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Cutoff Point at Voice Handicap Index Used to Screen Voice Disorders Among Persian Speakers
Cutoff Point at Voice Handicap Index Used to Screen Voice Disorders Among Persian Speakers *Negin Moradi, †Abbas Pourshahbaz, ‡Majid Soltani, and ‡Shiva Javadipour, *yTehran, zAhvaz, Iran Summary: Purpose. This study aimed to determine the cutoff point at Voice Handicap Index (VHI) as a diagnostic tool in the process of voice disorder assessment. It further surveyed a correlation between diagnosis made by speech specialist and a corresponding opinion reported by client on the existence/nonexistence of any voice disorder. Method. A sample of 160 individuals who completed the VHI questionnaire were assigned to clinical and nonclinical groups. They were asked about the opinions of their voices on a Likert scale. Results. A correlation was found between the specialists’ diagnosis and clients’ opinion on their own voices (r ¼ 0.882); however, this was reduced (r ¼ 0.717) when a mild voice disorder existed among the nonclinical group. The cutoff point, at which VHI sensitivity (for screening subjects with and without normal voices) reached its maximal value (92%) and its highest level of specificity (95%), was observed to be 14.5. Conclusion. Occasional incompatibility between specialists’ diagnoses and that of clients’ opinion about existence/ nonexistence of voice disorders within the individuals should be considered significant. Also, a score of 14.5 can be accepted as the cutoff point at VHI (Persian version) in the voice disorder assessment process. Key Words: Screening tool for voice disorder–Voice Handicap Index–Voice assessment–Persian. INTRODUCTION Although traditional voice disorder assessment procedures, including acoustic, aerodynamic, videostroboscopic, and perceptual assessments, can help in clarifying the nature of voice disorders, they do not provide any information about the effects these may leave on an individuals’ quality of life.1,2 The World Health Organization emphasizes on improving the quality of life as a treatment outcome.1 Thus, it is highly recommended to administer a complete and comprehensive assessment of the impairment, and of the resulting disability and handicap in patients with voice disorder.3 One of the most widely used instruments available in the field is5 the Voice Handicap Index (VHI) developed by Jacobson et al4 in 1997. It is used to evaluate the perceived disability resulting from dysphonia in individuals. The VHI questionnaire consists of three components, namely ‘‘Functional,’’ ‘‘Physical,’’ and ‘‘Emotional.’’ Each component contains 10 items, and each of the overall 30 items of the questionnaire is responded by a rating scale of five, graded from zero to four (never to always).4 The VHI questionnaire has been translated into many languages including Persian (or Farsi—the native language in Iran), and its validity, reliability, and sensitivity have been studied among patients with voice disorders1,2,6–22; a review of the previous studies reveals that the VHI questionnaire can be used as a screening tool to differentiate people with voice disorder from those with normal voice23; nevertheless, according to the authors of this article, the cutoff point for screening purposes has been estimated to be 12 only by the use of the Polish version of VHI.23 In a study
Accepted for publication August 16, 2012. From the *Department of Speech Therapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran; yDepartment of Clinical Psychology, University of Social Welfare & Rehabilitation Sciences, Tehran, Iran; and the zMusculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Address correspondence and reprint requests to Abbas Pourshahbaz, Department of Clinical Psychology, University of Social Welfare & Rehabilitation Sciences, Daneshju Boulvard, Daneshgah Square, Velenjak, Tehran, Iran. E-mail: [email protected] Journal of Voice, Vol. 27, No. 1, pp. 130.e1-130.e5 0892-1997/$36.00 Ó 2013 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2012.08.007
by Jacobson et al,4 the cutoff point of 30 was obtained when it was attempted to use the 30-items questionnaire to identify the people with healthy voice and those with mild voice disorder. The literature review indicates that the VHI has been used in so many occasions to differentiate individuals with disordered and healthy voices in two forms. Some studies such as those reported by Niebudek-Bogusz et al23 in 2011 directly applied VHI to distinguish dysphonic patients from individuals with normal voice using the obtained cutoff point. Similarly, Ohlsson and Dotevall17 in 2009 clearly reported that the Swedish version of VHI could distinguish between dysphonic and control subjects; nonetheless, the authors could not extract the definite cutoff point owing to the limited number of control subjects in their study. They just estimated that 20 points or less could be an approximate cutoff point. However, in studying the validity of VHI, Jacobson et al4 and many others surveyed how VHI distinguished between individuals with healthy and dysfunctional voices and found the significant differences between these individuals. These authors have put emphasis on the diagnostic capability of VHI as an important aspect of the questionnaire in the trend of clinical validity assessment.2,4,6,8–22 To put the emphasis on the individual’s perception of their own voice served as an intention to survey the correlation between a perceived vocal condition and a reciprocal diagnosis for whether or not any voice disorder existed. Usually, the two terms ‘‘sign’’ and ‘‘symptom’’ are used in the related literature to examine the presence or the lack of any vocal disorder, and these two concepts have an important role in the diagnostic process. In fact, the ‘‘symptom’’ is what the clients complain about and how they report the pertaining characteristics,24 which in turn may be a true or a false belief25; but the ‘‘sign’’ connotes the visible and tangible features of the voice evaluated by a specialist24 aimed to find the cause of the disorder.25 Both the therapist and the patient may sometimes show an agreement on the presence of a voice disorder and both compromise on the necessity of treatment. Another condition is that of a disagreement between the two when the client denies the presence of
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a vocal disorder and/or vice versa. A variety of the situations that may occur in relation to the ‘‘sign’’ and ‘‘symptom’’ can affect the treatment process.25 Thus, any attempt to examine a relationship between perceived own voice condition and a compatible diagnosis may lead to a better understanding of the nature of the present problem, of a true diagnosis, and the enhancement of the interactions between the two sides in the diagnosis and treatment processes. Hence, the first objective of this study was to evaluate the correlation between the therapist’s and patient’s opinion about the existence/nonexistence of a voice disorder. The second goal can be explained as follows: although the study of the ‘‘construct validity’’ is essential for every psychometry intervention, this cannot be a sufficient clue to make the decision on using a tool toward a specific purpose or in clinical application, and, therefore, the term ‘‘clinical utility’’ may be substituted. The study on ‘‘clinical utility’’ determines whether a new tool can help with the increase in the accuracy of a diagnosis, case identification, prediction of a risky behavior, and the estimates of a real-life performance. ‘‘Sensitivity’’ and ‘‘specificity’’ can be mentioned as two important aspects of ‘‘clinical utility’’ of every instrument. Sensitivity is defined as the ability of a test to correctly diagnose a disorder.26 In fact, sensitivity is the probability that someone with a particular attitude will be appropriately diagnosed by a special assessment.27 Specificity is defined as the ability of a test in making correct diagnosis of the individuals without any disorder,26 that is, the likelihood of what a person without a specific attitude will be diagnosed by a specific assessment tool; or a proportion of negative cases that are well diagnosed by an assessment tool.27 The cutoff point can be determined based on the two indicators of ‘‘sensitivity’’ and ‘‘specificity’’ both of which are used in screening and clinical programs; furthermore, one of the assessment methods of clinical utility based on ‘‘sensitivity’’ and ‘‘specificity’’ of the instrument includes using the ‘‘receiver operating characteristics’’ (ROC) curve. The ROC curve represents the relationship between ‘‘sensitivity’’ and ‘‘specificity’’ of a test, and it is a simple analytical procedure to determine the best-fitted and real cutoff point and to compare the results of two administered tests.26 A second objective of this study was to determine the cutoff point in differentiating the dysphonic from healthy individuals. METHODS Subjects who participated in this study were selected from the self-referral clients to both otorhinolaryngology clinic and other clinics in the Rasoul-e-Akram Hospital in Tehran. Given the medical examinations by an otorhinolaryngologist and a speech and language pathologist in the referred clinic, these were allocated to two groups of individuals with and without a voice disorder. None of the experts were aware of the particulars and the chief complaints in the referrals before the medical examinations. The three stages of data collection procedure At the first stage, all participants were asked to give their opinion about their voices individually through a Likert form. Here,
130.e2
the examiner addressed them simply with this same instruction: ‘‘would you please give your opinion about your voice by using this self-assessment scale?’’ and continued to explain the scale and the way of responding to it. This self-assessment scale had four items that were scored as follows: ‘‘0 represented normal voice, 1 represented mild voice disorder, 2 represented moderate voice disorder, and 3 represented severe voice disorder.’’ In this way, they mentioned their opinion about the existence or nonexistence of a voice disorder as a possible symptom that could be reported by a client. At the second stage, in accordance with the written instruction of the VHI (Persian version), all individuals filled in the questionnaire without any help or additional explanation by the examiner. The questionnaire instruction was as thus: ‘‘These are the statements that many people have used to describe their voices and the effects of their voices on their lives. Choose the response that indicates how frequently you have the same experience.’’ Although the time limitation was not the case, the required time for the questionnaire completion was expected to be approximately 10 minutes. The two above-mentioned stages took place in a quiet room outside of the otorhinolaryngology clinic. At the third stage, an otorhinolaryngologist and a speech and language pathologist were asked to evaluate the subjects’ voice by using a comprehensive voice assessment form. This form comprised the components of a medical history; an oral examination; and the perceptual, acoustic, and respiratory assessments. They also performed videostroboscopy. In fact, the experts’ opinion about the existence or nonexistence of the voice disorder as a sign was determined by the common process of voice assessment in the voice clinics. Videostroboscopy and other voice assessment tools were complementary to each other in differentiating nonclinical and clinical groups. The specialists confirmed that no one was found to be with normal voice condition when the videostroboscopy was used as an assessment tool; however, the opposite condition was observed when the other voice assessment instruments were used and vice versa. It is necessary to mention that the participants were diagnosed as either normal or a patient when both experts concurred on this. Finally, the participants in this study were assigned into two groups namely normal and patient considering the diagnoses made by the specialists. The patient group was divideded into four subgroups based on the videostroboscopic findings. The subgroup 1 (ie, neurogenic) included patients with unilateral and bilateral vocal fold paralysis and spasmodic dysphonia (ie, adductor, abductor, and mixed). The subgroup 2 (ie, mass lesion) consisted of patients with unilateral or bilateral nodules, polyps, and cysts. Patients with chronic laryngitis because of ‘‘reflux laryngitis,’’ ‘‘Reinke’s edema,’’ and ‘‘overused laryngitis’’ were included in the inflammatory subgroup 3. The subgroup 4 (ie, functional) included patients with hypokinetic and muscle tension dysphonia and with normal larynx structure. All the participants went through the aforementioned three stages sequentially within a day. At the end of the above-mentioned stages, some participants were excluded from the study for some reasons, such
130.e3 as withdrawal from the questionnaire completion or from going through the whole three stages of the study. Eventually, the group with voice disorders included 80 patients with dysphonia (40 males and 40 females), aged between 18 and 82 years and with a mean age of 44.4 ± 14.5 years. They were allocated to the groups 1–4 based on videostroboscopic findings. There were 80 subjects (40 males and 40 females) in the normal group who had no history of voice or speech therapy. The mean age of the participants without voice disorders was 44.1 ± 11.7 years (range: 18–75). According to the reports by otorhinolaryngologist and speech and language pathologist, they did not have voice disorders; and based on the videostroboscopic findings, no problem was observed in their laryngeal structure and function. Normal cognitive function was an inclusion criterion for the participants in this study. All the subjects signed a written consent for their participation in the study. The participants were assured that their personal particulars would remain confidential both during and after the research. Statistical analysis The Kolmogorov-Smirnov test was used to examine the normality of data distribution. The statistical analysis was performed to determine total VHI scores in participants with normal voice, and with mild, moderate, and severe voice disorder based on the self-assessment scale. Regarding the first purpose of the study, the correlation between the experts’ and participants’ assessment of the existence/nonexistence of voice disorder led the group assignment procedure toward two forms: in the first, the subjects who evaluated their voice as 0 on the self-assessment scale were considered as a healthy voice group and the other subjects were included in the voice disorder group. And again, a score of 0 was interpreted as nonexistence, and the scores 1, 2, and 3 was interpreted as the existence of a voice disorder. In the second form, the subjects who marked their voices as normal or saw a mild voice disorder in themselves and registered the scores of 0 or 1 on the Likert scale were assigned to the normal group and the others were assigned to the voice disorder group. In other words, the scores of 0 and 1, reported by the participants on the self-assessment scale, were considered as indicating a lack of the voice disorder and the scores of 2 and 3 illustrated the existence of voice disorder. Overall, the Spearman’s test was used to analyze the correlation between specialists’ and participants’ separate assessments given in the both forms. To meet the second purpose of the study, the ROC curve test was used to study the ‘‘clinical utility’’ of the VHI questionnaire based on its ‘‘sensitivity’’ and ‘‘specificity.’’ Given the fact that the quality of life related to voice is not correlated with sex,26 the cutoff point was not calculated for men and women separately. The Statistical Package for Social Sciences program, version 16.0, (SPSS Inc., Chicago, IL) was used to run the statistical
Journal of Voice, Vol. 27, No. 1, 2013
analyses. The significance level of the derived data was considered as <0.05. RESULTS The research data distribution by the Kolmogorov-Smirnov statistical test was not normal. Table 1 illustrates the mean and standard deviation of the total VHI scores in the participants with normal voice, and those with mild, moderate, and severe voice disorder. The Spearman test results showed that, although the data interpretation of the patients’ voice self-assessment for ¼ 0 and ¼ 1 was, respectively normal and abnormal (ie, mild, moderate, and severe), a correlation was found between the patients’ self-assessment and that of the specialists’ assessment (r ¼ 0.882). Although the patients’ voice self-assessment showed as: ¼ 0 (ie, normal and mild) and ¼ 1 (ie, moderately or severely abnormal), it was indicated to be a correlation between the specialists’ and the patients’ voice assessment, yet with less correlation than the former (r ¼ 0.717). Based on the specialists’ diagnoses regarding the existence/ nonexistence of the voice disorders, the ROC curve test determined the cutoff point at VHI as equal to 14.5, with 0.92 sensitivity and 0.95 specificity (Figure 1). DISCUSSION Given the importance of the two concepts of ‘‘symptom’’ and ‘‘sign’’ in the diagnostic process of voice disorders, the first purpose of this study was to evaluate the correlation between the specialists’ diagnoses and the patients’ voice self-assessment. The results showed a correlation between the specialists’ diagnoses and the patients’ voice self-assessment; however, the mild voice disorder observed in the normal group lowered the value levels within the correlation (r ¼ 0.717). Given the complicated nature of human voice, it seems that a multidimensional assessment of the voice and the pertaining evaluations made by both patients and the specialists hold special importance.24,27,28 Although it is not necessary to bring more findings from other sources into the stages of the current voice evaluation, but because the diagnoses made by the specialists cover only one aspect of the whole procedure, and as other studies have emphasized,29,30 the self-reports by the patients are of great importance in laryngological evaluation31,32 as a complementary component effective in the whole assessment process.25 The results of descriptive statistics showed that 35% of the participants reported their voices as normal, whereas the
TABLE 1. Mean Values and Standard Deviation for VHI Total Scale Scores as a Function of Self-Assessment Subject Normal Slight Moderate Severe
N (%)
Mean
Standard Deviation
56 (35) 33 (20.6) 39 (24.4) 32 (20)
5.5000 14.9697 33.7436 72.9063
2.48633 9.54425 12.09332 22.73743
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FIGURE 1. ROC curve. diagnoses made by the specialists state that 50% of the participants had normal voices. This suggests an occurrence of spontaneity irrelevant to outer conditions of the therapeutic context but rather within the clients. Usually, such dichotomy between ‘‘sign’’ and ‘‘symptom,’’ according to Aronson and Bless,25 can be attributed to an ‘‘overreaction’’ toward phenomena, which may indicate the presence of perfectionism, hostility, and de-
pression. Therefore, it appears that a psychological evaluation can be helpful or facilitating in the diagnostic process of voice disorder and, yet, can be effective in subsequent studies to evaluate the relationships between symptoms reported by the patients and the specialists’ diagnoses about the severity of the voice disorder. However, the incompatibility with the reports on the existence or nonexistence of voice disorder makes it necessary to use different self-assessment tools and apply different methods to investigate various symptoms. What a patient reports about the present problem and its characteristics must be registered completely because it can provide important and different information and can play a pertinent role in the diagnostic process. Nevertheless, the present study asked the participants to demonstrate whether or not a voice disorder exists in them. We did not have their opinion about the other symptoms. Hence, it is recommended to those researchers in the future who seek to investigate the relationships between the diagnosed as well as the perceived symptoms of the voice disorder to ask the subjects for what Colton et al24 in 2011 called as ‘‘common symptoms.’’ The second objective of this research was to study the ‘‘clinical utility’’ of VHI questionnaire. Hence, the relationship between ‘‘sensitivity’’ and ‘‘specificity’’ was examined and the needed cutoff point to distinguish the subjects with and without voice disorders was extracted. The cutoff point at the VHI questionnaire was equal to 14.5, and that, the ‘‘sensitivity’’ and ‘‘specificity’’ were at their highest values as 0.92 and 0.95. This means that by the score of 14.5 within a group comprising 100 subjects with
TABLE 2. Coordinates of the Curve Positive if Greater Than or Equal to 0.0000 1.000 2.5000 3.5000 4.5000 5.5000 6.5000 7.5000 8.5000 9.5000 10.5000 11.0000 12.0000 13.5000 14.5000 16.0000 17.5000 18.5000 19.5000 21.0000
Sensitivity
1-Specificity
Positive if Greater Than or Equal to*
1.000 0.962 0.962 0.962 0.962 0.962 0.962 0.962 0.962 0.962 0.950 0.950 0.925 0.925 0.912 0.900 0.888 0.875 0.850 0.825
1.000 0.988 0.925 0.875 0.750 0.688 0.612 0.400 0.312 0.262 0.213 0.150 0.075 0.062 0.050 0.050 0.037 0.037 0.037 0.025
23.0000 24.5000 26.5000 28.5000 30.0000 31.5000 33.0000 34.5000 36.0000 37.5000 38.5000 40.0000 41.5000 42.5000 43.5000 44.5000 45.5000 46.5000 47.5000 48.5000
Sensitivity 0.812 0.788 0.775 0.750 0.725 0.700 0.662 0.650 0.638 0.625 0.588 0.575 0.562 0.525 0.475 0.462 0.450 0.438 0.425 0.362
1-Specificity
Positive if Greater Than or Equal to
Sensitivity
1-Specificity
0.012 0.012 0.012 0.012 0.012 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
49.5000 50.5000 51.5000 52.5000 55.5000 59.0000 61.5000 65.5000 70.5000 73.5000 74.5000 76.5000 82.5000 88.0000 90.0000 92.0000 95.0000 100.0000 105.5000 108.0000
0.325 0.312 0.300 0.275 0.262 0.238 0.225 0.212 0.200 0.188 0.175 0.162 0.150 0.138 0.125 0.088 0.075 0.062 0.050 0.000
0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
The sensitivity and 1-specificity of the cutoff point of 14.5 in this study and the cutoff points of 30 and 12 obtained through the previous studies are highlighted with bold type.
130.e5 voice disorders, 92 individuals gained positive scores based on the VHI questionnaire and so they were diagnosed as patients, whereas 95 of 100 individuals in a group with normal voices obtained negative scores based on the VHI questionnaire and were diagnosed as healthy individuals. In this study, the cutoff point of 14.5 was compared with the cutoff points of 30 and 12 obtained through the previous studies,4,23 the sensitivity of VHI was respectively higher than (0.72) and lower than (0.92), and the specificity of VHI was respectively lower than (0.98) and higher than (0.92) (Table 2). For the future researches, it is proposed to consider the other aspects of clinical utility of VHI including the ‘‘incremental clinical utility’’ in the concept of incremental value of data in clinical judgment. This kind of clinical utility can demonstrate the degree to which acquired assessment data increase the power, sensitivity, specificity, and predictive efficacy of clinical judgment beyond that associated with other assessment data such as the signs reported by specialist and speech and language pathologist.27 CONCLUSIONS This study examined the correlation between the specialists’ diagnoses and the patients’ opinion. The results emphatically suggested that sometimes differences can be found between the physician’s diagnosis and the patient’s opinion about the existence or nonexistence of voice disorder. Given the other purpose of this study, it can be concluded that the score of 14.5 is considered as the cutoff point in the Persian version of the VHI questionnaire to distinguish individuals with and without voice disorders, and this score should be assumed to be a threshold for rating the handicap owing to the voice disorders. Therefore the VHI questionnaire can be used as a screening test in the research and clinical practice in Iran. Acknowledgment The authors are indebted to Mrs. Nahid Jalilevand, Head of Speech Therapy Department of the Faculty of Medical Sciences, Tehran University, for her invaluable assistance in this research. REFERENCES 1. Behlau M, Alves Dos Santos Lde M, Oliveira G. Cross-cultural adaptation and validation of the voice handicap index into Brazilian Portuguese. J Voice. 2009;25:354–359. 2. Schindler A, Ottaviani F, Mozzanica F, Bachmann C, Favero E, Schettino I, Ruoppolo G. Cross-cultural adaptation and validation of the voice handicap index into Italian. J Voice. 2009;24:708–714. 3. Gunther S, Rasch T, Klotz M, Hoppe U, Eysholdt U, Rosanowski F. Determination of the subjective impairment in dysphonia. A methodological comparison. HNO. 2005;53:895–900. 902–904. [Article in German]. 4. Jacobson BH, Johnson A, Grywalski C, Silbergleit A, Jacobson G, Benninger MS, Newman CW. The voice handicap index (VHI): development and validation. Am J Speech Lang Pathol. 1997;6:66–70. 5. Franic DM, Bramlett RE, Bothe AC. Psychometric evaluation of disease specific quality of life instruments in voice disorders. J Voice. 2005;19:300–315. 6. Datta R. Translation and validation of the voice handicap index (VHI) in Hindi. J Laryngol Voice. 2011;1:12–17. 7. Hakkesteegt MM, Wieringa MH, Gerritsma EJ, Feenstra L. Reproducibility of the Dutch version of the Voice Handicap Index. Folia Phoniatr Logop. 2006;58:132–138.
Journal of Voice, Vol. 27, No. 1, 2013 8. Helidoni ME, Murry T, Moschandreas J, Lionis C, Printza A, Velegrakis GA. Cross-cultural adaptation and validation of the Voice Handicap Index into Greek. J Voice. 2008;24:221–227. 9. Hsiung MW, Lu P, Kang BH, Wang HW. Measurement and validation of the voice handicap index in voice-disordered patients in Taiwan. J Laryngol Otol. 2003;117:478–481. 10. Kilic MA, Okur E, Yildirim I, et al. Reliability and validity of the Turkish version of the Voice Handicap Index. Kulak Burun Bogaz Ihtis Derg. 2008; 18:139–147 [Article in Turkish]. 11. Lam PK, Chan KM, Ho WK, Kwong E, Yiu EM, Wei WI. Cross-cultural adaptation and validation of the Chinese Voice Handicap Index-10. Laryngoscope. 2006;116:1192–1198. 12. Malki KH, Mesallam TA, Farahat M, Bukhari M, Murry T. Validation and cultural modification of Arabic voice handicap index. Eur Arch Otorhinolaryngol. 2010;267:1743–1751. 13. Nawka T, Wiesmann U, Gonnermann U. Validation of the German version of the Voice Handicap Index. HNO. 2003;51:921–930 [Article in German]. 14. Nunez-Batalla F, Corte-Santos P, Senaris-Gonzalez B, Llorente-Pendas JL, Gorriz-Gil C, Suarez-Nieto C. Adaptation and validation to the Spanish version of the Voice Handicap Index (VHI-30) and its shortened version (VHI-10). Acta Otorrinolaringol Esp. 2007;58:386–392 [Article in Spanish]. 15. Verdonck-de Leeuw IM, Kuik DJ, De Bodt M, et al. Validation of the voice handicap index by assessing equivalence of European translations. Folia Phoniatr Logop. 2008;60:173–178. 16. Moradi N, Pourshahbaz A, Soltani M, Javadipour S, Hashemi H, Soltaninejad N. Cross-cultural adaptation and validation of the voice handicap index into Persian. Presented at: Tenth Congress of Speech Therapy; Ahvaz Jundishapur University of Medical Sciences; Ahvaz, Iran, February 15–17, 2011. 17. Ohlsson AC, Dotevall H. Voice handicap index in Swedish. Logoped Phoniatr Vocol. 2009;34:60–66. 18. Woisard V, Bodin S, Puech M. The Voice Handicap Index: impact of the translation in French on the validation. Rev Laryngol Otol Rhinol (Bord). 2004;125:307–312 [Article in French]. 19. Guimaraes I, Abberton E. An investigation of the Voice Handicap Index with speakers of Portuguese: preliminary data. J Voice. 2004;18:71–82. 20. Pruszewicz A, Obrebowski A, Wiskirska-Woznica B, Wojnowski W. Complex voice assessment - Polish version of the Voice Handicap Index (VHI). Otolaryngol Pol. 2004;58:547–549 [Article in Polish]. 21. Rosen CA, Lee AS, Osborne J, Zullo T, Murry T. Development and validation of the voice handicap index 10. Laryngoscope. 2004;114:1549–1556. 22. Xu W, Han D, Li H, Hu R, Zhang L. Application of the Mandarin Chinese version of the Voice Handicap Index. J Voice. 2009;24:702–707. 23. Niebudek-Bogusz E, Kuzanska A, Woznicka E, Sliwinska-Kowalska M. Assessment of the voice handicap index as a screening tool in dysphonic patients. Folia Phoniatr Logop. 2011;63:269–272. 24. Colton RH, Casper JK, Leonard R. Understanding Voice Problems: A Physiological Perspective for Diagnosis and Treatment. 4th ed. Philadelphia: Lippincott; 2011. 25. Aronson AE, Bless DM. Clinical Voice Disorders. New York: Thieme; 2009. 26. Carter RE, Lubinsky J, Domholdt E. Rehabilitation Research: Principles and Applications. New York: Elsevier Saunders; 2000. 27. Kendall PC, Butcher JN, Holmbeck GN. Handbook of Research Methods in Clinical Psychology. New Jersey: J. Wiley & Sons; 1999. 28. Krischke S, Weigelt S, Hoppe U, Kollner V, Klotz M, Eysholdt U, Rosanowski F. Quality of life in dysphonic patients. J Voice. 2005;19:132–137. 29. Carding P, Wilson J, MacKenzie K, Deary I. Measuring voice outcomes: state of the science review. J Laryngol Otol. 2009;123:823–829. 30. Andrews ML. Manual of Voice Treatment: Pediatrics Through Geriatrics. New York: Thomson Delmar Learning; 2006. 31. Webb A, Carding P, Deary I, MacKenzie K, Steen I, Wilson J. Optimising outcome assessment of voice interventions. I: reliability and validity of three self-reported scales. J Laryngol Otol. 2007;121:763–767. 32. Steen I, MacKenzie K, Carding P, Webb A, Deary I, Wilson J. Optimising outcome assessment of voice interventions. II: sensitivity to change of selfreported and observer-rated measures. J Laryngol Otol. 2008;122:46–51.
Accepted for publication August 16, 2012. From the *Department of Speech Therapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran; yDepartment of Clinical Psychology, University of Social Welfare & Rehabilitation Sciences, Tehran, Iran; and the zMusculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Address correspondence and reprint requests to Abbas Pourshahbaz, Department of Clinical Psychology, University of Social Welfare & Rehabilitation Sciences, Daneshju Boulvard, Daneshgah Square, Velenjak, Tehran, Iran. E-mail: [email protected] Journal of Voice, Vol. 27, No. 1, pp. 130.e1-130.e5 0892-1997/$36.00 Ó 2013 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2012.08.007
by Jacobson et al,4 the cutoff point of 30 was obtained when it was attempted to use the 30-items questionnaire to identify the people with healthy voice and those with mild voice disorder. The literature review indicates that the VHI has been used in so many occasions to differentiate individuals with disordered and healthy voices in two forms. Some studies such as those reported by Niebudek-Bogusz et al23 in 2011 directly applied VHI to distinguish dysphonic patients from individuals with normal voice using the obtained cutoff point. Similarly, Ohlsson and Dotevall17 in 2009 clearly reported that the Swedish version of VHI could distinguish between dysphonic and control subjects; nonetheless, the authors could not extract the definite cutoff point owing to the limited number of control subjects in their study. They just estimated that 20 points or less could be an approximate cutoff point. However, in studying the validity of VHI, Jacobson et al4 and many others surveyed how VHI distinguished between individuals with healthy and dysfunctional voices and found the significant differences between these individuals. These authors have put emphasis on the diagnostic capability of VHI as an important aspect of the questionnaire in the trend of clinical validity assessment.2,4,6,8–22 To put the emphasis on the individual’s perception of their own voice served as an intention to survey the correlation between a perceived vocal condition and a reciprocal diagnosis for whether or not any voice disorder existed. Usually, the two terms ‘‘sign’’ and ‘‘symptom’’ are used in the related literature to examine the presence or the lack of any vocal disorder, and these two concepts have an important role in the diagnostic process. In fact, the ‘‘symptom’’ is what the clients complain about and how they report the pertaining characteristics,24 which in turn may be a true or a false belief25; but the ‘‘sign’’ connotes the visible and tangible features of the voice evaluated by a specialist24 aimed to find the cause of the disorder.25 Both the therapist and the patient may sometimes show an agreement on the presence of a voice disorder and both compromise on the necessity of treatment. Another condition is that of a disagreement between the two when the client denies the presence of
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a vocal disorder and/or vice versa. A variety of the situations that may occur in relation to the ‘‘sign’’ and ‘‘symptom’’ can affect the treatment process.25 Thus, any attempt to examine a relationship between perceived own voice condition and a compatible diagnosis may lead to a better understanding of the nature of the present problem, of a true diagnosis, and the enhancement of the interactions between the two sides in the diagnosis and treatment processes. Hence, the first objective of this study was to evaluate the correlation between the therapist’s and patient’s opinion about the existence/nonexistence of a voice disorder. The second goal can be explained as follows: although the study of the ‘‘construct validity’’ is essential for every psychometry intervention, this cannot be a sufficient clue to make the decision on using a tool toward a specific purpose or in clinical application, and, therefore, the term ‘‘clinical utility’’ may be substituted. The study on ‘‘clinical utility’’ determines whether a new tool can help with the increase in the accuracy of a diagnosis, case identification, prediction of a risky behavior, and the estimates of a real-life performance. ‘‘Sensitivity’’ and ‘‘specificity’’ can be mentioned as two important aspects of ‘‘clinical utility’’ of every instrument. Sensitivity is defined as the ability of a test to correctly diagnose a disorder.26 In fact, sensitivity is the probability that someone with a particular attitude will be appropriately diagnosed by a special assessment.27 Specificity is defined as the ability of a test in making correct diagnosis of the individuals without any disorder,26 that is, the likelihood of what a person without a specific attitude will be diagnosed by a specific assessment tool; or a proportion of negative cases that are well diagnosed by an assessment tool.27 The cutoff point can be determined based on the two indicators of ‘‘sensitivity’’ and ‘‘specificity’’ both of which are used in screening and clinical programs; furthermore, one of the assessment methods of clinical utility based on ‘‘sensitivity’’ and ‘‘specificity’’ of the instrument includes using the ‘‘receiver operating characteristics’’ (ROC) curve. The ROC curve represents the relationship between ‘‘sensitivity’’ and ‘‘specificity’’ of a test, and it is a simple analytical procedure to determine the best-fitted and real cutoff point and to compare the results of two administered tests.26 A second objective of this study was to determine the cutoff point in differentiating the dysphonic from healthy individuals. METHODS Subjects who participated in this study were selected from the self-referral clients to both otorhinolaryngology clinic and other clinics in the Rasoul-e-Akram Hospital in Tehran. Given the medical examinations by an otorhinolaryngologist and a speech and language pathologist in the referred clinic, these were allocated to two groups of individuals with and without a voice disorder. None of the experts were aware of the particulars and the chief complaints in the referrals before the medical examinations. The three stages of data collection procedure At the first stage, all participants were asked to give their opinion about their voices individually through a Likert form. Here,
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the examiner addressed them simply with this same instruction: ‘‘would you please give your opinion about your voice by using this self-assessment scale?’’ and continued to explain the scale and the way of responding to it. This self-assessment scale had four items that were scored as follows: ‘‘0 represented normal voice, 1 represented mild voice disorder, 2 represented moderate voice disorder, and 3 represented severe voice disorder.’’ In this way, they mentioned their opinion about the existence or nonexistence of a voice disorder as a possible symptom that could be reported by a client. At the second stage, in accordance with the written instruction of the VHI (Persian version), all individuals filled in the questionnaire without any help or additional explanation by the examiner. The questionnaire instruction was as thus: ‘‘These are the statements that many people have used to describe their voices and the effects of their voices on their lives. Choose the response that indicates how frequently you have the same experience.’’ Although the time limitation was not the case, the required time for the questionnaire completion was expected to be approximately 10 minutes. The two above-mentioned stages took place in a quiet room outside of the otorhinolaryngology clinic. At the third stage, an otorhinolaryngologist and a speech and language pathologist were asked to evaluate the subjects’ voice by using a comprehensive voice assessment form. This form comprised the components of a medical history; an oral examination; and the perceptual, acoustic, and respiratory assessments. They also performed videostroboscopy. In fact, the experts’ opinion about the existence or nonexistence of the voice disorder as a sign was determined by the common process of voice assessment in the voice clinics. Videostroboscopy and other voice assessment tools were complementary to each other in differentiating nonclinical and clinical groups. The specialists confirmed that no one was found to be with normal voice condition when the videostroboscopy was used as an assessment tool; however, the opposite condition was observed when the other voice assessment instruments were used and vice versa. It is necessary to mention that the participants were diagnosed as either normal or a patient when both experts concurred on this. Finally, the participants in this study were assigned into two groups namely normal and patient considering the diagnoses made by the specialists. The patient group was divideded into four subgroups based on the videostroboscopic findings. The subgroup 1 (ie, neurogenic) included patients with unilateral and bilateral vocal fold paralysis and spasmodic dysphonia (ie, adductor, abductor, and mixed). The subgroup 2 (ie, mass lesion) consisted of patients with unilateral or bilateral nodules, polyps, and cysts. Patients with chronic laryngitis because of ‘‘reflux laryngitis,’’ ‘‘Reinke’s edema,’’ and ‘‘overused laryngitis’’ were included in the inflammatory subgroup 3. The subgroup 4 (ie, functional) included patients with hypokinetic and muscle tension dysphonia and with normal larynx structure. All the participants went through the aforementioned three stages sequentially within a day. At the end of the above-mentioned stages, some participants were excluded from the study for some reasons, such
130.e3 as withdrawal from the questionnaire completion or from going through the whole three stages of the study. Eventually, the group with voice disorders included 80 patients with dysphonia (40 males and 40 females), aged between 18 and 82 years and with a mean age of 44.4 ± 14.5 years. They were allocated to the groups 1–4 based on videostroboscopic findings. There were 80 subjects (40 males and 40 females) in the normal group who had no history of voice or speech therapy. The mean age of the participants without voice disorders was 44.1 ± 11.7 years (range: 18–75). According to the reports by otorhinolaryngologist and speech and language pathologist, they did not have voice disorders; and based on the videostroboscopic findings, no problem was observed in their laryngeal structure and function. Normal cognitive function was an inclusion criterion for the participants in this study. All the subjects signed a written consent for their participation in the study. The participants were assured that their personal particulars would remain confidential both during and after the research. Statistical analysis The Kolmogorov-Smirnov test was used to examine the normality of data distribution. The statistical analysis was performed to determine total VHI scores in participants with normal voice, and with mild, moderate, and severe voice disorder based on the self-assessment scale. Regarding the first purpose of the study, the correlation between the experts’ and participants’ assessment of the existence/nonexistence of voice disorder led the group assignment procedure toward two forms: in the first, the subjects who evaluated their voice as 0 on the self-assessment scale were considered as a healthy voice group and the other subjects were included in the voice disorder group. And again, a score of 0 was interpreted as nonexistence, and the scores 1, 2, and 3 was interpreted as the existence of a voice disorder. In the second form, the subjects who marked their voices as normal or saw a mild voice disorder in themselves and registered the scores of 0 or 1 on the Likert scale were assigned to the normal group and the others were assigned to the voice disorder group. In other words, the scores of 0 and 1, reported by the participants on the self-assessment scale, were considered as indicating a lack of the voice disorder and the scores of 2 and 3 illustrated the existence of voice disorder. Overall, the Spearman’s test was used to analyze the correlation between specialists’ and participants’ separate assessments given in the both forms. To meet the second purpose of the study, the ROC curve test was used to study the ‘‘clinical utility’’ of the VHI questionnaire based on its ‘‘sensitivity’’ and ‘‘specificity.’’ Given the fact that the quality of life related to voice is not correlated with sex,26 the cutoff point was not calculated for men and women separately. The Statistical Package for Social Sciences program, version 16.0, (SPSS Inc., Chicago, IL) was used to run the statistical
Journal of Voice, Vol. 27, No. 1, 2013
analyses. The significance level of the derived data was considered as <0.05. RESULTS The research data distribution by the Kolmogorov-Smirnov statistical test was not normal. Table 1 illustrates the mean and standard deviation of the total VHI scores in the participants with normal voice, and those with mild, moderate, and severe voice disorder. The Spearman test results showed that, although the data interpretation of the patients’ voice self-assessment for ¼ 0 and ¼ 1 was, respectively normal and abnormal (ie, mild, moderate, and severe), a correlation was found between the patients’ self-assessment and that of the specialists’ assessment (r ¼ 0.882). Although the patients’ voice self-assessment showed as: ¼ 0 (ie, normal and mild) and ¼ 1 (ie, moderately or severely abnormal), it was indicated to be a correlation between the specialists’ and the patients’ voice assessment, yet with less correlation than the former (r ¼ 0.717). Based on the specialists’ diagnoses regarding the existence/ nonexistence of the voice disorders, the ROC curve test determined the cutoff point at VHI as equal to 14.5, with 0.92 sensitivity and 0.95 specificity (Figure 1). DISCUSSION Given the importance of the two concepts of ‘‘symptom’’ and ‘‘sign’’ in the diagnostic process of voice disorders, the first purpose of this study was to evaluate the correlation between the specialists’ diagnoses and the patients’ voice self-assessment. The results showed a correlation between the specialists’ diagnoses and the patients’ voice self-assessment; however, the mild voice disorder observed in the normal group lowered the value levels within the correlation (r ¼ 0.717). Given the complicated nature of human voice, it seems that a multidimensional assessment of the voice and the pertaining evaluations made by both patients and the specialists hold special importance.24,27,28 Although it is not necessary to bring more findings from other sources into the stages of the current voice evaluation, but because the diagnoses made by the specialists cover only one aspect of the whole procedure, and as other studies have emphasized,29,30 the self-reports by the patients are of great importance in laryngological evaluation31,32 as a complementary component effective in the whole assessment process.25 The results of descriptive statistics showed that 35% of the participants reported their voices as normal, whereas the
TABLE 1. Mean Values and Standard Deviation for VHI Total Scale Scores as a Function of Self-Assessment Subject Normal Slight Moderate Severe
N (%)
Mean
Standard Deviation
56 (35) 33 (20.6) 39 (24.4) 32 (20)
5.5000 14.9697 33.7436 72.9063
2.48633 9.54425 12.09332 22.73743
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FIGURE 1. ROC curve. diagnoses made by the specialists state that 50% of the participants had normal voices. This suggests an occurrence of spontaneity irrelevant to outer conditions of the therapeutic context but rather within the clients. Usually, such dichotomy between ‘‘sign’’ and ‘‘symptom,’’ according to Aronson and Bless,25 can be attributed to an ‘‘overreaction’’ toward phenomena, which may indicate the presence of perfectionism, hostility, and de-
pression. Therefore, it appears that a psychological evaluation can be helpful or facilitating in the diagnostic process of voice disorder and, yet, can be effective in subsequent studies to evaluate the relationships between symptoms reported by the patients and the specialists’ diagnoses about the severity of the voice disorder. However, the incompatibility with the reports on the existence or nonexistence of voice disorder makes it necessary to use different self-assessment tools and apply different methods to investigate various symptoms. What a patient reports about the present problem and its characteristics must be registered completely because it can provide important and different information and can play a pertinent role in the diagnostic process. Nevertheless, the present study asked the participants to demonstrate whether or not a voice disorder exists in them. We did not have their opinion about the other symptoms. Hence, it is recommended to those researchers in the future who seek to investigate the relationships between the diagnosed as well as the perceived symptoms of the voice disorder to ask the subjects for what Colton et al24 in 2011 called as ‘‘common symptoms.’’ The second objective of this research was to study the ‘‘clinical utility’’ of VHI questionnaire. Hence, the relationship between ‘‘sensitivity’’ and ‘‘specificity’’ was examined and the needed cutoff point to distinguish the subjects with and without voice disorders was extracted. The cutoff point at the VHI questionnaire was equal to 14.5, and that, the ‘‘sensitivity’’ and ‘‘specificity’’ were at their highest values as 0.92 and 0.95. This means that by the score of 14.5 within a group comprising 100 subjects with
TABLE 2. Coordinates of the Curve Positive if Greater Than or Equal to 0.0000 1.000 2.5000 3.5000 4.5000 5.5000 6.5000 7.5000 8.5000 9.5000 10.5000 11.0000 12.0000 13.5000 14.5000 16.0000 17.5000 18.5000 19.5000 21.0000
Sensitivity
1-Specificity
Positive if Greater Than or Equal to*
1.000 0.962 0.962 0.962 0.962 0.962 0.962 0.962 0.962 0.962 0.950 0.950 0.925 0.925 0.912 0.900 0.888 0.875 0.850 0.825
1.000 0.988 0.925 0.875 0.750 0.688 0.612 0.400 0.312 0.262 0.213 0.150 0.075 0.062 0.050 0.050 0.037 0.037 0.037 0.025
23.0000 24.5000 26.5000 28.5000 30.0000 31.5000 33.0000 34.5000 36.0000 37.5000 38.5000 40.0000 41.5000 42.5000 43.5000 44.5000 45.5000 46.5000 47.5000 48.5000
Sensitivity 0.812 0.788 0.775 0.750 0.725 0.700 0.662 0.650 0.638 0.625 0.588 0.575 0.562 0.525 0.475 0.462 0.450 0.438 0.425 0.362
1-Specificity
Positive if Greater Than or Equal to
Sensitivity
1-Specificity
0.012 0.012 0.012 0.012 0.012 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
49.5000 50.5000 51.5000 52.5000 55.5000 59.0000 61.5000 65.5000 70.5000 73.5000 74.5000 76.5000 82.5000 88.0000 90.0000 92.0000 95.0000 100.0000 105.5000 108.0000
0.325 0.312 0.300 0.275 0.262 0.238 0.225 0.212 0.200 0.188 0.175 0.162 0.150 0.138 0.125 0.088 0.075 0.062 0.050 0.000
0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
The sensitivity and 1-specificity of the cutoff point of 14.5 in this study and the cutoff points of 30 and 12 obtained through the previous studies are highlighted with bold type.
130.e5 voice disorders, 92 individuals gained positive scores based on the VHI questionnaire and so they were diagnosed as patients, whereas 95 of 100 individuals in a group with normal voices obtained negative scores based on the VHI questionnaire and were diagnosed as healthy individuals. In this study, the cutoff point of 14.5 was compared with the cutoff points of 30 and 12 obtained through the previous studies,4,23 the sensitivity of VHI was respectively higher than (0.72) and lower than (0.92), and the specificity of VHI was respectively lower than (0.98) and higher than (0.92) (Table 2). For the future researches, it is proposed to consider the other aspects of clinical utility of VHI including the ‘‘incremental clinical utility’’ in the concept of incremental value of data in clinical judgment. This kind of clinical utility can demonstrate the degree to which acquired assessment data increase the power, sensitivity, specificity, and predictive efficacy of clinical judgment beyond that associated with other assessment data such as the signs reported by specialist and speech and language pathologist.27 CONCLUSIONS This study examined the correlation between the specialists’ diagnoses and the patients’ opinion. The results emphatically suggested that sometimes differences can be found between the physician’s diagnosis and the patient’s opinion about the existence or nonexistence of voice disorder. Given the other purpose of this study, it can be concluded that the score of 14.5 is considered as the cutoff point in the Persian version of the VHI questionnaire to distinguish individuals with and without voice disorders, and this score should be assumed to be a threshold for rating the handicap owing to the voice disorders. Therefore the VHI questionnaire can be used as a screening test in the research and clinical practice in Iran. Acknowledgment The authors are indebted to Mrs. Nahid Jalilevand, Head of Speech Therapy Department of the Faculty of Medical Sciences, Tehran University, for her invaluable assistance in this research. REFERENCES 1. Behlau M, Alves Dos Santos Lde M, Oliveira G. Cross-cultural adaptation and validation of the voice handicap index into Brazilian Portuguese. J Voice. 2009;25:354–359. 2. Schindler A, Ottaviani F, Mozzanica F, Bachmann C, Favero E, Schettino I, Ruoppolo G. Cross-cultural adaptation and validation of the voice handicap index into Italian. J Voice. 2009;24:708–714. 3. Gunther S, Rasch T, Klotz M, Hoppe U, Eysholdt U, Rosanowski F. Determination of the subjective impairment in dysphonia. A methodological comparison. HNO. 2005;53:895–900. 902–904. [Article in German]. 4. Jacobson BH, Johnson A, Grywalski C, Silbergleit A, Jacobson G, Benninger MS, Newman CW. The voice handicap index (VHI): development and validation. Am J Speech Lang Pathol. 1997;6:66–70. 5. Franic DM, Bramlett RE, Bothe AC. Psychometric evaluation of disease specific quality of life instruments in voice disorders. J Voice. 2005;19:300–315. 6. Datta R. Translation and validation of the voice handicap index (VHI) in Hindi. J Laryngol Voice. 2011;1:12–17. 7. Hakkesteegt MM, Wieringa MH, Gerritsma EJ, Feenstra L. Reproducibility of the Dutch version of the Voice Handicap Index. Folia Phoniatr Logop. 2006;58:132–138.
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