Today the US Patent & Trademark Office published a patent application from Apple that relates to a possible future health related feature regarding the diagnosis and monitoring of bruxism using motion sensors in AirPods.

Teeth grinding and jaw clenching (bruxism) are the most common parafunctional behavior manifested during sleep and awakeness. Awake bruxism has been mostly associated with emotions like anxiety, stress, frustration or tension. During sleep it causes sleep disorders and arousals. Individuals are mostly unaware of the occurrent and severity of their bruxing habits. The unawareness results in a myriad of orofacial muscle pain and dental consequences like teeth damage, wear and fractures.

Commercial devices in dental practice to monitor and treat bruxism are expensive, inconvenient for frequent daily use. For instance, Polysomnography (PSG) studies that target the monitoring of sleep bruxism, require patients to sleep in a clinical setting overnight. Further, most portable of wearable Electromyography (EMG) based devices for out-of-clinic use require individuals to attach the EMC electrodes on face muscles.

Apple's invention relates to the use of AirPods with special motion sensors to diagnose and monitor a user's bruxism.   

The location of the AirPods is a proper spot to capture distinct profiles of teeth activities. The sound vibration produced by teeth motions reach the inner ear by the conduction through the bones of the skull. In this way, bony prominence like the mastoid part of the temporal bone and ear canal are appropriate locations to locate the transducer and directly sense those vibrations.  

The patent covers the following segments:

• Bruxism Overview
• Example System (see FIG. 2 below)
• Pre-Processing Stage
• Audio Segmentation and Feature Extraction Stage
• Classification Stage, and
• Other Orofacial Activities Data Collection

Apple's patent FIG.1 below illustrates an earbud inserted in the ear of a user and the accelerometer capturing sound vibrations in the audio band caused by bruxism events; FIG. 2 is a block diagram illustrating a system for diagnosing and monitoring bruxism; FIG. 3 are spectrogram plots of example acoustic profiles of orofacial activities.

Apple's patent FIG. 6 below is a flow chart of a data processing pipeline for diagnosing and monitoring bruxism events.

(Click on image to Enlarge)

For more details, review Apple's patent application number 20220313153 A1.

It's clear how this can work during the day with the current AirPods design. For monitoring a user's bruxism at night, however, may require Apple to redesign AirPods so that nothing protrudes from the ear, making it harder for them to fall out for side-sleepers.