Prevalence of Vocal Tract Discomfort in the Flemish Population Without Self-Perceived Voice Disorders , *Anke Luyten, *Laura Bruneel, *Iris Meerschman, *Evelien D’haeseleer, †,‡Mara Behlau, *Camille Coffe and *Kristiane Van Lierde, *Gent, Belgium, and yzS~ao Paulo, Brazil Summary: Objectives. The main aim of this study was to assess the prevalence of Vocal Tract Discomfort (VTD) in the Flemish population without self-perceived voice disorders using the VTD scale and to examine the relationship between vocal load and VTD symptoms. In addition, consistency between the VTD scale and the Voice Handicap Index (VHI) and the Corporal Pain scale was evaluated. Methods. A total of 333 participants completed the VTD scale, the VHI, and the Corporal Pain scale. Patient information about study and voice-related hobbies (for students), state of (non)professional voice user (for employees), smoking, shouting, allergy, and voice therapy was taken into account. Results. A median number of three VTD symptoms was reported, and 88% of the participants showed at least one symptom of VTD. Dryness (70%), tickling (62%), and lump in the throat (54%) were the most frequently occurring symptoms. The frequency and severity of VTD were significantly higher in participants who followed voice-related studies, played a team sport, were part of a youth movement, shouted frequently, and received voice therapy in the past (P < 0.05). Finally, low correlations were obtained between frequency and severity of the VTD scale and total VHI score (r ¼ 0.226–0.411) or frequency and intensity of the Corporal Pain scale (r ¼ 0.016–0.408). Conclusions. The prevalence of VTD is relatively high in the Flemish population without self-perceived voice disorders, although the frequency and severity of the symptoms are rather low. Vocal load seems to influence the frequency and severity of VTD. Finally, the VTD scale seems to reveal clinically important information that cannot be gathered from any other protocol. Key Words: Voice–Vocal Tract Discomfort–Vocal load.
INTRODUCTION Quality of life is considered to be of paramount importance in clinical practice. To assess patients’ quality of life, health care providers should not only focus on functional status, but the assessment should cover physical, psychological, social, as well as spiritual domains of life.1 One of the parameters that should be included in the assessment of quality of life according to The World Health Organization Quality of Life (WHOQOL) Group1 is ‘‘pain and discomfort.’’ Pain can be defined as ‘‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage,’’2 whereas discomfort is a subjective experience of ‘‘something that causes one to feel uncomfortable.’’3 Pain and discomfort at the vocal tract are frequently heard complaints of voice patients, but they are not always properly considered when assessing the patient. The most used instrument for self-assessment of vocal problems, the Voice Handicap Index (VHI),4 does not evaluate pain and discomfort itself. Even if discomfort may not be one of the most common symptoms of a voice problem, it may cause several maladjustments on the process of voice production. Therefore, specific evaluation of these
Accepted for publication April 29, 2015. L.B. has contributed equally to this study. From the *Department of Speech, Language and Hearing Sciences, Ghent University, Gent, Belgium; yDepartamento de Fonoaudiologia, Universidade Federal de S~ao Paulo, S~ao Paulo, Brazil; and the zCentro de Estudos da Voz - CEV, S~ao Paulo, Brazil. Address correspondence and reprint requests to Anke Luyten, Department of Speech, Language and Hearing Sciences, Ghent University, De Pintelaan 185, 2P1, 9000 Gent, Belgium. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-7 0892-1997/$36.00 Ó 2015 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2015.04.017
symptoms can reveal important information about the patient’s current status of and the influence of therapy on the patient’s quality of life. To quantify the severity and frequency of an individual’s throat discomfort by means of qualitative descriptors, Mathieson et al5 developed a self-rating Vocal Tract Discomfort (VTD) scale. This scale has been demonstrated to be a very reliable tool with good sensitivity, specificity, and efficiency.6 Few studies have reported on the usefulness of the VTD scale in diagnosing voice patients. Mathieson et al5 used the VTD scale to evaluate the effects of laryngeal manual therapy in patients with muscle tension dysphonia. According to the authors, this scale is a useful perceptual indicator of sensory changes. Similarly, Woznicka et al7 concluded that the VTD scale can successfully be used to monitor the progress in treatment of occupational voice disorders. Furthermore, Rodrigues et al6 verified the VTD in teachers with and without vocal complaints and found a correlation between the self-perceived voice and VTD. Teachers with self-reported voice problems presented with higher frequencies and greater severity scores of all VTD symptoms than teachers without complaints. Finally, Lopes et al8 observed differences in VTD on the basis of the type of voice disorder. Patients with lesions in the membranous portion of the vocal folds and voice disorders caused by gastroesophageal reflux showed a higher number of VTD symptoms, particularly in comparison with disorders of neurologic etiology. The results of these few studies indicate that the importance of pain and particularly discomfort may have been underestimated in the voice clinic. Hitherto, all studies were conducted in a Britain, Polish, or Brazilian population, and little information is yet available on the prevalence of VTD in a nonclinical population.
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Nevertheless, mapping the prevalence of VTD in a nonclinical population in relation to vocal load activities would provide a framework to which the symptoms of VTD in patients with voice disorders could be weighted. Moreover, the consistency between the VTD scale and other questionnaires frequently used in diagnosing voice problems is still uncertain. Therefore, the main aim of the present study was to assess the presence of VTD in the Flemish population without self-perceived voice disorders. The relationship with activities that demand heavy vocal use and/or vocal abuse will be verified. In addition, the consistency between the VTD scale and the VHI and the Corporal Pain scale will be evaluated. MATERIALS AND METHODS The present study was approved by the Ethics Committee of the Ghent University Hospital, Belgium (EC2013/1067). All subjects signed an informed consent before participation. Participants Students of the Speech-Language Therapy education of the Ghent University, Belgium, recruited 333 participants without self-perceived voice problems by convenience sampling between October 2013 and September 2014. Friends, family, and acquaintances were contacted either face-to-face or by
phone or e-mail to ask if they wanted to participate. In addition, snowball sampling was used to raise the number of participants. No material incentive for participation was offered. The sample consisted of 207 women (62%) and 126 men (38%) with a mean age of 30 years (range, 18–81 years). An equal number of students (n ¼ 170) and employees/job seekers/ pensioners (n ¼ 163) were included. Students were particularly recruited at the Ghent University, whereas employees/job seekers/pensioners were sought in the researchers’ circle of acquaintances. Within this last category, 14% (47/333) were professional voice users. Overall, 8% (28/333) of the participants were smokers, 16% (54/333) reported to shout frequently, 23% (78/333) had at least one allergy, and 3% (11/333) received voice therapy. An overview of the participants’ details and their exposure to vocal risk factors is presented in Table 1. Methods The participants were asked to complete the Dutch translation of the VTD scale5 to assess the prevalence of VTD symptoms in the current Flemish sample (Appendix 1). This scale consisted of eight symptoms or sensations that can be felt in the throat (ie, burning, tight, dry, aching, tickling, sore, irritable, and lump in the throat). For all items, the participants were asked to indicate the frequency (never, seldom, sometimes, more than sometimes, often, very often, always) and severity
TABLE 1. Overview of the Participants’ Details and Their Exposure to Vocal Risk Factors Parameters n Mean age (range) Gender Study
Vocal load
Smoking
Shouting
Allergy
Voice therapy
Students 170 (51%) 21 y (18–28 y) 122 \, 48 _ 44 (26%) Speech-Language Therapy 4 (2%) Teacher 19 (11%) Physical Therapy 15 (9%) Psychology 13 (8%) Communication Sciences 12 (7%) Chemistry 5 (3%) Law 58 (34%) Other 43 (25%) member of youth movement 38 (22%) team sport 35 (21%) member of student’s union 13 (8%) music school 9 (5%) yes 92 (54%) no 69 (41%) missing 24 (14%) frequently 77 (45%) not frequently 69 (41%) missing 36 (21%) yes 65 (38%) no 69 (41%) missing 3 (2%) yes 88 (52%) no 79 (46%) missing
Employees, Job Seekers, Pensioners
All
163 (49%) 46 y (21–81 y) 85 \, 78 _ Not applicable
333 (100%) 30 y (18–81 y) 207 \, 126 _ Not applicable
47 (14%) professional voice users 185 (56%) nonprofessional voice users 101 (30%) missing 19 (12%) yes 144 (88%) no
Not applicable
30 (18%) frequently 133 (82%) not frequently 42 (26%) yes 121 (74%) no 8 (5%) yes 149 (91%) no 6 (4%) missing
28 (8%) yes 236 (71%) no 69 (21%) missing 54 (16%) frequently 210 (63%) not frequently 69 (21%) missing 78 (23%) yes 186 (56%) no 69 (21%) missing 11 (3%) yes 237 (71%) no 85 (26%) missing
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Vocal Tract Discomfort in the Flemish Population
(no, almost no, limited, more than limited, moderate, more than moderate, severe perception) on a seven-point Likert scale. The instructions were provided in written. In addition, the participants completed the standardized Dutch translation of the VHI,4 which assesses the psychosocial influence of voice disorders on the quality of life, and the Corporal Pain scale,9 which is used to study the presence of corporal pain symptoms. The VHI consisted of 30 questions, which cover emotional (n ¼ 10), physical (n ¼ 10), and functional (n ¼ 10) aspects of the voice. The questions were rated according to a five-point ordinal scale (never, almost never, sometimes, almost always, always). The total score ranged from 0 (no problem perceived) to 120 (severely disabled). The Corporal Pain scale asked for the symptoms of 12 corporal pains of two categories: proximal corporal pain located next to the larynx, neck, and shoulder girdle (ie, temporomandibular joint/ mandible pain, tongue pain, sore throat, shoulder pain, neck pain, and diffuse pain) and distal corporal pain located in other regions of the body (ie, headache, back pain, chest pain, arm pain, hand pain, and earache). For each corporal pain, the frequency (never, sometimes, often, almost always, always) and intensity (score on 10) needed to be indicated. The questionnaires were provided to the participants via e-mail or in paper. Statistical analysis Statistical analysis was performed using SPSS software (Version 22, IBM Corp, Armonk, NY) with significance levels set at a ¼ 0.05. Descriptive statistical analysis assessed the occurrence frequency of categorical variables as well as the median and range for continuous variables. Nonparametric MannWhitney U tests were performed for between–subject group comparisons of ordinal variables. Moreover, nonparametric
Spearman rank correlation coefficients were calculated to assess the consistency between the VTD scale (ordinal variables), the VHI (continuous variable), and the Corporal Pain scale (ordinal variables). In addition, Mann-Whitney U tests were used to compare the frequency and severity of VTD symptoms of participants with a total VHI score above and below the cutoff score of 20. RESULTS Prevalence of Vocal Tract Discomfort Table 2 presents the prevalence of symptoms of VTD reported by the Flemish participants. Overall, the participants reported a median number of three symptoms of VTD (range 0–8), and 88% (292/333) of all participants mentioned at least one symptom. When the frequency ‘‘seldom’’ was not taken into account, a median number of one symptom of VTD (range 0–8) was obtained, and 71% (237/333) of all participants mentioned at least one VTD symptom. Dryness, lump in the throat, and tickling were the most frequently occurring symptoms, whereas aching and soreness were hardly reported with a frequency more than seldom. When symptoms of VTD occurred, most rated the severity between ‘‘almost no perception’’ and ‘‘more than limited perception.’’ Influencing variables. Within the Flemish participants, the frequency (P ¼ 0.001) and severity (P ¼ 0.001) of the symptom tightness were significantly higher for women compared with those for men. Students reported a significantly higher frequency and more severe perceptions of the symptoms dryness (F: P ¼ 0.049, S: P ¼ 0.003), tickling (F: P ¼ 0.033, S: P ¼ 0.004), and lump in the throat (F: P ¼ 0.003, S: P ¼ 0.008) compared with employees/job seekers/pensioners. Within this group of students, participants with a voice-related
TABLE 2. Results on the Vocal Tract Discomfort Scale Expressed in Percent n ¼ 333 Frequency Never Seldom Sometimes More than sometimes Often Very often Always Severity No perception Almost no perception Limited perception More than limited perception Moderate perception More than moderate perception Severe perception
Burning
Tight
Dry
Aching
Tickling
Sore
Irritable
Lump
68% (228) 14% (47) 14% (45) 3% (9) 1% (4) 0% (0) 0% (0)
67% (222) 13% (42) 14% (45) 5% (17) 2% (5) 0% (1) 0% (1)
30% (101) 25% (84) 26% (86) 14% (46) 4% (13) 1% (2) 0% (1)
83% (277) 11% (35) 4% (13) 2% (5) 1% (3) 0% (0) 0% (0)
38% (126) 25% (85) 22% (74) 10% (33) 5% (15) 0% (0) 0% (0)
88% (294) 7% (23) 2% (8) 2% (5) 1% (3) 0% (0) 0% (0)
65% (215) 17% (57) 11% (35) 5% (17) 2% (8) 0% (1) 0% (0)
46% (154) 13% (44) 22% (72) 10% (32) 8% (25) 2% (6) 0% (0)
69% (228) 8% (26) 11% (38) 7% (22)
67% (222) 11% (35) 13% (43) 7% (23)
30% (101) 19% (64) 23% (76) 18% (58)
84% (279) 7% (24) 5% (16) 3% (10)
37% (124) 21% (71) 20% (65) 13% (44)
89% (295) 5% (15) 2% (8) 2% (8)
65% (216) 12% (39) 12% (39) 6% (21)
46% (153) 12% (39) 17% (57) 13% (44)
5% (15) 1% (3)
2% (8) 0% (1)
8% (25) 1% (4)
1% (3) 0% (1)
8% (25) 1% (3)
1% (3) 1% (4)
3% (11) 2% (7)
8% (26) 4% (12)
0% (1)
0% (1)
1% (4)
0% (0)
0% (1)
0% (0)
0% (0)
1% (2)
Note: The exact count is presented between brackets.
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TABLE 3. Results on the Voice Handicap Index (VHI) Parameters
Median Minimum Maximum
Functional score (on 40) Emotional score (on 40) Physical score (on 40) Total score (on 120)
2 0 2 6
0 0 0 0
14 19 21 50
study (ie, study for a profession that involves heavy vocal use, here speech-language therapist and teacher) showed significantly more complaints of soreness (P ¼ 0.039) and irritation (P ¼ 0.036) as well as significantly higher severity scores for tightness (P ¼ 0.044), soreness (P ¼ 0.031), and irritation (P ¼ 0.025) compared with students with a non–voice-related study. Moreover, playing a team sport and being a member of a youth movement, both hobbies associated with heavy vocal use and/or vocal abuse, was related with higher frequency and severity scores for, respectively, irritation (F: P ¼ 0.012, S: P ¼ 0.010), and tickling (F: P ¼ 0.023, S: P ¼ 0.012), soreness (F: P ¼ 0.010, S: P ¼ 0.009) and irritation (F: P ¼ 0.009, S: P ¼ 0.004). Being a member of a student union or going to a music school had no significant influence on the VTD (P > 0.05). Furthermore, no significant differences (P > 0.05) in VTD were noted between professional and nonprofessional voice users, smokers and nonsmokers, or participants with and without an allergy. However, participants who reported to shout frequently showed significantly higher frequency and severity scores for all symptoms of VTD (P < 0.05), except for soreness. Finally, participants who received voice therapy reported significantly more frequently the symptoms tightness (P ¼ 0.019), dryness (P ¼ 0.034), and aching (P ¼ 0.001) and had a significantly more severe perception of aching (P < 0.01).
Correlations between the VTD scale and the VHI and corporal pain scale The participants’ scores on the VHI and the Corporal Pain scale are provided in Tables 3 and 4, respectively. The median total VHI score was 6 (range, 0–50). Ninety percent (298/333) obtained a total VHI score of 20, indicating absence of a disability, whereas 10% (32/333) and 1% (3/333) presented with a mild (score 21–40) and moderate (score 41–60) disability, respectively. Furthermore, a median number of one type of corporal pain was reported by the participants (range, 0–11). The most frequently occurring type was sore throat (64%, 212/ 332), followed by headache (29%, 96/332) and neck pain (23%, 78/332). For all types of corporal pain, a median intensity score of 0 was obtained, except for sore throat (median 2). The Spearman rank correlations, calculated for the frequency and severity of all items of the VTD scale and the total VHI score, were all positive and significant (P < 0.001; Table 5). However, the correlation coefficients (r) were low, as they varied between 0.232 and 0.411 for frequency and between 0.226 and 0.388 for severity. Comparison of patients with a total VHI score above and below the cutoff score of 20 revealed that all symptoms of VTD were significantly more frequent and more severe reported by the first group (P < 0.001 or P ¼ 0.001). Regarding the frequency (r ¼ 0.020–0.374) and severity/intensity (r ¼ 0.016–0.408) of VTD sensations and corporal pain symptoms, low to very low positive correlation coefficients were obtained (Table 6). DISCUSSION In addition to specific vocal complaints such as hoarseness, VTD symptoms are often reported by voice patients in clinical practice. Although these symptoms are not directly treated by the voice therapist,6 previous studies have demonstrated that traditional voice therapy7 and laryngeal manual therapy5 might
TABLE 4. Results on the Corporal Pain Scale Frequency n ¼ 333 Headache TMJ/mandible pain Tongue pain Sore throat Neck pain Shoulder pain Back pain Diffused pain Earache Hand pain Chest pain Arm pain
Intensity (Score on 10)
Never
Sometimes
Often
Almost Always
Always
Median
Minimum
Maximum
71% (237) 88% (292) 96% (320) 36% (121) 77% (255) 82% (273) 80% (267) 95% (316) 91% (303) 97% (323) 94% (313) 96% (319)
25% (83) 12% (39) 4% (12) 55% (183) 18% (59) 14% (46) 13% (45) 4% (12) 7% (23) 3% (9) 6% (19) 3% (10)
3% (11) 1% (2) 0% (1) 8% (26) 4% (12) 3% (11) 5% (15) 1% (4) 2% (6) 0% (1) 0% (1) 1% (2)
1% (2) 0% (0) 0% (0) 1% (3) 2% (7) 1% (3) 1% (4) 0% (0) 0% (1) 0% (0) 0% (0) 0% (0)
0% (0) 0% (0) 0% (0) 0% (0) 0% (0) 0% (0) 1% (2) 0% (1) 0% (0) 0% (0) 0% (0) 1% (2)
0 0 0 2 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
9 6 6 8 9 9 9 7 8 6 8 8
Note: The frequency is expressed in percent with the exact count presented between brackets. Moreover, the median and minimum and maximum intensity scores are provided. Abbreviation: TMJ, temporomandibular joint.
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Vocal Tract Discomfort in the Flemish Population
TABLE 5. Spearman Rank Correlations Between the Frequency and Severity of VTD Symptoms and the Total VHI Score Parameters Frequency Total VHI Severity Total VHI
Burning
Tight
Dry
Aching
Tickling
Sore
Irritable
Lump
r ¼ 0.365 P < 0.001
r ¼ 0.344 P < 0.001
r ¼ 0.403 P < 0.001
r ¼ 0.325 P < 0.001
r ¼ 0.278 P < 0.001
r ¼ 0.232 P < 0.001
r ¼ 0.367 P < 0.001
r ¼ 0.411 P < 0.001
r ¼ 0.353 P < 0.001
r ¼ 0.338 P < 0.001
r ¼ 0.363 P < 0.001
r ¼ 0.322 P < 0.001
r ¼ 0.277 P < 0.001
r ¼ 0.226 P < 0.001
r ¼ 0.383 P < 0.001
r ¼ 0.388 P < 0.001
additionally lead to a decrease in VTD symptoms. Little information is, however, yet available about the distribution of VTD symptoms in the general population. Nevertheless, this would be valuable to have a framework to which results of patients with voice disorders can be weighted. Therefore, the main aim of the present study was to assess the prevalence of VTD in the Flemish population without self-perceived voice disorders and to examine the relationship between vocal load and VTD. A relatively high number of participants reported symptoms of VTD, although the frequency and severity of these symptoms were rather low. Eighty-eight percent of the participants reported at least one VTD symptom, and a median of three symptoms per participants was noted. This finding was comparable with the mean number of symptoms (ie, 2.8) reported by Rodrigues et al6 for teachers without vocal complaints, indicating that a few low-frequency/severity sensations of VTD are not necessarily related to the voice disorder in patients consulting a voice clinic. As expected, the mean number of symptoms reported in studies that assessed VTD symptoms in a clinical population was higher. Lopes et al,8 for example, reported a mean of 4.01 symptoms in patients with various types of voice disorders who did not receive voice therapy. Moreover, a mean number of 6.3 symptoms was reported for teachers with nontreated self-reported voice problems by Rodrigues et al.6 In the Flemish sample, dryness (70%), tickling (62%), and lump in the throat (54%) were the most frequently reported VTD symptoms. Similarly, Woznicka et al7 reported the highest median frequency scores (ie, 4, ‘‘often’’) for dry, tickling, and lump in the throat in teachers with occupational dysphonia before speech therapy. However, although aching (17%) and soreness (22%) were rarely mentioned by the Flemish participants in the present study, Lopes et al8 described aching (71%) and sore throat (59%) to be part of the most frequently reported VTD symptoms of patients with various voice disorders. Consequently, it is still unclear whether the distribution of voice symptoms (independent of the magnitude) is similar for the nonclinical and clinical population. Further research in this field is required. Overall, the frequency and severity of VTD symptoms, particularly irritation and soreness, seemed to be related to the participants’ vocal load. Shouting frequently, participating in a youth movement, performing a voice-related study, and playing a team sport seemed to be significant influencing factors, which is in line with the general consensus that increased
vocal load might induce voice disorders.10 Remarkably, no significant differences in frequency or severity of VTD symptoms were observed between professional and nonprofessional voice users or between smokers and nonsmokers. However, previous studies observed an increased prevalence of voice disorders in professional voice users such as teachers11 as well as in smokers.12 The current finding might be explained by the relatively low number of professional voice users and smokers included in this study. Further research with equal groups of (non)professional and (non)smokers seems to be necessary to draw reliable conclusions. Moreover, it would be interesting to explore the prevalence and severity of VTD in behavioral dysphonia as compared with organic voice problems. An additional aim of the present study was to assess the consistency between the VTD scale and other related questionnaires such as the VHI4 and the Corporal Pain scale.9 Low correlations were obtained between the frequency and severity of the VTD scale on the one hand and the total VHI score (r ¼ 0.226–r ¼ 0.411) and the frequency and intensity of the Corporal Pain scale (r ¼ 0.016–r ¼ 0.408) on the other hand. Nevertheless, all correlations with the total VHI score and most correlations with the Corporal Pain scale were significant. Similarly, Woznicka et al7 obtained a significant low positive correlation between the total VHI score and the VTD frequency (r ¼ 0.466) and severity (r ¼ 0.477) after voice therapy. Before voice therapy, the nonsignificant correlation coefficients were even lower (r ¼ 0.221 and r ¼ 0.178). Thus, although the three questionnaires seem to be significantly related, they seem to use somehow different perspectives to assess a vocal problem. Additional valuable clinically important information about one’s sensations in the head and neck region can be obtained with the VTD scale. No other instrument completely deals with this type of information. Therefore, it can be considered to use this scale in consultations of voice patients in addition to the VHI. The main limitation of the present study involves a relatively high number of missing values about the presence or absence of vocal load (ie, smoking, shouting, allergy, voice therapy, (non) professional voice user), which might have affected the results. Moreover, the amount of vocal abuse during activities which require heavy vocal use was not questioned. Therefore, it was not possible to reveal a causal relationship between vocal load and VTD. In addition, clinical examination of voice disorders using videolaryngostroboscopic assessment as well as
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TABLE 6. Spearman Rank Correlations Between the Frequency and Severity of VTD Symptoms and Frequency and Severity of the Corporal Pain Symptoms Subtest
Parameters
Frequency
Frequency Headache TMJ*
Burning
Tight
Dry
Aching
Tickling
Sore
Irritable
r ¼ 0.229 P < 0.001 r ¼ 0.160 P ¼ 0.003
r ¼ 0.129 P ¼ 0.019 r ¼ 0.135 P ¼ 0.014 r ¼ 0.116 P ¼ 0.035 r ¼ 0.275 P < 0.001 r ¼ 0.140 P ¼ 0.010 r ¼ 0.141 P ¼ 0.010 r ¼ 0.138 P ¼ 0.011 r ¼ 0.141 P ¼ 0.010 r ¼ 0.128 P ¼ 0.019
r ¼ 0.237 P < 0.001 r ¼ 0.136 P ¼ 0.013 r ¼ 0.184 P ¼ 0.001 r ¼ 0.374 P < 0.001 r ¼ 0.165 P ¼ 0.003 r ¼ 0.119 P ¼ 0.030 r ¼ 0.131 P ¼ 0.017 r ¼ 0.163 P ¼ 0.003 r ¼ 0.153 P ¼ 0.005
r ¼ 0.198 P < 0.001
r ¼ 0.200 P < 0.001
r ¼ 0.164 P ¼ 0.003
r ¼ 0.204 P < 0.001
r ¼ 0.187 P ¼ 0.001
r ¼ 0.109 P ¼ 0.047 r ¼ 0.348 P < 0.001
r ¼ 0.263 P < 0.001
r ¼ 0.147 P ¼ 0.007 r ¼ 0.184 P ¼ 0.001 r ¼ 0.169 P ¼ 0.002
r ¼ 0.132 P ¼ 0.016 r ¼ 0.139 P ¼ 0.011 r ¼ 0.164 P ¼ 0.003 r ¼ 0.109 P ¼ 0.048 r ¼ 0.131 P ¼ 0.017
Tongue Throat Neck
r ¼ 0.335 P < 0.001 r ¼ 0.125 P ¼ 0.023
Shoulder Back Diffused Earache
r ¼ 0.136 P ¼ 0.013 r ¼ 0.125 P ¼ 0.023 r ¼ 0.130 P ¼ 0.017
r ¼ 0.147 P ¼ 0.007 r ¼ 0.319 P < 0.001 r ¼ 0.156 P ¼ 0.004 r ¼ 0.152 P ¼ 0.005 r ¼ 0.174 P ¼ 0.001 r ¼ 0.137 P ¼ 0.013 r ¼ 0.142 P ¼ 0.010 r ¼ 0.161 P ¼ 0.003 r ¼ 0.164 P ¼ 0.003 r ¼ 0.138 P ¼ 0.012
r ¼ 0.124 P ¼ 0.023 r ¼ 0.147 P ¼ 0.007 r ¼ 0.153 P ¼ 0.005 r ¼ 0.185 P ¼ 0.001 r ¼ 0.151 P ¼ 0.006
r ¼ 0.191 P < 0.001 r ¼ 0.178 P ¼ 0.001
r ¼ 0.168 P ¼ 0.002
r ¼ 0.162 P ¼ 0.003
r ¼ 0.141 P ¼ 0.010
r ¼ 0.232 P < 0.001
r ¼ 0.314 P < 0.001
r ¼ 0.165 P ¼ 0.003 r ¼ 0.285 P < 0.001
r ¼ 0.254 P < 0.001
Hand r ¼ 0.111 P ¼ 0.043
Chest Arm
Intensity
Severity Headache TMJ*
r ¼ 0.228 P < 0.001 r ¼ 0.167 P ¼ 0.002
Tongue Throat
r ¼ 0.366 P < 0.001
Neck Shoulder Back Diffused Earache
r ¼ 0.155 P ¼ 0.005
r ¼ 0.111 P ¼ 0.043 r ¼ 0.128 P ¼ 0.020 r ¼ 0.137 P ¼ 0.012 r ¼ 0.270 P < 0.001 r ¼ 0.118 P ¼ 0.032 r ¼ 0.148 P ¼ 0.007 r ¼ 0.110 P ¼ 0.045 r ¼ 0.136 P ¼ 0.013 r ¼ 0.133 P ¼ 0.015
Hand Chest
r ¼ 0.109 P ¼ 0.047
Arm Note: Only the significant correlations (P < 0.05) are presented. Abbreviation: TMJ, temporomandibular joint.
r ¼ 0.120 P ¼ 0.028 r ¼ 0.189 P ¼ 0.001 r ¼ 0.139 P ¼ 0.011 r ¼ 0.185 P ¼ 0.001 r ¼ 0.408 P < 0.001
r ¼ 0.123 P ¼ 0.025 r ¼ 0.192 P < 0.001
r ¼ 0.123 P ¼ 0.024
r ¼ 0.136 P ¼ 0.013 r ¼ 0.133 P ¼ 0.016 r ¼ 0.110 P ¼ 0.045 r ¼ 0.140 P ¼ 0.011 r ¼ 0.108 P ¼ 0.049 r ¼ 0.112 P ¼ 0.041 r ¼ 0.112 P ¼ 0.041
r ¼ 0.253 P < 0.001
r ¼ 0.365 P < 0.001
r ¼ 0.154 P ¼ 0.005 r ¼ 0.180 P ¼ 0.001 r ¼ 0.210 P < 0.001 r ¼ 0.184 P ¼ 0.001 r ¼ 0.178 P ¼ 0.001
r ¼ 0.110 P ¼ 0.045 r ¼ 0.148 P ¼ 0.007 r ¼ 0.185 P ¼ 0.001 r ¼ 0.181 P ¼ 0.001 r ¼ 0.123 P ¼ 0.025 r ¼ 0.204 P < 0.001 r ¼ 0.180 P ¼ 0.001
Lump
r ¼ 0.128 P ¼ 0.019 r ¼ 0.267 P < 0.001
r ¼ 0.108 P ¼ 0.049 r ¼ 0.149 P ¼ 0.006 r ¼ 0.162 P ¼ 0.003
r ¼ 0.135 P ¼ 0.013
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Vocal Tract Discomfort in the Flemish Population
perceptual and objective assessment of voice quality was not included in the present study, although it would have been useful to determine the absence of voice disorders more accurately. Finally, the current Flemish sample was relatively young (mean age 30 years). Considering the high prevalence of voice disorders in the elderly population,13 further research should focus on the prevalence of VTD symptoms in older people. CONCLUSIONS In conclusion, a relatively high prevalence of VTD symptoms is present in the Flemish population, although the occurrence frequency and severity are overall rather low. Vocal load seems to influence the frequency and severity of VTD. Considering that the VTD scale showed low correlations with the VHI and Corporal Pain scale, the VTD scale might reveal valuable extra information when used during voice consultations in addition to the VHI. REFERENCES 1. The WHOQOL Group. The World Health Organization Quality of Life Assessment (WHOQOL): development and general psychometric properties. Soc Sci Med. 1998;46:1569–1585. 2. International Association for the Study of Pain, Vol 2015. Wachington D.C., USA: IASP Taxonomy; 2012. 3. Oxford Dictionaries. Discomfort, Vol 2015. Oxford: Oxford University Press; 2015. 4. Jacobson BH, Johnson A, Grywalski C, Silbergleit A, Jacobson G, Benninger MS. The Voice Handicap Index (VHI): development and validation. Am J Speech-Lang Pathol. 1997;6:66–70. 5. Mathieson L, Hirani SP, Epstein R, Baken RJ, Wood G, Rubin JS. Laryngeal manual therapy: a preliminary study to examine its treatment effects in the management of muscle tension dysphonia. J voice. 2009;23:353–366. 6. Rodrigues G, Zambon F, Mathieson L, Behlau M. Vocal tract discomfort in teachers: its relationship to self-reported voice disorders. J Voice. 2013;27: 473–480. 7. Woznicka E, Niebudek-Bogusz E, Kwiecien J, Wiktorowicz J, SliwinskaKowalska M. Applicability of the vocal tract discomfort (VTD) scale in evaluating the effects of voice therapy of occupational voice disorders. Med Pr. 2012;63:141–152. 8. Lopes LW, Cabral GF, Figueiredo de Almeida AA. Vocal tract discomfort symptoms in patients with different voice disorders. J Voice. 2014;29: 317–323. 9. Van Lierde KM, D’Haeseleer E, Wuyts FL, et al. The objective vocal quality, vocal risk factors, vocal complaints, and corporal pain in Dutch female students training to be speech-language pathologists during the 4 years of study. J Voice. 2010;24:592–598. 10. Schneider-Stickler B, Knell C, Aichstill B, Jocher W. Biofeedback on voice use in call center agents in order to prevent occupational voice disorders. J Voice. 2012;26:51–62. 11. Martins RH, Pereira ER, Hidalgo CB, Tavares EL. Voice disorders in teachers. A review. J Voice. 2014;28:716–724. 12. Byeon H. Relationships among smoking, organic and functional voice disorders in Korean general population. J Voice. 2014;29:312–316. 13. Golub JS, Chen PH, Otto KJ, Hapner E, Johns MM. Prevalence of perceived dysphonia in a geriatric population. J Am Geriatr Soc. 2006;54:1736–1739.
APPENDIX 1 Dutch translation of Vocal Tract Discomfort scale Gelieve bij elk van de onderstaande gewaarwordingen aan te geven hoe frequent deze ervaring voorkomt en in welke mate u deze ervaart. Hieronder vindt u enige uitleg over de door ons gebruikte begrippen. Branderig: gloeiend en ontstoken Geknepen: spanning ter hoogte van de keel Droog: schurend Zeurende pijn: continue, doffe, oppervlakkige pijn Kriebelend: tintelend gevoel dat niet overgaat bij het stemgeven of hoesten Stekende pijn: plots opkomende pijn bij het stemgeven of bij het aanraken van de keel Ge€ırriteerd: prikkelend, warm Globusgevoel: gevoel van een ‘‘brok in de keel’’ waardoor men de neiging heeft te hoesten, de keel te schrapen of te slikken
Frequentie van voorkomen waarbij: 0 ¼ nooit 1 ¼ zelden 2 ¼ soms 3 ¼ meer dan soms 4 ¼ vaak 5 ¼ heel vaak 6 ¼ altijd Hoe hoger het cijfer, hoe hoger de frequentie
Branderig Geknepen Droog Zeurende pijn Kriebelend Stekende pijn Ge€ırriteerd Globusgevoel
0123456 0123456 0123456 0123456 0123456 0123456 0123456 0123456
Intensiteit van voorkomen waarbij: 0 ¼ geen gewaarwording 1 ¼ bijna geen gewaarwording 2 ¼ geringe gewaarwording 3 ¼ meer dan geringe gewaarwording 4 ¼ matige gewaarwording 5 ¼ meer dan matige gewaarwording 6 ¼ ernstige gewaarwording Hoe hoger het cijfer, hoe hoger de intensiteit 0123456 0123456 0123456 0123456 0123456 0123456 0123456 0123456
INTRODUCTION Quality of life is considered to be of paramount importance in clinical practice. To assess patients’ quality of life, health care providers should not only focus on functional status, but the assessment should cover physical, psychological, social, as well as spiritual domains of life.1 One of the parameters that should be included in the assessment of quality of life according to The World Health Organization Quality of Life (WHOQOL) Group1 is ‘‘pain and discomfort.’’ Pain can be defined as ‘‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage,’’2 whereas discomfort is a subjective experience of ‘‘something that causes one to feel uncomfortable.’’3 Pain and discomfort at the vocal tract are frequently heard complaints of voice patients, but they are not always properly considered when assessing the patient. The most used instrument for self-assessment of vocal problems, the Voice Handicap Index (VHI),4 does not evaluate pain and discomfort itself. Even if discomfort may not be one of the most common symptoms of a voice problem, it may cause several maladjustments on the process of voice production. Therefore, specific evaluation of these
Accepted for publication April 29, 2015. L.B. has contributed equally to this study. From the *Department of Speech, Language and Hearing Sciences, Ghent University, Gent, Belgium; yDepartamento de Fonoaudiologia, Universidade Federal de S~ao Paulo, S~ao Paulo, Brazil; and the zCentro de Estudos da Voz - CEV, S~ao Paulo, Brazil. Address correspondence and reprint requests to Anke Luyten, Department of Speech, Language and Hearing Sciences, Ghent University, De Pintelaan 185, 2P1, 9000 Gent, Belgium. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-7 0892-1997/$36.00 Ó 2015 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2015.04.017
symptoms can reveal important information about the patient’s current status of and the influence of therapy on the patient’s quality of life. To quantify the severity and frequency of an individual’s throat discomfort by means of qualitative descriptors, Mathieson et al5 developed a self-rating Vocal Tract Discomfort (VTD) scale. This scale has been demonstrated to be a very reliable tool with good sensitivity, specificity, and efficiency.6 Few studies have reported on the usefulness of the VTD scale in diagnosing voice patients. Mathieson et al5 used the VTD scale to evaluate the effects of laryngeal manual therapy in patients with muscle tension dysphonia. According to the authors, this scale is a useful perceptual indicator of sensory changes. Similarly, Woznicka et al7 concluded that the VTD scale can successfully be used to monitor the progress in treatment of occupational voice disorders. Furthermore, Rodrigues et al6 verified the VTD in teachers with and without vocal complaints and found a correlation between the self-perceived voice and VTD. Teachers with self-reported voice problems presented with higher frequencies and greater severity scores of all VTD symptoms than teachers without complaints. Finally, Lopes et al8 observed differences in VTD on the basis of the type of voice disorder. Patients with lesions in the membranous portion of the vocal folds and voice disorders caused by gastroesophageal reflux showed a higher number of VTD symptoms, particularly in comparison with disorders of neurologic etiology. The results of these few studies indicate that the importance of pain and particularly discomfort may have been underestimated in the voice clinic. Hitherto, all studies were conducted in a Britain, Polish, or Brazilian population, and little information is yet available on the prevalence of VTD in a nonclinical population.
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Nevertheless, mapping the prevalence of VTD in a nonclinical population in relation to vocal load activities would provide a framework to which the symptoms of VTD in patients with voice disorders could be weighted. Moreover, the consistency between the VTD scale and other questionnaires frequently used in diagnosing voice problems is still uncertain. Therefore, the main aim of the present study was to assess the presence of VTD in the Flemish population without self-perceived voice disorders. The relationship with activities that demand heavy vocal use and/or vocal abuse will be verified. In addition, the consistency between the VTD scale and the VHI and the Corporal Pain scale will be evaluated. MATERIALS AND METHODS The present study was approved by the Ethics Committee of the Ghent University Hospital, Belgium (EC2013/1067). All subjects signed an informed consent before participation. Participants Students of the Speech-Language Therapy education of the Ghent University, Belgium, recruited 333 participants without self-perceived voice problems by convenience sampling between October 2013 and September 2014. Friends, family, and acquaintances were contacted either face-to-face or by
phone or e-mail to ask if they wanted to participate. In addition, snowball sampling was used to raise the number of participants. No material incentive for participation was offered. The sample consisted of 207 women (62%) and 126 men (38%) with a mean age of 30 years (range, 18–81 years). An equal number of students (n ¼ 170) and employees/job seekers/ pensioners (n ¼ 163) were included. Students were particularly recruited at the Ghent University, whereas employees/job seekers/pensioners were sought in the researchers’ circle of acquaintances. Within this last category, 14% (47/333) were professional voice users. Overall, 8% (28/333) of the participants were smokers, 16% (54/333) reported to shout frequently, 23% (78/333) had at least one allergy, and 3% (11/333) received voice therapy. An overview of the participants’ details and their exposure to vocal risk factors is presented in Table 1. Methods The participants were asked to complete the Dutch translation of the VTD scale5 to assess the prevalence of VTD symptoms in the current Flemish sample (Appendix 1). This scale consisted of eight symptoms or sensations that can be felt in the throat (ie, burning, tight, dry, aching, tickling, sore, irritable, and lump in the throat). For all items, the participants were asked to indicate the frequency (never, seldom, sometimes, more than sometimes, often, very often, always) and severity
TABLE 1. Overview of the Participants’ Details and Their Exposure to Vocal Risk Factors Parameters n Mean age (range) Gender Study
Vocal load
Smoking
Shouting
Allergy
Voice therapy
Students 170 (51%) 21 y (18–28 y) 122 \, 48 _ 44 (26%) Speech-Language Therapy 4 (2%) Teacher 19 (11%) Physical Therapy 15 (9%) Psychology 13 (8%) Communication Sciences 12 (7%) Chemistry 5 (3%) Law 58 (34%) Other 43 (25%) member of youth movement 38 (22%) team sport 35 (21%) member of student’s union 13 (8%) music school 9 (5%) yes 92 (54%) no 69 (41%) missing 24 (14%) frequently 77 (45%) not frequently 69 (41%) missing 36 (21%) yes 65 (38%) no 69 (41%) missing 3 (2%) yes 88 (52%) no 79 (46%) missing
Employees, Job Seekers, Pensioners
All
163 (49%) 46 y (21–81 y) 85 \, 78 _ Not applicable
333 (100%) 30 y (18–81 y) 207 \, 126 _ Not applicable
47 (14%) professional voice users 185 (56%) nonprofessional voice users 101 (30%) missing 19 (12%) yes 144 (88%) no
Not applicable
30 (18%) frequently 133 (82%) not frequently 42 (26%) yes 121 (74%) no 8 (5%) yes 149 (91%) no 6 (4%) missing
28 (8%) yes 236 (71%) no 69 (21%) missing 54 (16%) frequently 210 (63%) not frequently 69 (21%) missing 78 (23%) yes 186 (56%) no 69 (21%) missing 11 (3%) yes 237 (71%) no 85 (26%) missing
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Vocal Tract Discomfort in the Flemish Population
(no, almost no, limited, more than limited, moderate, more than moderate, severe perception) on a seven-point Likert scale. The instructions were provided in written. In addition, the participants completed the standardized Dutch translation of the VHI,4 which assesses the psychosocial influence of voice disorders on the quality of life, and the Corporal Pain scale,9 which is used to study the presence of corporal pain symptoms. The VHI consisted of 30 questions, which cover emotional (n ¼ 10), physical (n ¼ 10), and functional (n ¼ 10) aspects of the voice. The questions were rated according to a five-point ordinal scale (never, almost never, sometimes, almost always, always). The total score ranged from 0 (no problem perceived) to 120 (severely disabled). The Corporal Pain scale asked for the symptoms of 12 corporal pains of two categories: proximal corporal pain located next to the larynx, neck, and shoulder girdle (ie, temporomandibular joint/ mandible pain, tongue pain, sore throat, shoulder pain, neck pain, and diffuse pain) and distal corporal pain located in other regions of the body (ie, headache, back pain, chest pain, arm pain, hand pain, and earache). For each corporal pain, the frequency (never, sometimes, often, almost always, always) and intensity (score on 10) needed to be indicated. The questionnaires were provided to the participants via e-mail or in paper. Statistical analysis Statistical analysis was performed using SPSS software (Version 22, IBM Corp, Armonk, NY) with significance levels set at a ¼ 0.05. Descriptive statistical analysis assessed the occurrence frequency of categorical variables as well as the median and range for continuous variables. Nonparametric MannWhitney U tests were performed for between–subject group comparisons of ordinal variables. Moreover, nonparametric
Spearman rank correlation coefficients were calculated to assess the consistency between the VTD scale (ordinal variables), the VHI (continuous variable), and the Corporal Pain scale (ordinal variables). In addition, Mann-Whitney U tests were used to compare the frequency and severity of VTD symptoms of participants with a total VHI score above and below the cutoff score of 20. RESULTS Prevalence of Vocal Tract Discomfort Table 2 presents the prevalence of symptoms of VTD reported by the Flemish participants. Overall, the participants reported a median number of three symptoms of VTD (range 0–8), and 88% (292/333) of all participants mentioned at least one symptom. When the frequency ‘‘seldom’’ was not taken into account, a median number of one symptom of VTD (range 0–8) was obtained, and 71% (237/333) of all participants mentioned at least one VTD symptom. Dryness, lump in the throat, and tickling were the most frequently occurring symptoms, whereas aching and soreness were hardly reported with a frequency more than seldom. When symptoms of VTD occurred, most rated the severity between ‘‘almost no perception’’ and ‘‘more than limited perception.’’ Influencing variables. Within the Flemish participants, the frequency (P ¼ 0.001) and severity (P ¼ 0.001) of the symptom tightness were significantly higher for women compared with those for men. Students reported a significantly higher frequency and more severe perceptions of the symptoms dryness (F: P ¼ 0.049, S: P ¼ 0.003), tickling (F: P ¼ 0.033, S: P ¼ 0.004), and lump in the throat (F: P ¼ 0.003, S: P ¼ 0.008) compared with employees/job seekers/pensioners. Within this group of students, participants with a voice-related
TABLE 2. Results on the Vocal Tract Discomfort Scale Expressed in Percent n ¼ 333 Frequency Never Seldom Sometimes More than sometimes Often Very often Always Severity No perception Almost no perception Limited perception More than limited perception Moderate perception More than moderate perception Severe perception
Burning
Tight
Dry
Aching
Tickling
Sore
Irritable
Lump
68% (228) 14% (47) 14% (45) 3% (9) 1% (4) 0% (0) 0% (0)
67% (222) 13% (42) 14% (45) 5% (17) 2% (5) 0% (1) 0% (1)
30% (101) 25% (84) 26% (86) 14% (46) 4% (13) 1% (2) 0% (1)
83% (277) 11% (35) 4% (13) 2% (5) 1% (3) 0% (0) 0% (0)
38% (126) 25% (85) 22% (74) 10% (33) 5% (15) 0% (0) 0% (0)
88% (294) 7% (23) 2% (8) 2% (5) 1% (3) 0% (0) 0% (0)
65% (215) 17% (57) 11% (35) 5% (17) 2% (8) 0% (1) 0% (0)
46% (154) 13% (44) 22% (72) 10% (32) 8% (25) 2% (6) 0% (0)
69% (228) 8% (26) 11% (38) 7% (22)
67% (222) 11% (35) 13% (43) 7% (23)
30% (101) 19% (64) 23% (76) 18% (58)
84% (279) 7% (24) 5% (16) 3% (10)
37% (124) 21% (71) 20% (65) 13% (44)
89% (295) 5% (15) 2% (8) 2% (8)
65% (216) 12% (39) 12% (39) 6% (21)
46% (153) 12% (39) 17% (57) 13% (44)
5% (15) 1% (3)
2% (8) 0% (1)
8% (25) 1% (4)
1% (3) 0% (1)
8% (25) 1% (3)
1% (3) 1% (4)
3% (11) 2% (7)
8% (26) 4% (12)
0% (1)
0% (1)
1% (4)
0% (0)
0% (1)
0% (0)
0% (0)
1% (2)
Note: The exact count is presented between brackets.
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TABLE 3. Results on the Voice Handicap Index (VHI) Parameters
Median Minimum Maximum
Functional score (on 40) Emotional score (on 40) Physical score (on 40) Total score (on 120)
2 0 2 6
0 0 0 0
14 19 21 50
study (ie, study for a profession that involves heavy vocal use, here speech-language therapist and teacher) showed significantly more complaints of soreness (P ¼ 0.039) and irritation (P ¼ 0.036) as well as significantly higher severity scores for tightness (P ¼ 0.044), soreness (P ¼ 0.031), and irritation (P ¼ 0.025) compared with students with a non–voice-related study. Moreover, playing a team sport and being a member of a youth movement, both hobbies associated with heavy vocal use and/or vocal abuse, was related with higher frequency and severity scores for, respectively, irritation (F: P ¼ 0.012, S: P ¼ 0.010), and tickling (F: P ¼ 0.023, S: P ¼ 0.012), soreness (F: P ¼ 0.010, S: P ¼ 0.009) and irritation (F: P ¼ 0.009, S: P ¼ 0.004). Being a member of a student union or going to a music school had no significant influence on the VTD (P > 0.05). Furthermore, no significant differences (P > 0.05) in VTD were noted between professional and nonprofessional voice users, smokers and nonsmokers, or participants with and without an allergy. However, participants who reported to shout frequently showed significantly higher frequency and severity scores for all symptoms of VTD (P < 0.05), except for soreness. Finally, participants who received voice therapy reported significantly more frequently the symptoms tightness (P ¼ 0.019), dryness (P ¼ 0.034), and aching (P ¼ 0.001) and had a significantly more severe perception of aching (P < 0.01).
Correlations between the VTD scale and the VHI and corporal pain scale The participants’ scores on the VHI and the Corporal Pain scale are provided in Tables 3 and 4, respectively. The median total VHI score was 6 (range, 0–50). Ninety percent (298/333) obtained a total VHI score of 20, indicating absence of a disability, whereas 10% (32/333) and 1% (3/333) presented with a mild (score 21–40) and moderate (score 41–60) disability, respectively. Furthermore, a median number of one type of corporal pain was reported by the participants (range, 0–11). The most frequently occurring type was sore throat (64%, 212/ 332), followed by headache (29%, 96/332) and neck pain (23%, 78/332). For all types of corporal pain, a median intensity score of 0 was obtained, except for sore throat (median 2). The Spearman rank correlations, calculated for the frequency and severity of all items of the VTD scale and the total VHI score, were all positive and significant (P < 0.001; Table 5). However, the correlation coefficients (r) were low, as they varied between 0.232 and 0.411 for frequency and between 0.226 and 0.388 for severity. Comparison of patients with a total VHI score above and below the cutoff score of 20 revealed that all symptoms of VTD were significantly more frequent and more severe reported by the first group (P < 0.001 or P ¼ 0.001). Regarding the frequency (r ¼ 0.020–0.374) and severity/intensity (r ¼ 0.016–0.408) of VTD sensations and corporal pain symptoms, low to very low positive correlation coefficients were obtained (Table 6). DISCUSSION In addition to specific vocal complaints such as hoarseness, VTD symptoms are often reported by voice patients in clinical practice. Although these symptoms are not directly treated by the voice therapist,6 previous studies have demonstrated that traditional voice therapy7 and laryngeal manual therapy5 might
TABLE 4. Results on the Corporal Pain Scale Frequency n ¼ 333 Headache TMJ/mandible pain Tongue pain Sore throat Neck pain Shoulder pain Back pain Diffused pain Earache Hand pain Chest pain Arm pain
Intensity (Score on 10)
Never
Sometimes
Often
Almost Always
Always
Median
Minimum
Maximum
71% (237) 88% (292) 96% (320) 36% (121) 77% (255) 82% (273) 80% (267) 95% (316) 91% (303) 97% (323) 94% (313) 96% (319)
25% (83) 12% (39) 4% (12) 55% (183) 18% (59) 14% (46) 13% (45) 4% (12) 7% (23) 3% (9) 6% (19) 3% (10)
3% (11) 1% (2) 0% (1) 8% (26) 4% (12) 3% (11) 5% (15) 1% (4) 2% (6) 0% (1) 0% (1) 1% (2)
1% (2) 0% (0) 0% (0) 1% (3) 2% (7) 1% (3) 1% (4) 0% (0) 0% (1) 0% (0) 0% (0) 0% (0)
0% (0) 0% (0) 0% (0) 0% (0) 0% (0) 0% (0) 1% (2) 0% (1) 0% (0) 0% (0) 0% (0) 1% (2)
0 0 0 2 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0
9 6 6 8 9 9 9 7 8 6 8 8
Note: The frequency is expressed in percent with the exact count presented between brackets. Moreover, the median and minimum and maximum intensity scores are provided. Abbreviation: TMJ, temporomandibular joint.
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Vocal Tract Discomfort in the Flemish Population
TABLE 5. Spearman Rank Correlations Between the Frequency and Severity of VTD Symptoms and the Total VHI Score Parameters Frequency Total VHI Severity Total VHI
Burning
Tight
Dry
Aching
Tickling
Sore
Irritable
Lump
r ¼ 0.365 P < 0.001
r ¼ 0.344 P < 0.001
r ¼ 0.403 P < 0.001
r ¼ 0.325 P < 0.001
r ¼ 0.278 P < 0.001
r ¼ 0.232 P < 0.001
r ¼ 0.367 P < 0.001
r ¼ 0.411 P < 0.001
r ¼ 0.353 P < 0.001
r ¼ 0.338 P < 0.001
r ¼ 0.363 P < 0.001
r ¼ 0.322 P < 0.001
r ¼ 0.277 P < 0.001
r ¼ 0.226 P < 0.001
r ¼ 0.383 P < 0.001
r ¼ 0.388 P < 0.001
additionally lead to a decrease in VTD symptoms. Little information is, however, yet available about the distribution of VTD symptoms in the general population. Nevertheless, this would be valuable to have a framework to which results of patients with voice disorders can be weighted. Therefore, the main aim of the present study was to assess the prevalence of VTD in the Flemish population without self-perceived voice disorders and to examine the relationship between vocal load and VTD. A relatively high number of participants reported symptoms of VTD, although the frequency and severity of these symptoms were rather low. Eighty-eight percent of the participants reported at least one VTD symptom, and a median of three symptoms per participants was noted. This finding was comparable with the mean number of symptoms (ie, 2.8) reported by Rodrigues et al6 for teachers without vocal complaints, indicating that a few low-frequency/severity sensations of VTD are not necessarily related to the voice disorder in patients consulting a voice clinic. As expected, the mean number of symptoms reported in studies that assessed VTD symptoms in a clinical population was higher. Lopes et al,8 for example, reported a mean of 4.01 symptoms in patients with various types of voice disorders who did not receive voice therapy. Moreover, a mean number of 6.3 symptoms was reported for teachers with nontreated self-reported voice problems by Rodrigues et al.6 In the Flemish sample, dryness (70%), tickling (62%), and lump in the throat (54%) were the most frequently reported VTD symptoms. Similarly, Woznicka et al7 reported the highest median frequency scores (ie, 4, ‘‘often’’) for dry, tickling, and lump in the throat in teachers with occupational dysphonia before speech therapy. However, although aching (17%) and soreness (22%) were rarely mentioned by the Flemish participants in the present study, Lopes et al8 described aching (71%) and sore throat (59%) to be part of the most frequently reported VTD symptoms of patients with various voice disorders. Consequently, it is still unclear whether the distribution of voice symptoms (independent of the magnitude) is similar for the nonclinical and clinical population. Further research in this field is required. Overall, the frequency and severity of VTD symptoms, particularly irritation and soreness, seemed to be related to the participants’ vocal load. Shouting frequently, participating in a youth movement, performing a voice-related study, and playing a team sport seemed to be significant influencing factors, which is in line with the general consensus that increased
vocal load might induce voice disorders.10 Remarkably, no significant differences in frequency or severity of VTD symptoms were observed between professional and nonprofessional voice users or between smokers and nonsmokers. However, previous studies observed an increased prevalence of voice disorders in professional voice users such as teachers11 as well as in smokers.12 The current finding might be explained by the relatively low number of professional voice users and smokers included in this study. Further research with equal groups of (non)professional and (non)smokers seems to be necessary to draw reliable conclusions. Moreover, it would be interesting to explore the prevalence and severity of VTD in behavioral dysphonia as compared with organic voice problems. An additional aim of the present study was to assess the consistency between the VTD scale and other related questionnaires such as the VHI4 and the Corporal Pain scale.9 Low correlations were obtained between the frequency and severity of the VTD scale on the one hand and the total VHI score (r ¼ 0.226–r ¼ 0.411) and the frequency and intensity of the Corporal Pain scale (r ¼ 0.016–r ¼ 0.408) on the other hand. Nevertheless, all correlations with the total VHI score and most correlations with the Corporal Pain scale were significant. Similarly, Woznicka et al7 obtained a significant low positive correlation between the total VHI score and the VTD frequency (r ¼ 0.466) and severity (r ¼ 0.477) after voice therapy. Before voice therapy, the nonsignificant correlation coefficients were even lower (r ¼ 0.221 and r ¼ 0.178). Thus, although the three questionnaires seem to be significantly related, they seem to use somehow different perspectives to assess a vocal problem. Additional valuable clinically important information about one’s sensations in the head and neck region can be obtained with the VTD scale. No other instrument completely deals with this type of information. Therefore, it can be considered to use this scale in consultations of voice patients in addition to the VHI. The main limitation of the present study involves a relatively high number of missing values about the presence or absence of vocal load (ie, smoking, shouting, allergy, voice therapy, (non) professional voice user), which might have affected the results. Moreover, the amount of vocal abuse during activities which require heavy vocal use was not questioned. Therefore, it was not possible to reveal a causal relationship between vocal load and VTD. In addition, clinical examination of voice disorders using videolaryngostroboscopic assessment as well as
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TABLE 6. Spearman Rank Correlations Between the Frequency and Severity of VTD Symptoms and Frequency and Severity of the Corporal Pain Symptoms Subtest
Parameters
Frequency
Frequency Headache TMJ*
Burning
Tight
Dry
Aching
Tickling
Sore
Irritable
r ¼ 0.229 P < 0.001 r ¼ 0.160 P ¼ 0.003
r ¼ 0.129 P ¼ 0.019 r ¼ 0.135 P ¼ 0.014 r ¼ 0.116 P ¼ 0.035 r ¼ 0.275 P < 0.001 r ¼ 0.140 P ¼ 0.010 r ¼ 0.141 P ¼ 0.010 r ¼ 0.138 P ¼ 0.011 r ¼ 0.141 P ¼ 0.010 r ¼ 0.128 P ¼ 0.019
r ¼ 0.237 P < 0.001 r ¼ 0.136 P ¼ 0.013 r ¼ 0.184 P ¼ 0.001 r ¼ 0.374 P < 0.001 r ¼ 0.165 P ¼ 0.003 r ¼ 0.119 P ¼ 0.030 r ¼ 0.131 P ¼ 0.017 r ¼ 0.163 P ¼ 0.003 r ¼ 0.153 P ¼ 0.005
r ¼ 0.198 P < 0.001
r ¼ 0.200 P < 0.001
r ¼ 0.164 P ¼ 0.003
r ¼ 0.204 P < 0.001
r ¼ 0.187 P ¼ 0.001
r ¼ 0.109 P ¼ 0.047 r ¼ 0.348 P < 0.001
r ¼ 0.263 P < 0.001
r ¼ 0.147 P ¼ 0.007 r ¼ 0.184 P ¼ 0.001 r ¼ 0.169 P ¼ 0.002
r ¼ 0.132 P ¼ 0.016 r ¼ 0.139 P ¼ 0.011 r ¼ 0.164 P ¼ 0.003 r ¼ 0.109 P ¼ 0.048 r ¼ 0.131 P ¼ 0.017
Tongue Throat Neck
r ¼ 0.335 P < 0.001 r ¼ 0.125 P ¼ 0.023
Shoulder Back Diffused Earache
r ¼ 0.136 P ¼ 0.013 r ¼ 0.125 P ¼ 0.023 r ¼ 0.130 P ¼ 0.017
r ¼ 0.147 P ¼ 0.007 r ¼ 0.319 P < 0.001 r ¼ 0.156 P ¼ 0.004 r ¼ 0.152 P ¼ 0.005 r ¼ 0.174 P ¼ 0.001 r ¼ 0.137 P ¼ 0.013 r ¼ 0.142 P ¼ 0.010 r ¼ 0.161 P ¼ 0.003 r ¼ 0.164 P ¼ 0.003 r ¼ 0.138 P ¼ 0.012
r ¼ 0.124 P ¼ 0.023 r ¼ 0.147 P ¼ 0.007 r ¼ 0.153 P ¼ 0.005 r ¼ 0.185 P ¼ 0.001 r ¼ 0.151 P ¼ 0.006
r ¼ 0.191 P < 0.001 r ¼ 0.178 P ¼ 0.001
r ¼ 0.168 P ¼ 0.002
r ¼ 0.162 P ¼ 0.003
r ¼ 0.141 P ¼ 0.010
r ¼ 0.232 P < 0.001
r ¼ 0.314 P < 0.001
r ¼ 0.165 P ¼ 0.003 r ¼ 0.285 P < 0.001
r ¼ 0.254 P < 0.001
Hand r ¼ 0.111 P ¼ 0.043
Chest Arm
Intensity
Severity Headache TMJ*
r ¼ 0.228 P < 0.001 r ¼ 0.167 P ¼ 0.002
Tongue Throat
r ¼ 0.366 P < 0.001
Neck Shoulder Back Diffused Earache
r ¼ 0.155 P ¼ 0.005
r ¼ 0.111 P ¼ 0.043 r ¼ 0.128 P ¼ 0.020 r ¼ 0.137 P ¼ 0.012 r ¼ 0.270 P < 0.001 r ¼ 0.118 P ¼ 0.032 r ¼ 0.148 P ¼ 0.007 r ¼ 0.110 P ¼ 0.045 r ¼ 0.136 P ¼ 0.013 r ¼ 0.133 P ¼ 0.015
Hand Chest
r ¼ 0.109 P ¼ 0.047
Arm Note: Only the significant correlations (P < 0.05) are presented. Abbreviation: TMJ, temporomandibular joint.
r ¼ 0.120 P ¼ 0.028 r ¼ 0.189 P ¼ 0.001 r ¼ 0.139 P ¼ 0.011 r ¼ 0.185 P ¼ 0.001 r ¼ 0.408 P < 0.001
r ¼ 0.123 P ¼ 0.025 r ¼ 0.192 P < 0.001
r ¼ 0.123 P ¼ 0.024
r ¼ 0.136 P ¼ 0.013 r ¼ 0.133 P ¼ 0.016 r ¼ 0.110 P ¼ 0.045 r ¼ 0.140 P ¼ 0.011 r ¼ 0.108 P ¼ 0.049 r ¼ 0.112 P ¼ 0.041 r ¼ 0.112 P ¼ 0.041
r ¼ 0.253 P < 0.001
r ¼ 0.365 P < 0.001
r ¼ 0.154 P ¼ 0.005 r ¼ 0.180 P ¼ 0.001 r ¼ 0.210 P < 0.001 r ¼ 0.184 P ¼ 0.001 r ¼ 0.178 P ¼ 0.001
r ¼ 0.110 P ¼ 0.045 r ¼ 0.148 P ¼ 0.007 r ¼ 0.185 P ¼ 0.001 r ¼ 0.181 P ¼ 0.001 r ¼ 0.123 P ¼ 0.025 r ¼ 0.204 P < 0.001 r ¼ 0.180 P ¼ 0.001
Lump
r ¼ 0.128 P ¼ 0.019 r ¼ 0.267 P < 0.001
r ¼ 0.108 P ¼ 0.049 r ¼ 0.149 P ¼ 0.006 r ¼ 0.162 P ¼ 0.003
r ¼ 0.135 P ¼ 0.013
Anke Luyten, et al
7
Vocal Tract Discomfort in the Flemish Population
perceptual and objective assessment of voice quality was not included in the present study, although it would have been useful to determine the absence of voice disorders more accurately. Finally, the current Flemish sample was relatively young (mean age 30 years). Considering the high prevalence of voice disorders in the elderly population,13 further research should focus on the prevalence of VTD symptoms in older people. CONCLUSIONS In conclusion, a relatively high prevalence of VTD symptoms is present in the Flemish population, although the occurrence frequency and severity are overall rather low. Vocal load seems to influence the frequency and severity of VTD. Considering that the VTD scale showed low correlations with the VHI and Corporal Pain scale, the VTD scale might reveal valuable extra information when used during voice consultations in addition to the VHI. REFERENCES 1. The WHOQOL Group. The World Health Organization Quality of Life Assessment (WHOQOL): development and general psychometric properties. Soc Sci Med. 1998;46:1569–1585. 2. International Association for the Study of Pain, Vol 2015. Wachington D.C., USA: IASP Taxonomy; 2012. 3. Oxford Dictionaries. Discomfort, Vol 2015. Oxford: Oxford University Press; 2015. 4. Jacobson BH, Johnson A, Grywalski C, Silbergleit A, Jacobson G, Benninger MS. The Voice Handicap Index (VHI): development and validation. Am J Speech-Lang Pathol. 1997;6:66–70. 5. Mathieson L, Hirani SP, Epstein R, Baken RJ, Wood G, Rubin JS. Laryngeal manual therapy: a preliminary study to examine its treatment effects in the management of muscle tension dysphonia. J voice. 2009;23:353–366. 6. Rodrigues G, Zambon F, Mathieson L, Behlau M. Vocal tract discomfort in teachers: its relationship to self-reported voice disorders. J Voice. 2013;27: 473–480. 7. Woznicka E, Niebudek-Bogusz E, Kwiecien J, Wiktorowicz J, SliwinskaKowalska M. Applicability of the vocal tract discomfort (VTD) scale in evaluating the effects of voice therapy of occupational voice disorders. Med Pr. 2012;63:141–152. 8. Lopes LW, Cabral GF, Figueiredo de Almeida AA. Vocal tract discomfort symptoms in patients with different voice disorders. J Voice. 2014;29: 317–323. 9. Van Lierde KM, D’Haeseleer E, Wuyts FL, et al. The objective vocal quality, vocal risk factors, vocal complaints, and corporal pain in Dutch female students training to be speech-language pathologists during the 4 years of study. J Voice. 2010;24:592–598. 10. Schneider-Stickler B, Knell C, Aichstill B, Jocher W. Biofeedback on voice use in call center agents in order to prevent occupational voice disorders. J Voice. 2012;26:51–62. 11. Martins RH, Pereira ER, Hidalgo CB, Tavares EL. Voice disorders in teachers. A review. J Voice. 2014;28:716–724. 12. Byeon H. Relationships among smoking, organic and functional voice disorders in Korean general population. J Voice. 2014;29:312–316. 13. Golub JS, Chen PH, Otto KJ, Hapner E, Johns MM. Prevalence of perceived dysphonia in a geriatric population. J Am Geriatr Soc. 2006;54:1736–1739.
APPENDIX 1 Dutch translation of Vocal Tract Discomfort scale Gelieve bij elk van de onderstaande gewaarwordingen aan te geven hoe frequent deze ervaring voorkomt en in welke mate u deze ervaart. Hieronder vindt u enige uitleg over de door ons gebruikte begrippen. Branderig: gloeiend en ontstoken Geknepen: spanning ter hoogte van de keel Droog: schurend Zeurende pijn: continue, doffe, oppervlakkige pijn Kriebelend: tintelend gevoel dat niet overgaat bij het stemgeven of hoesten Stekende pijn: plots opkomende pijn bij het stemgeven of bij het aanraken van de keel Ge€ırriteerd: prikkelend, warm Globusgevoel: gevoel van een ‘‘brok in de keel’’ waardoor men de neiging heeft te hoesten, de keel te schrapen of te slikken
Frequentie van voorkomen waarbij: 0 ¼ nooit 1 ¼ zelden 2 ¼ soms 3 ¼ meer dan soms 4 ¼ vaak 5 ¼ heel vaak 6 ¼ altijd Hoe hoger het cijfer, hoe hoger de frequentie
Branderig Geknepen Droog Zeurende pijn Kriebelend Stekende pijn Ge€ırriteerd Globusgevoel
0123456 0123456 0123456 0123456 0123456 0123456 0123456 0123456
Intensiteit van voorkomen waarbij: 0 ¼ geen gewaarwording 1 ¼ bijna geen gewaarwording 2 ¼ geringe gewaarwording 3 ¼ meer dan geringe gewaarwording 4 ¼ matige gewaarwording 5 ¼ meer dan matige gewaarwording 6 ¼ ernstige gewaarwording Hoe hoger het cijfer, hoe hoger de intensiteit 0123456 0123456 0123456 0123456 0123456 0123456 0123456 0123456
