Using Voice Change as an Indicator of Dysphagia: A Systematic Review

Voice change post-swallow, observed during a clinical swallow examination, is often used as a clinical indicator of dysphagia risk. However, there has been limited research that evaluated the level of agreement between voice change and swallow dysfunction reported to date. This systematic review aims to investigate existing evidence relating to the relationship between vocal change post-swallow and swallow deficits identified on a Videofluoroscopic Swallow Study (VFSS). The studies were selected by two independent evaluators for inclusion, without restriction on language or date of publication and the methodological quality and the risk of bias were assessed using QUADAS-2. Following the PRISMA recommendation, 271 articles were analyzed, of which 17 were included in the study. Of these, the methodology described in five studies employed voice analyses using only acoustic methods, seven others conducted only auditory-perceptual analyses, and five other studies used both. Across the studies there was no homogeneity in the voice quality parameters assessed, analytic methods used, and results obtained. Forty seven per cent of the studies presented a high risk of bias in the analysis of vocal quality due to lack of clarity and blinding of VFSS. There was no homogeneity in the choice of consistencies evaluated during swallowing, as well as standardization of the outcome investigated in VFSS without a vocal parameter attributable to accurate detection in each outcome. It is not possible to obtain a consensus regarding the recommendation of the use of vocal evaluation as an accurate method for identifying swallowing alterations due to heterogeneity of the vocal evaluation methods, the outcomes evaluated in the VFSS examination, heterogeneity in food and liquid consistencies, and the methodological quality of the studies.