SpiroConfidence: Determining the Validity of Smartphone Based Spirometry Using Machine Learning

Varun Viswanath, Jake Garrison, Shwetak Patel

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A patient performs a smartphone spirometry effort. The app using our proposed method recognizes that there was too much background noise, so it rejected the effort from analysis.

Abstract

Prior work has shown that smartphone spirometry can effectively measure lung function using the phone’s built-in microphone and could one day play a critical role in making spirometry more usable, accessible, and cost-effective. Although traditional spirometry is performed with the guidance of a medical expert, smartphone spirometry lacks the ability to provide the patient feedback or guarantee the quality of a patient’s spirometry efforts. Smartphone spirometry is particu- larly susceptible to poorly performed efforts because any sounds in the environment (e.g., a person’s voice) or mistakes in the effort (e.g., coughs or short breaths) can invalidate the results. We introduce two approaches to analyze and estimate the quality of smartphone spirometry efforts. A gradient boosting model achieves 98.2% precision and 86.6% recall identifying invalid efforts when given expert tuned audio features, while a Gated-Convolutional Recurrent Neural Network achieves 98.3% precision and 88.0% recall and automatically develops patterns from a Mel-spectrogram, a more general audio feature.