國立臺北護理健康大學語言治療與聽力學系 碩士論文

國立臺北護理健康大學語言治療與聽力學系 碩士論文 Department of Speech Language Pathology and Audiology National Taipei University of Nursing and Health Sciences Master Thesis. 女性空服人員嗓音問題之盛行率與危險因子初探. Prevalence and Risk Factors of Voice Problems in Female Cabin Crew Members — A Preliminary Study. 管若妤 Jo-Yu Kuan. 指導教授：盛 華 博士 Advisor: Sheng Hwa Chen, Ph.D. 中華民國 109 年 1 月 January, 2020.

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ABSTRACT Cabin crew members are Type-II occupational voice users whose voice is an integral part of their profession and their work performance can be compromised by moderate voice problems. However, apart from their health conditions, there are many risk factors in the cabin proven to jeopardize the voice quality of cabin crew members. Low-frequency noise with infrasound (ILFN), dry and poor air quality in the cabin, and the high work stress environment that may have a negative impact on their psychological and physiological health, putting cabin crew members at high risks of encountering a voice problem. This current study used questionnaires as research tools, including: “cabin crew member’s voice questionnaire”, revised Voice Handicap Index- Chinese version (VHI-30), investigated 123 female cabin crew members of commercial airlines in Taiwan. Statistical analysis was performed with Fisher's correct probability test, linear regression, Mann-Whitney U test, Independent Sample t-test, univariate and multivariable logistic regression. The results showed that cabin crew members’ “current” voice problem prevalence was 23.6%, while “past” voice problem prevalence was 25.7%. However, the voice problem prevalence was 47.9% when evaluating voice problems via VHI30. Furthermore, hormone problems, feeling the need to clear throat due to foreign object sensation, and usage of wet towels or masks are factors correlated for the female cabin crew members to have a voice problem. In addition, significant was found between voice problem and physical sub-scale (P) score of VHI-30. The findings can be used as a reference for speech-language pathologists’ evaluation, action plans, prevention and interventions in the future.. Key words: female cabin crew members, occupational voice users, prevalence, risk factors, voice problems iii.

TABLE OF CONTENTS 1.INTRODUCTION.....................................................................................................1 1.1. Objectives and issues ..........................................................................................3 1.2. Research questions ..............................................................................................3 1.3. Research hypothesis ............................................................................................4 2. AN OVERVIEW OF RELEVANT LITERATURE .............................................5 2.1. Occupational voice users and voice disorder ......................................................5 2.2. Prevalence of voice problems among type II occupational voice users ..............6 2.3. Cabin crew members and their voice ..................................................................9 2.4. Risk factors of voice problems for cabin crew members ..................................10 2.5. Effects of voice problem life quality in occupational voice users ....................21 3. RESEARCH METHOD ........................................................................................23 3.1. Research framework ..........................................................................................23 3.2. Participant recruitment ......................................................................................25 3.3. Research materials.............................................................................................26 3.4. Research procedure ...........................................................................................30 3.5. Statistical analysis .............................................................................................33 4. RESULTS ...............................................................................................................36 4.1 Prevalence of voice problems in female cabin crew members of commercial airlines in Taiwan………………………………………………………………….36 4.2 Correlation analysis of variables and prevalence of voice problems………….53 4.3 Impact of voice problems on cabin crew members……………………………59 5. DISCUSSION……...…………………………………………………………….70 5.1 The prevalence of voice problems among female cabin crew members…....…71 5.2 Relationship between the prevalence of voice problems amongst female cabin crew members and potential risk factors……………………………………….….73 5.3 Impact of voice problem for female commercial cabin crew members…….....85 5.4 Clincial implication……………………………………………………………88 iv.

5.5 Research limitations……………………………………………………….......88 5.6 Recommondation for future research………………………………..…...…....89 REFERENCES………………………………………………………………...........90 APPENDIX A: Cabin Crew Members Voice Questionnaire………………………106 APPENDIX B: Chinese version of VHI….………………………………………..111 APPENDIX C: Ethical Review Approval……………………………………........112. v.

1. INTRODUCTION The Aviation Safety Council of Taiwan pointed out that world airline industry is growing rapidly with a significant increase in international air transportation for passengers over the past decade (Aviation Safety Council [ASC], 2017). Passenger traffic rose by 7.9% in 2017 and the trend is set to continue (International Air Transport Association [IATA], 2018). There are 7,943 cabin crew members serving commercial airlines in Taiwan, that constitute 33.25% of the total air transport industry workforce (Civil Aeronautics Administration [CAA], 2018; Ministry of Labor, Republic of China [MOL], 2017) The voice is considered as an essential part for cabin crew profession. Being front-line service provider, a cabin crew member is expected to present themselves with a pleasant voice quality during passenger flight duties. It is evident that, among cabin crew duties listed by the International Civic Aviation Organization (ICAO), including meal service, duty-free sales, cabin cleaning, acting on emergencies and ensuring passenger safety, a considerable amount of cabin crew members’ voice is needed on a basis of 1:25 to 1:50 cabin crew member to customer ratio in-flight (Civil Aviation Safety Authority [CASA], 2016; ICAO, 2008). Research had classified cabin crew members as Type-II professional voice users based on a hierarchy of vocal use, performance and need, indicating voice is an integral part of cabin crew members’ profession and whose work performance can be compromised when there are moderate voice problems (Mendes et al., 2012; Koufman & Isacson, 1991). Voice disorder exists when a person’s voice quality, pitch and loudness differ from those of similar age, gender, cultural background, and geographic location (Stemple et al., 2000). Voice disorder may result from the structure, function, or both of the laryngeal mechanism no longer meeting the voicing requirements of the speaker, and is manifested by vocal fatigue, hoarseness, aphonia, weakness, strained harshness, poor pitch and loudness modulation, as well as abnormal throat sensations during speech (Colton, et al., 2006; Hsiao, 1999). Cabin crew members are a type of professional voice users whose voice is an integral part of their profession and their work performance can be compromised by moderate voice problem. However, apart from their health conditions, there are many risk factors in the cabin proven to jeopardize voice quality of cabin crew 1.

members. Health conditions that may affect a cabin crew member’s voice include respiratory symptoms, sleeping quality, endocrine system, stress and psychological health. Moreover, low-humidity, noise and low-frequency noise with infrasound (ILFN) in the cabin environment increase the risk of voice damage to crew members (Mendes, et al., 2008; Robert & Feder 1984). Studies have been done to analyze acoustic parameters of commercial airline pilots and cabin crew members, and significant differences were found in perturbation and temporal measures (fundamental frequency, jitter percent and maximum phonation frequency range) comparing to the normative data (Mendes et al., 2014, 2012 & 2008). The findings might serve as an indication of histologic change on the characteristics of vocal folds for this group of workers. Previous studies focused on acoustic analysis of aircraft crew members but the self-reported voice condition was not included, and the risk factors of voice problems for cabin crew members was not systematically reviewed. In addition, whether voice problems affect the life quality of cabin crew members still remains unknown. Lastly, there is still limited research on voice problems among cabin crew members working on commercial airlines in Taiwan. In this preliminary study, the researcher seeks to determine the prevalence of voice problems of cabin crew members in Taiwan, identify the risk factors affecting the voice of cabin crew members and understand the quality of life of cabin crew members affected by voice problems. Through in-person and remote interviews, this study will conduct surveys that include a cabin crew member voice questionnaire and the Voice Handicap Index to understand issues of voice health of the concerned group. With the cabin crew member voice questionnaire, the researcher analyzed the prevalence of voice problems as well as whether and how the voice problems relate to flight duties, living habits, health conditions, vocal demands, vocal usages, working environments and voice qualities of these cabin crew members. From the Voice Handicap Index, the researcher sought to understand how voice problems impacted the quality of life of these crew members functionally, physically and emotionally. By summarizing the findings and developing suggestions that could alleviate the voice problems, this research hope to provide an overview of the current 2.

condition and to serve as reference for developing potential action plans that may be implemented by airlines. Furthermore, this research might provide an avenue for speech language pathologists to offer a more focal voice management and treatment plan to alleviate stress and further improve cabin crew members’ vocal health.. 1.1. Objectives and Issues The first goal of this study is to investigate the prevalence of voice problems among female cabin crew members in Taiwan. Secondly, to identify the potential risk factors contributing to voice problem. Lastly, to understand how these voice problems affect the quality of life functionally, physically and emotionally. This study aimed to interview approximately 120 female cabin crew members of Taiwan. Based on such interviews, this study aims to achieve the following objectives – 1. Determine the existence of voice problems among the female cabin crew member population; 2. Identify the risk factors related to voice problems among the female cabin crew members; 3. Investigate whether female cabin crew members’ quality of life is correlated with voice problems; 4. Serve as a platform to develop action plans to be implemented by the airlines, speech-language pathologists as well as the cabin crew members to alleviate stress and further improve the voice health of these workers.. 1.2. Research Questions 1. What is the prevalence of voice problem among female cabin crew members working on Taiwan commercial airlines? 2. What are the risk factors related to voice problems for female cabin crew members in “personal and flight duty information”, “living habits and health condition”, “vocal load and voice usage”, “working environment” and the “voice quality of life”? 3. Do voice problems correlate with female cabin crew members’ quality of life in “functional”, “physical” and “emotional” aspects? 3.

1.3. Research Hypothesis This research seeks to test three hypotheses: 1. The prevalence of voice problems among female cabin crew members is higher than the general population. 2. The prevalence of voice problems is different in “living habits and health condition”, “vocal load and voice usage”, “working environment” aspects. 3. Female cabin crew members’ quality of life in “functional”, “physical” and “emotional” aspects is correlated with voice problems.. 4.

2. AN OVERVIEW OF RELEVANT LITERATURE 2.1. Occupational Voice Users and Voice Disorder The production of voice requires coordination between respiration, phonation and the resonance system. Voice disorder can occur when any of the voice production related systems are impaired, including respiratory, resonance and the laryngeal systems (Stemple, Glaze & Klaben, 2010), and the voice may be compromised in quality, pitch and loudness (Colton, Casper & Leonard, 2006). Voice disorder is perceived when one is not able to produce his/her voice as usual, or the perception of his/her voice is altered, affecting the communication and/or quality of life (Roy, Stemple, Merrill & Thomas, 2007). Voice disorder is also present when an individual expresses concern about the voice not meeting the daily needs even when not perceived as different by others (Stemple, Glaze, & Klaben, 2010; Verdolini & Ramig, 2001; American Speech-Language-Hearing Association [ASHA], 1993). In the United States, one third of the working population needs a wellfunctioning voice for work performance (Vilkman, 2004; Verdolini & Ramig, 2001). Professionals whose working performances reply on their voice are defined as occupational voice users (Mitchell, 1996). Occupational voice users include teachers, singers, actors and telemarketers (Rammage, Morrison & Nichol, 2001; Colton, et al., 2006; Titze, Lemke & Montequin, 1997). Working performances of occupational voice users will be impacted if voice problems occur. Nevertheless, due to high vocal demand, voice disorders are common among this group of workers (Seifpanahi et al., 2016; Williams, 2003), and a voice disorder can be considered as work-related when the voice is affected to the extent that does not meet the vocal demand required at work (Vilkman, 2004). Occupational voice disorders should be viewed with a multidimensional approach instead of a purely personal problem, and it is crucial to consider structural characteristics of the workplace when assessing occupational voice disorder (Rubin, Sataloff & Korovin, 2014). Voice abuse and misuse, speaking environment, living habits and psychological stress level are the common causes and risk factors of voice problem among occupational voice users (Rammage et al., 2001). The risk factors can contribute to pathologies including vocal nodules, vocal cord contact ulcer, 5.

gastroesophageal reflux disease, fatigue, etc. and lead to voice disorder (Stemple et al., 2010). Koufman & Isaacson (1991) classified occupational voice users into four categories according to vocal demand and vocal loading (Table 1). From the highest to the lowest vocal demand and loading— the elite vocal performer (singers, actors etc.), the professional voice user (teachers, cabin crew members, etc.), the non-vocal professional (lawyers, doctors etc.), and the non-vocal nonprofessional (laborers, clerks, etc.). This classification on levels of vocal usage helps to examine the question on voice disorder risk probabilities of different population groups. Categories. Descriptions. Examples. I. The Elite Vocal Performer. A slight aberration of voice may have. Singers, actors, etc.. direct consequences II. The Professional Voice Use. Moderate vocal problem might prevent. Teachers, clergy,. adequate job performance. telephone operators, cabin crew members, etc.. III. The Non-Vocal Professional. Severe vocal problem would prevent. Lawyers, physicians,. adequate job performance. businessmen, etc.. IV. The Non-Vocal Non-Professional Vocal quality is not a prerequisite for. Clerks, laborers,. adequate job performance; may suffer. administrative workers,. social liability from voice disorder but not. etc.. prevented from performing work Table 1. Occupational Voice Use Classification (Koufman & Isaacson, 1991).. 2.2. Prevalence of Voice Problems among Type II Occupational Voice Users The awareness on occupational voice problems rose across the world. In the recent years, many studies have been carried out for voice users in different occupational groups, and many have found that voice problems may affect job performance and life quality of occupational voice users. It is important to recognize the characteristic, prevalence and risk factors of voice problems among specific 6.

populations (Boone, McFarland, Berg & Zraick, 2014). Yet, current literature on voice of cabin crew members is still scarce, and this section will discuss voice disorder prevalence among the occupational voice users group relevant to cabin crew members. In addition to cabin crew members, professions such as school teachers, aerobic exercise coaches and customer service representatives are also female-dominant Type II occupational voice users (Civil Aeronautics Administration [CAA], 2018; United States Department of Labor [DOL], 2015; Mendes et al., 2012; Koufman & Isaacson, 1991) therefore; the following section will be focused on this occupational voice user group. Teachers are at high risk of voice problems (Roy et al., 2001), and they are the second largest population in the workforce with the highest number of voice disorder incidence (Titze et al., 1997). The prevalence of voice problem range from 38% (Smith, Lemke, Taylor, Kirchner & Hoffman, 1998) to as high as 80% (Gotaas & Starr, 1993) in the United States. Common voice problems among teachers are vocal fatigue, breathiness, lower in tone, effortful production, hoarseness, etc.; one third of American teachers had complained of inability to sing high pitches (Smith, Gray, Dove, Kirchner & Heras, 1997). Voice problem prevalence was also among teachers in Taipei City, Taiwan. The research spans preschool, primary school and junior high school teachers. Through self-administered questionnaires, 47% of junior high school teachers reported hoarseness, effortful and weakness vocal symptoms (Chen et al., 1985). Primary school teachers had significantly higher voice disorder prevalence when compared with the general population (34.9% vs. 15.2%) (Chen, 2009). This result of higher prevalence rate in teachers than the general population corresponds with previous studies in the United States (Roy, Merrill, Thibeault, Gray, & Smith, 2004). Preschool educators in Taipei City reported similar prevalence rates as day-care center teachers in Finland (38.8% vs. 37%) (Liu, 2017; Sala, Laine. Simberg, Pentti & Suonpää, 2001). Past findings demonstrate a higher incident rate in teachers when compared with other working population in Taiwan and in other countries. Physical education teachers had more vocal complaints than other teachers, especially in female population (Jonsdottir, Boyle, Martin & Sigurdardottir, 2002; 7.

Smith et al., 1998). Similar with physical education teachers, aerobic exercise coaches need to project their voice in an open space and under physical demand; therefore, they are under high risk of voice disorders and have higher voice disorder rate when compared to the general population (Yang, Su, & Cheng, 2004; Smith et al., 1998). There are more female aerobic exercise coaches than male (Yen, 2012). In Taiwan, aerobic exercise coaches had a voice disorder prevalence rate of 28.37%, and voice disorder prevalence was considerably higher in female than male coaches (32.38% vs. 9.38%) (Yen, 2012). Among college aerobic dancing teachers, 69.3 % had voice disorder experience (female participants consisted 97.3% in this study) (Yang et al., 2004). For call center operators in India, the point and career prevalence of voice problems were revealed at 27% and 59% respectively (Devadas & Rajashekhar, 2013). This result corresponds with the prevalence other female-dominant voiceintense occupations studied in Taiwan (Table 2). Various studies have been conducted for the voice problems among female Type-II occupational voice users including teachers and aerobic exercise coaches. However, research on voice problems of cabin crew members, who have the same professional voice user’s classification as teachers, is relatively rare. Thus, this current study aimed to investigate the voice problems among cabin crew members. Reference. Population. Method. Prevalence. Yang et al., (2004) Aerobic dance teachers. Questionnaire. 69.3% (voice disorder experience). Chen (2009). Primary education teachers. Questionnaire. 34.9% (current voice disorder) 65.6% (voice disorder experience). Yen, (2012). Aerobic exercise coaches. Questionnaire. 28.37% (current voice disorders). Liu, (2017). Preschool educators. Questionnaire. 38.8% (current voice problems) 63.6% (voice problem experience). Table 2. Voice Problems Prevalence for Type II Occupational Voice Users Studied With Questionnaire in Taiwan.. 8.

2.3. Cabin Crew Members and Their Voice 2.3.1. Increased international flights, increased stress on crew member voice Global airline industry grows rapidly with significant increases in international air transportation for passengers in the past decade. Compared to 2016, global passenger traffic demand increased by 7.9% in 2017, which exceeded the 10-year average growth rate of 5.5% by 2.4% (IATA, 2018). Furthermore, due to an increase in route options and economic development, Asia-Pacific airline lead their counterparts by an average passenger load factor of 79.6% (IATA, 2018). In this context, there are approximately 7,943 cabin crew members employed by commercial airlines in Taiwan, and over 93.4% of these crew members are female (Civil Aeronautics Administration[CAA], 2018). Voice of cabin crew members is essential for job performance. According to the International Civic Aviation Organization (ICAO), duties of cabin crew members includes meal service, duty-free sales, cabin cleaning, acting on emergencies and ensuring the safety of passengers. Voice use is needed in most of these duties and considerable amount of voice is used while cabin crew members are assigned to a typical flight with a 1:25 to 1:50 cabin crew member to customer ratio (CASA, 2016; ICAO, 2008). 2.3.2. Voice quality as a preference of employers in Taiwan Passengers recognize cabin crew members as the front-line service provider for airlines, and service quality of air travel highly relates to cabin crew performance, especially on long-haul flights (Chang, 2006). As front-line service providers, pleasant voice quality is required for cabin crew members to carry out their job duties, for effective communication and airline representation (www.1111.com.tw [1111], 2013). Airline such as Virgin Atlantic Airlines of the United Kingdom have implanted voice training program for cabin crew. Aiming to enhance service quality in flight, the voice training program enables cabin crew members to speak with specific tone volume and sentiment in the voice range of 20 to 30 decibels, while conversation typically ranges between 60 to 70 decibels when serving in the cabin, to provide a pleasant service without disturbing any customers. 9.

Cabin crew members are classified as Type- II professional voice users based on the hierarchy of occupational voice use (Mendes et al., 2012; Koufman & Isacson, 1991), categorized under the same vocal demands as teachers. It indicates that the voice of cabin crew members is an integral part of their profession and their professional performance could be compromised by a moderate voice problem. Consequently, finding out risk factors is crucial to prevent vocal problems for cabin crew members.. 2.4. Risk Factors of Voice Problems for Cabin Crew members 2.4.1. Years of service There are more voice disorder incidents for aerobic exercise coaches with longer working years (Long, Williford, Olson & Wolfe, 1998; Newman & Kersner, 1998). However, correlation between length of service and voice disorder occurrence is not significant in separate researches for teachers (Lee, Lao & Yu, 2010; Huang, 2009; Kooijman, Thomas, Grannmans & de Jong, 2007). Previous study has revealed that the fundamental frequency of cabin crew members increased in both genders as the years of service increased; while perturbation measure, jitter (%) changed significantly (p<0.05) for female cabin crew members as the occupational years accumulated (Mendes et al., 2012). Mendes et al., (2014) collected the acoustic parameters of aviation crew members (including 36 airline pilots and 12 cabin crew members) and found increased fundamental frequency (F0) both for crew in flight deck and cabin as years of professional activities increased. Past study results could indicate a histological change on the vocal folds with longer working years. Apart from direct voice problems, health condition leading to voice disorders may become more serious with longer service years. Sharma (2007) suggested serious attention on occupational health problems among cabin crew members who served for 10 years or more. The author investigated the effect of flying on cabin crew members in India (n=130) that flew from 11 years and up to 30 years, and the five major health problems relevant to voice disorder faced by those crew members were stress (88.85%), back pain (72.65%) and loss of hearing (51.34%).. 10.

2.4.2. Gender It has been reported that voice disorder prevalence has been reported to be higher in women than men (Cohen, Kim, Roy, Asche & Courey, 2012) due to structure and perception differences between genders, such as glottic configuration, glottic bowing, asymmetric concentration of hyaluronic acid in the lamina propria of the female larynx, hormonal influence and self-perception on voice qualities (Bulter, Hammond and Gray, 2001). Of medical records of dysphonia patients between ages of 20 and 60 (n=2019), 38.93% were male while 61.07% were female (Martins et al., 2016). Women also are more likely to report vocal health problems than men in vocally demanding careers (Hunter, Tanner & Smith, 2011). Mendes et al., (2008) assessed the spectral, temporal and perturbation measures among 37 European-Portuguese airline cabin crew members. For both genders, the mean speaking F0, HNR, frequency tremor (Fftr) and amplitude tremor (Fatr) were within normal limits (with exception of male crew members in the [10-19] years of service group, HNR mean were significantly above norm); shimmer and HNR mean performance were significantly below the norm (p <.05). However, for mean speaking F0, female cabin crew members performed slightly below the norm, while male cabin crew performed slightly above the norm. the jitter mean was significantly above the norm for female cabin crew members on sustained vowels /a/ and /u/ (p <.05) but within normal limits for male crew members. For temporal measures (maximum phonation time [MPT] and S/Z ratio), female cabin crew members in the [30-39] years of service group presented significant reduction in mean for both variable while the mean value were within normal limits for male cabin crew members in the temporal measures. While the mean of lowest, highest and range of maximum phonation frequency range (MPFR) were within normal limits for males, female cabin crew members’ data in MPFR F0100 and MPFR F0100-0 were significantly lower than the normative population (Mendes et al., 2012). We can understand from the past studies that gender has an impact on the voice performance and the result may imply the inefficient coordination between the respiratory and phonatory system in female cabin crew members. By the end of 2017, 93.4% of the cabin crew members in Taiwan were women, although the proportion of males has been growing in the past decades, the occupation is still predominantly female (CAA, 2018). Hence, this current study rules out male 11.

cabin crew members to avoid gender bias and focus on the prevalence and potential risk factors of voice disorders among female cabin crew members. 2.4.3. Working hours Previous research on work hour’s impact on voice of occupational voice users have mainly focused on teachers. Self-report questionnaires were conducted for junior high school teachers in Taipei City for vocal problems, the study found that vocal nodules occurrence is in linear correlation with increased teaching hours (Chen et al., 1986). However, another study did not show significant difference in longstanding voice symptoms when assessing the relationship between work time and voice problems in 911 emergency tele-communicators, but the self-rating on voice functioning at the end of the day was related to the shift length (Johns-Fiedler & van Mersbergen, 2014). Working hours and shift length for cabin crew members are relatively unstable compare to other occupations (Sharma, 2007), and to the author’s understanding, studies associated with flight duty hours and voice of cabin crew members is still rare; therefore; this study aims to find out if hours of work is related to voice symptoms for cabin crew members. 2.4.4. Health condition Physical health condition and psychological stressors are inseparable with one’s vocal health. Status of overall health, mucosal and muscle problems (including neck, shoulders and lower back) are three major risk factors for voice disorders (Tavares & Martins, 2007; Kooijman et al., 2006; Morrison & Rammage, 1993). Health-related factors associated with voice problems for cabin crew members include upper respiratory infection, nasal allergy, gastrointestinal reflux, and so forth (McNeely, et al., 2014). Potential health hazards in the aircraft for cabin crew members are raised. Studies revealed both female teachers (n=331) and cabin crew members (n =1,824) reported higher prevalence of work related upper respiratory symptoms and cold or flu than other working populations in the United States (Whelan et al., 2003). In the United States, cabin crew health conditions associated with the length of aircraft environment exposure and years of service (n=4,011). After adjusting for age, gender, body mass index (BMI), education and smoking habits, health conditions that are related to voice symptoms and increased with longer job tenure for cabin crew 12.

member were chronic bronchitis, hearing loss, depression and anxiety (McNeely, et al., 2014). Frequent symptoms (lasting 5 to 7 days) for cabin crew members include sinus congestion (29.0%), fatigue (27.3%) and anxiety (20.0%). Notable conditions that need medical attention include reactive airways, sinusitis and allergies (54.7%), fatigue (36.8%), shortness of breath and reduced lung capacity (15.5%) and other respiratory symptoms (14.6%). Conditions diagnosed by a care provider during working years as cabin crew members include depression and anxiety (36.3%), hearing loss (17%) and chronic bronchitis (15.6%) (McNeely, et al., 2014). Upper respiratory tract problems may cause voice problem (Simberg, Sala, Tuomainen & Rönnemaa, 2009) and cabin crew members experience higher rates of work related upper respiratory symptoms compared to other working women (McNelly, et al., 2014; Whelan et al., 2003). Apart from physical health condition, voice disorder may coexist with emotional and psychological stress (Chen, Chiang, Chung, Hsiao & Hsiao, 2010; Melnyk et al, 2003), psychogenic causes of voice disorders include chronic stress disorders, anxiety, depression and conversion reaction such as conversion aphonia and dysphonia, and relationship between stress and voice may be bidirectional (Johns-Fiedler & van Mersbergen, 2014). Still, among the health condition effects from working as a cabin crew member in India (n=101), working stress (88.5%) scored the highest among participants compared to other conditions (Sharma, 2007). Cabin crew members in Taiwan also reported high-medium working stress and scored medium-low in subjective wellbeing (Lai, 2012; Chiu, 2008; Kuo, 1999). High levels of stress has negatively affects both physiological and psychological health, and constantly working under high-stress environment can increase the stress level of cabin crew members (Hsu & Yu, 2005). 2.4.5. Medication Medications that can affect vocal qualities include hormonal drug, sleeping pill, psychoactive drugs, bronchodilators, corticosteroids, antitussive and antihistamine medications, etc. The effects and side effects from medication alter with sex, age, metabolism, dosage, length of intake and concurrent use (Sataloff, 2017). Hormonal drug may alter the secretion of hormones, leading to structural 13.

changes on the vocal folds, and subsequently influence vocal quality. Hormonal medication containing high levels of progesterone such as oral contraceptives may cause alterations in androgenic hormones, leading to changes in vocal quality (Sataloff, 2017). While past research found oral contraceptives as a risk factor for voice quality change, better voice quality and stability were found among the young female group who use birth control over a 36-to-45 day based on acoustic measures. Lower values were found in all acoustic measures (including frequency perturbation, amplitude perturbation and noise indicates) through voice turbulence index (Amir & Kishon-Rabin, 2004). There are several medications that may act as a drying agent to the larynx, which may influence voice quality after long period use, such as sleeping pills, psychoactive drugs, inhaled bronchodilators, antitussives and antihistamines. Sleeping pills can be a drying agent to larynx after long period use, and influence phonation (Sataloff, 2017). Psychoactive medications such as tricyclic antidepressants and Phenothiazine and selective serotonin repuptake inhibitors could dry out the upper respiratory tract, affecting phonation (Alessi & Crummy, 2008). Inhaled bronchodilators for asthma can lead to laryngitis (Sataloff, 2017). During inhalation of dry powder inhaler (DPI), a form of bronchodilator therapy for asthma, high-impact force of the medication and carrier allow the deposition of particles in the upper airway. DPI can cause changes in the surface of mucosa and lead to dysphonia (Mirza, Kasper Schwartz, & Antin-Ozerkis, 2004). Antitussives, medications for cough, relieve symptoms through thinning and reducing the mucus in the airways; the adverse effects include drying up of the vocal folds and larynx, affecting the phonation process (Sataloff, 2017; Stemple et al., 2010). Antihistamines relieve nasal congestion, allergies and cold symptoms. Antihistamines inhibit the gland secreting mucosa, drying out the vocal folds and larynx (Cohn, Spiegel & Sataloff, 1995).. 14.

Corticosteroids can be used to treat inflammation which can alleviate acute laryngitis (Sataloff, 1997). Depending on the amount of use, side effects include peptic ulcer disease, mild aridity of mucosa or hemorrhage, etc. Therefore corticosteroids cause tissue dehydration, and dryness may affect the phonation process (Stemple et al., 2000). A recent study assessed the vocal quality of bronchial asthma patients who used inhaled corticosteroids (ICS) through acoustic analysis and videolaryngoscopy. Among ICS users, 57.7% had dysphonia, and 56.7 % showed vocal folds erythema. The study revealed that the use of inhaled corticosteroids resulted in adverse effects on both the function and the structure of vocal folds (Hassen & Hasseba, 2016). 2.4.6. Living habits Drinking alcoholic beverages and caffeine may be risk factors to voice disorder; both alcohol and caffeine intake may relate with possible gastroesophageal reflux disease (GERD), a common cause of voice disorder (Stemple et al., 2000). (1) Caffeine and alcohol Caffeine may excite the central nervous system and cause hyperactivity, tremor, laryngeal dehydration and GERD (Stemple et al., 2000). Those situations may lead to throat clearing, redness, swelling or dry throat, and jeopardize the voice quality (Tung, 1999). Preciado-Lopez, Pérez-Fernández, Calzada-Uriondo & PreciadoRuiz,(2008) investigated teachers with voice disorders (n=579) and teachers without voice disorders (n=326); they revealed higher caffeine beverage intake in voice disorder group than no voice disorder group. However, cabin crew members in Taiwan reported that alcohol and caffeine intake habits complemented with work (Cheng, 2011). Almost half (47.4% to 50.7%) of the cabin crew members (n=211) on international flights in Taiwan reported caffeine consumption habit prior and during flights to avoid fatigue (Cheng, 2011). While alcoholic beverage use can cause blood vessel dilatation, but alcohol can also cause dehydration of the vocal fold mucosa membrane and the inhibition of the central nervous system (Stemple et al., 2000). Among female cabin crew members in India, 36.1% of these individuals consumed alcoholic beverages habitually, which is 7.2 times higher than the general female population in India (Sharma. 2007). In Taiwan, 14.7 % of cabin crew members on long haul flights (n=211) reported alcohol consumption habits up to six times a week as a sleeping aid, which 5.7% reported 15.

alcohol intake after flight duty for restorative purposes (Cheng, 2011). Chang (2006) also found the prevalence of alcohol consumption 17.8% among the female cabin crew members on long haul flights of China Airlines in Taiwan (n=264) (Chang, 2006), which is 17 times higher comparing to the Taiwanese female general population (1.0%) (n=5663) (Liang, Chou, Ho, Shieh & Yang, 2004). (2) Eating habits Frequent intake of dairy products such as milk and ice-cream can also thicken the mucosa and hinder the vibration of vocal folds, lead to voice hoarseness (Tung, 1999). Stimulants such as spicy food may cause inflammation or dryness to the throat (Boone, et al., 2014). (3) Smoking Cigarettes contain irritative chemicals, inhaling the stimulants with heat during smoking may stimulate the mucosal membrane and lead to vocal tract inflammation (Hirano & Bless, 1993). Smoking can be a major risk factor that jeopardize vocal health and can have adverse effects on vocal quality (Menvielle, Luce, Goldberg, Bugel & Leclerc, 2004). Vocal quality for smokers is unstable (Vincent & Gilbert, 2012), a lower fundamental frequency was found in smokers than in non-smokers through acoustic analysis (Awan, 2011; Wiskirska-Woźnica, Obrebowski, Swidziński, Wojnowski & Wojciechowska, 2004). Smoking is independently associated with voice disorders in Korean general population. Cross-sessional study conducted to compare smokers and non-smokers between Korean adults (n = 7491) aged 19 years or older through survey. After adjusting covariates in age, gender, education level, occupation, income, alcohol drinking and self-reported voice and health status, results showed smokers are more likely to have organic voice disorders than non-smokers, although smoking was not associated with functional disorders in this study (Byeon, 2015). Smokers also showed lower fundamental frequency and speaking fundamental frequency in French and in Arabic, and had more voice complaints when age height and weight were controlled (Ayoub, Larrouy-Maestri & Morsomme, 2018). Of female cabin crew members in India, 8.7% of them were smokers, which is 870 times more than the general female population (Sharma, 2007). Smokers consisted of 9.5% of the female cabin crew members of China Airlines in Taiwan (n=264) (Chang, 2006), slightly higher to the rate of 4.63% among female general 16.

population in Taiwan (Pan & Yen, 2000). (4) Sleeping quality Poor sleeping quality and irregular sleep cycle will affect one’s health condition and voice performance (Stemple et al., 2000). Due to the varying and frequent schedules for travel and work, cabin crew members encounter common problems such as irregular shifts, insufficient sleep and/or inadequate sleeping quality (Caldwell & Gilreath, 2002). Cabin crew members reported a 2 to 5.7 times higher rate of sleep disorders and fatigue compared to the general population (McNeely et al., 2014). Women who work with irregular work shifts, jet lag and sleep deprivation are also associated with menstrual cycle irregularity, which can cause change in hormones secretion (Mahoney, 2010), and endocrine disorder is also a risk factor for voice disorder (Stemple et al., 2000). 2.4.7. Vocal hygiene To avoid voice problems, voice training and vocal hygiene is crucial for occupational voice users (Mendes et al., 2012 ; Casper & Leonard, 2006), and lack of vocal hygiene knowledge or effective voice training can be a major risk factor of voice disorder (Mattiske, Oates, & Greenwood, 1998), especially to occupational voice users (Vilkman, 2004). Vocal hygiene education and vocal trainings have been proven to prevent and reduce voice problems and disorders in occupational voice users (Nanjundeswaran, Li, Chan, Wong, Liu & Verdolini-Abbott, 2012; Bovo, Galceran, Petruccelli & Hatzopoulos, 2007). Chen et al., (2007) investigated the resonant voice therapy outcome on 24 female teachers in Taipei City, the therapy held once a week and 90minutes per session. After 8 training sessions, results showed significant reduction in the severity of vocal symptoms in auditory perceptual judgments, the severity of vocal fold pathology in video stroboscopic examination, the phonation threshold pressure and the physical sub-scale score in the Voice Handicap Index. Few programs were implanted in the airline training for cabin crew members. In the United Kingdom, commercial airlines employed voice training lessons aimed to enhance service quality, training the crew members to speak with appropriate tone, volume and sentiment in-flight. Cabin crew members were trained to whisper,. 17.

keeping their voices at 20-30 decibels while normal conversation range between 6070 decibels during flights to accommodate passengers (Carbone, 2012). However, whispering should be avoided for those who have voice disorders. The compression of anterior and middle thirds of the true vocal folds is required during whispering, causing change in glottal configuration and may further lead to laryngeal hyper function (Rubin, Praneetvatakul, Gherson, Moyer & Sataloff, 2006). Although formal voice education and training should be provided to the cabin crew members (Simberg, 2004), comprehensive vocal hygiene knowledge for this group of occupational users are still less than optimal. 2.4.8. Working environment The number of cabin crew employees of national airlines has increased by 41.8% within the recent 5 years (CAA, 2018). The airline industry has changed over the past decades, with longer flight times and quicker turn-around times between flights, increasing passenger loads and occupancy aboard all flights (CAA, 2018). These conditions may intensify the physical demands of work in restricted cabin space, with air contaminations, low humidity, noise, vibration and gravitational forces, as well as straining relations between cabin crew members and customers (Feder, 1984). There are more complaints about work environment of dry and stuffy air, static electricity and noise in cabin crew members than office workers (Caldwell & Gilreath, 2002), and cabin crew members’ voice use can be greatly affected by their working environment of vast background noise, limited working space and air quality (Vilkman, 2004). Moreover, low humidity, background noise and infrasound and lowfrequency noise (ILFN) can cause potential vocal irritations and/or injuries to professional voice users who travel in flights (Feder, 1984). (1) Noise A louder environment increases the vocal load of occupational voice users, and such increased vocal loading may cause voice problems (Johns-fiedler & Van Mersbergen, 2014). Klingholz, Siegert, Schlepper & Thamm (1978) investigated 40 participants and asked the subjects to speak with background noise at 80 decibels (dB), 30% of the participants showed compensatory behavior and abnormal phonation 18.

pattern (e.g. raised volume) and 80% of the participants showed the compensatory behavior and abnormal phonation pattern when the background noise level rises to 85 dB. This result responds to the Lombard effect, which suggests voice features will alter under noisy environments. As loudness and intensity of ones’ speaking level increases, tension and vibration of vocal folds also increase, which would raise risk of vocal abuse and vocal misuse (Alku & Vintturi & Vilkman 2002). Significant pathologic voice patterns tend to occur when one speaks above loud and continuous environment noise, and works under noisy environment for an extended period of time, both of which may increase the chance of vocal abuse and vocal misuse (Feder, 1984). Working environments with high noise level has an impact on the vocal behavior in women with voice-intensive occupations (Portela, Granqvist, Ternström & Södersten, 2017), and working under noise may lead to stress factors and result in voice problem such as strain throat and increased speaking intensity (Lane & Tranel, 1971). In line with the past finding with teachers, the aerobic exercise coaches reported higher voice disorder prevalence with louder background noise when coaching (Ku, 2010; Ferrand, 2006; Heidel & Torgerson, 1993). Cabin crew members on long-haul flights in Taiwanese airlines perceived noise in cabin as one factor of fatigue during work (Cheng, 2011), and to work under noisy environment for a long period of time is one of the leading stress factors for Taiwanese cabin crew members (Taipei Association of Wage-Earners, 2000). There are different sources of noise in aircraft cabin during operation. Loud noises include air-conditioning noise, engine noise, boundant-later noise, equipment noises. Moreover, infrasound and low-frequency noise (ILFN), may cause direct changes on the vocal folds (Feder, 1984). ILFN is the noise specifically below 500Hz in frequency and includes infrasound, which may act directly on the vocal folds. Long-term exposure to infrasound and low-frequency noise may cause vibroacoustic disease (VAD), a systematic non-inflammatory pathology that results in the abnormal growth of the extra-cellular matrices, specifically on collagen and elastin, affecting the respiratory tract (Branco & Alves-Pereira, 2004). ILFN-exposed animal models also revealed thickening of respiratory tract structures due to the abnormal growth of collagen 19.

(Castelo et al., 2003). ILFN-exposed occupations include pilots, cabin crew members, restaurant workers and ship machinists. When comparing to normative population, those ILFNexposed workers presented significant different voice acoustic patterns in perturbation and temporal measures even when no vocal symptoms presented (Mendes, et al., 2012). Suggestions are made from previous studies that there may be histological changes in the laryngeal system and vocal fold characteristics for cabin crew members. As past studies demonstrate the acoustic parameter as an indication of changes on vocal fold for cabin crew members, but how this vocal fold change relate to the voice of cabin crew members still needs further research. (2) Air quality Poor air quality in the working environment is one of the risk factors that may disturb voice production (Vilkman, 1996), and is considered as an additional vocal loading factors that can affect the fundamental frequency (Vilkman, 2004). Dry cabin environment can cause headache, dry skin and allergy in the upper respiratory tract. Through survey, passengers also reported headache, dried eyes and burning throat (Van Netten, 1998). The humidity value in the cabin environment was investigated to be around 18.5% (Nagda & Koontz, 2003). Past research also compared moisture level in the cabin and office buildings, which revealed the average moisture level in the cabin lies between 10% to 20%, comparing to 40% to 60% for in office buildings (Space, Johnson, Rankin & Nagda, 2000). The moisture level of air in the cabin is relative low, and may cause discomfort for cabin crew members (Lee et al., 2000). Cabin crew members in New Zealand (n = 228) after long-haul flights reported in a survey that 73% suffered from dehydration and 70% suffered from ear, nose and throat problems (Criglington, 1998). Cheng (2011) surveyed Taiwanese cabin crew members (n=211) in long-haul flights on their perception of working environment and found dryness in the cabin as one of the top factors affecting cabin crews’ subjectively perceived fatigue. This finding is also consistent with past results for Taiwanese cabin crew members serving for short-haul flights (Shao, Yen & Ye, 2008; Lu, 2007). Cabin moisture level is 30% to 40% lower than that of office buildings, and thus the dry air in the cabin environment cause crew members to experience discomfort (Lee et al., 2000), including headache, dried eyes and burning throat (Van Netten, 1998). 20.

Furthermore, dehydrating the vocal folds increases their viscosity, requiring more sub-glottal pressure during phonation, increasing vocal load (Hsiao, 1999; Hemler, Wieneke, Lebacq & Dejonckere, 2001). All the potential risk factors mentioned above put cabin crew members under great risks of developing voice disorder. However, the research on voice-related problems is still minimal.. 2.5. Effects of voice problem life quality in occupational voice users The voice serve an important role in occupational activities for occupational voice users, and voice disorder can bring multidimensional problems in social, public health and economic aspects (Niebudek-Bogusz & Śliwińska-Kowalska, 2013). Voice problems among occupational voice users increase the health-care expenses (Verdolini & Ramig, 2001); moreover, theses problems adversely affect the quality of life of the occupational voice users (Roy et al., 2004; Ma & Yiu, 2001). The World Health Organization (WHO) proposed the multidimensional concept of health as physical, mental and social well-being, how much an individual’s quality of life has affected due to voice disorder should be considered when assessing voice disorder (WHO, 1980). Therefore, self-perceived voice problem should be taken into account for occupational voice users (Niebudek-Bogusz & Sliwinska-Kowalska, 2013). Job performance was affected by vocal symptoms in call center operators in India, especially among females, who are taking more time off work due to voice problems (Devadas & Rajashekhar, 2013). Daily activities and participation in activities is limited due to voice disorders in primary school teachers in Taipei City. Huang (2009) investigated the effects of voice disorder in primary school teachers in Taipei City on their occupation, communication, emotion and social aspects. The results revealed that multiple functions were negatively affected by voice disorder among those teachers, specifically in “degraded job quality”, “additional work pressure”, “feeling upset for voice problem” and “avoidance of conversations” when compared to the general population. Similar with teachers, the life quality of female aerobic exercise coaches was impacted by voice problems (Ku, 2010). Due to voice problems, female aerobic 21.

exercise coaches demonstrated “working quality affected”, “stress level increased”, “way of living changed”, “upset for voice problems” and “conversations and talking time decreased” (Ku, 2010). From the past researches, we could see that life quality in teachers and aerobic exercise coaches was affected by voice problems, notably in “work”, “emotion” and “communication” aspects. This study aims to find out whether cabin crew members’ life quality is correlated and how it is different or in resonance with other femaledominant occupations.. 22.

3. RESEARCH METHOD A cross-sectional survey research design was used to fulfill the purpose of this pilot study. The cabin crew member’s voice questionnaire (Appendix A.) is used to determine the current and past voice problem prevalence and its risk factors. With Voice Handicap Index (Appendix 2.), investigate the consequences on quality of life resulting from voice problems among female cabin crew members of commercial airlines in Taiwan. Research framework, participant recruitment, materials and tools, research procedures and data analysis will be discussed in the following sections.. 3.1. Research framework The aim of this pilot study is to determine the prevalence and risk factors of voice problems in female cabin crew members of commercial airlines in Taiwan. Moreover, this study investigates how voice problems are correlated with the quality of life in this specific occupational group physically, functionally and emotionally. Concluded from the past literature review above, voice disorder is a multifold problem for occupational voice users, needing to be discussed in various aspects. Therefore, the five sections in the cabin crew member voice questionnaire were established based on —“A series research on Teachers’ Voice: Part II Risk Factors and Effects of Voice Disorders of Primary Education Teachers In Taipei City” (Huang, 2009), “The Cabin Safety and Health Management Handbook” (Wan, 2016) and past researches on acoustic parameters of cabin crew members (Mendes et al., 2014, 2012 & 2008). The cabin crew member voice questionnaire gathered influential information and potential risk factors of voice problems for cabin crew members, from participants’ personal and work information, living habits (smoking, alcohol, caffeine, spicy and late night food consumption), health-related problems (medication intake, sleeping quality and stress level), vocal loading, different voice use behaviors, working environment (noise, humidity, air quality and coping strategies) and selfperception on hearing status and vocal health. Questions are designed to elicit participants’ response in order to determine the prevalence and cause of voice disorder. Furthermore, the Voice Handicap Index was used to assess if voice problems are in correlation those cabin crew members’ qualify of life functionally, physically and emotionally.. 23.

Scheme 1. Research framework. 24.

3.2. Participant recruitment Secion 3.2 includes selection criteria, ethical issues and sample size of the participants. 3.2.1. Selecting criteria The following participant selection criteria were used: 1) female 2) currently working for international passenger airlines in Taiwan 3) present hearing abilities and middle ear functions are within normal limits, and 4) agree to participate in this current study and filled out informed consent. Excluding participants that: 1) presenting flu symptoms within a week, 2) having professional vocal training or voice therapy 3) have undergone any medical surgery known to affect voice, and 4) have not been on a flight duty for more than 3 months. The target population of this study consists of female cabin crew members from two major commercial airlines in Taiwan: China Airlines and EVA Air (CAA, 2018). Through convenience non-probability sampling, the study invited 124 female cabin crew members from commercial airlines in Taiwan to participate in the proposed study on a voluntary basis. The expected response rate and the number of questionnaires issued were taken into consideration as the response rate will affect the final sample size (Kalton, 1983). A keychain was provided as an incentive to increase the response rate. 3.2.2 Ethical issues Ethical approval was granted by the Research Ethics Office, Office of Research and Development at National Taiwan University. After explaining the purpose of the study and the research content to the participants by the researcher, informed consent was secured prior to participation in the survey. 3.2.3. Sample size This study analysis was conducted on the basis of the results of the “cabin crew members’ self-perceived voice problems questionnaire” (Appendix A.), collected from a total of 124 female cabin crew member participants. The questionnaire was distributed and collected within 30 days with a total of 124 questionnaires returned, with one invalid questionnaire; 99% overall response rate with a total of 123 effective questionnaires.. 25.

3.3. Research materials The instrument used in this study includes the cabin crew voice questionnaires and the Voice Handicap Index-30 (VHI-30) in Chinese. 3.3.1. Cabin crew members voice questionnaire The cabin crew members voice questionnaire (Appendix A.) was developed referencing from past occupational voice users’ researches—“The Cabin Safety and Health Management Handbook” (Wan, 2016) and the voice questionnaires from “A series research on Teachers’ Voice: Part II Risk Factors and Effects of Voice Disorders of Primary Education Teachers In Taipei City” (Huang, 2009). The questionnaire is consisted of five categories: “personal/ flight duty (work) information”, “living habits and health condition”, “vocal load and voice use behaviors”, “voice use environment” and “self-perception on hearing status and vocal health”. Responding formats in this survey include closed questions (yes/no response, single/multiple choices and frequency scales), contingency questions and fill-in the blank questions. A five-point frequency scale with “always,” “often” “sometimes,” “seldom,” and “never” was used to rate the “self-perceived voice and laryngeal symptoms” section for the internal consistency of five-point scale. Questionnaire outline A total of 31 questions were distributed into the following five main sections: “personal/ flight duty (work) information”, “living habits and health condition”, “vocal load and voice use behaviors”, “voice use environment” and “self-perception on hearing status and vocal health”. 【I: Personal / Flight Duty Information】 Demographic information includes age, ranking and year of service and average duty hours per month. Personal information does not include “sex” since this current study recruit only female participants. Previous studies indicated higher voice disorder prevalence in chronological age and longer years of service and revealed increased fundamental frequency for both gender as years of service increased for cabin crew members (Mendes et al., 2014; Roy et al., 2004). Personal and flight duty information. Designed to assess the demographic information that may be risk factors based on past findings. Year and month of birth, to access the participants’ age (Q1); years of service, fill in the blank question to access the length 26.

of service (Q2); average duty hours per month, fill in the blank question for monthly service hours (Q3); and ranking, five check box categories of occupational ranking from “chief purser”, “purser”, “assistant purser”, “cabin crew member” and “trainee” (Q4). 【II: Living Habits and Health Conditions】 This section aims to understand risk factors of voice disorder from the participants’ living habits and health-related conditions. Its structured with reference from the “Living and Health Information” section in “A Series Research on Teachers’ Voice: Part II Risk Factors and Effects of Voice Disorders of Primary Education Teachers In Taipei City” (Huang, 2009) and the research result of “Lifestyle, Flying and Associated Health Problems in Female cabin crew members” (Sharma, 2007). Personal living habits. Includes “smoking, alcohol, caffeine, spicy and late night food consumption” (Q5-12). A filter question is provided for caffeine (Q5) and alcohol (Q7) intake in order to further investigate the frequency and amount of consumption (Q6, Q8 & Q10). Smoking habit (Q9) as modified based on the “Taiwanese Adult Smoking Behavior Survey” conducted by the Health Promotion Administration, Ministry of Health and Welfare in 2016. The definition of smoking habit in this reference is when an individual had smoked over 100 cigarettes (5 packages) to date. The type of smoker will be defined according to the definition of adult smoker from the Ministry of Health and Welfare (2017): “current smoker” (consumed more than 100 cigarettes and smoke at least once a day), “occasional smoker” (had more than 100 cigarettes but does not smoke daily), “experimenter” (smokes occasionally with less than 100 cigarettes consumed) and the “non-smoker”. Health Condition. Consists of health-related questions on general health and current medical diagnosis, medicine consumption, sleeping quality and working stress level (Q12-Q15). 【III: Vocal Load and Voice Use Behaviors】 Questions in this section seeks to understand the risk factors regarding functional and occupational usage of the participants’ voice. Vocal Load. Referenced from the “Loading Effects of Work” (Lehto, 2007; Vilkman, 2004). Respondents are asked to answer on subjectively perceived vocal loading and the need to adjust the voice during work (Q16-Q17). Voice use behavior. Structured base on the “Voice Use Behavior” section in “A Series 27.

Research on Teachers’ Voice: Part II Risk Factors and Effects of Voice Disorders of Primary Education Teachers In Taipei City” (Huang, 2009). 【IV: Voice Use Environment】 This section of the questionnaire aims to investigate the risk factors mentioned in previous research relating to the working environment for cabin crew members (Feder, 1984). Voice Use Environments. To identify perceived noise, moisture, air quality and vocal usage level in cabin environment; furthermore, if any actions were taken to prevent noise or dryness (Q18-Q22). A question on throat discomfort (including dryness, pain or strain) experiences in cabin and/or during layover (Q23) is added to this section since frequent international layovers may cause health problems in cabin crew members (Sharma, 2007). 【V: Self-Perception on Hearing Status and Vocal Health】 This section includes self-perception on current hearing status (Q24) and vocal health conditions (Q25-Q28), vocal hygiene and voice training experience (Q29-Q30) and if any professional help sought for voice or laryngeal problems (Q31). Self-perceived hearing condition. Added as voice abnormalities and voice disorders can be associated with hearing loss (Coelho, Medved & Brasolotto, 2015) and loss of hearing had been reported as one of the top five major problems cabin crew members face (Sharma, 2007). Self-perceived vocal health condition. Structured reference from the “Self-Perception on Vocal Health” section in “A Series Research on Teachers’ Voice: Part II Risk Factors and Effects of Voice Disorders of Primary Education Teachers In Taipei City” (Huang, 2009). The prevalence of voice disorder was estimated for four frames in this section: 1) prior to the cabin crew member career, 2) during the beginning of the cabin crew member career, 3) a few years after the cabin crew member’s career, and 4) any other time period. The time frames were used by Yen (2012) in “Prevalence of Voice Disorder for Aerobic Exercise Coaches” study; and it was chosen in this study to provide a more comprehensive data on voice problem history. 3.3.2. Voice Handicap Index (VHI)—Chinese Version The VHI was conducted alongside the cabin crew members’ voice 28.

questionnaire, aiming to measure and evaluate the level of impact of voice problems on ones’ daily life through self-report questionnaires. Voice questionnaires that possess reliability and validity include the Voice Handicap Index (Jacobson et al., 1997), Voice-Related Quality of Life Measure (VRQOL) (Hogikyan, & Sethuraman, 1994) and Voice Symptom Scale (VoiSS) (Deary, Wilson, Carding & MacKenzie, 2003). The VHI is one of the most commonly used self-administer voice questionnaire (Stemple et al., 2010) that consists of functional (F), physical (P) and emotional (E) sub-sections with a five-point interval scale assessment rating from 0 to 4 (0-never, 1-almost never, 2-sometimes, 3-almost always, 4-always). The VHI has been translated into various languages from English in the past decades, the Chinese version, established by researchers in Hong Kong has been proven to be a reliable and valid clinical tool to allow voice disorder patients to identify their discomfort to the therapist in the Chinese-speaking population (Lam et al., 2006). The VHI is a valid tool to assess the psychosocial impacts of voice and voice problems (Thomas et al., 2007). Natour et al. (2018) used the VHI to assess street vendors’ perception on vocal handicap and found high perception of vocal handicap in three subsections and total score in this group. Sung (2012) studied female occupational voice users’ self-perception of voice problem by comparing the difference of Taiwanese female aerobic exercise coaches with and without selfreported voice problems with the Chinese version of VHI. Results revealed that VHI scores were significantly higher in total and the emotional subsection for the selfreported voice problem group. From the past research results, we also found VHI as a valuable tool for occupational voice users on their self-perception of voice. Previous studies on prevalence of voice disorders were mostly conducted through voice questionnaires for its specific targeted population. In this current study, the Chinese version of VHI (Appendix B.) was used to complement the researcher designed questionnaire for cabin crew members to assess the effects of voice problems on the quality of life. 3.3.3. Validity and reliability of the questionnaire It is crucial to measure the accuracy and consistency in research questionnaires (Bolarinwa, 2015). Expert validity and test-retest reliability was conducted for the cabin crew member voice questionnaire to ensure its appropriateness and stability. 29.

Expert validity was conducted prior to issuing the questionnaires. Following the method suggested by Chang (2008), experts can rate the each question separately with “appropriate”, “appropriate after adjustment” and “remove”, where the question will be kept with “appropriate” rated over 80%, and will be removed if it is lower than 80%. The cabin crew voice questionnaire was submitted and examined by one speechlanguage pathologist, one otorhinolaryngologist and three cabin crew members for comments on appropriateness of the questions, and was edited upon professional suggestions. Test-retest reliability is to understand the stability of the results after a period of time and is suitable for examining questionnaires (Wallen & Fraenkel, 2013). The test-retest gap period of this questionnaire will be set as one week. The Pearson’s product-moment correlation needs to reach 0.70 to confirm the stability of the test result. To establish the stability of this questionnaire, 5 participants from the target population were asked to fill out the questionnaire twice with one week gap in between. Pearson’s product-moment correlation was calculated from the results through IBM SPSS 20.0 version.. 3.4. Research procedure The research procedures consisted of four stages, participant recruitment, research methods, data analysis, and discussion. 3.4.1. Participation recruitment The target population of this study is female commercial airline cabin crew members; convenience non-probability sampling was used for this study. 3.4.2. Research method Researcher instructed two representatives for the distribution and interview procedures, the participants was explained with the purpose and the procedure of this study. The representatives instructed the participants to fill out the questionnaires and explained the questions of the VHI and voice questionnaire to participants when needed. Informed consent was secured prior to participation. A keychain was provided as an incentive to increase the response rate. 3.4.3. Data analysis. 30.

The results of the questionnaire were conducted through quantitative analysis by the researcher. The participants will be divided into two groups based on the answer of question number 25 in the cabin crew members’ voice questionnaire. Participants who answered “yes” were placed into voice problem group (VP group); the others were placed into the no voice problem group (NVP group). The voice problem prevalence was calculated and the variables between the VP and NVP group weree analyzed in order to identify the quality of life impacted and risk factors of voice problems for cabin crew members. The variables include “personal and flight duty information”, “living habits and health condition”, “vocal demand and usage” “working environment” and “voice quality of life”. 3.4.4. Result and discussion After the collection of questionnaires, data was sorted and analyzed to derive the prevalence, risk factors and the correlation between life quality and voice problems. The study investigated the prevalence, identify the potential risk factors for female cabin crew members and discuss how to further improve of the voice health of this specific occupational group. Last, research limitations and future research suggestions are included in this section.. 31.

Scheme 2. Research flowchart. 32.

3.5. Statistical analysis Descriptive statistics and inferential statistics were performed with IBM Statistical Products and Service Solutions (IBM SPSS, version 20.0) and Statistical Analysis System 9.4 (SAS9.4) for this study. To expolre the prevalence of female cabin crew members’ voice problems, the potential risk factors, and its impact on quality of life. 3.5.1 Descriptive statistics 1. The prevalence of “current” and “past” self-perceived voice problems, throat and voice-related symptoms among the female cabin crew members in Taiwan commercial airlines. 1). Nominal scale variables shown in number of participants and percentage for self-perceived “current and “past” voice problems.. 2). Nominal scale variables shown in number of participants and percentage for self-perceived throat and voice-related symptoms.. 2. The characteristics of the female cabin crew members’ voice problems Nominal scale variables shown in number of participants and percentage for the distribution between the female cabin crew members who current self-perceive healthy voice condition, and those whose self-perceive voice problems in terms of “Personal Information”, “Living and Health Information”, “Voice Use Demand and Behaviors”, “Voice Use Environment”, and “Self-perceived Voice Health Conditions”. 3. Correlation between female cabin crew members’ quality of life and current voice problem 1). Presented with median and IQR of Functional (F), Physical (P), Emotional (E) sub-scale scores and the total (T) VHI-score.. 2). Presented in number of participants and percentage for occurrence rate on Functional (F), Physical (P), and Emotional (E) of VHI sub-sclaes, to. 33.