Researchers in Switzerland are developing a new diagnostic tool that can detect the first signs of neurodegenerative changes using a sensor belt.
Neurodegenerative changes occur decades before impaired cognitive ability becomes apparent. These changes can be detected, but the procedures are expensive or invasive and are not suitable for large-scale early warning programs. Now Empa researchers are working with partners from Cantonal Hospital and the Geriatric Clinic in St. Gallen, all in Switzerland, on a non-invasive diagnostic method that detects the early processes of dementia.
Patrick Eggenberger and Simon Annaheim from Empa’s Biomimetic Membranes and Textiles lab in St. Gallen are using a sensor belt – already used for ECG measurements – equipped with sensors for other relevant parameters such as body temperature and gait. According to the team, subtle changes that occur are expressed through unconscious bodily responses, and these changes can only be accurately captured when measurements are taken over a longer period of time.
“It should be possible to integrate the long-term measurements into everyday life,” says Annaheim.
Skin-friendly and comfortable monitoring systems are essential for measurements suitable for everyday use. The belt will be based on flexible sensors with electrically conductive or light-conducting fibres, plus sensors for movement and temperature measurement.
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To enable such long-term measurements, the researchers integrate the collected data into mathematical models developed on Empa, the Swiss Federal Laboratories for Materials Science and Technology†
The goal is an early warning system that can estimate the progression of cognitive impairment. Another advantage is that the data measurements can be integrated into telemonitoring solutions and improve patient care in familiar environments.
An important indicator of the onset of dementia is body temperature, which remains constant in a range of 1Oc.
According to Empa, values naturally fluctuate over the course of the day. This daily rhythm changes with age and is conspicuous in neurodegenerative diseases such as dementia or Parkinson’s disease. In Alzheimer’s patients, the core body temperature is increased to 0.2OC. At the same time, the peaks in the daily temperature fluctuations are dampened.
In a study, the researchers showed that altered skin temperature readings, measured with the sensor strap, provide an indication of subjects’ cognitive performance, and can do so long before dementia develops.
The subjects in the study included healthy people with or without mild brain damage. This mild cognitive impairment (MCI) does not represent a disability in everyday life, but is considered a possible precursor to Alzheimer’s disease.
The subjects took part in long-term measurements and neuropsychological tests and it was found that a lower body temperature, which fluctuated more during the day, was associated with better cognitive performance. In subjects with MCI, body temperature varied less and was generally slightly elevated.
The researchers also looked at heart health as an indicator of the onset of neurodegeneration. The heart rate is subject to natural variations that show how the nervous system adapts to sudden challenges. The small pause between two heartbeats, which lasts about a second, is important for health because there can be problems with the nervous system if the pause always remains the same.
A study by researchers at ETH Zurich has found that worse readings in older, healthy people can be improved within six months through cognitive-motor dance training. In these ‘exergames’ the subjects imitated sequences of steps from a video. In contrast, participants who instead trained only in straight lines on a treadmill, but also trained their memory, benefited less.
“The point is to intervene early with proper training as soon as the first negative signals can be measured,” Eggenberger said. “With our sensor system, any improvements in cognitive performance can be tracked through movement-based forms of therapy.”
Using long-term monitoring studies, it is now becoming clear how the sensor measurements can be used to predict the course of mild brain disorders.