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New earplug will tell us more about sleep disorders

New earplug will tell us

more about sleep disorders

Monitoring brain activity through the ear can give doctors completely new insight into the phenomenon of sleep. Professor (Docent) Kidmose is behind technology that in years to come will have a major impact on diagnosis and treatment of patients suffering from sleep disorders, and the consequences of these. Photo: Lars Kruse.

By inserting a small computer in the ear, researchers can wirelessly monitor brain activity while we are asleep. They are now conducting a comprehensive clinical study to find new answers to how doctors can optimise treatment of sleep disorders.

Sleep disorders are far more widespread than most people think. It is reckoned that at least 40 per cent of Danes suffer from a sleep disorder to such an extent that it affects their health and quality of life. Sleep disorders cost society billions, but we know very little about why the problems arise and how we can treat them.

For many years, doctors at Danish sleep clinics have been using so-called polysomnography measurements to diagnose the most seriously affected patients. This takes place using EEG equipment which, via electrodes stuck to the patient’s head and face, measures voltage fluctuations in the cerebral cortex for a defined time period corresponding to one night.

The method is accurate, but it has the major disadvantage that it must be carried out at a hospital. A successful night monitoring requires at least eight electrodes on the patient’s head and four on the face, which is wrapped in gauze to secure the equipment and the wires. This is both an intrusive and expensive method of diagnosis, as Professor (Docent) of Engineering Preben Kidmose explains:

“It goes without saying that the equipment disturbs the patient’s sleep and measurements may therefore differ significantly from the patient’s average sleep patterns. Our ear computer can measure with the same accuracy, but it doesn’t disturb sleep, and it offers completely new opportunities to improve the quality of intervention studies. At the same time, it goes without saying that you can save time that currently goes to fitting the equipment on patients and then manually reviewing the results.”

Professor (Docent) Kidmose has spent a large part of his research career on developing the technology, which now makes it possible to detect and decode the signals from the brain through the ear.

First long-term studies of sleep
The earplug used by the researchers in the clinical trials contains miniature electrodes to measure and collect signals from the brain. It is powered by an external magnetic field and therefore has very low electricity consumption. Therefore, the device works without a battery, which means it can operate for a long time. In principle, researchers can therefore carry out continuous monitoring of human brain activity for weeks and perhaps even months.

“Long-term monitoring enables doctors to obtain a detailed insight into the nature of sleep disorders and thereby a better basis for recommending relevant treatment with behavioural therapy or drugs. We can see how phases of sleep take over from each other, and we can map out where the system is muddled,” says Professor (Docent) Kidmose.

Another research benefit from replacing the conventional EEG systems with discreet, comfortable and wireless technology is that measurements can be taken outside the clinic in patients’ everyday surroundings.

Over time, sleep disorders break down our cognitive functions, and the researchers hope that the technology will be a tool for doctors to conduct more accurate diagnoses and treatment.

Mental disorders can perhaps be treated better
The new method for long-term sleep monitoring could also pave the way for new knowledge about psychiatric diseases where patients often have severe sleep complications. Today, we assume that poor sleep patterns are induced by the diseases, but we don’t know for sure. The causality has never been reported in the literature.

“This opens up for a fascinating research field. We can now study relationships between mental disorders and sleep patterns, and we can investigate whether specific types of sleep disorders are linked to specific diseases. At the same time, we have an objective way to measure the effect of a given treatment,” says Professor (Docent) Kidmose.

Concurrently with the clinical trials, researchers will try to develop a number of algorithms capable of translating the signals from the brain to valuable information about sleep in its various phases. This will make it possible for a computer to automatically score the individual patient’s sleep and efficiently present long-term measurements for doctors.

“Every phase of sleep is characterised by some specific patterns in the electrical signals that the tiny electrodes in the ear pick up and identify. This enables us to say something about what the individual patient’s sleep cycle looks like and how the patient moves through the sleep phases down into deep sleep,” says Professor (Docent) Kidmose.

Deep sleep, where electrical activity in the brain is characterised by very slow oscillations, is particularly important for well-being. In the long term, the researchers hope that doctors will be able to use ear measurements to treat mentally ill patients, because they will have better opportunities to plan relevant sleep interventions for the individual patient.