Assessment of Nasality in Adult Patients with Partial Deafness

Nasality is often present in hearing impaired patients. Various studies show that hypoacusis causes voice disorders as result of a disturbed control of a complex process of voice production. First studies on voice in partial deafness (PD) were performed at Institute of Physiology and Pathology of Hearing in Warsaw, however nasality associ-ated with PD was not examined. The paper describes our study on nasality in 20 Polish adult patients with post lingual partial deafness. The results show that PD patients develop nasality in their voices when compared with control group of individuals. Observations made 9 months after partial deafness cochlear implantation indicated reduction of nasality and the changes of acoustic parameters achieved statistical dif-ferences. Background/Objectives: The purpose of the study was to check whether par-tial deafness (PD) causes changes in nasal resonance (nasality) in adult patients and check whether partial deafness cochlear implantation (PDCI) influences the level of nasality. Methods: Voice samples of 20 patients with partial deafness were analyzed and compared with 20 individuals with normal hearing. Then voice samples of the same patients were analyzed 9 months after cochlear implantation. For objective measure, acoustic analysis was performed to assess the level of nasality using FFT (Fast Fourier Transform). Nasality levels in voice samples were also described subjectively by two experienced medical professionals (medical doctor and clinical acoustician). At the final stage of the study Pearson analysis was performed to look into correlations between objective and subjective assessment. T-test Paired Two Samples for Means was used for statistical analysis. As voice analysis is a part of standard clinical proce-dure in patients qualified for partial deafness cochlear implantation and data were analyzed retrospectively, approval from a bioethical committee was not required. All patients of the Institute of Physiology and Pathology of Hearing in Warsaw declare their deliberate consent to all necessary diagnostic and therapeutical procedures on admittance. Results: Results of the study show that post lingual partial deafness caus-es nasality in adult patients when measured both objectively and subjectively. Average objective level of nasality achieved 21 dB (SD 4,5), subjective achieved average grade 1,25. Level of nasality presented positive correlation with time partial deafness. As-sessment performed 9 months after cochlear implantation showed reduction of nasal-ity achieving 17 dB (SD 4,2) in objective measurement and grade 0,5 assessed subjec-tively. Pearson analysis showed weak correlation level between objective measurement and subjective assessment. Conclusions: Post lingual partial deafness in adults causes nasality. Nasality positively correlates with the time of hearing impairment. Partial deafness cochlear implantation reduces nasality in 9 months observation, which was proved both objectively (MDVP) and subjectively (perceptual assessment). However, correlation between objective and subjective results is rather weak, therefore objective acoustic methods (MDVP) should preferably be used for more credible assessment, whilst subjective method may only serve as g rough and general tool in everyday clinical use.