A Proposed Biomechanical Phenotype-Based Framework for Therapy Selection in Voice Disorders: A Clinical Decision-Making Model

Traditional organic-functional classifications of voice disorders do not specify the biomechanical targets of voice therapy. This article proposes a rule-based classification of biomechanical phenotypes to support the selection of candidate therapeutic approaches, and specifies how it should be validated.

The two-dimensional organicity-tonicity arrangement^1,2 was adapted into a categorical rubric that uses only videolaryngostroboscopy (VLS) and GRBAS ratings from the European Laryngological Society-Union of the European Phoniatricians Core Dataset. Inputs are a tissue axis (X, 0-3), a mobility flag (M), hyperadductory and hypoadductory subscores (H, L), and a nonlesional glottal gap flag (G). Aerodynamic, acoustic, and kinematic measures were excluded from assignment and reserved as external validators. Logical consistency was checked by exhaustive enumeration, and validation sample sizes were derived by exact and Monte Carlo methods.

Ordered rules yield six phenotypes (Hyperfunctional, Hypofunctional, Structural-Rigid, Structural-Lesional, Mixed-A, and Mixed-B) plus a Eutonic/Unclassified category, and assign exactly one label to each of 7680 admissible input combinations (36 decision cells, no conflicts). A stratified reliability sample of 105 cases (15 per category) gives a 95% confidence-interval half-width for Fleiss' κ of at most 0.082. Confirmatory convergent-validity contrasts cannot be adequately powered in a consecutive cohort of feasible size; a staged design with enrichment of rare phenotypes is therefore specified.

The rubric is logically exhaustive and mutually exclusive, and its confirmatory validation hypotheses rely on measures that play no part in assignment. Its clinical validity and the phenotype-to-technique mapping remain to be tested prospectively.