Oral Breathing Challenge in Participants With Vocal Attrition

Vocal folds undergo osmotic challenge by mouth breathing during singing, exercising, and loud speaking. Just 15 min of obligatory oral breathing, to dry the vocal folds, increases phonation threshold pressure (Pth) and expiratory vocal effort in healthy speakers (M. Sivasankar & K. Fisher, 2002). We questioned whether oral breathing is more detrimental to phonation in healthy participants with a history of temporary vocal attrition. The effects of a 15-min oral or nasal breathing challenge on Pthand perceived expiratory vocal effort were compared for participants reporting symptoms of vocal attrition (N= 18, ages 19–38 years) and normal controls (N= 20, ages 19–33 years). Postchallenge-prechallenge differences in Pth(ΔPth) and effort (ΔEffort) revealed that oral breathing, but not nasal breathing, increased Pth(p> .001) and effort (p> .001) at low, comfortable, and high pitch. ΔPthwas significantly greater in participants with vocal attrition than in normal controls (p> .001). Nasal breathing reduced Pthfor all controls but not for all participants reporting vocal attrition. ΔPthwas significantly and linearly correlated with ΔEffort (rvocal attrition=.81,p> .001;rcontrol=.84,p> .001). We speculate that the greater increases in Pthin participants reporting vocal attrition may result from delayed or inadequate compensatory response to superficial laryngeal dehydration. Obligatory oral breathing may place voice users at risk for exacerbating vocal attrition. That sol layer depletion by obligatory oral breathing increased Pthand vocal effort provides support for the role of superficial hydration in maintaining ease of phonation.