Ear EEG-based Hypoglycaemia Alarm

EAR COMPUTER

PREDICTS HYPOGLYCAEMIA

Brain-computer interface (BCI), one of today’s most fascinating technologies. Lately, researchers have come a long way in the development of micro-computers and advanced algorithms that can interpret electrical activity in the brain cells and thereby reveal the mental states of human beings. The photo shows Professor (Docent) Preben Kidmose, a specialist in in-the-ear EEG. An insulin shock detector is just one of the many potential applications of the technology. Photo Lise Balsby.

A small device in the ear protects diabetes patients from hypoglycaemia. Small electrodes measure electrical brain signals and warn the patient if their blood sugar drops to a critically low level.

Diabetes is one of the most wide-spread, rapidly spreading and expensive diseases in the world. One of the most serious complications of the disease is hypoglycaemia, also called insulin shock, which occurs when the blood sugar drops to a level where the brain no longer functions normally. This is a serious condition with a risk of both coma and death.

Researchers from Aarhus University have therefore started working on a device that prevents hypoglycaemia by warning the patient so that they can take preventative action. The vision is to help people with diabetes by providing better treatment and a better quality of life.

Measuring electrical activity in the brain
The device detects the risk of hypoglycaemia by measuring the electrical activity in the brain by means of small electrodes in the ear.

In case of low blood glucose levels, characteristic changes appear in the electrical signals from the brain. These signals can be measured and analysed by using advanced algorithms, which makes it possible to detect low blood sugar levels before hypoglycaemia occurs.

The device functions via three small electrodes and a micro-computer that decode the activity in the brain. The design of the device will be similar to the design of a traditional hearing aid and it will be very comfortable for the user and almost invisible in the ear canal.

Little and discreet
The technology for measuring electrical activity in the brain is called EEG monitoring. While EEG technology is already well-known, the experiment with electrodes in the ear is new. The device has great potential because it is non-invasive and discreet, and at the same time the measurements are very precise.

"The patient has to wear the device 24 hours a day so user-friendliness is crucial for the product’s potential for commercialisation. Today, EEG measurement takes place via electrodes on the head, which requires a form of helmet. Ear EEG will give the technology completely new applications," says Preben Kidmose.

Around 20 percent of all patients with insulin-requiring diabetes are not able to sense when they have low blood sugar levels. Some patients may not even wake up if their blood sugar levels drop during the night. And other diabetics have deliberately increased blood sugar values to avoid hypoglycaemia.

There is no equipment currently available that can warn patients when they are going into insulin shock so the ear EEG technology has major clinical and commercial potential.

The success criteria for the project are to establish a technical and clinical proof-of-concept for an Ear EEG-based hypoglycaemia alarm.

The main technical challenge addressed by the project is the development of a platform consisting of dry electrodes and corresponding electronic instrumentation to provide high quality EEG recordings from the ear. To meet the requirements for high accuracy, noise immunity, low power consumption and physical size that allow the device to be placed in the ear canal, the electronic instrumentation will be implemented in an application specific integrated circuit (ASIC) using state-of-the-art chip technology. The characterisation of EEG signals and the detection of hypoglycaemia episodes require advanced signal processing techniques and the development of dedicated signal processing algorithms.

Advanced signal processing
The success criteria for the project are to establish a technical and clinical proof-of-concept for an Ear EEG-based hypoglycaemia alarm.

The main technical challenge addressed by the project is the development of a platform consisting of dry electrodes and corresponding electronic instrumentation to provide high quality EEG recordings from the ear. To meet the requirements for high accuracy, noise immunity, low power consumption and physical size that allow the device to be placed in the ear canal, the electronic instrumentation will be implemented in an application specific integrated circuit (ASIC) using state-of-the-art chip technology.

The characterisation of EEG signals and the detection of hypoglycaemia episodes require advanced signal processing techniques and the development of dedicated signal processing algorithms.


PHOTO TOP: The researchers have produced the first prototype of a small, discreet ear computer that can prevent insulin shock in diabetics by measuring their brain activity (Photo: Lise Balsby)