NORMATIVE NASALANCE VALUES ACROSS STIMULI AND GENDER IN MALAYALAM SPEAKING INDIVIDUALS

摘要

Nasality is the common problem in subjects with repaired / unrepaired cleft palate, which affects the speech intelligibility. Nasal resonance is not only seen in disordered speech, even normal speech also consist some amount of nasality. Example: Among the Indian languages, Malayalam has got more nasal resonance than any other languages. Nasality can be assessed by subjective as well as objective methods. Perceptual judgment of nasality is done using various rating scales. These rating scales have used different rating points ranging from five point scale to nine point scales. The judges for these rating scales were from trained speech pathologists to clients themselves. Since this is a subjective task, standard data / normative data cannot be established due to many disadvantages associated with this method. Hence, standard objective methods are essential to assess the velopharyngeal dysfunction and to provide guidelines for suitable rehabilitation method. Nasometer is a non-invasive measurement technique which can be used outside medical settings. Nasometer assesses the nasality of speech by measuring the acoustic output from both the nasal and oral cavity by using two microphones, separated by an acoustic shield that rests on the upper lip, which is mounted on a head set which gives appropriate position for the microphones. Additionally it is a personal computer based device that can be easily installed and can measure the nasality at any point of the sample. Extensive studies on the nasometer?s validity have generally shown high levels of correspondence between listener judgments and measures made by device (3,7,9).In addition to research directed to a direct clinical application of Nasometer measurements, there have been investigations into factors that influence nasalance measures in normal speech. These studies have shown that nasalance of normal speech is sensitive to phonetic composition of the speech stimulus 26, native language1, age and gender 21. However, the findings are not universally consistent