Background and Aim: Glottic closure pattern is one of the most important stroboscopic signs in judging the normality of laryngeal function. According to the recent researches, complete glottic closure is not the only pattern in normal phonation. The aim of this study was to investigate the glottic closure pattern in normal subjects and to understand the role of sex in having different glottic closure patterns.
Methods: In a cross-sectional study, 80 subjects (58 females and 22 males mean age of 21.19 years) were randomly selected from a population of 218 students. After taking a full medical history and performing perceptual and voice self assessment, subjects without any vocal disorders were recruited. Videolaryngoscopic assessment was performed during producing the vowel sound /i/ in habitual, high, low, loud and soft levels of phonation. Glottic closure patterns were analyzed in different phonation and also were compared between males and females.
Results: Although complete closure was the most frequent pattern, Y posterior chink was the second pattern in males (20.2%) and females (39.4%) in all phonation. The results revealed significant difference between males and females in glottic closure pattern (p=0.001). Moreover, significant differences were observed in habitual (p=0.004), high (p=0.006) and soft (p=0.02) phonations between males and females however, the differences in low (p=0.7) and loud (p=0.19) phonations between males and females were not significant.
Conclusion: Y posterior chink, as well as complete closure, are likely to be normal findings in people with normal voice. Besides, gender has a significant influence on glottic closure pattern.