Effect of nasal speaking valve on speech intelligibility under velopharyngeal incompetence: a questionnaire survey

Summary Velopharyngeal incompetence is known as a contributing factor to speech disorders. Suwaki et al. reported that nasal speaking valve (NSV) could improve dysarthria by regulating nasal emission utilising one‐way valve. However, disease or condition which would be susceptible to treatment by NSV has not been clarified yet. This study aimed to evaluate the effect of NSV by questionnaire survey using ready‐made NSV. Subjects were recruited through the internet bulletin, and NSV survey set was sent to the applicant. Sixty‐six participants, who agreed to participate in this study, used NSV and mailed back the questionnaire which included self‐evaluation and third‐party evaluation of speech intelligibility. Statistical analysis revealed that the use of NSV resulted in significant speech intelligibility improvement in both self‐evaluation and third‐party evaluation (P