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Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Validity
ARTICLE IN PRESS
Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Validity *Gabriele Rodrigues Bastilha, *Karina Carlesso Pagliarin, †Denis Altieri de Oliveira Moraes, and *Carla Aparecida Cielo, *ySanta Maria, Brasil Summary: Objective. To present evidence of the reliability and validity in the Spectrographic Vocal Assessment Protocol. Methods. The sample consisted of 50 female participants, aged 25−62 years old, 24 with a otorhinolaryngological diagnosis of the normal larynx or posterior glottal gap, and 26 diagnosed with vocal fold disturbances. The emission of the vowel /a:/ was analyzed by the Real Time Spectrogram software. The spectrographs were analyzed with a protocol by two speech therapist judges. For reliability analysis, inter- and intrajudge analysis were performed using the Kendall coefficient. For criterion validity, the t test for matched samples with Bonferroni correction was used to compare the average performance of the protocol between the two groups of subjects. Results. Protocol reliability: for broadband items, the agreement between judges ranged from moderate (0.462) to almost perfect (0.888), and it is significant for all items, and an intrajudge agreement was almost perfect and significant (0.865−1.000) for all items. For narrowband items, the agreement between judges ranged from moderate (0.469) to almost perfect (0.922), and it is significant for all items except for the presence of “subharmonics in high frequencies” where agreement was moderate (0.504), but not significant, and the intrajudge agreement was almost perfect (0.874−1.000) and significant for all items. Criterion validity: for most broadband and narrowband items, the groups with normal or altered diagnosis differed statistically. Conclusion. The Spectrographic Vocal Assessment Protocol presented adequate evidence in reliability and validity. Key Words: Acoustics−Spectrography−Validation studies−Speech, language and hearing sciences−Voice.
INTRODUCTION Vocal spectrography allows the analysis of the spectrographic characteristics of the sound produced by the vocal folds, as well as the changes generated by the vocal tract. This assessment makes it possible to analyze, among other aspects, the darkening of the trace color of the formants (F) and the different frequency ranges, noise presence, F definition, trace regularity, number of harmonics, and presence of subharmonics. However, it depends on the judge's visual analysis, which is a subjective aspect.1−9 Although it is a complementary analysis of the auditoryperceptive voice assessment, the visual support of the spectrographic image significantly increases the reliability of this assessment. Some authors try to correlate the spectrographic data to the different types of voices.7,9−14 Hoarseness is related to the substitution of the trace noise. In hoarseness, the harmonics may be completely erased and this is a characteristic sign vocal fold vibration. In the breathy voice, reduced energy is observed high frequencies, with weak harmonics and the presence of noise between Accepted for publication February 20, 2020. From the *Department of Speech-Language Pathology and Audiology, Universidade Federal de Santa Maria/UFSM, Santa Maria, Rio Grande do Sul, Brasil; and the yDepartment of Statistics, Universidade Federal de Santa Maria/UFSM, Santa Maria, Rio Grande do Sul, Brasil. Address correspondence and reprint requests to Gabriele Rodrigues Bastilha, Department of Speech-Language Pathology and Audiology, Universidade Federal de Santa Maria/UFSM, Av. Roraima no 1000, Prédio 26 - Fonoaudiologia, UFSM, Bairro Camobi, Santa Maria, RS, CEP: 97105-900, Brasil. E-mail: [email protected] Journal of Voice, Vol. &&, No. &&, pp. &&−&& 0892-1997 © 2020 The Voice Foundation. Published by Elsevier Inc. All rights reserved. https://doi.org/10.1016/j.jvoice.2020.02.017
them. The unstable vocal quality is characterized disturbance in the waveform. There are frequency breaks when there are abrupt changes in tracing the fundamental frequency (f0). Abrupt interruptions in the recording are characteristic loudness breaks.13,14 The presence of subharmonics in narrowband spectrography is common in rough and diplophonic voices.10,12 The bandwidth of F relates to the perceptual hearing parameter of breathiness.9 In research, a spectrographic evaluation of hoarse, rough, and normal voices was carried out. It was found that harmonics were present in large quantities and greater definition in normal voices, and decreased in quantity and quality in rough and hoarse voices. The noise was present in large quantities and diffusely in hoarse voices and a lesser amount in rough and normal voices. In normal voices, there was a large number of harmonics in the high frequencies (above 3 kHz). In altered voices, there was an absence of harmonics in the high frequencies, so that the region above 3 kHz could appear darkened with the presence of only noise.11 There is a great clinical and scientific demand for assessment instruments suitable to the various realities in all scientific fields, but especially in the health area. For the voice area growing, the use of accurate, valid, and sensitive tests is of utmost importance.15−17 Standardizing the aspects that are important in spectrographic analysis, the Spectrographic Vocal Assessment Protocol (SVAP) was developed in another study and presented content evidence considered as satisfactory.18 This article presents the theoretical basis used for the construction of SVAP items and their development process.18
ARTICLE IN PRESS 2 A recent study aimed to identify, through a systematic literature review, the use of psychometrics in the field of speech therapy and the processes used to search for evidence of the validity of instruments in the area. It concluded that the use of principles of the search for shreds of evidence the validity of instruments speech therapy area is still scarce. However, most studies have been developed in recent years, showing a current trend to pay attention to the need for improvement of instruments and advances in this area. The authors of the research cited found only four published studies on the validation of specific instruments in the voice area.16 And so far, there is no validated SVAP. It is believed that most of the difficulties lie in the professionals' lack of knowledge of the methodological and psychometric aspects necessary for an instrument, in addition to the cost involved in this process.15−17,19 Considering the importance of conducting psychometric studies with vocal assessment instruments and the lack of validated spectrographic vocal assessment instrument, this study aimed to present the evidence of reliability and criterion validity for SVAP. METHODS Participants The sample consisted of 50 records of women, recruited the database of the Voice Laboratory, Speech Therapy Course of the institution of origin (24 had an ENT/otorhinolaryngological diagnosis of the normal larynx or posterior glottal gap, and 26 had an ENT diagnosis of vocal fold disturbances). Of the 26 participants had an otorhinolaryngological diagnosis of vocal fold disturbances, 13 had a glottal gap and vocal nodules, 9 had a glottal gap (except the posterior glottal gap), and 4 had vocal cysts. It is noteworthy that the groups (normal and with vocal folds disturbances) were paired exactly by age in years, presenting a general average of 39.6 years and a standard deviation of 11.3 years. The inclusion criteria adopted were: presenting ENT diagnosis; age group from 19 to 64 years old (adult and middle age—DeCS, 2019), absent the period of vocal change and presbyphonia. Exclusion criteria were: a self-reported previous history of neurological, gastric, psychiatric, endocrinological, respiratory, pregnancy, and the presence of hearing loss. These criteria may influence vocal performance, voice self-monitoring, and/or vocal quality.
Procedures and instruments The study was approved by the Research Ethics Committee of the institution of origin with the number 1.570.886. Data collection occurred with the participants in a standing position, and they asked to emit the vowel /a:/ in usual pitch and loudness after deep inspiration, at maximum phonation time. The emissions recorded with a Behringer ECM 8000 omnidirectional professional microphone, coupled with the Zoom model H4n professional digital recorder, positioned in front and at a 90° angle at a distance of 4 cm
Journal of Voice, Vol. &&, No. &&, 2020
between the microphone and mouth. The recordings were made in a room with environmental noise below 50 dBNPS, measured with an Instrutherm digital sound pressure level meter, model Dec-480.4,5,14,20−25 The vowel /a:/ was used because it best represents the glottic function, it has less interference of the transfer factor relative to the resonance of the sound during passage through the vocal tract, and it is the one with the most accurate f0 measurements, and, therefore, it suffers less noise influence.14,24,26−29 It is noteworthy that the procedures described above are standardized in the school clinic and in the laboratory research where the research was performed, thus having uniformity in the records and data stored in the database. The emission of the vowel /a:/ was analyzed by Real Time Spectrogram software (Kay Pentax (USA)), resulting in images of the spectral acoustic vocal analysis. In the broadband filter, 100 points (646.00 Hz) and 1024 points (63.09 Hz) narrowband filter used, both with 11 kHz sampling rate and 16 bits of analog-to-digital conversion, in a window of 5 kHz.5,6,14,25,30 For spectrographic analysis, SVAP (Appendix A) was used. SVAP consists of two parts: Broadband Spectrography and Narrowband Spectrography (NS), with their respective parameters.18 To fill the SVAP, a linear analog scale with a score ranging from 0 to 10 cm is used. The assessment of each parameter should be performed by marking a vertical line at any point of the millimeter ruler, according to the observed gradation.2,5,6,23,25,31 For parameter analysis, low frequencies below 1500 Hz, medium frequencies between 1500 and 3000 Hz, and high frequencies above 3000 Hz are considered,3,10−12,32 and each instrument item has a brief orientation.
Reliability For inter- and intrajudge reliability analysis, two speechlanguage pathologists, nonauthors, with at least 5 years' experience in voice and spectrographic analysis participated. Such judges were blinded to the research objectives, identification, and diagnosis of the subjects.31,33,34 The judges did not receive prior individual or joint training because such training would be a methodological bias, affecting the results. The judges had previous experience and knowledge in spectrographic evaluation, verified by their curriculum.5,14,21,30 The 50 spectrographs were analyzed using SVAP individually by the two expert judges (interjudge reliability). After 30 days, the same judges analyzed the same spectrographs again (intrajudge reliability). The spectrographic images were sent to the judges through Dropbox (USA) (examples of the spectrographs analyzed by the judges are in Figures 1 and 2). For data analysis, the Kendall coefficient of the agreement was used, and significant results were considered when p£0.001. Assessing agreement, the following values were used: >0.81 (almost perfect), 0.61−0.8 (substantial),
ARTICLE IN PRESS Gabriele Rodrigues Bastilha, et al
Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 3
FIGURE 1. Normal spectrographic image.
FIGURE 2. Spectrographic image of subject with glottal gap and vocal nodules.
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TABLE 1. Inter- and Intrajudge Agreement on SVAP Broadband Items
0.41−0.6 (moderate), 0.21−0.4 (fair), and 0.0−0.2 (slight), <0.0 (poor).35
Protocol Item
Criterion validity Criterion validity is one of the steps for instrument validation. In this study, to verify the criterion validity of the SVAP, as recommended by Psychometry, the “criterion” used was to present or not a disturbance in vocal folds, according to an ENT diagnosis. From this, the spectrographs of the two groups were analyzed: 24 with normal larynx or posterior glottal gap and 26 with vocal fold disturbance. SVAP was answered by one of the expert judges. The data obtained from this analysis were tabulated and the realiability analyzed in SPSS version 21 for Windows, the t test for matched samples with Bonferroni correction to control for alpha slippage was performed with the R software,36 considering significant results when P ≤ 0.05.
Tracing color intensity of F1 Tracing color intensity of F2 Tracing color intensity of F3 Tracing color intensity of F4 Tracing color intensity of low frequencies Tracing color intensity of medium frequencies Tracing color intensity of high frequencies Tracing color intensity in vocal spectrogram as a whole Definition and regularity of F1 Definition and regularity of F2 Definition and regularity of F3 Definition and regularity of F4 Regularity of vertical striation tracing at low frequencies Regularity of vertical striation tracing at medium frequencies Regularity of vertical striation tracing at high frequencies Regularity of vertical striation tracing in vocal spectrogram as a whole Bandwidth of F1 Bandwidth of F2 Bandwidth of F3 Bandwidth of F4 Anti-resonance/damping immediately above F1 Anti-resonance/damping at low frequencies Anti-resonance/damping at medium frequencies Anti-resonance/damping at high frequencies Anti-resonance/damping in vocal spectrogram as a whole
Kendall Inter
Kendall Intra
0.462*
0.902*
0.547*
0.902*
0.697*
0.981*
0.529*
0.933*
0.642*
0.875*
0.578*
0.865*
0.616*
1.000*
0.882*
0.919*
0.587*
0.933*
0.661*
0.918*
0.729*
0.881*
0.477*
0.979*
0.789*
0.988*
0.740*
0.952*
0.642*
1.000*
0.682*
0.904*
0.770* 0.627* 0.778** 0.745* 0.836*
0.942* 0.918** 0.873* 0.913** 0.984*
0.848*
0.959*
0.804*
0.965*
0.867*
0.969*
0.888*
0.952*
* Significant values P ≤ 0.001. Subtitle: F1-1st Formant; F2-2nd Formant; F3-3rd Formant; F4-4th Formant. Kendall coefficient.
RESULTS For SVAP broadband items (Table 1), the agreement between judges ranged from moderate to almost perfect, being significant for all items, and an intrajudge agreement was almost perfect and significant for all items. For SVAP narrowband items (Table 2), the agreement between judges ranged from moderate to almost perfect, and it was significant for all items except for the “presence of high-frequency subharmonics” where the agreement was moderate but not significant (P = 0.120). The intrajudge agreement was almost perfect and significant for all SVAP narrowband items. Regarding the validity of the SVAP criterion, the groups with normal or altered ENT diagnosis differ statistically in the vast majority of broadband (Table 3) and narrowband (Table 4) items. DISCUSSION Contributing to the standardization of visual analysis of vocal spectrographs and the reduction of subjectivity in this type of assessment, the analysis of reliability and validity of SVAP criteria was performed. The inter and intra expert judge agreement ranged from moderate to almost perfect, being significant for all SVAP items, except for the “presence of subharmonics in high frequencies” (NS) where the agreement was moderate but not significant. Still, it was possible to verify that there is a difference between the subjects with normal or altered ENT diagnosis regarding the performance of SVAP. The results obtained were satisfactory, and they indicated that SVAP presents good evidence and it can be used in clinical practice and research as an instrument to assess vocal spectrographs. A recent study developed a spectrographic evaluation protocol, but only performed its content validation, without presenting evidence of reliability or criterion validity.8 Therefore, to date, there is no other validated SVAP in the literature, which makes it difficult to discuss and compare
ARTICLE IN PRESS Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 5
Gabriele Rodrigues Bastilha, et al
TABLE 2. Inter- and Intrajudge Agreement on SVAP Narrowband Items Protocol Item Tracing color intensity of low frequencies Tracing color intensity of medium frequencies Tracing color intensity of high frequencies Tracing color intensity in vocal spectrogram as a whole Presence of noise at low frequencies Presence of noise at medium frequencies Presence of noise at high frequencies Presence of noise in vocal spectrogram as a whole Replacement of harmonics by noise at low frequencies Replacement of harmonics by noise at medium frequencies Replacement of harmonics by noise at high frequencies Replacement of harmonics by noise in vocal spectrogram as a whole Definition and regularity of harmonics at low frequencies Definition and regularity of harmonics at medium frequencies Definition and regularity of harmonics at high frequencies Definition and regularity of harmonics in vocal spectrogram as a whole Number of harmonics at low frequencies Number of harmonics at medium frequencies Number of harmonics at high frequencies Number of harmonics in vocal spectrogram as a whole Presence of sub-harmonics at low frequencies
Kendall Inter
Kendall Intra
0.659*
0.893*
0.568*
0.875*
0.469*
1.000*
0.679*
0.982*
0.737*
1.000*
0.708*
1.000*
0.742*
0.942*
0.804*
0.989*
0.776*
1.000*
0.586*
0.925*
0.612*
0.984*
0.878*
0. 952*
0.885*
1.000*
0.488*
0.941*
0.699*
0.986*
0.784*
0.942*
0.845*
1.000*
0.743*
0.932*
0.776*
1.000*
0.922*
0.924*
0.636*
0.874*
0.628*
0.934* (Continued)
TABLE 2. (Continued ) Protocol Item Presence of sub-harmonics at medium frequencies Presence of sub-harmonics at high frequencies Presence of sub-harmonics in vocal spectrogram as a whole
Kendall Inter
Kendall Intra
0.504
1.000*
0.651*
0.874*
* Significant values P ≤ 0.001. Kendall coefficient.
the results obtained in the present study with other research. Still, no correlations were made with other instruments precisely because there are no similar standardized protocols for this type of analysis. Reliability is defined as the degree to which results obtained in a test are expected to be consistent or reproductive when examined by the same judge. Also, to be reliable, when applied to the same group by two or more judges, the same test should yield very similar results. The more similar the scores of participants in different applications, the greater the reliability of a test.19,37 Therefore, through the results obtained, it is possible to affirm that the SVAP presents adequate reliability. In another study, we assessed the reliability and validity of auditory perceptual and acoustic measures (Praat software) in patients with adductor spasmodic dysphonia. To assess interand intrajudge reliability, Pearson's correlation coefficient was used. In the auditory perceptual assessment, the intrajudge reliability ranged from r = 0.802 to r = 0.978, and between evaluators ranged from r = 0.747 to r = 0.947. In the acoustic analysis, the intrajudge reliability was r = 0.645 (frequency changes), r = 0.969 (aperiodic segments), and r = 1.0 (phonation breaks), and interjudge it ranged from r = 0.102 to r = 1.0 Sensitivity and specificity of the measurements were examined, and auditory perceptual assessment showed high sensitivity (91.7%) and specificity (100%), while acoustic analysis showed low sensitivity (70.8%) and high specificity (100%). To compare the overall degree of vocal alteration by auditory perceptual assessment between subjects with adductor spasmodic dysphonia and a control group with normal subjects, the Student's t test was used. The results showed that the group with dysphonia presented overall degree significantly higher than the control group (t [23.086] = 7.849, P < 0.001).38 Although vocal assessment measures other than those assessed by SVAP were used, the study cited38 presented results similar to those obtained in SVAP for inter and intrajudge reliability. Still, it presented greater alteration in the group with dysphonia when compared to the normal group, as it was verified in our study in the criterion validity. In BS, all SVAP items had higher scores for the group with normal ENT diagnosis, except for items related to F bandwidth and antiresonance or damping, which was
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TABLE 3. Criterion Validity for SVAP Broadband Items Protocol Item
ENT Diagnosis
n
Mean
SD
Tracing color intensity of F1
Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered
24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26
5.50 4.31 5.33 4.19 3.92 3.19 2.67 1.88 5.17 4.08 4.67 4.23 2.25 2.00 5.25 3.81 5.29 4.12 4.54 3.81 3.38 3.27 2.25 1.77 5.17 3.54 5.46 3.54 3.96 2.81 5.46 3.92 3.79 4.88 3.79 5.73 3.46 5.62 3.79 6.00 2.04 6.00 2.33 5.27 1.92 4.92 1.88 5.54 2.17 5.35
0.978 0.788 1.465 0.895 1.283 1.201 1.341 1.211 1.204 0.891 1.090 0.908 1.152 1.020 0.847 0.749 1.334 0.993 1.414 1.021 1.345 1.185 1.152 0.863 1.049 0.582 0.779 0.761 0.859 0.694 1.141 0.796 0.977 1.107 1.021 0.827 0.884 0.804 1.062 0.632 1.160 0.748 0.963 0.667 1.018 0.935 1.035 0.761 1.090 0.797
Tracing color intensity of F2 Tracing color intensity of F3 Tracing color intensity of F4 Tracing color intensity of low frequencies Tracing color intensity of medium frequencies Tracing color intensity of high frequencies Tracing color intensity in vocal spectrogram as a whole Definition and regularity of F1 Definition and regularity of F2 Definition and regularity of F3 Definition and regularity of F4 Regularity of vertical striation tracing at low frequencies Regularity of vertical striation tracing at medium frequencies Regularity of vertical striation tracing at high frequencies Regularity of vertical striation tracing in vocal spectrogram as a whole Bandwidth of F1 Bandwidth of F2 Bandwidth of F3 Bandwidth of F4 Anti-resonance/damping immediately above F1 Anti-resonance/damping at low frequencies Anti-resonance/damping at medium frequencies Anti-resonance/damping at high frequencies Anti-resonance/damping in vocal spectrogram as a whole
T
P Value
4.74
≤0.001
3.29
0.002
2.06
0.045
2.16
0.035
2.54
0.001
1.54
0.130
0.81
0.420
6.38
≤0.001
3.51
0.001
2.11
0.039
0.29
0.769
1.67
0.100
6.70
≤0.001
8.81
≤0.001
5.23
≤0.001
5.47
≤0.001
3.69
0.001
7.40
≤0.001
9.03
≤0.001
8.84
≤0.001
14.20
≤0.001
12.61
≤0.001
10.88
≤0.001
14.34
≤0.001
11.83
≤0.001
t test with Bonferroni correction*. Subtitle: F1-1st Formant; F2-2nd Formant; F3-3rd Formant; F4-4th Formant; SD-standard deviation; normal-otorhinolaryngological diagnosis of normal larynx or posterior glottal gap; altered-otorhinolaryngological diagnosis of vocal fold disturbance.
expected. F bandwidth represents the effective response frequency range of the resonator, and increased bandwidth may suggest hypernasality.9,29 Also, a recent study related
the increase of F1 bandwidth with the auditory perceptual characteristic of breathiness.9 Antiresonance or damping is described in the literature as an acoustic dampening due to
ARTICLE IN PRESS Gabriele Rodrigues Bastilha, et al
Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 7
TABLE 4. Criterion Validity for SVAP Narrowband Items Protocol Item
ENT Diagnosis
n
Mean
SD
T
p Value
Tracing color intensity of low frequencies
Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered
24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26
5.46 3.81 5.04 3.96 2.25 2.04 5.30 3.65 2.63 5.35 2.42 4.62 1.71 3.96 2.63 5.35 1.63 4.12 1.75 3.15 1.25 3.65 1.67 4.73 5.75 3.23 5.42 3.58 2.13 1.73 5.83 3.35 5.92 3.69 5.58 3.69 1.92 1.58 5.88 3.35 0.25 0.85 0.17 0.77 0.17 0.31 0.25 0.88
0.721 0.895 0.806 0.825 1.482 0.825 0.876 0.629 1.096 0.892 1.060 1.472 1.301 1.928 1.056 0.797 0.770 0.816 0.944 1.567 1.032 1.853 0.816 0.827 0.737 0.815 0.776 0.643 1.569 1.002 0.637 0.689 0.881 0.788 1.258 0.679 1.442 1.065 0.797 0.689 0.442 0.834 0.381 0.863 0.381 0.618 0.442 0.864
7.14
≤0.001
4.67
≤0.001
0.61
0.5314
7.64
≤0.001
9.66
≤0.001
6.01
≤0.001
4.80
≤0.001
10.33
≤0.001
11.07
≤0.001
3.87
0.001
5.72
≤0.001
13.16
≤0.001
11.42
≤0.001
9.15
≤0.001
1.06
0.291
13.21
≤0.001
9.42
≤0.001
6.57
≤0.001
0.95
0.346
12.02
≤0.001
3.19
0.003
3.23
0.003
0.980
0.341
3.30
0.002
Tracing color intensity of medium frequencies Tracing color intensity of high frequencies Tracing color intensity in vocal spectrogram as a whole Presence of noise at low frequencies Presence of noise at medium frequencies Presence of noise at high frequencies Presence of noise in vocal spectrogram as a whole Replacement of harmonics by noise at low frequencies Replacement of harmonics by noise at medium frequencies Replacement of harmonics by noise at high frequencies Replacement of harmonics by noise in vocal spectrogram as a whole Definition and regularity of harmonics at low frequencies Definition and regularity of harmonics at medium frequencies Definition and regularity of harmonics at high frequencies Definition and regularity of harmonics in vocal spectrogram as a whole Number of harmonics at low frequencies Number of harmonics at medium frequencies Number of harmonics at high frequencies Number of harmonics in vocal spectrogram as a whole Presence of sub-harmonics at low frequencies Presence of sub-harmonics at medium frequencies Presence of sub-harmonics at high frequencies Presence of sub-harmonics in vocal spectrogram as a whole
t test with Bonferroni correction*. Subtitle: SD-standard deviation; normal-otorhinolaryngological diagnosis of normal larynx or posterior glottal gap; altered-otorhinolaryngological diagnosis of vocal fold disturbance.
sound damping, and it may be related to the direction of the sound to the nasal cavity.29,39 Such aspects may be present to a greater degree in subjects with laryngeal alteration, as observed in our study.
In the SVAP NS items, the presence of noise and subharmonics and the replacement of harmonics by noise presented higher scores in the group with altered ENT diagnosis. The presence of noise on spectrography is an
ARTICLE IN PRESS 8 important indicator of the presence of vocal and/or laryngeal alterations, while the emission or in specific sections.8,39 The more aperiodic the vocal signal, the greater the replacement of the harmonic structure by noise.8,29 The subharmonic, in turn, is generally associated with the vibratory irregularity of the vocal fold mucosa, and it may be related to the presence of roughness present at emission and/or more intense vocal deviation.25,28,30 For the construction of the SVPA, all aspects analyzed in spectrographic vocal assessments were considered and the largest possible number of parameters available in the literature was included in a single protocol.1,6,14,18,20,22,26−30,35,37 −40
It is noteworthy that SVAP is a reliable and valid means to complement the data obtained in other voice assessments. Speech-language assessment should consider all aspects of vocal production, so a multidimensional assessment, including auditory perceptual, self-assessment, aerodynamic, otorhinolaryngological, and acoustic measurements is prioritized.1−6,22,23 CONCLUSIONS The SVAP presented adequate evidence of reliability and validity, being significantly reliable for the spectrographic vocal evaluation. It is considered that the instrument can be used in clinical practice and research in the field of voice, and it is suggested to continue studies regarding SVAP, such as discriminant and factor analysis. ACKNOWLEDGEMENTS This study was financed in part by the Coordena¸c ~ao de Aperfei¸c oamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. C. A. Cielo acknowledges support from Brazilian agency CNPq (Grant 301326/2017-7).
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APPENDIX A SPECTROGRAPHIC VOCAL ASSESSMENT PROTOCOL (SVAP) [Bastilha GR, Pagliarin KC, Cielo CA. (in press). Development and evidence of content validity of the Spectrographic Vocal Assessment Protocol (SVAP). J Voice. 2020.] Instructions: Using a linear analog scale with a score ranging from 0 to 10 cm, the evaluation of each aspect of the protocol should be carried out by marking a vertical line at any point on the ruler, according to the gradation observed at each aspect. For purposes of parameter analysis, low frequencies below 1500 Hz, medium frequencies between 1500 and 3000 Hz, and high frequencies above 3000 Hz should be considered.
BROADBAND VOCAL SPECTROGRAPHY 1. Color intensity of tracing In this item, zero corresponds to the total colorlessness of the trace, and 10 corresponds to the extreme color intensity of the spectrographic trace.
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Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 9
2. Definition and regularity of formants In this item, zero corresponds to the total irregularity and indefinition and 10 to the maximum regularity and definition of the formants.
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3. Trace regularity In this item, zero corresponds to the total irregularity and 10 to the maximum regularity of the trace.
5. Antiresonance/damping In this item, zero corresponds to the total absence of erasures (blanks or much lighter than the rest in the spectrography) and 10 to the presence/domain of the erasure spectrography window.
4. Bandwidth In this item, zero corresponds to fully reduced/absent and 10 to fully increased.
ARTICLE IN PRESS Gabriele Rodrigues Bastilha, et al
Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 11
NARROWBAND VOCAL SPECTROGRAPHY 1. Color intensity of tracing In this item, zero corresponds to the total colorlessness of the trace, and 10 corresponds to the extreme color intensity of the spectrographic trace.
2. Presence of noise In this item, zero corresponds to the total absence of noise and 10 to the maximum noise (shaded image) present.
3. Noise replacement of harmonics In this item, zero corresponds to the absence of noise harmonic replacement and 10 to the total noise harmonic replacement.
ARTICLE IN PRESS 12 4. Harmonic definition and regularity In this item, zero corresponds to the total irregularity and indefinition and 10 to the total regularity and definition of the harmonics.
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5. Number of harmonics In this item, zero corresponds to the absence of harmonics and 10 to the complete filling of the harmonic spectrographic image.
ARTICLE IN PRESS Gabriele Rodrigues Bastilha, et al
Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 13
6. Presence of subharmonics In this item, zero corresponds to the absence of subharmonics and 10 to the presence of subharmonics throughout the spectrography.
REFERENCES 1. Sataloff RT, Hawkshaw MJ, Johnson JL, et al. Prevalence of abnormal laryngeal findings in healthy singing teachers. J Voice. 2012;26:577–583. https://doi.org/10.1016/j.jvoice.2012.01.002. 2. Paes SM, Zambon F, Yamasaki R, et al. Immediate effects of the finish resonance tube method on behavioral dysphonia. J Voice. 2013;27:717–722. https://doi.org/10.1016/j.jvoice.2013.04.007. 3. Behlau M. Voz: o Livro do Especialista. Rio de Janeiro: Revinter; 2013:348. 4. Cielo CA, Christmann MK. Finger Kazoo: spectrographic acoustic modifications and vocal self-assessment. Rev CEFAC. 2014;16:1239– 1254. https://doi.org/10.1590/1982-021620145513. 5. Cielo CA, Ribeiro VV, Bastilha GR, et al. Quality of life in voice, perceptual-auditory assessment and voice acoustic analysis of teachers with vocal complaints. Audiol Commun Res. 2015;20:130–140. https:// doi.org/10.1590/S2317-6431201500020000151. 6. Fu S, Theodoros DG, Ward EC. Intensive versus traditional voice therapy for vocal nodules: perceptual, physiological, acoustic and aerodynamic changes. J Voice. 2015;29. https://doi.org/10.1016/j. jvoice.2014.06.005. 260.e31-44.
7. Souza A, Gama ACC. Spectrographic trace visual support: impact on reliability of auditoryperceptual voice analysis by inexperienced evaluators. Disturb Comun. 2015;27:483–490. 8. Lopes LW, Alves GAS, Melo ML. Content evidence of a spectrographic analysis protocol. Rev CEFAC. 2017;19:510–528. https://doi. org/10.1590/1982-021620171942917. 9. Narasimhan SV, VishaL K. Spectral measures of hoarseness in persons with hyperfunctional voice disorder. J Voice. 2017;31:57–61. https:// doi.org/10.1016/j.jvoice.2016.03.005. 10. Nunez-Batalla F, Nieto SC, Pinto MC, et al. Estudio sonográfico de la disfonía: Subarm onicos. Acta Otorrinolaringol Esp. 2000;51:23–27. 11. Pontes PAL, Vieira VP, Goncalves MIR, et al. Characteristics of hoarse, rough and normal voices: acoustic spectrographic comparative analysis. Rev Bras Otorrinolaringol. 2002;68:182–188. https://doi.org/ 10.1590/S0034-72992002000200005. 12. Nunez-Batalla F, Santos PC, González BS, et al. Evaluaci on espectral cuantitativa de la hipofunci on vocal. Acta Otorrinolaringol Esp. 2004;55:327–333. https://doi.org/10.1016/S0001-6519(04)78531-3. 13. Martens J, Versnel H, Dejonckere PH. The effect of visible speech in the perceptual rating of pathological voices. Arch Otolaryngol Head Neck Surg. 2007;133(2):178–185. https://doi.org/10.1001/archotol.133.2.178. 14. C^ ortes MG, Gama ACC. Visual analysis of spectrographic parameters before and after dysphonia therapy. Rev Soc Bras Fonoaudiol. 2010;15: 243–249. https://doi.org/10.1590/S1516-80342010000200016. 15. Pires IC. Protocolo de Análise da voz, da Expressividade e dos Hábitos de Professores Por Meio de Registros Audiovisuais. 103f. S~ao Paulo: Universidade de S~ao Paulo; 2012. [Dissertation]. 16. Gurgel LG, Kaiser V, Reppold CT. The search for validity evidence in the development of instruments in speech therapy: a systematic review. Audiol Commun Res. 2015;20:371–383. https://doi.org/10.1590/23176431-2015-1600. 17. Pernambuco L, Espelt A, Virgílio HMJ, et al. Recommendations for elaboration, transcultural adaptation and validation process of tests in Speech, Hearing and Language Pathology. CoDAS. 2017;29:5–8. https://doi.org/10.1590/2317-1782/20172016217. 18. Bastilha GR, Pagliarin KC, Cielo CA. Development and evidence of content validity of the Spectrographic Vocal Assessment Protocol (SVAP). J Voice. 2020. https://doi.org/10.1016/j.jvoice.2019.12.008. (In press). 19. Pagliarin KC, Ortiz KZ, Parente MA, et al. Montreal-toulouse language assessment battery for aphasia: validity and reliability evidence. Neuro Rehab. 2014;34:463–471. https://doi.org/10.3233/NRE-141057. 20. Titze IR. Workshop on Acoustic Voice Analysis: Summary Statement. Denver: National Center for Voice and Speech; 1995:36. 21. Gama ACC, Santos LLM, Sanches NA, et al. Studying the effect of spectrogram visual support of in the auditory-perceptive voice evaluation reliability. Rev CEFAC. 2011;13:314–321. https://doi.org/10.1590/ S1516-18462010005000123. 22. Lima JPM. Modifica¸c ~oes Vocais e Laríngeas Imediatas em Mulheres Apos a Técnica de Fona¸c ~ao em Tubo de Vidro Imerso em Agua. 134f. Santa Maria: Universidade Federal de Santa Maria; 2013. [Dissertation]. 23. Guzmán M, Callejas C, Castro C, et al. Efecto terapéutico de los ejercicios con tracto vocal semiocluido en pacientes con disfonía m usculo tensional tipo I. Rev Logop Fon Aud. 2012;32:139–146. https://doi.org/ 10.1016/j.rlfa.2012.05.004. 24. Cielo CA, Ribeiro VVR, Bastilha GRB. Spectrographic voice measures, vocal complaints and occupational data of elementary school teachers. Disturb Comum. 2015;27:299–308. 25. Medina V, Simoes-Zenari M, Nemr NK. Acoustic voice analysis: effect of an audio-visual training for speech therapy undergraduates. Audiol Commun Res. 2015;20:123–129. https://doi.org/10.1590/S231764312015000200001419. 26. Barros APB, Carrara de Angelis E. Análise ac ustica da voz. Dedivitis RA, Barros APB, eds. Análise ac ustica da voz. Métodos de Avalia¸c ~ao e Diagnostico da Laringe e Voz. 2002:200–221. 27. Vieira VP, Biase N, PonteS P. Análise ac ustica e perceptiva auditiva versus coapta¸c ~ao gl otica em altera¸c ~ao estrutural mínima. Acta ORL. 2006;24:174–180.
ARTICLE IN PRESS 14 28. Valentim AF, C^ ortes MG, Gama AC. Spectrographic analysis of the voice: effect of visual training on the reliability of evaluation. Rev Soc Bras Fonoaudiol. 2010;15:335–342. https://doi.org/10.1590/S151680342010000300005. 29. Beber BC, Cielo CA. Features of wide and narrow band spectrography as for vocal emission of men with larynx without diseases. Rev CEFAC. 2012;14:290–297. https://doi.org/10.1590/S1516-18462012005000008. 30. Rodriguez-Parra MJ, Adrian JA, Casado JC. Comparing voice-therapy and vocal-hygiene treatments in dysphonia using a limited multidimensional evaluation protocol. J Commun Disord. 2011;44:615–630. https://doi.org/10.1016/j.jcomdis.2011.07.003. 31. Falc~ ao LMG, Masson MLV, Oliveira G, et al. Spectrographic analysis of the effect of vocal warm-up on the voice of choir girls. Audiol Commun Res. 2014;19:380–386. https://doi.org/10.1590/S2317-64312014 000300001372. 32. Sprecher A, Olszewski A, Jiang JJ. Updating signal typing in voice: addition of type 4 signals. J Acoust Soc Am. 2010;127:3710–3716. https://doi.org/10.1121/1.3397477. 33. Grant JS, Davis LL. Selection and use of content experts for instrument development. Res Nurs Health. 1997;20:269–274. https://doi.org/10.1002/ (SICI)1098-240X(199706)20:3<269:AID-NUR9>3.0.CO;2-G.
Journal of Voice, Vol. &&, No. &&, 2020 34. Alexandre NMC, Coluci MZO. Content validity in the development and adaptation processes of measurement instruments. Ci^enc Saude Coletiva. 2011;16:3061–3068. https://doi.org/10.1590/S1413-81232011 000800006. 35. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33:159–174. 36. R Core Team. R: a Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing; 2017. https://www.R-project.org/. 37. Hutz CS, Bandeira DR, Trentini CM. Psicometria. Porto Alegre: Artmed; 2015:192. 38. Yanagida S, Nishizawa N, Hashimoto R, et al. Reliability and validity of speech evaluation in adductor spasmodic dysphonia. J Voice. 2018;32:585–591. https://doi.org/10.1016/j.jvoice.2017. 06.022. 39. Ozbal-Koc EA, Koc B, Ercan I, et al. Effects of septoplasty on speech and voice. J Voice. 2014;28. https://doi.org/10.1016/j.jvoice. 2013.09.008. 393.e11-5. 40. Lopes LW, Alves GAS, Melo ML. Content evidence of a spectrographic analysis protocol. Rev CEFAC. 2017;19:510–528. https://doi. org/10.1590/1982-021620171942917.
Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Validity *Gabriele Rodrigues Bastilha, *Karina Carlesso Pagliarin, †Denis Altieri de Oliveira Moraes, and *Carla Aparecida Cielo, *ySanta Maria, Brasil Summary: Objective. To present evidence of the reliability and validity in the Spectrographic Vocal Assessment Protocol. Methods. The sample consisted of 50 female participants, aged 25−62 years old, 24 with a otorhinolaryngological diagnosis of the normal larynx or posterior glottal gap, and 26 diagnosed with vocal fold disturbances. The emission of the vowel /a:/ was analyzed by the Real Time Spectrogram software. The spectrographs were analyzed with a protocol by two speech therapist judges. For reliability analysis, inter- and intrajudge analysis were performed using the Kendall coefficient. For criterion validity, the t test for matched samples with Bonferroni correction was used to compare the average performance of the protocol between the two groups of subjects. Results. Protocol reliability: for broadband items, the agreement between judges ranged from moderate (0.462) to almost perfect (0.888), and it is significant for all items, and an intrajudge agreement was almost perfect and significant (0.865−1.000) for all items. For narrowband items, the agreement between judges ranged from moderate (0.469) to almost perfect (0.922), and it is significant for all items except for the presence of “subharmonics in high frequencies” where agreement was moderate (0.504), but not significant, and the intrajudge agreement was almost perfect (0.874−1.000) and significant for all items. Criterion validity: for most broadband and narrowband items, the groups with normal or altered diagnosis differed statistically. Conclusion. The Spectrographic Vocal Assessment Protocol presented adequate evidence in reliability and validity. Key Words: Acoustics−Spectrography−Validation studies−Speech, language and hearing sciences−Voice.
INTRODUCTION Vocal spectrography allows the analysis of the spectrographic characteristics of the sound produced by the vocal folds, as well as the changes generated by the vocal tract. This assessment makes it possible to analyze, among other aspects, the darkening of the trace color of the formants (F) and the different frequency ranges, noise presence, F definition, trace regularity, number of harmonics, and presence of subharmonics. However, it depends on the judge's visual analysis, which is a subjective aspect.1−9 Although it is a complementary analysis of the auditoryperceptive voice assessment, the visual support of the spectrographic image significantly increases the reliability of this assessment. Some authors try to correlate the spectrographic data to the different types of voices.7,9−14 Hoarseness is related to the substitution of the trace noise. In hoarseness, the harmonics may be completely erased and this is a characteristic sign vocal fold vibration. In the breathy voice, reduced energy is observed high frequencies, with weak harmonics and the presence of noise between Accepted for publication February 20, 2020. From the *Department of Speech-Language Pathology and Audiology, Universidade Federal de Santa Maria/UFSM, Santa Maria, Rio Grande do Sul, Brasil; and the yDepartment of Statistics, Universidade Federal de Santa Maria/UFSM, Santa Maria, Rio Grande do Sul, Brasil. Address correspondence and reprint requests to Gabriele Rodrigues Bastilha, Department of Speech-Language Pathology and Audiology, Universidade Federal de Santa Maria/UFSM, Av. Roraima no 1000, Prédio 26 - Fonoaudiologia, UFSM, Bairro Camobi, Santa Maria, RS, CEP: 97105-900, Brasil. E-mail: [email protected] Journal of Voice, Vol. &&, No. &&, pp. &&−&& 0892-1997 © 2020 The Voice Foundation. Published by Elsevier Inc. All rights reserved. https://doi.org/10.1016/j.jvoice.2020.02.017
them. The unstable vocal quality is characterized disturbance in the waveform. There are frequency breaks when there are abrupt changes in tracing the fundamental frequency (f0). Abrupt interruptions in the recording are characteristic loudness breaks.13,14 The presence of subharmonics in narrowband spectrography is common in rough and diplophonic voices.10,12 The bandwidth of F relates to the perceptual hearing parameter of breathiness.9 In research, a spectrographic evaluation of hoarse, rough, and normal voices was carried out. It was found that harmonics were present in large quantities and greater definition in normal voices, and decreased in quantity and quality in rough and hoarse voices. The noise was present in large quantities and diffusely in hoarse voices and a lesser amount in rough and normal voices. In normal voices, there was a large number of harmonics in the high frequencies (above 3 kHz). In altered voices, there was an absence of harmonics in the high frequencies, so that the region above 3 kHz could appear darkened with the presence of only noise.11 There is a great clinical and scientific demand for assessment instruments suitable to the various realities in all scientific fields, but especially in the health area. For the voice area growing, the use of accurate, valid, and sensitive tests is of utmost importance.15−17 Standardizing the aspects that are important in spectrographic analysis, the Spectrographic Vocal Assessment Protocol (SVAP) was developed in another study and presented content evidence considered as satisfactory.18 This article presents the theoretical basis used for the construction of SVAP items and their development process.18
ARTICLE IN PRESS 2 A recent study aimed to identify, through a systematic literature review, the use of psychometrics in the field of speech therapy and the processes used to search for evidence of the validity of instruments in the area. It concluded that the use of principles of the search for shreds of evidence the validity of instruments speech therapy area is still scarce. However, most studies have been developed in recent years, showing a current trend to pay attention to the need for improvement of instruments and advances in this area. The authors of the research cited found only four published studies on the validation of specific instruments in the voice area.16 And so far, there is no validated SVAP. It is believed that most of the difficulties lie in the professionals' lack of knowledge of the methodological and psychometric aspects necessary for an instrument, in addition to the cost involved in this process.15−17,19 Considering the importance of conducting psychometric studies with vocal assessment instruments and the lack of validated spectrographic vocal assessment instrument, this study aimed to present the evidence of reliability and criterion validity for SVAP. METHODS Participants The sample consisted of 50 records of women, recruited the database of the Voice Laboratory, Speech Therapy Course of the institution of origin (24 had an ENT/otorhinolaryngological diagnosis of the normal larynx or posterior glottal gap, and 26 had an ENT diagnosis of vocal fold disturbances). Of the 26 participants had an otorhinolaryngological diagnosis of vocal fold disturbances, 13 had a glottal gap and vocal nodules, 9 had a glottal gap (except the posterior glottal gap), and 4 had vocal cysts. It is noteworthy that the groups (normal and with vocal folds disturbances) were paired exactly by age in years, presenting a general average of 39.6 years and a standard deviation of 11.3 years. The inclusion criteria adopted were: presenting ENT diagnosis; age group from 19 to 64 years old (adult and middle age—DeCS, 2019), absent the period of vocal change and presbyphonia. Exclusion criteria were: a self-reported previous history of neurological, gastric, psychiatric, endocrinological, respiratory, pregnancy, and the presence of hearing loss. These criteria may influence vocal performance, voice self-monitoring, and/or vocal quality.
Procedures and instruments The study was approved by the Research Ethics Committee of the institution of origin with the number 1.570.886. Data collection occurred with the participants in a standing position, and they asked to emit the vowel /a:/ in usual pitch and loudness after deep inspiration, at maximum phonation time. The emissions recorded with a Behringer ECM 8000 omnidirectional professional microphone, coupled with the Zoom model H4n professional digital recorder, positioned in front and at a 90° angle at a distance of 4 cm
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between the microphone and mouth. The recordings were made in a room with environmental noise below 50 dBNPS, measured with an Instrutherm digital sound pressure level meter, model Dec-480.4,5,14,20−25 The vowel /a:/ was used because it best represents the glottic function, it has less interference of the transfer factor relative to the resonance of the sound during passage through the vocal tract, and it is the one with the most accurate f0 measurements, and, therefore, it suffers less noise influence.14,24,26−29 It is noteworthy that the procedures described above are standardized in the school clinic and in the laboratory research where the research was performed, thus having uniformity in the records and data stored in the database. The emission of the vowel /a:/ was analyzed by Real Time Spectrogram software (Kay Pentax (USA)), resulting in images of the spectral acoustic vocal analysis. In the broadband filter, 100 points (646.00 Hz) and 1024 points (63.09 Hz) narrowband filter used, both with 11 kHz sampling rate and 16 bits of analog-to-digital conversion, in a window of 5 kHz.5,6,14,25,30 For spectrographic analysis, SVAP (Appendix A) was used. SVAP consists of two parts: Broadband Spectrography and Narrowband Spectrography (NS), with their respective parameters.18 To fill the SVAP, a linear analog scale with a score ranging from 0 to 10 cm is used. The assessment of each parameter should be performed by marking a vertical line at any point of the millimeter ruler, according to the observed gradation.2,5,6,23,25,31 For parameter analysis, low frequencies below 1500 Hz, medium frequencies between 1500 and 3000 Hz, and high frequencies above 3000 Hz are considered,3,10−12,32 and each instrument item has a brief orientation.
Reliability For inter- and intrajudge reliability analysis, two speechlanguage pathologists, nonauthors, with at least 5 years' experience in voice and spectrographic analysis participated. Such judges were blinded to the research objectives, identification, and diagnosis of the subjects.31,33,34 The judges did not receive prior individual or joint training because such training would be a methodological bias, affecting the results. The judges had previous experience and knowledge in spectrographic evaluation, verified by their curriculum.5,14,21,30 The 50 spectrographs were analyzed using SVAP individually by the two expert judges (interjudge reliability). After 30 days, the same judges analyzed the same spectrographs again (intrajudge reliability). The spectrographic images were sent to the judges through Dropbox (USA) (examples of the spectrographs analyzed by the judges are in Figures 1 and 2). For data analysis, the Kendall coefficient of the agreement was used, and significant results were considered when p£0.001. Assessing agreement, the following values were used: >0.81 (almost perfect), 0.61−0.8 (substantial),
ARTICLE IN PRESS Gabriele Rodrigues Bastilha, et al
Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 3
FIGURE 1. Normal spectrographic image.
FIGURE 2. Spectrographic image of subject with glottal gap and vocal nodules.
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TABLE 1. Inter- and Intrajudge Agreement on SVAP Broadband Items
0.41−0.6 (moderate), 0.21−0.4 (fair), and 0.0−0.2 (slight), <0.0 (poor).35
Protocol Item
Criterion validity Criterion validity is one of the steps for instrument validation. In this study, to verify the criterion validity of the SVAP, as recommended by Psychometry, the “criterion” used was to present or not a disturbance in vocal folds, according to an ENT diagnosis. From this, the spectrographs of the two groups were analyzed: 24 with normal larynx or posterior glottal gap and 26 with vocal fold disturbance. SVAP was answered by one of the expert judges. The data obtained from this analysis were tabulated and the realiability analyzed in SPSS version 21 for Windows, the t test for matched samples with Bonferroni correction to control for alpha slippage was performed with the R software,36 considering significant results when P ≤ 0.05.
Tracing color intensity of F1 Tracing color intensity of F2 Tracing color intensity of F3 Tracing color intensity of F4 Tracing color intensity of low frequencies Tracing color intensity of medium frequencies Tracing color intensity of high frequencies Tracing color intensity in vocal spectrogram as a whole Definition and regularity of F1 Definition and regularity of F2 Definition and regularity of F3 Definition and regularity of F4 Regularity of vertical striation tracing at low frequencies Regularity of vertical striation tracing at medium frequencies Regularity of vertical striation tracing at high frequencies Regularity of vertical striation tracing in vocal spectrogram as a whole Bandwidth of F1 Bandwidth of F2 Bandwidth of F3 Bandwidth of F4 Anti-resonance/damping immediately above F1 Anti-resonance/damping at low frequencies Anti-resonance/damping at medium frequencies Anti-resonance/damping at high frequencies Anti-resonance/damping in vocal spectrogram as a whole
Kendall Inter
Kendall Intra
0.462*
0.902*
0.547*
0.902*
0.697*
0.981*
0.529*
0.933*
0.642*
0.875*
0.578*
0.865*
0.616*
1.000*
0.882*
0.919*
0.587*
0.933*
0.661*
0.918*
0.729*
0.881*
0.477*
0.979*
0.789*
0.988*
0.740*
0.952*
0.642*
1.000*
0.682*
0.904*
0.770* 0.627* 0.778** 0.745* 0.836*
0.942* 0.918** 0.873* 0.913** 0.984*
0.848*
0.959*
0.804*
0.965*
0.867*
0.969*
0.888*
0.952*
* Significant values P ≤ 0.001. Subtitle: F1-1st Formant; F2-2nd Formant; F3-3rd Formant; F4-4th Formant. Kendall coefficient.
RESULTS For SVAP broadband items (Table 1), the agreement between judges ranged from moderate to almost perfect, being significant for all items, and an intrajudge agreement was almost perfect and significant for all items. For SVAP narrowband items (Table 2), the agreement between judges ranged from moderate to almost perfect, and it was significant for all items except for the “presence of high-frequency subharmonics” where the agreement was moderate but not significant (P = 0.120). The intrajudge agreement was almost perfect and significant for all SVAP narrowband items. Regarding the validity of the SVAP criterion, the groups with normal or altered ENT diagnosis differ statistically in the vast majority of broadband (Table 3) and narrowband (Table 4) items. DISCUSSION Contributing to the standardization of visual analysis of vocal spectrographs and the reduction of subjectivity in this type of assessment, the analysis of reliability and validity of SVAP criteria was performed. The inter and intra expert judge agreement ranged from moderate to almost perfect, being significant for all SVAP items, except for the “presence of subharmonics in high frequencies” (NS) where the agreement was moderate but not significant. Still, it was possible to verify that there is a difference between the subjects with normal or altered ENT diagnosis regarding the performance of SVAP. The results obtained were satisfactory, and they indicated that SVAP presents good evidence and it can be used in clinical practice and research as an instrument to assess vocal spectrographs. A recent study developed a spectrographic evaluation protocol, but only performed its content validation, without presenting evidence of reliability or criterion validity.8 Therefore, to date, there is no other validated SVAP in the literature, which makes it difficult to discuss and compare
ARTICLE IN PRESS Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 5
Gabriele Rodrigues Bastilha, et al
TABLE 2. Inter- and Intrajudge Agreement on SVAP Narrowband Items Protocol Item Tracing color intensity of low frequencies Tracing color intensity of medium frequencies Tracing color intensity of high frequencies Tracing color intensity in vocal spectrogram as a whole Presence of noise at low frequencies Presence of noise at medium frequencies Presence of noise at high frequencies Presence of noise in vocal spectrogram as a whole Replacement of harmonics by noise at low frequencies Replacement of harmonics by noise at medium frequencies Replacement of harmonics by noise at high frequencies Replacement of harmonics by noise in vocal spectrogram as a whole Definition and regularity of harmonics at low frequencies Definition and regularity of harmonics at medium frequencies Definition and regularity of harmonics at high frequencies Definition and regularity of harmonics in vocal spectrogram as a whole Number of harmonics at low frequencies Number of harmonics at medium frequencies Number of harmonics at high frequencies Number of harmonics in vocal spectrogram as a whole Presence of sub-harmonics at low frequencies
Kendall Inter
Kendall Intra
0.659*
0.893*
0.568*
0.875*
0.469*
1.000*
0.679*
0.982*
0.737*
1.000*
0.708*
1.000*
0.742*
0.942*
0.804*
0.989*
0.776*
1.000*
0.586*
0.925*
0.612*
0.984*
0.878*
0. 952*
0.885*
1.000*
0.488*
0.941*
0.699*
0.986*
0.784*
0.942*
0.845*
1.000*
0.743*
0.932*
0.776*
1.000*
0.922*
0.924*
0.636*
0.874*
0.628*
0.934* (Continued)
TABLE 2. (Continued ) Protocol Item Presence of sub-harmonics at medium frequencies Presence of sub-harmonics at high frequencies Presence of sub-harmonics in vocal spectrogram as a whole
Kendall Inter
Kendall Intra
0.504
1.000*
0.651*
0.874*
* Significant values P ≤ 0.001. Kendall coefficient.
the results obtained in the present study with other research. Still, no correlations were made with other instruments precisely because there are no similar standardized protocols for this type of analysis. Reliability is defined as the degree to which results obtained in a test are expected to be consistent or reproductive when examined by the same judge. Also, to be reliable, when applied to the same group by two or more judges, the same test should yield very similar results. The more similar the scores of participants in different applications, the greater the reliability of a test.19,37 Therefore, through the results obtained, it is possible to affirm that the SVAP presents adequate reliability. In another study, we assessed the reliability and validity of auditory perceptual and acoustic measures (Praat software) in patients with adductor spasmodic dysphonia. To assess interand intrajudge reliability, Pearson's correlation coefficient was used. In the auditory perceptual assessment, the intrajudge reliability ranged from r = 0.802 to r = 0.978, and between evaluators ranged from r = 0.747 to r = 0.947. In the acoustic analysis, the intrajudge reliability was r = 0.645 (frequency changes), r = 0.969 (aperiodic segments), and r = 1.0 (phonation breaks), and interjudge it ranged from r = 0.102 to r = 1.0 Sensitivity and specificity of the measurements were examined, and auditory perceptual assessment showed high sensitivity (91.7%) and specificity (100%), while acoustic analysis showed low sensitivity (70.8%) and high specificity (100%). To compare the overall degree of vocal alteration by auditory perceptual assessment between subjects with adductor spasmodic dysphonia and a control group with normal subjects, the Student's t test was used. The results showed that the group with dysphonia presented overall degree significantly higher than the control group (t [23.086] = 7.849, P < 0.001).38 Although vocal assessment measures other than those assessed by SVAP were used, the study cited38 presented results similar to those obtained in SVAP for inter and intrajudge reliability. Still, it presented greater alteration in the group with dysphonia when compared to the normal group, as it was verified in our study in the criterion validity. In BS, all SVAP items had higher scores for the group with normal ENT diagnosis, except for items related to F bandwidth and antiresonance or damping, which was
ARTICLE IN PRESS 6
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TABLE 3. Criterion Validity for SVAP Broadband Items Protocol Item
ENT Diagnosis
n
Mean
SD
Tracing color intensity of F1
Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered
24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26
5.50 4.31 5.33 4.19 3.92 3.19 2.67 1.88 5.17 4.08 4.67 4.23 2.25 2.00 5.25 3.81 5.29 4.12 4.54 3.81 3.38 3.27 2.25 1.77 5.17 3.54 5.46 3.54 3.96 2.81 5.46 3.92 3.79 4.88 3.79 5.73 3.46 5.62 3.79 6.00 2.04 6.00 2.33 5.27 1.92 4.92 1.88 5.54 2.17 5.35
0.978 0.788 1.465 0.895 1.283 1.201 1.341 1.211 1.204 0.891 1.090 0.908 1.152 1.020 0.847 0.749 1.334 0.993 1.414 1.021 1.345 1.185 1.152 0.863 1.049 0.582 0.779 0.761 0.859 0.694 1.141 0.796 0.977 1.107 1.021 0.827 0.884 0.804 1.062 0.632 1.160 0.748 0.963 0.667 1.018 0.935 1.035 0.761 1.090 0.797
Tracing color intensity of F2 Tracing color intensity of F3 Tracing color intensity of F4 Tracing color intensity of low frequencies Tracing color intensity of medium frequencies Tracing color intensity of high frequencies Tracing color intensity in vocal spectrogram as a whole Definition and regularity of F1 Definition and regularity of F2 Definition and regularity of F3 Definition and regularity of F4 Regularity of vertical striation tracing at low frequencies Regularity of vertical striation tracing at medium frequencies Regularity of vertical striation tracing at high frequencies Regularity of vertical striation tracing in vocal spectrogram as a whole Bandwidth of F1 Bandwidth of F2 Bandwidth of F3 Bandwidth of F4 Anti-resonance/damping immediately above F1 Anti-resonance/damping at low frequencies Anti-resonance/damping at medium frequencies Anti-resonance/damping at high frequencies Anti-resonance/damping in vocal spectrogram as a whole
T
P Value
4.74
≤0.001
3.29
0.002
2.06
0.045
2.16
0.035
2.54
0.001
1.54
0.130
0.81
0.420
6.38
≤0.001
3.51
0.001
2.11
0.039
0.29
0.769
1.67
0.100
6.70
≤0.001
8.81
≤0.001
5.23
≤0.001
5.47
≤0.001
3.69
0.001
7.40
≤0.001
9.03
≤0.001
8.84
≤0.001
14.20
≤0.001
12.61
≤0.001
10.88
≤0.001
14.34
≤0.001
11.83
≤0.001
t test with Bonferroni correction*. Subtitle: F1-1st Formant; F2-2nd Formant; F3-3rd Formant; F4-4th Formant; SD-standard deviation; normal-otorhinolaryngological diagnosis of normal larynx or posterior glottal gap; altered-otorhinolaryngological diagnosis of vocal fold disturbance.
expected. F bandwidth represents the effective response frequency range of the resonator, and increased bandwidth may suggest hypernasality.9,29 Also, a recent study related
the increase of F1 bandwidth with the auditory perceptual characteristic of breathiness.9 Antiresonance or damping is described in the literature as an acoustic dampening due to
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Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 7
TABLE 4. Criterion Validity for SVAP Narrowband Items Protocol Item
ENT Diagnosis
n
Mean
SD
T
p Value
Tracing color intensity of low frequencies
Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered Normal Altered
24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26 24 26
5.46 3.81 5.04 3.96 2.25 2.04 5.30 3.65 2.63 5.35 2.42 4.62 1.71 3.96 2.63 5.35 1.63 4.12 1.75 3.15 1.25 3.65 1.67 4.73 5.75 3.23 5.42 3.58 2.13 1.73 5.83 3.35 5.92 3.69 5.58 3.69 1.92 1.58 5.88 3.35 0.25 0.85 0.17 0.77 0.17 0.31 0.25 0.88
0.721 0.895 0.806 0.825 1.482 0.825 0.876 0.629 1.096 0.892 1.060 1.472 1.301 1.928 1.056 0.797 0.770 0.816 0.944 1.567 1.032 1.853 0.816 0.827 0.737 0.815 0.776 0.643 1.569 1.002 0.637 0.689 0.881 0.788 1.258 0.679 1.442 1.065 0.797 0.689 0.442 0.834 0.381 0.863 0.381 0.618 0.442 0.864
7.14
≤0.001
4.67
≤0.001
0.61
0.5314
7.64
≤0.001
9.66
≤0.001
6.01
≤0.001
4.80
≤0.001
10.33
≤0.001
11.07
≤0.001
3.87
0.001
5.72
≤0.001
13.16
≤0.001
11.42
≤0.001
9.15
≤0.001
1.06
0.291
13.21
≤0.001
9.42
≤0.001
6.57
≤0.001
0.95
0.346
12.02
≤0.001
3.19
0.003
3.23
0.003
0.980
0.341
3.30
0.002
Tracing color intensity of medium frequencies Tracing color intensity of high frequencies Tracing color intensity in vocal spectrogram as a whole Presence of noise at low frequencies Presence of noise at medium frequencies Presence of noise at high frequencies Presence of noise in vocal spectrogram as a whole Replacement of harmonics by noise at low frequencies Replacement of harmonics by noise at medium frequencies Replacement of harmonics by noise at high frequencies Replacement of harmonics by noise in vocal spectrogram as a whole Definition and regularity of harmonics at low frequencies Definition and regularity of harmonics at medium frequencies Definition and regularity of harmonics at high frequencies Definition and regularity of harmonics in vocal spectrogram as a whole Number of harmonics at low frequencies Number of harmonics at medium frequencies Number of harmonics at high frequencies Number of harmonics in vocal spectrogram as a whole Presence of sub-harmonics at low frequencies Presence of sub-harmonics at medium frequencies Presence of sub-harmonics at high frequencies Presence of sub-harmonics in vocal spectrogram as a whole
t test with Bonferroni correction*. Subtitle: SD-standard deviation; normal-otorhinolaryngological diagnosis of normal larynx or posterior glottal gap; altered-otorhinolaryngological diagnosis of vocal fold disturbance.
sound damping, and it may be related to the direction of the sound to the nasal cavity.29,39 Such aspects may be present to a greater degree in subjects with laryngeal alteration, as observed in our study.
In the SVAP NS items, the presence of noise and subharmonics and the replacement of harmonics by noise presented higher scores in the group with altered ENT diagnosis. The presence of noise on spectrography is an
ARTICLE IN PRESS 8 important indicator of the presence of vocal and/or laryngeal alterations, while the emission or in specific sections.8,39 The more aperiodic the vocal signal, the greater the replacement of the harmonic structure by noise.8,29 The subharmonic, in turn, is generally associated with the vibratory irregularity of the vocal fold mucosa, and it may be related to the presence of roughness present at emission and/or more intense vocal deviation.25,28,30 For the construction of the SVPA, all aspects analyzed in spectrographic vocal assessments were considered and the largest possible number of parameters available in the literature was included in a single protocol.1,6,14,18,20,22,26−30,35,37 −40
It is noteworthy that SVAP is a reliable and valid means to complement the data obtained in other voice assessments. Speech-language assessment should consider all aspects of vocal production, so a multidimensional assessment, including auditory perceptual, self-assessment, aerodynamic, otorhinolaryngological, and acoustic measurements is prioritized.1−6,22,23 CONCLUSIONS The SVAP presented adequate evidence of reliability and validity, being significantly reliable for the spectrographic vocal evaluation. It is considered that the instrument can be used in clinical practice and research in the field of voice, and it is suggested to continue studies regarding SVAP, such as discriminant and factor analysis. ACKNOWLEDGEMENTS This study was financed in part by the Coordena¸c ~ao de Aperfei¸c oamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. C. A. Cielo acknowledges support from Brazilian agency CNPq (Grant 301326/2017-7).
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APPENDIX A SPECTROGRAPHIC VOCAL ASSESSMENT PROTOCOL (SVAP) [Bastilha GR, Pagliarin KC, Cielo CA. (in press). Development and evidence of content validity of the Spectrographic Vocal Assessment Protocol (SVAP). J Voice. 2020.] Instructions: Using a linear analog scale with a score ranging from 0 to 10 cm, the evaluation of each aspect of the protocol should be carried out by marking a vertical line at any point on the ruler, according to the gradation observed at each aspect. For purposes of parameter analysis, low frequencies below 1500 Hz, medium frequencies between 1500 and 3000 Hz, and high frequencies above 3000 Hz should be considered.
BROADBAND VOCAL SPECTROGRAPHY 1. Color intensity of tracing In this item, zero corresponds to the total colorlessness of the trace, and 10 corresponds to the extreme color intensity of the spectrographic trace.
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Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 9
2. Definition and regularity of formants In this item, zero corresponds to the total irregularity and indefinition and 10 to the maximum regularity and definition of the formants.
ARTICLE IN PRESS 10
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3. Trace regularity In this item, zero corresponds to the total irregularity and 10 to the maximum regularity of the trace.
5. Antiresonance/damping In this item, zero corresponds to the total absence of erasures (blanks or much lighter than the rest in the spectrography) and 10 to the presence/domain of the erasure spectrography window.
4. Bandwidth In this item, zero corresponds to fully reduced/absent and 10 to fully increased.
ARTICLE IN PRESS Gabriele Rodrigues Bastilha, et al
Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 11
NARROWBAND VOCAL SPECTROGRAPHY 1. Color intensity of tracing In this item, zero corresponds to the total colorlessness of the trace, and 10 corresponds to the extreme color intensity of the spectrographic trace.
2. Presence of noise In this item, zero corresponds to the total absence of noise and 10 to the maximum noise (shaded image) present.
3. Noise replacement of harmonics In this item, zero corresponds to the absence of noise harmonic replacement and 10 to the total noise harmonic replacement.
ARTICLE IN PRESS 12 4. Harmonic definition and regularity In this item, zero corresponds to the total irregularity and indefinition and 10 to the total regularity and definition of the harmonics.
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5. Number of harmonics In this item, zero corresponds to the absence of harmonics and 10 to the complete filling of the harmonic spectrographic image.
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Spectrographic Vocal Assessment Protocol (SVAP): Reliability and Criterion Valid 13
6. Presence of subharmonics In this item, zero corresponds to the absence of subharmonics and 10 to the presence of subharmonics throughout the spectrography.
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