Hearables, headphones or earphones that use digital technology to improve the listening experience, connect us to smart assistants or monitor our health, are set to be one of the next big revolutions in wearables. Here’s a look at how that will happen.
As smart earphones become the norm, the market for hearables will grow massively. Beyond listening to audio, these devices are getting smarter, thanks to integrations with digital assistants like Alexa or Siri. And increasingly they contain sensors that will allow for all kinds of health monitoring functions.
Analyst Nick Hunn, who has been following this technology for years, predicts a market size of $80 billion by 2025. The Covid-19 pandemic has disrupted the supply chain, but the sector is still expected to grow, with GlobalData projecting a market of $146 billion by 2030. The potential is clearly huge but, before we consider some of the things that hearables can do, let’s briefly examine how we got to where we are today.
Improved listening experiences
Most people use earphones to listen to music or watch video on the move. There are an estimated 600 million users of streaming music services worldwide, for example. The first Bluetooth headphones traded audio quality for convenience but over the last 10 years quality has improved to the point where wireless earphones are good enough for all but the most dedicated audiophile.
At the 2020 Consumer Electronics Show, a new standard, Bluetooth LE Audio was announced, which increases the capabilities of Bluetooth to support hearing aids, streaming to multiple devices and LC3 – the Low Complexity Communications Codex, which promises better listening quality when bandwidth is low.
Headphones have been further augmented with microphones that aid noise cancellation or, the reverse, allow external sounds in, above what’s being listened to. Nuheara’s IQbuds, for example, adapt to the listener’s hearing profile and can amplify to make it easier to hear in noisy environments. Similarly, EVEN’s headphones are designed to compensate for hearing loss, which happens to us all as we age, by amplifying certain aspects of sound.
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Hearables and health monitoring
As well as improving hearing, devices worn in the ear are ideal for monitoring health and wellness. Hearables have a number of advantages over wrist-worn health trackers, starting with the fact that the inside of the ear is dark, closer to the body’s core and the arteries are close to the surface, which makes it better for heart rate monitoring. The ear is an ideal location for monitoring the brain, eyes, speech and head movement. Sensor provider Valencell argues that signals from the ear are as much as 100-times clearer than those on the wrist.
This makes sense for practical reasons, as well as biological ones. When tracking exercise, for example, the wrist is frequently in motion and there are muscles and tendons for sensors to work around. Also, skin gets damp with sweat and the device itself may not fit snugly. All this makes it harder to get a good signal. In contrast, our heads move much less during exercise and the devices themselves are more likely to stay put.
The first hearables began to emerge in the mid-2000s. One of the first was Bragi’s Dash, which embedded a range of sensors to provide motion tracking, heart rate monitoring and other capabilities in addition to the expected audio playback and hands-free calling functionality.
The first version of Dash launched on Kickstarter in 2014, around the same time as a rival company, Doppler Labs, was founded in the US. The two companies were among the early movers in what would be known as the hearables space. Doppler went out of business in 2017, while Bragi pivoted to become a software supplier to audio product manufacturers. Starting a new hardware category is hard.
A particular challenge for a device that you wear in your ear is that it must be very carefully designed to balance its capabilities with overall size and weight. The device must be big enough for the sensors and the battery that powers them. As more functions are added, battery life has to get shorter or the battery has to be bigger. Six years on, it remains a challenge.
Using inside information
Sensors are added for all kinds of reasons. Apple’s Airpods contain light sensors, for example, to determine whether the earphone is in your ear and start or stop playback accordingly. But there are numerous health and wellness applications for in-ear sensors.
Sensors can be used for Photoplethysmography (PPG) – using light to detect changes in blood volume, which can determine things such as oxygen saturation (SpO2), blood pressure and pulse rate. Blood pressure is a good measure of overall health, while SpO2 can monitor lung conditions, sleep apnea and patients with cardiac conditions, among other things. Analysing changes in this data could provide early indication of heart or blood pressure problems, as well as things like stress or drowsiness.
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Heart rate variability, for example, is the time difference between beats of your heart. A heartbeat of 60bpm is not literally one beat every second. The gaps between beats will vary and the greater the variability, the better condition you are in. Using an in-ear sensor to measure this can help track overall fitness or recovery from a heart procedure.
Heart activity can also be monitored with Electrocardiography (ECG) sensors, which track electrical impulses, rather than blood volume, while Electrodermal activity (EDA) sensors could be used to analyse breathing patterns. Electroencephalography (EEG) sensors, like those in the Kokoon sleep headphones, can monitor brain activity by detecting electrical activity. Kokoon uses this to detect when the wearer is asleep and change the audio accordingly, playing in white noise to drown out night-time disturbances, for example. Brain monitoring is developing rapidly and could be used to monitor stress, epilepsy or even complex mental illnesses.
These are far from the only options. Temperature, motion, and other metrics can all be gathered from hearables. Electrical signals can track eye movement, which offers a way to monitor attention and alertness. Measuring the shape of a user’s ear canal can identify facial expressions, which could become a means for controlling these devices or play a role in mood tracking.
The data that these sensors gather can be useful for telling us what is going on in the body right now. For example, if you are exercising you might want to stay within a certain heart rate range and hearables could use an audible signal to tell you if your heart rate is too low or too high.
But trend data can be even more useful. Once a system begins to understand what is normal for you and your body, it can use anomalies to detect potential health problems. Once lots of people are using these devices and their data can be analysed together – with appropriate privacy controls and anonymity – artificial intelligence and analytics can look for patterns and draw conclusions beyond those that can be derived from individual data.
Combining lots of these measures, along with things like voice recognition and head movement could provide a powerful way to monitor overall health and wellbeing and then trigger responses. These could range from suggesting a minute of deep breathing to combat stress to scheduling an appointment with a specialist to deal with emerging cardiac symptoms.
Many of these applications are some time away from being reliable and widely used technologies but the pace of innovation is fast and increasing. We are just a few years away from widespread consumer use of hearables for health monitoring but specific, niche medical uses are already happening. The potential for hearables is already more than music to our ears.
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