Changes in people's voices recoded on a smartphone can signal a serious flare up in symptoms of chronic obstructive pulmonary disease (COPD), according to a pilot study presented at the European Respiratory Society (ERS) Congress in Vienna, Austria [1].
COPD, which includes emphysema and chronic bronchitis, is a serious and long-term lung condition. According to the World Health Organisation, COPD is the third leading cause of death worldwide.
A flare-up in symptoms, such as difficulty breathing and coughing, is known as an exacerbation. During an exacerbation patients may need extra treatment or hospitalisation, and their risk of dying increases. However, if treatment can be given at a very early stage, these risks are far lower.
The study was presented by Ms Loes van Bemmel, a researcher in the department of respiratory medicine at Maastricht University Medical Centre in the Netherlands. She said: "After an exacerbation, patients report a lower quality of life, their lung function can decline, and patients are at an increased and prolonged risk for cardiovascular events such as heart attack and stroke. It's vital to detect exacerbations as early as possible so appropriate treatment can be given. Unfortunately, it has proved difficult to detect exacerbations at their onset, since symptoms usually start when patients are at home.
"Patients and their families have told us that there are voice changes before and during exacerbations. We wanted to see if we could record patients' speech at home and analyse these recordings for early signs of an exacerbation."
Twenty-eight people with COPD took part in the research. Researchers asked them to record their voices via a smartphone app every day for 12 weeks. They recorded themselves saying "aah" for as long as they could manage with one breath, then either reading a short paragraph of a story or answering a question.
Participants also completed a daily questionnaire to gauge their COPD symptoms. During the study, there were 16 occasions when a patient experienced a flare-up of symptoms.
Researchers analysed the voice recordings and looked for changes that coincided with symptom flare-ups. They found that patients' voices became higher pitched when an exacerbation was imminent. They also found more 'jitter' in patients voices when an exacerbation was beginning. Jitter is when a voice sounds breathy or hoarse.
Ms van Bemmel said: "There were clear differences between patients' recordings on a normal day and on the first day of an exacerbation. This confirmed our hypothesis that speech changes significantly, even at the very beginning of an exacerbation.
"These are preliminary results, so our findings need to be validated in larger numbers of patients with COPD. If we are able to do this, it would pave the way for early detection and diagnosis of exacerbations in the home environment. This would enable patients to manage these events themselves at home.
"While every disease is different, speech analysis could potentially help in other respiratory diseases as well. We suspect there are speech biomarkers for many respiratory diseases."
Ms van Bemmel and her colleagues are now planning research to build on their findings. In partnership with researchers at Radboud University Medical Centre in the Netherlands, the team will co-create a mobile app with people living with COPD. The SPEAK app will be used by patients to detect exacerbations via speech signals and give support for treating symptoms in the home. At the same time, the researchers are looking into ways to responsibly collect, store and analyse speech data so that the privacy of the speaker is maintained.
Professor Frits Franssen is Secretary of the ERS assembly on respiratory clinical care and physiology, Head of the Department of Respiratory Medicine at Maastricht University Medical Centre, Netherlands, and was not involved in the research. He says: "COPD is a common and serious condition. When symptoms flare up, it can lead to a long-term deterioration in health and can even be fatal. If we spot these exacerbations early and give treatment, we know that serious complications can often be averted. At the moment, that means the patient or their family deciding something is wrong then seeing a doctor for assessment and tests.
"This research is interesting because it suggests that the early signs of a COPD exacerbation can be picked up via changes in a patient's voice recorded on a smartphone. This finding needs to be tested in a larger study. If it can be validated, this could lead to a quick and efficient system to alert a patient and their doctor that treatment is needed. Because it works via a smartphone, voice analysis could be used by anyone, at anytime and anywhere. This could ultimately save money, time and patients' lives."
