Abstract:
Objective: Nasality is one of the important parameters in pathology of voice resonance. Voice of normal adults has nasality to some extent. It appears that nasality, like other parameters of voice, can be affected by loudness which can be measured in experimental evaluations. This study was conducted to determine the effect of vocal loudness on nasalance of vowels in normal adults and to identify the relationship between these two factors in 18-28 year-old normal Persian-speaking adults. Material and Methods: In this descriptive-analytic and cross sectional study, sample voices of sixty-five randomly selected male and female 18 to 28 year-old normal Persian-speaking students of Rehabilitation Faculty in Tehran University of Medical sciences were studied. Mean of Nasalance in Persian vowels was computed with Nasal View software. The findings were analyzed with descriptive statistical analysis and one-way ANOVA. Results: Maximum nasalance was in low voice and minimum nasalance was in loud voice in both men and women subjects. The statistical results show that nasalance in 3 levels of low, normal and loud voices have significant differences (p < 0.05). Conclusion: In normal adults, vowel nasalance is decreased with increase in vocal loudness. This is an aspect of normal speech mechanism. The findings can be explained considering function of velopharengeal port, raise in subglottal air pressure in loud voice, and increased muscle contraction of pharynx and palate.
Machine summary:
Iranian Rehabilitation Journal, Vol. 8, No. 12, December 2010 Original Article The effect of vocal loudness on Nasalance of vowels in Persian adults Vanoosheh Sadjadi*, Ali ghorbani, Farhad torabinezhad Yunes amiri, Mohammad Reza keyhani Tehran University of Medical Sciences, Tehran, Iran Objective: Nasality is one of the important parameters in pathology of voice resonance.
This study was conducted to determine the effect of vocal loudness on nasalance of vowels in normal adults and to identify the relationship between these two factors in 18-28 year-old normal Persian-speaking adults.
Material and Methods: In this descriptive-analytic and cross sectional study, sample voices of sixty-five randomly selected male and female 18 to 28 year-old normal Persian-speaking students of Rehabilitation Faculty in Tehran University of Medical sciences were studied.
From a clinical point of view, the relation between nasality and other vocal parameters such as fundamental frequency and loudness are important in diagnosing malfunction of velopharyngeal sphincter in patients with hypernasality, hearing impairment, dysartheria and cleft palate (1, 2&3).
Results of research studies have shown that speech sounds, including vowels, are somewhat nasal in normal individuals (4) and are influenced by other voice parameters (5).
According to the findings, increase in vocal loudness in normal individuals is an effective cause for reduction of nasalance but its role in resonance disorders, either due to anatomical or functional impairment, requires further study and evaluation.
Conclusion According to the findings of this study, it can be concluded that increase in vocal loudness in normal individuals is a factor in reduction of vowel nasalance and it is related to function of velopharyngeal sphincter.