- A reliable and non-stressful method that samples earwax and measures cortisol levels has been created by researchers
- The device is less time-consuming and expensive than current methods
- The lead researcher is setting up a company in the hope of bringing the device to market
Could you imagine a test that uses earwax to measure stress levels and diagnose depression? Well, researchers from the University College London Institute of Cognitive Neuroscience and King's College London have done just that, and believe it could “transform diagnostics and care for millions of people with depression or stress-related conditions”.
The team found that earwax retains concentrations of cortisol, also known as the “stress hormone”. Cortisol can cause an increase in heart rate and blood pressure, and is used to evaluate mental fitness in clinical settings.
Cortisol has also been considered as a possible biomarker for depression, but accurately measuring cortisol levels using traditional methods is challenging, the researchers said in a statement.
The most common technique to measure cortisol is via hair samples, which, however, is subject to short-term fluctuations. More than that, it is time-consuming and costly (compared to earwax), and not everyone has enough hair for a reliable sample.
“Cortisol sampling is notoriously difficult, as levels of the hormone can fluctuate, so a sample might not be an accurate reflection of a person’s chronic cortisol levels,” said Dr Andres Herane-Vives, a psychiatrist at UCL and lead author of the study.
“Moreover, sampling methods themselves can induce stress and influence the results.
“But cortisol levels in earwax appear to be more stable, and with our new device, it’s easy to take a sample and get it tested quickly, cheaply and effectively,” he added.
Herane-Vives told the BBC that diagnostic accuracy is “the only way to provide the right treatment”.
The new device can also be used at home without clinical supervision, which is beneficial in the context of the ongoing Covid-19 pandemic.
The findings were published in the academic journal Heliyon.
Earwax versus hair samples
Using the newly developed swab, Herane-Vives and colleagues from the UK, Chile and Germany collected earwax samples from 37 participants, and used them to measure their cortisol levels.
Participants' hair samples were also taken and analysed.
They found that the earwax samples produced more cortisol than hair samples. The new technique was also the least influenced by confounding factors, such as stressful events or alcohol consumption that can contribute to cortisol fluctuations.
Another benefit, they mentioned, was that the earwax technique was more comfortable than traditional methods.
Device inspired by honeycomb
The device was developed after Herane-Vives was inspired by honeycomb from bees, another natural wax.
Honeycomb is known to be resistant to bacterial contamination, and earwax has similar properties, the authors mentioned, making it well suited for home sampling, as the samples can be sent to a lab by post without a high risk of contamination.
The self-sampling device is similar to a cotton swab, but contains a brake that stops the swab from reaching too far into the ear and causing damage.
Herane-Vives hopes to bring the new device to market, and is currently setting up a company, Trears, with support from the UCL Hatchery startup incubator.
The researchers also stated that the device may have the potential to measure glucose levels (for monitoring diabetes) and Covid-19 antibodies that accumulate in earwax.
“After this successful pilot study, if our device holds up to further scrutiny in larger trials, we hope to transform diagnostics and care for millions of people with depression or cortisol-related conditions such as Addison's disease and Cushing syndrome, and potentially numerous other conditions,” Herane-Vives said.
Image: Getty/Aleksei Morozov