Research found potential “vocal” Covid-19 biomarkers that could potentially help identify the disease even before the onset of symptoms.
Infectious diseases really affect the whole body: in particular, they change the tone, volume, and many other characteristics of our voices. This conclusion was made by the staff of the Lincoln Laboratory at the Massachusetts Institute of Technology, who discovered 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 a study 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 articulatory apparatus and muscles involved in speaking. “Our approach is based on the complexity of neuromotor coordination between the speech subsystems involved in breathing, phonation (using the larynx to produce sound. – Ed.), And articulation. This is due to the different nature of Covid-19, manifested in the bronchi, diaphragm, trachea, larynx, pharynx, mouth, and nose, as well as evidence of neurological manifestations of the virus”, the authors of the article writing.
Despite the fact that the study is still in its early stages, the initial results motivate a more detailed study, scientists say. In addition, their findings can underlie the development of mobile applications for screening people for coronavirus disease, especially those without symptoms.
The head of the research team, Thomas Quatieri, has previously led research in this area: his focus has been on identifying vocal biomarkers of 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 by processing speech signals.
With the onset of the Covid-19 pandemic, the team wondered: can “vocal” biomarkers also exist in those infected with the coronavirus? Judging by the primary symptoms of the disease – when a person has difficulty breathing, he develops a dry cough, shortness of breath – this is quite real. Inflammation in the respiratory system affects the rate of air expiration when the patient says this air interacts with hundreds of other potentially inflamed muscles along the way to speech production. Thus, the tone of the voice, resonance, volume, and so on, change – and all these parameters can be measured and used as a complex of biomarkers, scientists decided.
During the experiments, they carefully compared the recordings of speeches by celebrities who got Covid-19 but did not yet show symptoms, and their interviews when they were definitely healthy (they found “before” and “after” videos on YouTube). Then the authors of the work applied algorithms to extract the parameters of voice signals from each audio recording. As suggested by scientists, coronavirus infection provokes muscle pairing, which leads to their obstructed movement. As a result, the diversity of sound signals is reduced. “Imagine that these speech subsystems are the wrists and fingers of an experienced pianist; As a rule, movements are independent and complex, explains Kvatieri. – Now imagine that the wrists and fingers seem to stick together and act as one. This will make the pianist play a simpler composition”.
According to the analysis, the researchers found that the speech movements of the sick Covid-19 were simplified compared to his speech before. The relationship between laryngeal movement and articulation was less noticeable. Thus, according to preliminary results, “vocal” biomarkers may indicate that a person is infected with a coronavirus.
Of course, for the final confirmation of this hypothesis, more data will be needed: now the authors of the study are working with the Carnegie Mellon University database containing audio recordings of the voices of people whose test gave a positive result on Covid-19.