patients with Parkinson disease. Chest, 124(3), 1009-1015.

  • Hammond, C. S., Goldstein, L. B., Zajac, D. J., Gray, L., Davenport, P. W., & Bolser, D. C. (2001). Assessment of aspiration risk in stroke patients with quantification of voluntary cough. Neurology, 56(4), 502-506.