# Wearable, Always-on Stethoscope for Early Detection of Asthma Attack

> **NIH NIH R01** · UNIVERSITY OF SOUTHERN CALIFORNIA · 2023 · $695,250

## Abstract

ABSTRACT
 This research aims to develop and test a wearable, always-on stethoscope to provide a solution to the
unmet need for the quantification of respiratory symptoms. Such a device is necessary for the accurate diagnosis
of asthma and assessment of asthma control in 6.8 million infants, young children and other populations with
intellectual disability who are unable to report their respiratory symptoms or perform lung function testing in the
United States. With accurate diagnosis and assessment of control, appropriate asthma therapy can be initiated
without delays to minimize adverse asthma outcomes. The key elements needed in the proposed wearable
stethoscope (i.e., a wireless stethoscope without a bulky acoustic coupler) are (1) resonant microphone array
with unprecedented sound detectability over 100 – 800 Hz and (2) ultra-low power signal processing. We propose
to develop a bank of acoustically-filtering microphones that are based on a high Q (quality factor) resonance of
a microphone diaphragm, for accurate detection of abnormal lung sounds. A bank of Q-filtered and Q-enhanced
microphones is proposed so that (1) feature-extracting filters may be avoided and (2) extremely small lung
sounds can be detected from the chest without an acoustic coupler.
 Lung sounds are very difficult to detect from the chest without a bulky acoustic coupler, as the sound
pressure level (SPL) is only 22 – 30 dB SPL, in free space, over a frequency range of 100 – 800 Hz. This kind
of SPL cannot be accurately detected by a commercial miniature microphone. Thus, we will develop and use an
array of 8 resonant microphones with Q of 40 – 60 (fabricated with a microfabrication process) to detect lung
sounds down to 22 dB SPL, 4 dB lower than the lowest sound a human ear can detect, and to automatically
segment the sound’s frequency components into 8 different narrowly-band-passed frequency regions over 100
– 800 Hz.
 We hypothesize that continuous ambulatory monitoring of lung sounds for acoustic characteristics of
asthma will improve the diagnostic accuracy and treatment in pediatric asthma patients. Currently, asthma is
diagnosed in small children primarily through caregiver history and brief in-office exam as direct patient history
and respiratory function testing are not available for these young patients. The proposed device is entirely novel
as currently there is no device capable of providing round-the-clock monitoring for signs of asthma. While
conventional microphones can detect cough and overt wheezing, their utility is limited by insufficient sensitivity,
and are not amenable for continuous, ambulatory monitoring.
 The proposed resonant microphone array will be integrated with ultralow power electronics for a wearable
stethoscope that continuously tracks lung sounds for the detection of asthma signs and symptoms such as cough
and wheeze which may occur during exercise or sleep (when caregivers are not present) and may be
misreported or ignored by young chi...

## Key facts

- **NIH application ID:** 10665806
- **Project number:** 5R01HL165138-02
- **Recipient organization:** UNIVERSITY OF SOUTHERN CALIFORNIA
- **Principal Investigator:** EUN SOK KIM
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $695,250
- **Award type:** 5
- **Project period:** 2022-08-01 → 2027-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10665806

## Citation

> US National Institutes of Health, RePORTER application 10665806, Wearable, Always-on Stethoscope for Early Detection of Asthma Attack (5R01HL165138-02). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10665806. Licensed CC0.

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