Cough Sounds Recorded via Smart Devices as Useful Non-Invasive Digital Biomarkers of Aspiration Risk: A Case Report

Hye-Seon Kang,Sun Im,Catherine Song,Andy Jung,Cheol-Ki Kim,Eung-Gu Lee

doi:10.3390/s21238056

Hye-Seon Kang, Sun Im + Show 4 more

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https://doi.org/10.3390/s21238056

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Abstract

Spirometer measurements can reflect cough strength but might not be routinely available for patients with severe neurological or medical conditions. A digital device that can record and help track abnormal cough sound changes serially in a noninvasive but reliable manner would be beneficial for monitoring such individuals. This report includes two cases of respiratory distress whose cough changes were monitored via assessments performed using recordings made with a digital device. The cough sounds were recorded using an iPad (Apple, Cupertino, CA, USA) through an embedded microphone. Cough sounds were recorded at the bedside, with no additional special equipment. The two patients were able to complete the recordings with no complications. The maximum root mean square values obtained from the cough sounds were significantly reduced when both cases were diagnosed with aspiration pneumonia. In contrast, higher values became apparent when the patients demonstrated a less severe status. Based on an analysis of our two cases, the patients’ cough sounds recorded with a commercial digital device show promise as potential digital biomarkers that may reflect aspiration risk related to attenuated cough force. Serial monitoring aided the decision making to resume oral feeding. Future studies should further explore the clinical utility of this technique.

Highlights

Pneumonia is the most common cause of infectious mortality, with more than two million adults dying from lower respiratory infections [1]
Collected data indicate that 60% of community-acquired pneumonia patients and 87% of hospitalacquired pneumonia patients are diagnosed with aspiration pneumonia [2]
A fiberoptic endoscopic evaluation of swallowing (FEES) performed prior to discharge confirmed neurogenic dysphagia and showed aspiration in liquid form; otherwise, he showed tolerable swallowing of puree forms with a functional oral intake scale (FOIS) level of 2 [12], which allowed only minimal bolus training during therapy, and he was mainly dependent on tube feeding

Summary

Introduction

Pneumonia is the most common cause of infectious mortality, with more than two million adults dying from lower respiratory infections [1]. Given the expectation that the incidence will continue to increase with the growth of both the total geriatric population and patients surviving a stroke, it has been proposed that evaluation of cough strength is effective in preventing respiratory complications [3]. With recent advances in digital devices, new sophisticated technologies have been introduced to record and analyze the acoustic properties of cough sounds. These have been validated to be useful in monitoring, diagnosis, and evaluation of response to treatment in patients with airway disorders, such as asthma and chronic obstructive pulmonary disease (COPD), or even in patients with coronavirus disease 2019 (COVID-19) [3,4,5,6,7].

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