Multiparameter Voice Assessment for Voice Disorder Patients: A Correlation Analysis Between Objective and Subjective Parameters Yu Ziwei, Pang Zheng, and Dong Pin, Shanghai, China Summary: Objective. The aim of this study was to establish a multiparameter voice assessment profile using objective multiparameter test and subjective voice quality assessment. Methods. We assessed 50 patients with voice disorders before and after operation. The assessment incorporates (1) subjective voice quality assessment, (2) patients’ self-assessment, and (3) objective acoustic analysis. The subjective voice quality assessment uses GRABS system to evaluates the grade of hoarseness (G), proposed by the Japanese Society for Logopedics and Phoniatrics. Patients’ self-assessment is modified based on the Chinese version of voice handicap index (VHI) scale, composed of functional (F), physiological (P), emotional (E) part, and a total score (T). The acoustical analysis evaluate the patients’ voice sample by voice analysis software ‘‘Dr. Speech’’. Three parameters, jitter (J), shimmer(S), and normalized noise energy (NNE), were taken in analysis. Results. We observed high correlations among subentries F, P, and the total score TvH of the VHI scale in patients’ subjective assessment. Parameter E does not correlate well with other assessed parameters. The Chinese version of VHI, which incorporate multifactors including age, education, and especially the cultural difference may account for the inconsistent correction in parameter E. In the objective acoustic analysis, high correlation among the three parameters J, S, and NNE is observed. Conclusion. Systemic assessment combining a subjective voice quality assessment, an objective acoustic analysis, and a self-assessment is helpful in clinical practice in the diagnosis and treatment for voice disorders. The E component in VHI scale assessment may not be a reliable parameter to evaluate treatment outcome. Key Words: Voice disorder–Subjective voice quality assessment–Self-assessment–Acoustic analysis.
INTRODUCTION Voice disorder is commonly seen in Otolaryngology patients. Disrupted voice function negatively impact patients’ psychology and social life, thereby affecting patients’ overall quality of life. In 1997, Jacobson1 proposed the voice handicap index (VHI) scale, a self-assessment approach, to evaluate the impact of voice disorders on patients’ physiological, social, and psychological functions. VHI score is widely used to evaluate patients’ quality of life under the condition of voice disorders. It is a self-evaluation of the degree of voice handicap and calculated as the sum of all questions (T) for the following three domains: functional (F), physiological (P), and emotional (E) components to evaluate the impact of voice disorders on patients’ physiological function, social self-adaptability, and emotional change. Self-assessment thus plays a key role in evaluating the degree of voice disorders and treatment outcomes. However, neither objective acoustical assessment nor morphologic assessment of laryngoscope can reflect patients’ feeling of voice disorders on their lives, work and social activities, or the impact of voice disorders on mental health. Lam et al2,3 reported formal testing of reliability and validity of the Chinese Hong Kong version of the VHI scale. Recently, Accepted for publication March 20, 2014. From the Department of Otolaryngology, Head and Neck Surgery, Shanghai Jiaotong University Affiliated First People’s Hospital, Shanghai, 200080, China. Address correspondence and reprint requests to Yu Ziwei, Department of Otolaryngology, Head and Neck Surgery, Shanghai Jiaotong University Affiliated First People’s Hospital, 100 Haining Road, Shanghai 200080, China. E-mail: [email protected] Journal of Voice, Vol. 28, No. 6, pp. 770-774 0892-1997/$36.00 Ó 2014 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2014.03.014
Xu et al4 reported their work on the Chinese edition of VHI scale, showing good reliability and validity in assessment. In China, the severity of voice disorder, evaluated in determining therapeutic effect and prognosis, has only recently been adopted by medical doctors. The assessment is based on the doctors’ subjective opinion by hearing patients’ voice. Such judgment is individual doctor-dependent, may lack a good reproducibility. With the development of computer-based assessment and medical research of voice, the objective voice detection methods are now available. These objective methods are designed primarily on voice detection of acoustics, aerodynamics, and physiological parameters. Auditory Perceptual Evaluation of Voice primarily used in clinical settings is the most direct judgment used by clinical physicians and other professionals in evaluating patients’ voice quality. The Auditory Perceptual Evaluation of Voice are mainly based on two criteria: (1) the GRBAS scale (grade, roughness, breathiness, asthenia, and strain scale), proposed by the Japanese Society for Logopedics and Phoniatrics and (2) the CAPE-V scale, proposed by the American Speech–Language–Hearing Association. The GRBAS scale is the most widely accepted scale for voice evaluation in clinics worldwide.5–7 In China, subjective evaluations are the prevailing method and used only in large hospitals. The outcomes largely depend on doctors’ clinical experience and assessment skills. The integrated use of various test parameters to assess (quantify) the quality of voice is still a debated yet important topic in clinical practice. Thus, the purpose of this study was to establish a multiparameter voice assessment method to improve voice quality evaluation.
Yu Ziwei, et al
771
Objective and Subjective Analysis for Voice Disorder Patients
METHODS Patients and therapeutic methods Fifty voice disorder patients were included in the study from the period of June 2010 to October 2011. All patients were admitted to the Department of Otolaryngology, Head and Neck Surgery, Shanghai Jiao Tong University Affiliated First People’s Hospital. The average age of patients is 47.08 ± 3.94 (standard deviation) years (range 25–70 years). Patients were diagnosed of vocal fold polyp (n ¼ 32), vocal fold nodule (n ¼ 5), vocal fold leukoplakia (n ¼ 5), vocal fold cyst (n ¼ 5), and vocal fold Reinke edema (n ¼ 3). For each patient, the removal of vocal fold lesion was performed under selfretaining laryngoscope, and inhalation treatment of Pulmicort Respules (AstraZeneca Pty Ltd.) was applied for 1 week after surgery. Instruments and voice assessment methods Subjective voice quality assessment. All sound measurements were recorded in the acoustic room with a highfidelity audio equipment (digital audio tapes). The distance between mouth and microphone was 10 cm. Each patient was asked to read an assigned sentence in his/her natural tone and loudness. The recorded materials from the digital audio tapes were then transferred to a computer. Three doctors were assigned to independently evaluate the voice quality. According to the grade of hoarseness (G) in GRABS system proposed by the Japanese Society for Logopedics and Phoniatrics, the voice quality was rated into one of four levels: 0 for normal voice, l for mild hoarseness, 2 for moderate hoarseness, and 3 for severe hoarseness. To minimize the assessment difference among the three doctors, thereby increasing the credibility of assessment results, each doctor was trained to recognize typical sound samples, and the subjects’ samples were also randomly arranged and presented to a given doctor three times. Each sound sample was thus assessed three times per doctor and then averaged. Self-assessment. On the VHI scale, the impact of voice disorder on patients’ quality of life is based on the assessment of functional (F), physiological (P), and emotional (E) components. The total score of the three components is T and to separate from the impact of E, sum of F and P is used as TvH (TvH ¼ F + P). Each component is evaluated based on 10 questions. Patients were asked to rate each question based on the frequency of occurrence: 0 for never, 1 for seldom, 2 for sometimes, 3 for regularly, and 4 for always. The score of each component range from 0 to 40, and the total score (T) is from 0 to 120. A higher score on a particular component indicates a greater impact of the voice disorder on this aspect for the patient; a higher total score means a worse self-recognition of the patient on voice disorder. Acoustic analysis. Acoustic test was conducted in an acoustic room. A microphone was placed 10 cm away from patients’ mouth. Subjects were then asked to pronounce the vowel /a/ for 3 seconds. Sound samples were recorded and then transferred into the computer for analysis using the voice analysis software. Acoustic analysis was conducted under the voice analysis
computer system (Tiger Electronics Co., Ltd) using the software Dr. Speech windows, version 4.0.8 Three parameters were selected for analysis: jitter (J, cycle-to-cycle variation in frequency), shimmer (S, cycle-to-cycle variation in intensity), and normalized noise energy (NNE, relative level of vocal noise to that of harmonics). Statistical analysis Matched t test was performed to analyze the differences between preoperation and postsurgery. Spearman correlation was carried out to analyze the correlations among the parameters. All data analyses were performed with SPSS version 13.0 (SPSS, Chicago, IL). RESULTS VHI scale assessment and acoustic analysis The results of VHI scale assessment and acoustic analysis show that both self-assessment and acoustic index significantly decreased 1 week after surgery (P < 0.01) compared with preoperative (Table 1). Correlation analysis of subentries on VHI scale Table 2 shows the correlation analysis results of selfassessment. Both before and after surgery, there were significantly strong positive correlations between F, P, and the sum TvH (TvH ¼ P + F). Preoperatively, the Spearman correlation
TABLE 1. Comparison of VHI Parameters and Acoustic Analysis Preoperative and 1 Week After Surgery (Mean ± Standard Deviation)
Variable VHI parameters P F E T Acoustic analysis J S NNE
P Value
Preoperative
Postoperative
21.43 ± 3.24 11.29 ± 1.76 2.85 ± 1.44 36.95 ± 3.05
4.02 ± 1.53 3.77 ± 1.63 1.54 ± 0.58 8.02 ± 1.94
0.008 0.007 0.007 0.008
0.82 ± 0.31 4.58 ± 0.14 4.88 ± 2.13
0.19 ± 0.22 1.42 ± 0.50 12.95 ± 2.01
0.005 0.005 0.006
All subentry P, F, E, and T scores of VHI were significantly reduced 1 week after surgery (P < 0.01), and J, S, and NNE of acoustic analysis were significantly reduced 1 week after surgery (P < 0.01).
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TABLE 2. Spearman Correlations Among Subentries of VHI Scale Preoperative Spearman Coefficient VHI Parameter F E T TvH
P
F
E
0.843* 0.282 0.552 0.931*
1.000 0.340 0.482 0.894*
1.000 0.283 0.262
Postoperative Spearman Coefficient T
P
F
E
T
1.000 0.356
0.821* 0.195 0.610 0.897*
1.000 0.296 0.502 0.855*
1.000 0.277 0.301
1.000 0.364
* P < 0.01 for the test.
coefficient between P and F was 0.843, between P and TvH was 0.931, and between F and TvH was 0.894. Likewise, postoperatively, the Spearman correlation coefficient between P and F was 0.821, between P and TvH was 0.897, and between F and TvH was 0.855. However, E and T were not found in correlation with other index. This suggests that except for the emotional components, in both preoperative and 1 week after surgery, there were positive correlations among three subentries, that is, functional component, physiological component, and the total of these two parts.
Correlation analysis of parameters in acoustic analysis All three parameters in the acoustic analysis are strongly correlated (Table 3). The pre- and post-operative Spearman correlation coefficient between J and S was 0.751 and 0.812, respectively; correlation coefficient between J and NNE was 0.708 and 0.743, respectively; and correlation coefficient between S and NNE was 0.653 and 0.703, respectively. This indicates that, preoperative and 1 week after surgery, there were positive correlations among these three parameters, that is, J, S, and NNE.
Correlation analysis of subentries of VHI scale and parameters in acoustic analysis Results in Table 4 show that except for the emotional part, in both preoperative and 1 week after surgery, there were positive correlations among all other components: functional, physiological, total of these two parts and J, S, and NNE, but not between E and T. TABLE 3. Spearman Correlations Among Acoustic Parameters Preoperative Spearman Coefficient
Acoustic Parameters S NNE
Postoperative Spearman Coefficient
J
S
J
S
0.751* 0.708*
1.000 0.653*
0.812* 0.743*
1.000 0.703*
* P < 0.01 for the test.
Correlation analysis of subjective voice quality assessment, subentries of VHI scale, and parameters in acoustic analysis There were strong correlations between the grade of hoarseness (G) and F, P, and TvH of VHI scale as well as J, S, and NNE in acoustic analysis (Table 5). This indicates that with the exception of the emotional part, both preoperative and 1 week after surgery, there were positive correlations between the grade of hoarseness and subentries of VHI scale and parameters in acoustic analysis.
DISCUSSION Natural voice consists of various physical features. It is common to use auditory perceptual evaluation as a reference measure for evaluating objective assessments.9 The GRBAS system, developed by the Japanese Society for Logopedics and Phoniatrics, is the prevailing auditory perceptual assessment. In this study, we included auditory perceptual evaluation in our voice assessment. The grade of hoarseness (G)10 provided the most reliable and stable results. Our results suggest that G can well reflect the severity of voice disorders and serves as a surrogate to evaluate the severity of voice disorder, providing a good guidance for subsequent treatment. Acoustic analysis as a method for objective assessment of voice quality has been available in clinics. Parameter J in acoustic analysis reflects the changes in sonic basic frequency between the time point and the same time point of the adjacent cycle; S reflects changes in wave amplitudes between the point and the same time point of adjacent cycle; and NNE reflects the normalized noise energy due to the incomplete glottal closure. Specifically, J reflects the rough sound level; S reflects the hoarse sound level; and NNE reflects breath sound level, after the hoarse sound level. The selection of parameters in objective voice assessment should meet three fundamental principles: (1) must have pathophysiological significance and have some application ‘‘history’’; (2) changes in assessment results should be consistent with that in the severity of voice disorders; and (3) normal and unusual voice can be effectively defined by values of the parameters. In this study, J, S, and NNE were noticeably reduced 1 week after surgery compared with preoperative measurements. However, the clinical features, that is, rough voice, hoarse voice, and breath sounds, were reduced. These changes indicate that the voice quality in voice disorder patients was
Yu Ziwei, et al
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Objective and Subjective Analysis for Voice Disorder Patients
TABLE 4. Spearman Correlations Between VHI Scales and Acoustic Parameters Preoperative Spearman Coefficient VHI Scale P F E T TvH
Postoperative Spearman Coefficient
J
S
NNE
J
S
NNE
0.841* 0.835* 0.210 0.329 0.593*
0.873* 0.793* 0.243 0.531 0.775*
0.885* 0.680* 0.265 0.412 0.654*
0.834* 0.902* 0.181 0.527 0.766*
0.742* 0.834* 0.203 0.582 0.732*
0.728* 0.921* 0.295 0.423 0.848*
* P < 0.01 for the test.
noticeably improved after surgery. Therefore, acoustic analyses in this study provide objective quantification to evaluate surgical outcome. Voice disorders lead to psychological problem and social difficulty, thus affecting patients’ quality of life. Subjective assessment using the VHI provides information in this aspect and therefore serves as a complement to clinical and acoustic detection. VHI as the voice self-assessment method possesses a degree of complexity that far exceeds those of objective measures. Because of the diversity in personal factors, such as social status, profession, social status, family situations, personality, and so on, the impact of voice on patients’ life varies.11 In this study, the VHI scale was used as the tool for subjective assessment. Our original design planned to analyze the total of E, F, and P as T. The experimental results showed poor correlation between E and the other parameters. There were strong correlations among the remaining parameters only when E was excluded from the analysis, and the total of F and P was recorded as TvH. This suggests that the VHI scale, which based on the patient’s subjective experience on impact of their voice disorder, only effectively reflect the patients’ perception on the functional and physiological aspects of their life, work, and social activities. The assessment is likely biased because of the traditional culture of China, where people in general are reluctant to express their negative emotions selected a lower score. Therefore, we found no significant changes
TABLE 5. Spearman Correlations Between G and Both Subentries of VHI Scale and Acoustic Parameters
Parameters P F E TvH J S NNE * P < 0.01 for the test.
Preoperative_G Spearman Coefficient
Postoperative_G Spearman Coefficient
0.944* 0.973* 0.221 0.987* 0.918* 0.974* 0.929*
0.954* 0.920* 0.196 0.965* 0.939* 0.968* 0.972*
in emotional scores before and after surgery. Answers to the emotional component of the VHI scale are also affected by the patients’ age, occupation, education background, patient compliance, and so on.12,13 The Chinese version of the VHI scale should therefore be revised to accommodate the eastern culture background. We recommend that the emotional part should be modified to be in line with the characteristic of Asian culture. Voice is a complex multidimensional phenomenon; pathologic changes of vocal fold usually reduce the voice quality in multiple aspects. Single parameter comes short to assess the vocal function in both normal and abnormal conditions. Each available assessment method only evaluates one particular aspect of the laryngeal function. Voice assessment should therefore include multiple parameters.14,15 CONCLUSIONS In this study, we find that the assessment method is composed of subjective assessment, objective assessment, and a selfassessment helps to improve clinical diagnosis and treatment of voice disorders. The use of a multiparameter voice assessment method is particularly helpful in the assessment in (1) the severity of voice disorders preoperatively, (2) evaluation of the treatment outcome, (3) comparing the outcomes of different treatment methods, (4) dynamic observation of the development and prognosis of disease, and (5) in patient follow-up observations. Integrated use of subjective and objective assessments can systematically evaluate and compare patients’ voice quality pre- and post-operatively. The task in clinic is not only to remove lesions and clinically cure patients but also to care for patients’ physiological recovery and their social adaptabilities as well. The multiparameter methods will help doctors design treatment targets that are consistent with the patients’ subjective feelings and life requirements. The assessment method introduced in this work is expected to play an important role for voice disorder in surgery treatment, outcome assessment, and in follow-up assessment. Acknowledgments The authors thank Drs. Lei Song and Lingeng Lu for their critical review of the article. This study was supported by the National Natural Science Foundation of China (Grant No: 81170925).
774 REFERENCES 1. Jacobson BH, Johnson A, Grywalsi C, et al. The voice Handicap Index (VHI):development and validation [J]. Am J Speech Lang Pathol. 1997;6:66. 2. Lam PK, Chen KM, Ho WK, et al. Cross- cultural adaptation and validation of the Chinese voice handicap index-10 [J]. Laryngoscope. 2006;116:1192. 3. Hsiung MW, Lu P, Kang BH, et al. Measurement and validation of the voice handicap index in voice-disordered patients in Taiwan [J]. J Laryngol Otol. 2003;117:478. 4. Xu W, Han D, Li H, et al. Application of the Mandarin Chinese version of the Voice Handicap Index. J Voice. 2010;24:702–707. 5. Hirano M. Clinical examination of the voice. New York: Springer Verlag; 1981:81–84. 6. Kempster GB, Gerratt BR, Verdolini Abbott K, et al. Consensus auditoryperceptual evaluation of voice: development of a standardized clinical protocol. Am J Speech Lang Pathol. 2009;18:124–132. 7. Wuyt s FL, Bodt MS, Heyning PH. Is the reliability of a visual analog scale higher than an ordinal scale ? An experiment with the GRBAS scale for the perceptual evaluation of dysphonia [J]. J Voice. 1999;13:508. 8. Huang ZM, Minifie FD, Kasuya H, et al. Measure of vocal function during changes in vocal effort level [J]. J Voice. 1995;9:429–438.
Journal of Voice, Vol. 28, No. 6, 2014 9. Katsuhide I, Aliaa AK, Charles NF, et al. Correlation between vocal functions and glottal measurements in patients with unilateral vocal fold paralysis [J]. Laryngoscope. 1997;107:782. 10. Antoine G, Joana R, Jean-Michel T. Objective aerodynamic and acoustic measurement of voice improvement after phonosurgery. Laryngoscope. 1999;109:656. 11. Wheeler KM, Collins SP, Sapienza CM. The relationship between VHI scores and specific acoustic measures of mildly disordered voice production [J]. J Voice. 2006;20:308. 12. Guimaraes I, Abberton E. An investigation of the voice handicap index with speakers of Portuguese: preliminary data [J]. J Voice. 2004;18:71. 13. Zur KB, Cotton S, Kelchner L, et al. Pediatric voice handicap index: a new tool for evaluating pediatric dysphonia [J]. Int J Pediatr Otorhinolaryngol. 2007;71:77. 14. Wuyts FL, De Bodt MS, Molenberghs G, et al. The dysphonia severity index: an objective measure of vocal quality based on a multiparameter approach. J Speech Hear Res. 2000;43:796. 15. Katsuhide I, Aliaa AK, Charles NF, et al. Correlation between vocal functions and glottal measurements in patients with unilateral vocal fold paralysis. Laryngoscope. 1997;107:782.
INTRODUCTION Voice disorder is commonly seen in Otolaryngology patients. Disrupted voice function negatively impact patients’ psychology and social life, thereby affecting patients’ overall quality of life. In 1997, Jacobson1 proposed the voice handicap index (VHI) scale, a self-assessment approach, to evaluate the impact of voice disorders on patients’ physiological, social, and psychological functions. VHI score is widely used to evaluate patients’ quality of life under the condition of voice disorders. It is a self-evaluation of the degree of voice handicap and calculated as the sum of all questions (T) for the following three domains: functional (F), physiological (P), and emotional (E) components to evaluate the impact of voice disorders on patients’ physiological function, social self-adaptability, and emotional change. Self-assessment thus plays a key role in evaluating the degree of voice disorders and treatment outcomes. However, neither objective acoustical assessment nor morphologic assessment of laryngoscope can reflect patients’ feeling of voice disorders on their lives, work and social activities, or the impact of voice disorders on mental health. Lam et al2,3 reported formal testing of reliability and validity of the Chinese Hong Kong version of the VHI scale. Recently, Accepted for publication March 20, 2014. From the Department of Otolaryngology, Head and Neck Surgery, Shanghai Jiaotong University Affiliated First People’s Hospital, Shanghai, 200080, China. Address correspondence and reprint requests to Yu Ziwei, Department of Otolaryngology, Head and Neck Surgery, Shanghai Jiaotong University Affiliated First People’s Hospital, 100 Haining Road, Shanghai 200080, China. E-mail: [email protected] Journal of Voice, Vol. 28, No. 6, pp. 770-774 0892-1997/$36.00 Ó 2014 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2014.03.014
Xu et al4 reported their work on the Chinese edition of VHI scale, showing good reliability and validity in assessment. In China, the severity of voice disorder, evaluated in determining therapeutic effect and prognosis, has only recently been adopted by medical doctors. The assessment is based on the doctors’ subjective opinion by hearing patients’ voice. Such judgment is individual doctor-dependent, may lack a good reproducibility. With the development of computer-based assessment and medical research of voice, the objective voice detection methods are now available. These objective methods are designed primarily on voice detection of acoustics, aerodynamics, and physiological parameters. Auditory Perceptual Evaluation of Voice primarily used in clinical settings is the most direct judgment used by clinical physicians and other professionals in evaluating patients’ voice quality. The Auditory Perceptual Evaluation of Voice are mainly based on two criteria: (1) the GRBAS scale (grade, roughness, breathiness, asthenia, and strain scale), proposed by the Japanese Society for Logopedics and Phoniatrics and (2) the CAPE-V scale, proposed by the American Speech–Language–Hearing Association. The GRBAS scale is the most widely accepted scale for voice evaluation in clinics worldwide.5–7 In China, subjective evaluations are the prevailing method and used only in large hospitals. The outcomes largely depend on doctors’ clinical experience and assessment skills. The integrated use of various test parameters to assess (quantify) the quality of voice is still a debated yet important topic in clinical practice. Thus, the purpose of this study was to establish a multiparameter voice assessment method to improve voice quality evaluation.
Yu Ziwei, et al
771
Objective and Subjective Analysis for Voice Disorder Patients
METHODS Patients and therapeutic methods Fifty voice disorder patients were included in the study from the period of June 2010 to October 2011. All patients were admitted to the Department of Otolaryngology, Head and Neck Surgery, Shanghai Jiao Tong University Affiliated First People’s Hospital. The average age of patients is 47.08 ± 3.94 (standard deviation) years (range 25–70 years). Patients were diagnosed of vocal fold polyp (n ¼ 32), vocal fold nodule (n ¼ 5), vocal fold leukoplakia (n ¼ 5), vocal fold cyst (n ¼ 5), and vocal fold Reinke edema (n ¼ 3). For each patient, the removal of vocal fold lesion was performed under selfretaining laryngoscope, and inhalation treatment of Pulmicort Respules (AstraZeneca Pty Ltd.) was applied for 1 week after surgery. Instruments and voice assessment methods Subjective voice quality assessment. All sound measurements were recorded in the acoustic room with a highfidelity audio equipment (digital audio tapes). The distance between mouth and microphone was 10 cm. Each patient was asked to read an assigned sentence in his/her natural tone and loudness. The recorded materials from the digital audio tapes were then transferred to a computer. Three doctors were assigned to independently evaluate the voice quality. According to the grade of hoarseness (G) in GRABS system proposed by the Japanese Society for Logopedics and Phoniatrics, the voice quality was rated into one of four levels: 0 for normal voice, l for mild hoarseness, 2 for moderate hoarseness, and 3 for severe hoarseness. To minimize the assessment difference among the three doctors, thereby increasing the credibility of assessment results, each doctor was trained to recognize typical sound samples, and the subjects’ samples were also randomly arranged and presented to a given doctor three times. Each sound sample was thus assessed three times per doctor and then averaged. Self-assessment. On the VHI scale, the impact of voice disorder on patients’ quality of life is based on the assessment of functional (F), physiological (P), and emotional (E) components. The total score of the three components is T and to separate from the impact of E, sum of F and P is used as TvH (TvH ¼ F + P). Each component is evaluated based on 10 questions. Patients were asked to rate each question based on the frequency of occurrence: 0 for never, 1 for seldom, 2 for sometimes, 3 for regularly, and 4 for always. The score of each component range from 0 to 40, and the total score (T) is from 0 to 120. A higher score on a particular component indicates a greater impact of the voice disorder on this aspect for the patient; a higher total score means a worse self-recognition of the patient on voice disorder. Acoustic analysis. Acoustic test was conducted in an acoustic room. A microphone was placed 10 cm away from patients’ mouth. Subjects were then asked to pronounce the vowel /a/ for 3 seconds. Sound samples were recorded and then transferred into the computer for analysis using the voice analysis software. Acoustic analysis was conducted under the voice analysis
computer system (Tiger Electronics Co., Ltd) using the software Dr. Speech windows, version 4.0.8 Three parameters were selected for analysis: jitter (J, cycle-to-cycle variation in frequency), shimmer (S, cycle-to-cycle variation in intensity), and normalized noise energy (NNE, relative level of vocal noise to that of harmonics). Statistical analysis Matched t test was performed to analyze the differences between preoperation and postsurgery. Spearman correlation was carried out to analyze the correlations among the parameters. All data analyses were performed with SPSS version 13.0 (SPSS, Chicago, IL). RESULTS VHI scale assessment and acoustic analysis The results of VHI scale assessment and acoustic analysis show that both self-assessment and acoustic index significantly decreased 1 week after surgery (P < 0.01) compared with preoperative (Table 1). Correlation analysis of subentries on VHI scale Table 2 shows the correlation analysis results of selfassessment. Both before and after surgery, there were significantly strong positive correlations between F, P, and the sum TvH (TvH ¼ P + F). Preoperatively, the Spearman correlation
TABLE 1. Comparison of VHI Parameters and Acoustic Analysis Preoperative and 1 Week After Surgery (Mean ± Standard Deviation)
Variable VHI parameters P F E T Acoustic analysis J S NNE
P Value
Preoperative
Postoperative
21.43 ± 3.24 11.29 ± 1.76 2.85 ± 1.44 36.95 ± 3.05
4.02 ± 1.53 3.77 ± 1.63 1.54 ± 0.58 8.02 ± 1.94
0.008 0.007 0.007 0.008
0.82 ± 0.31 4.58 ± 0.14 4.88 ± 2.13
0.19 ± 0.22 1.42 ± 0.50 12.95 ± 2.01
0.005 0.005 0.006
All subentry P, F, E, and T scores of VHI were significantly reduced 1 week after surgery (P < 0.01), and J, S, and NNE of acoustic analysis were significantly reduced 1 week after surgery (P < 0.01).
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Journal of Voice, Vol. 28, No. 6, 2014
TABLE 2. Spearman Correlations Among Subentries of VHI Scale Preoperative Spearman Coefficient VHI Parameter F E T TvH
P
F
E
0.843* 0.282 0.552 0.931*
1.000 0.340 0.482 0.894*
1.000 0.283 0.262
Postoperative Spearman Coefficient T
P
F
E
T
1.000 0.356
0.821* 0.195 0.610 0.897*
1.000 0.296 0.502 0.855*
1.000 0.277 0.301
1.000 0.364
* P < 0.01 for the test.
coefficient between P and F was 0.843, between P and TvH was 0.931, and between F and TvH was 0.894. Likewise, postoperatively, the Spearman correlation coefficient between P and F was 0.821, between P and TvH was 0.897, and between F and TvH was 0.855. However, E and T were not found in correlation with other index. This suggests that except for the emotional components, in both preoperative and 1 week after surgery, there were positive correlations among three subentries, that is, functional component, physiological component, and the total of these two parts.
Correlation analysis of parameters in acoustic analysis All three parameters in the acoustic analysis are strongly correlated (Table 3). The pre- and post-operative Spearman correlation coefficient between J and S was 0.751 and 0.812, respectively; correlation coefficient between J and NNE was 0.708 and 0.743, respectively; and correlation coefficient between S and NNE was 0.653 and 0.703, respectively. This indicates that, preoperative and 1 week after surgery, there were positive correlations among these three parameters, that is, J, S, and NNE.
Correlation analysis of subentries of VHI scale and parameters in acoustic analysis Results in Table 4 show that except for the emotional part, in both preoperative and 1 week after surgery, there were positive correlations among all other components: functional, physiological, total of these two parts and J, S, and NNE, but not between E and T. TABLE 3. Spearman Correlations Among Acoustic Parameters Preoperative Spearman Coefficient
Acoustic Parameters S NNE
Postoperative Spearman Coefficient
J
S
J
S
0.751* 0.708*
1.000 0.653*
0.812* 0.743*
1.000 0.703*
* P < 0.01 for the test.
Correlation analysis of subjective voice quality assessment, subentries of VHI scale, and parameters in acoustic analysis There were strong correlations between the grade of hoarseness (G) and F, P, and TvH of VHI scale as well as J, S, and NNE in acoustic analysis (Table 5). This indicates that with the exception of the emotional part, both preoperative and 1 week after surgery, there were positive correlations between the grade of hoarseness and subentries of VHI scale and parameters in acoustic analysis.
DISCUSSION Natural voice consists of various physical features. It is common to use auditory perceptual evaluation as a reference measure for evaluating objective assessments.9 The GRBAS system, developed by the Japanese Society for Logopedics and Phoniatrics, is the prevailing auditory perceptual assessment. In this study, we included auditory perceptual evaluation in our voice assessment. The grade of hoarseness (G)10 provided the most reliable and stable results. Our results suggest that G can well reflect the severity of voice disorders and serves as a surrogate to evaluate the severity of voice disorder, providing a good guidance for subsequent treatment. Acoustic analysis as a method for objective assessment of voice quality has been available in clinics. Parameter J in acoustic analysis reflects the changes in sonic basic frequency between the time point and the same time point of the adjacent cycle; S reflects changes in wave amplitudes between the point and the same time point of adjacent cycle; and NNE reflects the normalized noise energy due to the incomplete glottal closure. Specifically, J reflects the rough sound level; S reflects the hoarse sound level; and NNE reflects breath sound level, after the hoarse sound level. The selection of parameters in objective voice assessment should meet three fundamental principles: (1) must have pathophysiological significance and have some application ‘‘history’’; (2) changes in assessment results should be consistent with that in the severity of voice disorders; and (3) normal and unusual voice can be effectively defined by values of the parameters. In this study, J, S, and NNE were noticeably reduced 1 week after surgery compared with preoperative measurements. However, the clinical features, that is, rough voice, hoarse voice, and breath sounds, were reduced. These changes indicate that the voice quality in voice disorder patients was
Yu Ziwei, et al
773
Objective and Subjective Analysis for Voice Disorder Patients
TABLE 4. Spearman Correlations Between VHI Scales and Acoustic Parameters Preoperative Spearman Coefficient VHI Scale P F E T TvH
Postoperative Spearman Coefficient
J
S
NNE
J
S
NNE
0.841* 0.835* 0.210 0.329 0.593*
0.873* 0.793* 0.243 0.531 0.775*
0.885* 0.680* 0.265 0.412 0.654*
0.834* 0.902* 0.181 0.527 0.766*
0.742* 0.834* 0.203 0.582 0.732*
0.728* 0.921* 0.295 0.423 0.848*
* P < 0.01 for the test.
noticeably improved after surgery. Therefore, acoustic analyses in this study provide objective quantification to evaluate surgical outcome. Voice disorders lead to psychological problem and social difficulty, thus affecting patients’ quality of life. Subjective assessment using the VHI provides information in this aspect and therefore serves as a complement to clinical and acoustic detection. VHI as the voice self-assessment method possesses a degree of complexity that far exceeds those of objective measures. Because of the diversity in personal factors, such as social status, profession, social status, family situations, personality, and so on, the impact of voice on patients’ life varies.11 In this study, the VHI scale was used as the tool for subjective assessment. Our original design planned to analyze the total of E, F, and P as T. The experimental results showed poor correlation between E and the other parameters. There were strong correlations among the remaining parameters only when E was excluded from the analysis, and the total of F and P was recorded as TvH. This suggests that the VHI scale, which based on the patient’s subjective experience on impact of their voice disorder, only effectively reflect the patients’ perception on the functional and physiological aspects of their life, work, and social activities. The assessment is likely biased because of the traditional culture of China, where people in general are reluctant to express their negative emotions selected a lower score. Therefore, we found no significant changes
TABLE 5. Spearman Correlations Between G and Both Subentries of VHI Scale and Acoustic Parameters
Parameters P F E TvH J S NNE * P < 0.01 for the test.
Preoperative_G Spearman Coefficient
Postoperative_G Spearman Coefficient
0.944* 0.973* 0.221 0.987* 0.918* 0.974* 0.929*
0.954* 0.920* 0.196 0.965* 0.939* 0.968* 0.972*
in emotional scores before and after surgery. Answers to the emotional component of the VHI scale are also affected by the patients’ age, occupation, education background, patient compliance, and so on.12,13 The Chinese version of the VHI scale should therefore be revised to accommodate the eastern culture background. We recommend that the emotional part should be modified to be in line with the characteristic of Asian culture. Voice is a complex multidimensional phenomenon; pathologic changes of vocal fold usually reduce the voice quality in multiple aspects. Single parameter comes short to assess the vocal function in both normal and abnormal conditions. Each available assessment method only evaluates one particular aspect of the laryngeal function. Voice assessment should therefore include multiple parameters.14,15 CONCLUSIONS In this study, we find that the assessment method is composed of subjective assessment, objective assessment, and a selfassessment helps to improve clinical diagnosis and treatment of voice disorders. The use of a multiparameter voice assessment method is particularly helpful in the assessment in (1) the severity of voice disorders preoperatively, (2) evaluation of the treatment outcome, (3) comparing the outcomes of different treatment methods, (4) dynamic observation of the development and prognosis of disease, and (5) in patient follow-up observations. Integrated use of subjective and objective assessments can systematically evaluate and compare patients’ voice quality pre- and post-operatively. The task in clinic is not only to remove lesions and clinically cure patients but also to care for patients’ physiological recovery and their social adaptabilities as well. The multiparameter methods will help doctors design treatment targets that are consistent with the patients’ subjective feelings and life requirements. The assessment method introduced in this work is expected to play an important role for voice disorder in surgery treatment, outcome assessment, and in follow-up assessment. Acknowledgments The authors thank Drs. Lei Song and Lingeng Lu for their critical review of the article. This study was supported by the National Natural Science Foundation of China (Grant No: 81170925).
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