Assessing efficacy of voice treatments: a guideline.

The proposal of this guideline or basic protocol is an attempt to reach better agreement and uniformity concerning the methodology for functional assessment of pathological voices. The purpose is to allow relevant comparisons with the literature when presenting/publishing the results of voice treatment, e.g. a phonosurgical technique, or a new/improved instrument or procedure for investigating the pathological voice. Meta-analyses of results of voice treatments are generally limited--and even impossible--due to the major diversity in assessing functional outcomes. A minimal, multidimensional set of basic measurements is proposed, suitable for all "common" dysphonias: it includes 5 different approaches: perception (grade, roughness, breathiness), videostroboscopy (closure, regularity, mucosal wave and symmetry), acoustics (jitter, shimmer, Fo-range and softest intensity), aerodynamics (phonation quotient), and self rating by the patient. The protocol is elaborated on the base of an exhaustive review of the literature, the experience of the Committee members, and of plenary discussions within the European Laryngological Society. Instrumentation is kept to a minimum, but considered essential for professionals performing phonosurgery.