The study uncovered potential vocal biomarkers for Covid-19 that could potentially help detect disease before symptoms appear.
Infectious diseases do affect the entire body: in particular, they change the tone, volume, and many other characteristics of our voices. This conclusion was reached by the staff of the Lincoln Laboratory at the Massachusetts Institute of Technology, who found changes in the voice of asymptomatic carriers of the SARS-CoV-2 coronavirus - so subtle that people did not pay attention to them.
According to the authors of the study, which is published in the IEEE Open Journal of Engineering in Medicine and Biology, these "vocal" biomarkers were due to the fact that coronavirus pneumonia affects the respiratory system, larynx and, as a result, the entire articulation apparatus and muscles involved in speaking. “Our approach is based on the complexity of neuromotor coordination between speech subsystems involved in respiration, phonation (using the larynx to generate sound. - Ed.) And articulation. This is due to the different nature of Covid-19, manifested in the bronchi, diaphragm, trachea, larynx, pharynx, oral and nasal cavities, as well as evidence of the neurological manifestations of the virus,”the authors of the article write.
Although the research is still in its early stages, the initial results motivate more detailed study, the scientists note. In addition, their findings may form the basis for the development of mobile applications for screening people for coronavirus disease, especially those who have no symptoms.
Team Leader Thomas Quatieri has previously led research in this area, focusing on identifying vocal biomarkers for neurological disorders such as amyotrophic lateral sclerosis (ALS) and Parkinson's disease. These and many other diseases affect the ability of the human brain to turn thoughts into words - and such changes are detected through the processing of speech signals.
With the onset of the Covid-19 pandemic, the team wondered: can “vocal” biomarkers exist in those infected with the coronavirus? Judging by the primary symptoms of the disease - when a person has difficulty breathing, he has a dry cough, shortness of breath - this is quite real. Inflammation in the respiratory system affects the rate at which air is exhaled, and when the patient speaks, this air interacts with hundreds of other potentially inflamed muscles to produce speech. Thus, the tone of voice, resonance, loudness and so on change - and all these parameters can be measured and used as a complex of biomarkers, the scientists decided.
During the experiments, they carefully compared the recordings of speeches of celebrities who fell ill with Covid-19, but did not yet show symptoms, and their own interviews when they were definitely healthy (videos "before" and "after" were found on YouTube). Then the authors of the work applied algorithms to extract the parameters of the voice signals from each audio recording. As scientists suggested, coronavirus infection provokes muscle mating, which leads to their difficulty in moving. As a result, the variety of audio signals is reduced. “Imagine that these speech subsystems are the wrists and fingers of an experienced pianist; as a rule, the movements are independent and complex, - explains Quatier. - Now imagine that the wrists and fingers seem to stick together and act as one. This will force the pianist to play a simpler song.”
According to the results of the analysis, the researchers found that the speech movements of the patient with Covid-19 were simplified compared to his speech before. The relationship between laryngeal movement and articulation was less pronounced. Thus, according to preliminary results, "vocal" biomarkers may indicate that a person is infected with the coronavirus.
Of course, more data will be needed to finally confirm this hypothesis: now the authors of the study are working with the Carnegie Mellon University database containing audio recordings of the voices of people who tested positive for Covid-19.