Technical Reference

Why cough matters

Coughing is normal, even among completely healthy individuals. And it serves an essential purpose, protecting our lungs by removing “mucus, noxious substances, and infections from the larynx, trachea and larger bronchi.” Persistent coughing is a symptom of many illnesses, though occasional coughing is common even among those who are healthy (Chung 2003).

Although it is a universal human experience, only a small proportion of people with cough seek medical help (Chung 2008). Technology has enabled objective cough counting, which has the potential to identify meaningful changes in cough frequency that aren’t perceived using subjective measures, such as visual analogue scales and cough questionnaires (Birring 2015). We quantify many areas of our wellness - hours slept, calories consumed, steps taken – but we rarely quantify cough (Hall et al 2020). And it’s not because cough doesn’t matter – it does: in addition to being associated with health conditions, cough itself can affect the quality of life (French et al).

Knowledge is power. Being aware of how many times we have coughed – just like being aware of how many steps we take – may contribute to our overall well-being.

How we detect cough

CoughPro records sound continuously and sends files to a cloud server. These files are processed through algorithms which (a) detect cough-like sounds based on rapid changes in decibels picked up from your phone’s microphone and then (b) determine whether those sounds were coughs or not using a machine learning algorithm. The server tells the phone what the sound was, and the phone turns that information into visualizations (the chart and count of coughs). Some short (0.5 second), cough-like sounds are saved for later analysis and model improvement; longer sound files are immediately deleted after processing.

In technical terms, we use a combination of filters, transformations and neural network, a form of “deep learning”. The latter has been trained on a dataset of more than 270,000 labeled sounds, and is constantly improving. As with all models, it’s not perfect: sometimes it thinks a non-cough is a cough, and sometimes it misses a cough. But it’s getting better: we’re constantly working on improving our methods so as to better detect cough. And deep learning models are constantly improving in the realm of sound classification (Sejnowski).

What CoughPro does

CoughPro app is a wellness information tool. Just as other apps count calories (e.g., MyFitnessPal), workout repetitions (e.g., Count My Reps), snores (e.g., SnoreLab), and steps (e.g., Apple Health), CoughPro counts coughs.

What CoughPro doesn’t do

CoughPro is not a disease diagnosis or treatment tool, nor is it a health care or medical service. CoughPro does not provide medical advice, nor should it be considered a substitute for any form of professional health services. The accuracy of the data collected and presented through CoughPro is not intended to match that of dedicated medical devices or scientific instruments.

If you have any health concerns at all you should speak to your doctor. In the case of a medical emergency, call emergency services immediately.

References

Cough: Causes, Mechanisms and Therapy, Edited by Kian Fan Chung, John G. Widdicombe, Homer A. Boushey, 2003.
“Prevalence, pathogenesis, and causes of chronic cough,” Kian Fan Chung and Ian D Pavord, Lancet, Volume 371, Issue 9621, 19–25 April 2008, pp. 1364-1374.
Birring SS, Spinou A. How best to measure cough clinically. Curr Opin Pharmacol. 2015 Jun;22:37-40.
Hall, JI, Lozano M, Estrada-Petrocelli L, Birring S, Turner R. The present and future of cough counting tools. Journal of Thorac Dis 2020;12(9):5207-5223.
French CT, Fletcher KE, Irwin RS. A comparison of gender differences in health-related quality of life in acute and chronic coughers. Chest. 2005 Jun;127(6):1991-8.