Vocal dosimetry (APM) in opera and musical soloist singers during live performances in theatres: a pilot study

in clinical management of singers it’s important to identify risk components of vocal fatigue and glottic damage, predicting and assessing the vocal cost of the various vocal performances to avoid any risk. despite many difficulties, we made dosimetries on singers (9 opera and 9 musical) during live theatre performances. our aim was to evaluate phonatory behaviours before, during and after performances to determine the actual amount of vocal load and the possibility of assessing vocal fatigue and performative potential risks through the identification of a vocal recovery index (vri). since the analysis of numerical data from apM (fo, spl, vocal doses) doesn’t immediately highlight the extent of vocal load, we decided to elaborate data in order to propose a new index: vri. We found that a lower vri corresponds to difficult or fatiguing moments, while the opposite happens in moments of vocal rest or recovery. We suppose that there are different threshold ranges between males and females and between different vocal classes, therefore it would be desirable to establish vri thresholds for references in evaluation of data from dosimetries. in this study we also show differences between opera and musical soloist singers and describe fo histogram like a real vocal score profile, spl histogram like an on stage relative dynamic agility and phonation density graph like an on stage phonetogram to point out many vocal features. finally, through this method, it could be possible to adapt technical and behavioural measures to avoid and reduce the risk of vocal fatigue or damage. keywords : vocal dosimetry, vocal recovery index, vocal effort, vocal doses.