Acoustic and Perceptual Characteristics of the Voice in Patients With Vocal Polyps After Surgery and Voice Therapy *,†Mirjana Petrovic-Lazic, *Nadica Jovanovic, ‡Milan Kulic, †Snezana Babac, and §Vladimir Jurisic, *yBelgrade and xKragujevac, Serbia, and zRepublic of Srpska, Bosna and Hercegovina
Summary: Objective. The aim of the study was to assess the effect of endolaryngeal phonomicrosurgery (EPM) and voice therapy in patients with vocal fold polyps using perceptual and acoustic analysis before and after both therapies. Methods. The acoustic tests and perceptual evaluation of voice were carried out on 41 female patients with vocal fold polyp before and after EPM and voice therapy. Both therapy strategies were performed. Used acoustic parameters were Jitter percent (Jitt), pitch perturbation quotient (PPQ), shimmer percent (Shim), amplitude perturbation quotient (APQ), fundamental frequency variation (vF0), noise-to-harmonic ratio (NHR), Voice Turbulence Index (VTI). For perceptual evaluation, GRB scale was used. Results. Results indicated higher values of investigated parameters in patients’ group than in the control group (P < 0.01). Good correlation between the perceptual hoarseness factors of GRB scale and objective acoustic voice parameters were observed. All analyzed acoustic parameters improved after the phonomicrosurgery and voice therapy and tend to approach to values of the control group. For Jitt percent, Shim percent, vF0, VTI, and NHR, there were statistically significant differences. Perceptual voice evaluation revealed statistically significantly (P < 0.01) decreased rating of G (grade), R (rough) and B (breathy) after surgery and voice therapy. Conclusions. Our data indicated that both acoustic and perceptual characteristic of voice in patients with vocal polyps significantly improved after phonomicrosurgical and voice treatment. Key Words: Acoustic voice analysis–Perceptual voice evaluation–Vocal polyps–Voice–Phonomicrosurgery.
INTRODUCTION Polyps are caused by submucosal bleeding of the vocal cords, in combination with infection, allergy, pollution or endocrine disorders, voice misuse, and smoking.1 They can vary in size, shape, and color. Some polyps are roundish, limited, pedunculated, whereas some can be attached on a wider stem covering a larger part of the vocal fold.2 In size, they vary from a pinhead to those of a corn grain. They are usually located 3 mm behind the anterior commissure on the free edge or the subglottic surface of the vocal fold and most frequently unilateral.3 The clinical features are dominated by more or less prominent hoarseness, roughness, breathiness, depending on the size or position of the polyps. The increase in mass of one vocal fold tends to lower vocal pitch and to restrict pitch range. Acoustic analysis profile shows increase of Jitter and Shimmer measures because the polyp tends to lag behind the vocal fold vibration and has its own vibratory pattern, the successive vibrations of which are often aperiodic.3,4 The incompetent vocal fold adduction allows air to leak, causing an increase in noise in the vocal note, which is reflected in a reduced harmonic-to-noise ratio.3 Vocal polyps are usually removed surgically, after which the patient is referred to a vocal therapist who is then to decide on the
Accepted for publication July 17, 2014. From the *Faculty of Special Education and Rehabilitation, University of Belgrade, Belgrade, Serbia; yENT Clinic, Zvezdara Hospital and Clinical Centre, Belgrade, Serbia; zFaculty of Medicine, University of East Sarajevo, Republic of Srpska, Bosna and Hercegovina; and the xFaculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia. Address correspondence and reprint requests to Vladimir Jurisic, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-6 0892-1997/$36.00 Ó 2014 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2014.07.009
necessity, type, and duration of voice therapy.2,3 In view of the phonation complexity and of the vocal folds structure, it is necessary to plan the implementation of phonosurgical procedure very carefully and for each patient individually, because such procedure sometimes is not justified. It is also vital to determine the right timing for the procedure. Vocal polyps may also be treated with reflux medication and voice training when polyp is sessile and small. There is no general agreement with regard to which method is most appropriate for evaluating the outcome of voice therapy and the phonosurgical procedure. Several studies evaluated therapy effect using perceptual analyses performed by trained voice specialist.5 However, the definitions of the perceptual vocal measures (eg, hoarseness, strain, and roughness) may vary considerably among different professionals. These methodological issues present an obstacle for comparing different studies concerning voice quality. The GRBAS scale for subjective voice evaluation containing five voice quality parameters, G (grade), R (rough), B (breathy), A (asthenic), and S (strained) is most widely used voice scaling method.6 Acoustic analysis has the benefit of measuring and quantifying subtle differences in voice quality more precisely than perceptual measures. The attempts of objective acoustic evaluation of pathologic voice have been performed for about 20 years.7 The computerized multidimensional acoustic voice analysis enables visual and numeric information on the analyzed voice. The aim of such analysis program is to provide objective data and to support perceptual voice evaluation.8,9 Multi-Dimensional Voice Program (MDVP) is one of the instruments which provide the detailed acoustic analysis on all parameters. The MDVP appears to have potential for rapid quantitative assessments of voice in both research and clinical applications.10,11
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Journal of Voice, Vol. -, No. -, 2014
pulses, abnormal fluctuations in fundamental frequency; and B (breathy), an auditory impression of turbulent air, including short aphonic moments (unvoiced segments), were used in this study. These factors are assessed on a 4-point scale (0, normal; 1, slight; 2, moderate; and 3, extreme).14,15 GRB score was given at the end of the evaluation session. The recorded audiotapes of the ‘‘Today is a nice day’’ were then replayed after the evaluation session to reconsider the GRB scores. Any variation in GRB scores between reading and conversation was considered, and preference was given to the scores obtained during conversation.
The aim of the investigation was to evaluate the voice quality using perceptual assessment and acoustic analysis in patients with vocal polyps, before and after the endolaryngeal phonomicrosurgery (EPM) and voice therapy. It is necessary to determine to what extent the vocal fold polyps impair voice production and what impact the phonosurgical intervention has on the acoustic parameters of voice. Many people receive behavioral intervention, or voice therapy.12,13 MATERIALS AND METHODS The study included 41 female patients aged from 18 to 61 years (mean 48.43 ± 9.21) from clinical hospital ‘‘Zvezdara,’’ University of Belgrade, Serbia. This research has included only patients when the unilateral polyps are middle or have existed for a long time. Local Ethics Committee approved the research. The control group included 21 female patients aged 21–61 years (mean 47.57 ± 9.23), who did not have any vocal complaints nor laryngeal pathology in the last 6 months. The control group was stratified by gender and age. To verify that control and patients groups were comparable, with regard to age, chisquare test (c2) was conducted between the two groups. No significant differences were found (P > 0.05). Local ethic committee approved investigation. Voice recordings were subjects both to perceptual and acoustic evaluation. Voice therapy was conducted in all 41 patients. It was begun 10 days after operations, carried three times a week and delivered for 4 weeks. All patients came twice at the presurgery for voice therapeutic education.
Acoustical analysis All participants were examined by an otorhinolaryngologist with indirect laryngoscopy (using mirror) and videostroboscopy using RLS 9100 (Kay, Lincoln Park, NJ). After examination, a voice recording was made. Voice recordings were performed in a quiet room. A Sony ECM-T150 microphone (Sony, Tokyo, Japan), attached to a headset was placed at 5.0 cm distance from the subject’s mouth. The signal was recorded directly onto a computer. Each group repeated the sustained vowel /a/11,12,15–19 at their most comfortable loudness and pitch, for at least 3 seconds, three times, the token with the mean value being considered relevant for the analysis. After surgery, 4-week intensive (three times a week) voice therapy has been applied. MDVP (model 4300, Kay Elemetrics Corp.) and Computerized Speech Lab hardware for signal acquisition analysis and interpretation of data were used. Seven acoustic parameters were investigated: fundamental frequency variation (vF0), frequency perturbation measure, Jitter percent (Jitt), pitch perturbation quotient (PPQ), Shimmer percent (Shim) amplitude perturbation quotient (APQ, %), and two noise indices: noise-to-harmonic ratio (NHR) and Voice Turbulence Index (VTI). Sampling rate for analysis was set at 44 kHz. Statistical analysis was performed with the SPSS 10.0 for Windows (Statistical Package for the Social Sciences, Chicago, IL). The values for the variables are presented as arithmetic means and standard deviations. The change in parameters value before and after EPM was analyzed with the Student t-test for paired samples (for a parametric data, coefficient variation
Summary: Objective. The aim of the study was to assess the effect of endolaryngeal phonomicrosurgery (EPM) and voice therapy in patients with vocal fold polyps using perceptual and acoustic analysis before and after both therapies. Methods. The acoustic tests and perceptual evaluation of voice were carried out on 41 female patients with vocal fold polyp before and after EPM and voice therapy. Both therapy strategies were performed. Used acoustic parameters were Jitter percent (Jitt), pitch perturbation quotient (PPQ), shimmer percent (Shim), amplitude perturbation quotient (APQ), fundamental frequency variation (vF0), noise-to-harmonic ratio (NHR), Voice Turbulence Index (VTI). For perceptual evaluation, GRB scale was used. Results. Results indicated higher values of investigated parameters in patients’ group than in the control group (P < 0.01). Good correlation between the perceptual hoarseness factors of GRB scale and objective acoustic voice parameters were observed. All analyzed acoustic parameters improved after the phonomicrosurgery and voice therapy and tend to approach to values of the control group. For Jitt percent, Shim percent, vF0, VTI, and NHR, there were statistically significant differences. Perceptual voice evaluation revealed statistically significantly (P < 0.01) decreased rating of G (grade), R (rough) and B (breathy) after surgery and voice therapy. Conclusions. Our data indicated that both acoustic and perceptual characteristic of voice in patients with vocal polyps significantly improved after phonomicrosurgical and voice treatment. Key Words: Acoustic voice analysis–Perceptual voice evaluation–Vocal polyps–Voice–Phonomicrosurgery.
INTRODUCTION Polyps are caused by submucosal bleeding of the vocal cords, in combination with infection, allergy, pollution or endocrine disorders, voice misuse, and smoking.1 They can vary in size, shape, and color. Some polyps are roundish, limited, pedunculated, whereas some can be attached on a wider stem covering a larger part of the vocal fold.2 In size, they vary from a pinhead to those of a corn grain. They are usually located 3 mm behind the anterior commissure on the free edge or the subglottic surface of the vocal fold and most frequently unilateral.3 The clinical features are dominated by more or less prominent hoarseness, roughness, breathiness, depending on the size or position of the polyps. The increase in mass of one vocal fold tends to lower vocal pitch and to restrict pitch range. Acoustic analysis profile shows increase of Jitter and Shimmer measures because the polyp tends to lag behind the vocal fold vibration and has its own vibratory pattern, the successive vibrations of which are often aperiodic.3,4 The incompetent vocal fold adduction allows air to leak, causing an increase in noise in the vocal note, which is reflected in a reduced harmonic-to-noise ratio.3 Vocal polyps are usually removed surgically, after which the patient is referred to a vocal therapist who is then to decide on the
Accepted for publication July 17, 2014. From the *Faculty of Special Education and Rehabilitation, University of Belgrade, Belgrade, Serbia; yENT Clinic, Zvezdara Hospital and Clinical Centre, Belgrade, Serbia; zFaculty of Medicine, University of East Sarajevo, Republic of Srpska, Bosna and Hercegovina; and the xFaculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia. Address correspondence and reprint requests to Vladimir Jurisic, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia. E-mail: [email protected] Journal of Voice, Vol. -, No. -, pp. 1-6 0892-1997/$36.00 Ó 2014 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2014.07.009
necessity, type, and duration of voice therapy.2,3 In view of the phonation complexity and of the vocal folds structure, it is necessary to plan the implementation of phonosurgical procedure very carefully and for each patient individually, because such procedure sometimes is not justified. It is also vital to determine the right timing for the procedure. Vocal polyps may also be treated with reflux medication and voice training when polyp is sessile and small. There is no general agreement with regard to which method is most appropriate for evaluating the outcome of voice therapy and the phonosurgical procedure. Several studies evaluated therapy effect using perceptual analyses performed by trained voice specialist.5 However, the definitions of the perceptual vocal measures (eg, hoarseness, strain, and roughness) may vary considerably among different professionals. These methodological issues present an obstacle for comparing different studies concerning voice quality. The GRBAS scale for subjective voice evaluation containing five voice quality parameters, G (grade), R (rough), B (breathy), A (asthenic), and S (strained) is most widely used voice scaling method.6 Acoustic analysis has the benefit of measuring and quantifying subtle differences in voice quality more precisely than perceptual measures. The attempts of objective acoustic evaluation of pathologic voice have been performed for about 20 years.7 The computerized multidimensional acoustic voice analysis enables visual and numeric information on the analyzed voice. The aim of such analysis program is to provide objective data and to support perceptual voice evaluation.8,9 Multi-Dimensional Voice Program (MDVP) is one of the instruments which provide the detailed acoustic analysis on all parameters. The MDVP appears to have potential for rapid quantitative assessments of voice in both research and clinical applications.10,11
2
Journal of Voice, Vol. -, No. -, 2014
pulses, abnormal fluctuations in fundamental frequency; and B (breathy), an auditory impression of turbulent air, including short aphonic moments (unvoiced segments), were used in this study. These factors are assessed on a 4-point scale (0, normal; 1, slight; 2, moderate; and 3, extreme).14,15 GRB score was given at the end of the evaluation session. The recorded audiotapes of the ‘‘Today is a nice day’’ were then replayed after the evaluation session to reconsider the GRB scores. Any variation in GRB scores between reading and conversation was considered, and preference was given to the scores obtained during conversation.
The aim of the investigation was to evaluate the voice quality using perceptual assessment and acoustic analysis in patients with vocal polyps, before and after the endolaryngeal phonomicrosurgery (EPM) and voice therapy. It is necessary to determine to what extent the vocal fold polyps impair voice production and what impact the phonosurgical intervention has on the acoustic parameters of voice. Many people receive behavioral intervention, or voice therapy.12,13 MATERIALS AND METHODS The study included 41 female patients aged from 18 to 61 years (mean 48.43 ± 9.21) from clinical hospital ‘‘Zvezdara,’’ University of Belgrade, Serbia. This research has included only patients when the unilateral polyps are middle or have existed for a long time. Local Ethics Committee approved the research. The control group included 21 female patients aged 21–61 years (mean 47.57 ± 9.23), who did not have any vocal complaints nor laryngeal pathology in the last 6 months. The control group was stratified by gender and age. To verify that control and patients groups were comparable, with regard to age, chisquare test (c2) was conducted between the two groups. No significant differences were found (P > 0.05). Local ethic committee approved investigation. Voice recordings were subjects both to perceptual and acoustic evaluation. Voice therapy was conducted in all 41 patients. It was begun 10 days after operations, carried three times a week and delivered for 4 weeks. All patients came twice at the presurgery for voice therapeutic education.
Acoustical analysis All participants were examined by an otorhinolaryngologist with indirect laryngoscopy (using mirror) and videostroboscopy using RLS 9100 (Kay, Lincoln Park, NJ). After examination, a voice recording was made. Voice recordings were performed in a quiet room. A Sony ECM-T150 microphone (Sony, Tokyo, Japan), attached to a headset was placed at 5.0 cm distance from the subject’s mouth. The signal was recorded directly onto a computer. Each group repeated the sustained vowel /a/11,12,15–19 at their most comfortable loudness and pitch, for at least 3 seconds, three times, the token with the mean value being considered relevant for the analysis. After surgery, 4-week intensive (three times a week) voice therapy has been applied. MDVP (model 4300, Kay Elemetrics Corp.) and Computerized Speech Lab hardware for signal acquisition analysis and interpretation of data were used. Seven acoustic parameters were investigated: fundamental frequency variation (vF0), frequency perturbation measure, Jitter percent (Jitt), pitch perturbation quotient (PPQ), Shimmer percent (Shim) amplitude perturbation quotient (APQ, %), and two noise indices: noise-to-harmonic ratio (NHR) and Voice Turbulence Index (VTI). Sampling rate for analysis was set at 44 kHz. Statistical analysis was performed with the SPSS 10.0 for Windows (Statistical Package for the Social Sciences, Chicago, IL). The values for the variables are presented as arithmetic means and standard deviations. The change in parameters value before and after EPM was analyzed with the Student t-test for paired samples (for a parametric data, coefficient variation
