One of the common side effects of chronic diseases such as Parkinson’s disease, inflammatory bowel disease and rheumatoid arthritis are problems with fatigue and disturbed sleep. Among patients with these diseases, fatigue is often rated as one of the most disabling symptoms, affecting their daily activities and their quality of life.
Despite this, monitoring these symptoms often relies on simply asking patients to fill in a questionnaire about their experiences. This method can be affected by patients misremembering things and not having enough detail about the intensity of their fatigue throughout the day.
One way to provide more accurate and reliable results is for chronic disease patients to wear small devices to monitor these physiological signals throughout the day. In a paper published in Frontiers in Physiology, an international group of researchers used wearable devices to measure and record fatigue and sleep patterns in such patients to see how effective the technology could be.
The research is part of the Innovative Medicines Initiative (IMI) IDEA-FAST project, which aims to use digital technology to improve the efficiency of clinical trials.
“There's an increasing number of articles all pointing towards fatigue being one of the biggest, if not the biggest factor, leading to a loss of quality of life in these patients,” said paper co-author and IDEA-FAST consortium coordinator Professor Fai Ng of Newcastle University. He says that studying fatigue and disturbed sleep could be the first step in creating a ‘digital biomarker’ for these symptoms that are relevant to many chronic diseases.
The researchers first asked people with neurodegenerative disorders or immune-mediated inflammatory diseases if they were interested in taking part in their study. In total 136 participants agreed to take part, with patient groups in four European cities: one in the Netherlands, two in Germany, and one in the UK. Of these, 66 had inflammatory diseases, 31 had neurodegenerative disorders, while the remaining 39 participants were otherwise healthy individuals who acted as a control group.
To evaluate the effects of fatigue and disturbed sleep in real time, participants wore a small device called VitalPatch, a 12-cm long biosensor that adheres to the skin and is worn on the left side of the chest. It recorded their heart rate, the millisecond intervals between their heartbeats, and their breathing rate, among other things. This data was then encrypted and uploaded to a cloud-based platform.
Participants were asked to carry on with their regular home life while wearing the biosensor for most of the day, including while sleeping at night. This observation period typically lasted for four weeks; five days of wearing the biosensor, followed by two days of rest. While they wore the biosensor, participants were also asked their perceptions of fatigue and sleep quality four times per day over a survey app.
The data from the biosensor were then compared with patients’ self-reported fatigue and sleep disturbances. The researchers found that the biosensor was able to record data that correlated well with what the patients reported in the app.
The biosensor also revealed information that participants were unable to record. For example, after six minutes of light exercise (for example having a walk), biosensor data showed the significant difference in heartrate recovery between healthy people and those with a chronic disease. This can be an important predictor of certain factors that can lead to fatal health events, for example a heart attack.
Prof. Ng hopes that future research will be able to monitor additional physiological measures with a larger group of participants over a longer study period.
He says that although the paper represents an early pilot study, it shows that digital technologies can give clinicians realistic information when monitoring patients at home, differentiate chronic patients from healthy individuals, and monitor their quality of life.
It’s this latter point that Prof. Ng thinks has been overlooked until recently. In his experience researchers, drug manufacturers and national governments are now beginning to put more emphasis on the patient’s personal quality of life when overcoming a disease, rather than simply focussing on the known biology of the disease itself.
Prof. Ng gives the example of a patient getting medication to overcome a disease, but who still cannot go back to work because of lasting chronic fatigue. “I think until recently people didn’t quite appreciate the kind of quality-of-life issues that these patients suffer from,” he said. “People are now taking the patient’s perspective much more seriously. It's only in the last few years that I think the emphasis on patients’ perspective become more important.”
IDEA-FAST is supported by the Innovative Medicines Initiative, a partnership between the European Union and the European pharmaceutical industry.