Prosthetic Treatment for Palatopharyngeal Incompetence: Research and Clinical Implications

Abstract

Palatopharyngeal function during speech has been studied relative to the physiology of speech, direction of air flow, oral breath pressure, nasal sound power level, acoustic output, and perceptual characteristics of speech. Despite varied research efforts, including speech analysis and synthesis, understanding remains incomplete and a clinical need to clarify the effect of palatopharyngeal opening and nasal resonance upon speech perception persists. This investigation was based upon the premise that information germane to the major area of interest could be con— tributed through a multidimensional study of cleft palate subjects speaking with and without nasopharyngeal obturation. From a research viewpoint, cleft palate speakers with normal articu-lation who have been successfully fitted with prostheses provide an excellent opportunity to investigate the selective effect of nasopharyngeal opening upon speech function. By pairing observations of speech pro— duced with the nasopharynx open and functionally occluded, speech function can be evaluated under two experimental conditions existing in the same subject. As a result, control over many variables such as differences in articulatory skill is possible. Moreover, this control yields information which cannot be attained by studying grouped cleft palate data. In the latter instance, speakers can differ from each other in many respects other than in regard to palatopharyngeal function. In broad aspect, then, the purpose of this investigation is to make a comparative analysis of each cleft palate subject speaking with the nasopharynx open and with the nasopharynx functionally occluded. From a clinical viewpoint, comparative study of speech produced with and without prosthesis provides a realistic measure of the relative speech improvement achieved by prosthetic fitting. By further subgrouping