Voice Disorder Classifications: A Scoping Review – Part A

Abstract

Voice is a complex and multidimensional phenomenon of interest to different disciplines. Divergent terminologies and, consequently, classification systems constitute, historically, a difficulty in this field of knowledge, which limits communication between professionals from different countries, backgrounds, and clinical experiences, and well as limiting clinical management and discussion of scientific research findings. This article aims to map and analyze the different diagnostic classifications in voice by describing the findings of a scoping review, consisting of both electronic and manual searches. The results are presented in two parts. In Part A of this article, we explore propositions for comprehensive diagnostic classifications, which involve theoretical frameworks for the constitution of each proposal. The included studies were classified as either articles with theoretical propositions, called G1, or articles using automated computerized classification systems called G2. A total of 44 articles were included: 27 in G1 and 17 in G2. In G1, we found studies from 1947 to 2021, most of which were from the USA, the authors having created theoretical propositions on the subject, considering mainly the etiology of vocal disorder. In G2, we found studies from 2009 onwards, emphasizing automated extraction of acoustic measurements and machine learning to create classification systems. G1 shows the propositions of classifications ranging from two to 11 main groups, each with possible subgroups. In G2, the classifications ranged from four to seven groups, showing preference to distinguish them by descriptions of laryngeal conditions. Conclusion: There is limited convergence between the different theoretical classifications, which is highlighted by the need to create different subgroups, or categories, to include different vocal disorders. The studies with a computerized approach reduce this variability to a certain extent; however, although promising, they should consider theoretical foundations in the proposition of classifications to be applicable to clinical setting.