BACKGROUND
Speech is the main direct means of transmitting information between people. It also carries additional information depending on the state of the speaker: physical features, emotions, psychosocial traits and health conditions. Studying voice features is straightforward, does not require significant investment and can be carried out on a mass scale. However, speech analysis can only be used for initial diagnosis. The outcome of such a pre-diagnosis should indicate the need for standard medical tests. Although speech analysis is currently rarely used in medical diagnostics, it can enable earlier diagnosis and more effective treatment of patients.
OBJECTIVE
This paper is a systematic review and meta-analysis of recent advancements in using voice analysis for diagnosis and monitoring of some diseases. The goal of this article is to present and compare recent approaches to using speech and voice analysis as biomarkers of diseases. The article takes into account metabolic, respiratory, cardiovascular, endocrine and nervous system disorders.
METHODS
Articles published between 2010-2019 were selected from PubMed and ISCA Archive, using keywords ‘voice’ and ‘speech’ and respective disorder names. Further selection was performed to identify studies that assessed voice quality quantitatively in selected disorders by acoustic voice analysis (not only perceptual assessment). Information was extracted from each paper in order to compare various aspects of datasets, speech parameters, methods of analysis applied and results obtained. Each chapter starts with a medical description of how each disorder affects voice and contains a summary of different processing approaches, and is supplemented by tables comparing various investigations. Additional diagrams were prepared to illustrate general tendencies and to compare advancements in the state-of-the-art across the analyzed groups of diseases.
RESULTS
Over 90 research papers were reviewed and over 40 databases were summarized. Basic acoustic parameters which are significantly correlated with each given disorder were developed for cardiovascular, metabolic and endocrine diseases, as well as schizophrenia and amyotrophic lateral sclerosis. The affective and neurodegenerative disorders are well investigated and the majority of papers contain automatic voice recognition and machine learning methods. The main sources of problems were identified and some recommendation for future research were set.
CONCLUSIONS
Speech analysis is a promising tool for pre-diagnosis of certain disorders. Advanced computerized voice analysis and machine learning algorithms, and the widespread availability of smartphones, means that a diagnosis may be presented during the patient’s appointment with their physician, and even during a telephone conversation.