Lateral phase mucosal wave asymmetries in the clinical voice laboratory

Anecdotally, in some persons it has been observed by the Senior Author (K.K.) that asymmetries of the mucosal wave exist when examined videostroboscopically. In the vast majority of these people, no pathology is ever discovered. Mucosal wave asymmetries could cause concern for the otolaryngologist, who may consider them to be a forewarning of subclinical pathology and subject the patient to unnecessary, expensive, and anxiety-provoking investigations or interventions. The purpose of this study was to establish the prevalence of mucosal wave asymmetries in an asymptomatic population lacking laryngeal pathology. Acoustic spectral analysis is also utilized to determine if the presence of subharmonics might be associated. A hospital-based, cross-sectional study design was used. The subjects had no known vocal or medical pathologies, and were nonsmoking. The study group was composed of 30 males aged 35-50 years and 30 women between 22-55 years. Each of the males underwent acoustic spectral analysis; and all subjects completed a medical questionnaire, subjective talkativeness rating, and videostroboscopic laryngeal examination. 10.5% of the subjects (exact 95% CI = 4.0-21.5%) exhibited mucosal wave variations at stroboscopy, characterized as periodic lateral phase asymmetries found consistently in both the modal and upper registers. There was no association with the chosen acoustic spectral parameters, talkativeness scales, or questionnaire-based variables. Mucosal wave asymmetries may be a variance of normal, and are likely to be far more common in the general population than previously believed. The prevalence detected here is expected to be important in the clinical laryngology practice, where these asymmetries may be frequently encountered and influencing management decisions. There has been little normative data published for variations of the mucosal wave specifically for epidemiological purposes. Clinically, in the absence of such data, otolaryngologists may over interpret videostroboscopic findings, leading to unnecessary investigations or interventions.