카페인 섭취 전과 후 정상 성인 음성의 음향학적 변화 비교

Abstract

ABSTRACT

Comparison of acoustical change of the voice of adult before and after caffeine intake

Sim, Kwan Yong Advisor: Prof. Pyo, Hwa Young, Ph.D. Speech and Language Pathology Graduate School of Chosun University

As the consumption of caffeine, one of indulgent items, has recently been increased, the keen research about it is required. The consumption of caffeine causes the dryness of vocal cords or laryngeal mucosa that entails the severe shock of the vibration of vocal cords, and the rise in the figures of the blood flowing in the those vocal cords. This brings about thicker vocal cords accompanied by the increase of the irregularity of their vibration. The dispositional change in those vocal cords or laryngeal mucosa leads to the change of the tone quality. Analyzing the figures of the tone quality in order to investigate the dispositional change, a precedent study shows that the consumption of caffeine heightens the jitter, shimmer, PTP(phonation threshold pressure), affecting badly in the production of sounds. Yet, a few researches are not being conducted as to how the figures of the tone quality are being changed as time passes by. In this context, the purpose of the research study is to identify the differences in the changes in the figures of the tone quality of the voices and those between men and women before and after the consumption of caffeine with time passing by. To achieve the purpose, this study is meant to analyze the impacts of caffeine on voice and lay the foundation on the effective use and maintenance of voice involving the consumption of caffeine. In this regard, this research study selected 56 people as the research subjects with the participation of each 28 normal adult man and woman. It is indicated that the average age range of the men group was 25.5 years old, while that of the women group was 23.7 years old. Selected as the criteria of the research scope were people without the medical history of voice disorders for six months of the test, and those who neither take caffeine, alcohol, drugs affecting the voice for 24 hours of voice recording nor smoke, people without any problem with the production of voice, those who neigher suffer from the disease of the respiratory system nor the feeling of irritation in laryngopharynx, and people who are measured as 0 of G Scale in GRBAS Rating Scales. As the voice recording, Multi-Dimensional Voice Program(MDVP) was used to collect and study the voices of those research subjects. Besides, this study carried out the 1st voice recording before the consumption of caffeine and then allowed those research subjects to take caffeine. In order to control the voices of those research subjects in the process of recording after the consumption of caffeine, this made them ready to stand by, watching the video. And 30 minutes after the consumption of caffeine, the 2nd recording was conducted. Also 60 and 90 minutes after the consumption of caffeine, the 3rd and 4th recording was carried out, respectively in turn. For the analysis of the voice of those research subjects, this research study designated, as the invisible sections, the pitch deviation and voice deviation of the production of voice, "Ah" to conduct the analysis of it. The fundamental frequency(F0), jitter, shimmer, and noise to harmonic ratio(NHR) were measured and collected. In order to compare between the men and women groups after the consumption of caffeine, this research study analyzed and identified the variance F0, jitter, shimmer, NHR from before the consumption of caffeine until 30 minutes of the consumption of caffeine, from 30 minutes of the consumption of caffeine until 60 minutes of the consumption of caffeine, from 60 minutes of the consumption of caffeine until 90 minutes of the consumption of caffeine. To understand the differences in the figures of tone quality after the consumption of caffeine between the men and women groups, this study carried out Two-way mixed design ANOVA. This study conducted a post-hoc analysis or follow-up test of LSD(Least Significant Difference). In order to study the differences of the tone quality between the men and women groups with time passing by, One-way repeated measured ANOVA was undertaken. And this conducted a post-hoc analysis of LSD. This study used and tested the independent sample t-test to conduct a comparative analysis of the differences of the change in the acoustic rates between the men and women groups with time passing by. And this calibrated p-value, utilizing Bonferroni method (p=.016). According to the analytic research outcomes on the characteristics of the tone quality between those men and women groups before and after the consumption of caffeine, F0 declined 30 minutes after the consumption of caffeine, and as time passed by, the rate tended to return gradually to that reached before the consumption of caffeine. In the case of jitter, the rate rose 30 minutes after the consumption of caffeine, and as time went by, it returned to decline gradually at the almost same rate as that reached before the consumption of caffeine. As for the shimmer, the rate reached the hike 30 minutes after the consumption of caffeine, and as time passed by, it tended to decline gradually. Concerning NHR, the men group accounted for the highest rate 30 minutes after the consumption of caffeine, and as time went by, the rate declined gradually. The women group reached the high rate until 60 minutes after the consumption of caffeine, and the rate has declined, and 90 minutes after the consumption of caffeine, it tended to return to that reached before the consumption of caffeine. Compared with both men and women groups, there have been shown the significant differences in the jitter and shimmer. The women group took up the higher jitter and shimmer, 30 minutes after the consumption of caffeine, than the men group. And 90 minutes of the consumption of caffeine, as time passed by, the men group tended to have the same jitter and shimmer as those reached before the consumption of caffeine, while the women group has tended to show the lower figures of those factors but the higher figures than those reached before the consumption of caffeine. This research study is significant in the sense that this conducted an analytic survey of adult men and women about the figures of the tone quality of the voices as time passed by, before and after the consumption of caffeine. The research results show that 30 minutes after the consumption of caffeine, there has been the change in the figures of the tone quality of the voices, and as time went by, the impacts of caffeine were been reduced and the rate of the tone quality tended to return gradually to that reached before the consumption of caffeine. This study bolstered up the precedent study that caffeine influences voice cords and laryngeal mucosa, causing the change in the tone quality of the voices. It was turned out that compared with both men and women groups, the women group showed the high jitter and shimmer, compared with the men group, and as time went by, the figures tended to return slowly. This result supported the precedent study that the smaller amounts of caffeine have a relatively high impact. Based on the research findings, it can be found that there has been change in the tone quality of voice after the consumption of caffeine, and compared with the men group, the women group has been more influenced by caffeine. This research is significant in that this has bolstered up the report about the control of the consumption of caffeine in the education and training on voice health.