Pediatric voice-related quality of life and acoustic analysis of voice: a study in schoolchildren

ABSTRACT

Purpose:

to assess the self-reported voice-related quality of life of schoolchildren without voice complaints and correlate it to acoustic parameters of voice.

Methods:

the research population comprised 31 children, mean age 6.5 (±0.17) years. The children’s perception of their voice-related quality of life was verified with the Pediatric Voice-Related Quality of Life Survey, which has 10 closed-ended questions and three domains. The acoustic parameters assessed were fundamental frequency, jitter, shimmer, glottal-to-noise excitation ratio, and noise rate, besides the phonatory deviation diagram, based on the analysis of the emission of the sustained vowel /ɛ/ for 5 seconds.

Results:

all the children obtained scores close to 100% in the three domains of the Pediatric Voice-Related Quality of Life Survey. As for the acoustic parameters, most of them presented abnormal values in the phonatory deviation diagram and in shimmer. There was a difference between girls and boys only in fundamental frequency.

Conclusion:

the pediatric self-reported voice-related quality of life of the children studied had a positive impact, despite the acoustic changes found in the voices. There was no correlation between the pediatric voice-related quality of life and the acoustic parameters in voice in the group studied.

Keywords:
Voice; Dysphonia; Child; Quality of Life

RESUMO

Objetivo:

avaliar a qualidade de vida em voz pediátrica autorreferida em escolares, sem queixas vocais e correlacioná-la aos parâmetros acústicos vocais.

Métodos:

a população desta pesquisa foi constituída por 31 crianças, com média de idade de 6,5 (±0,17) anos. Para verificar a percepção das crianças sobre a qualidade de vida em voz, foi aplicado o protocolo Qualidade de Vida em Voz Pediátrico composto por dez questões fechadas e três domínios. Os parâmetros acústicos avaliados foram frequência fundamental, jitter, shimmer, glottal-to-noise excitation ratio e índice de ruído, além do diagrama de desvio fonatório, a partir da análise da emissão da vogal /ɛ/ sustentada por cinco segundos.

Resultados:

os três domínios do protocolo Qualidade de Vida em Voz Pediátrico apresentaram escores próximos a 100% para todas as crianças. Quanto aos parâmetros acústicos, a maioria apresentou valores fora da normalidade, no diagrama de desvio fonatório e nos valores de shimmer. Observou-se diferença entre as meninas e os meninos apenas na frequência fundamental.

Conclusão:

a qualidade de vida em voz pediátrica autorreferida, nas crianças estudadas, apresentou impacto positivo, a despeito das alterações acústicas vocais encontradas. Não houve correlação entre a qualidade de vida em voz pediátrica e os parâmetros acústicos vocais, no grupo estudado.

Descritores:
Voz; Disfonia; Criança; Qualidade de Vida

Introduction

Voice has an essential role in people’s lives, regardless of their age group, as it is one of the most used means of interpersonal communication and relationship¹. It undergoes changes from childhood to senescence as the larynx and vocal tract grow and develop². The pediatric voice has peculiar characteristics, due to neuromuscular immaturity of the larynx and differences in the configuration of the vocal folds^1,2.

The children’s involvement in situations that contribute to incorrect voice use may be related to their emotional status and personality since they express feelings with their voice. This type of behavior may cause changes in voice production³.

Pediatric dysphonia encompasses voice changes or problems that take place in children of different ages and may have either a functional or organic cause⁴. Pediatric dysphonia can hinder the development of the ability to communicate socially⁵ because the quality of voice influences directly the quality of life of children with dysphonia^5,6.

The quality of life is the person’s perception of the cultural context, systems of values, and position in society, considering objectives, expectations, standards, and interests that provide their full physical, mental, and social well-being⁷.

One of the great difficulties assessing pediatric voices is the definition of changed conditions for this age group since their characteristic manifestations occur due to the laryngeal structure and configuration^1,8. There are not many instruments that assess the impact of dysphonia on the quality of life. Three voice-related parental assessment instruments validated in Brazilian Portuguese can be pointed out, namely: Pediatric Voice Outcome Survey (PVOS), Pediatric Voice Handicap Index (PVHI), and Pediatric Voice-Related Quality-of-Life Survey (PVRQOL)⁹.

The PVRQOL is an instrument that assesses the impact of dysphonia on the quality of life, also used in children without dysphonia. It is brief and easy to administer, calculate, and interpret⁹; also, being easily understood, it can be answered by the children themselves^10,11. In addition to its efficiency and reliability, with excellent discrimination power, it can be used in screening even when the person has not been diagnosed with dysphonia¹².

It has been proposed to use protocols answered by the children considering that information acquired from a secondary source tends not to value the impacts of voice on the children’s quality of life. It has also been observed that children 5 years and older are aware and capable to report in detail their possible voice changes without any help. Moreover, the parents’ assessments of their children’s voice quality are not compatible with the children’s own assessment^13-15. Nonetheless, since voice is multidimensional, other parameters must be considered^16,17.

The acoustic analysis, for instance, besides being a noninvasive method that furnishes quantitative measures of voice function, is a method that assesses in detail the sound-generating mechanism, providing an indirect estimate of the vocal fold vibration patterns and the vocal tract shapes and changes. However, the acoustic analysis cannot estimate the impact of voice disorders on the patient’s daily life¹⁷.

In this regard, the Phonatory Deviation Diagram (PDD) of the Voxmetria software (CTS Informática) is an acoustic analysis resource that combines parameters, correlating four acoustic measures and presenting them in a bidimensional chart. It has been used in clinical practice to furnish a more reliable description of voice quality, as it correlates with the data from the auditory-perceptual assessment and helps identify different types and degrees of vocal deviation¹⁸. Despite not having demonstrated a capacity to distinguish healthy from changed pediatric voices, the PDD is sensitive to irregularities and noise in vocal emission and can be useful to assess and follow up the voice of children¹⁹.

The PDD has further advantages over other acoustic analysis tools: It combines irregularity and noise measures, which improves its sensitivity to different manifestations of vocal deviation; it includes an algorithm that ensures greater reliability in the analysis of signals with severe deviations; and it provides the result in a simple, easy-to-interpret chart, demonstrating the relationship with auditorily perceived voice quality deviations²⁰.

Thus, the acoustic measures alone furnish partial information on voice quality and the association between auditory and acoustic measures can be more representative of the voice studied^18,21. Nevertheless, the acoustic analysis can be used to screen children because in combination they present an acceptable capacity to discriminate between the presence and absence of laryngeal change²¹. Moreover, the glottal-to-noise excitation ratio (GNE), which indicates the glottal signal per excited noise ratio, was indicated as an option of voice screening procedure due to its robust measure that distinguishes healthy from changed pediatric voices¹⁹.

Therefore, considering the high prevalence of pediatric dysphonia, the special attention required by pediatric voice assessment and diagnosis^1,19, and the vocal deviations that might occur in children without complaints²², this study aimed to assess the self-reported voice-related quality of life and correlate it with the acoustic voice quality in schoolchildren without voice complaints.

Methods

This is a quantitative, observational, analytical, cross-sectional study, approved by the Human Research Ethics Committee of the Health Center of Federal University of Pernambuco, Brazil, under evaluation report number 2.576.176. For the children to participate in the research, their parents or guardians signed the informed consent form.

This research population comprised 31 children from a municipal school, mean age 6.5 (±0.17) years, without voice complaints. All the children aged 6 to 7 years enrolled in this school were included in the research. Those with neurological, cognitive, or hearing disorders reported by the parents were excluded. The children who had an acute respiratory condition at the time of collection were rescheduled for recording at a later date.

The data were collected by a Speech-Language-Hearing Sciences undergraduate student, supervised by the head speech-language-hearing therapist, in one of the school’s rooms with minimal outside noise interference. The children’s voices were recorded in an N3 Notebook with Voxmetria^® software, an Andrea PureAudio™ USB-AS adapter (which is a filtering and noise reduction device), and an Auricular Karsect HT-2 microphone placed about 4 centimeters away from the child’s mouth at an approximate angle of 45º.

The children’s perception of their voice-related quality of life was verified with the PVRQOL, which has 10 self-explanatory questions distributed into the general, physical, and socioemotional domains. The scores ranged from 0 to 100 and are calculated with a standard formula, whose interpretation is objective and easy to understand - the lower the general score, the worse the person’s quality of life; also, the domain with the lowest score is the main responsible for reducing the voice-related quality of life⁹.

When administering the protocol, the researcher read the PVRQOL questions to each child and explained their meaning to ensure all the children understood and gave a consistent answer.

For the acoustic analysis, the child was asked to emit a sustained vowel /ɛ/ in their usual tone for 5 seconds. For the analysis, the vowel /ɛ/ emission recorded in VoxMetria^® (CTS Informática) was edited, dismissing the initial and final seconds of the emission (for their greater instability); hence, about 3 seconds of the emission were considered for analysis. This recording was used to extract the following acoustic measures: fundamental frequency (f0), jitter, shimmer, glottal-to-noise excitation ratio (GNE), noise rate, and the PDD in the program itself. The acoustic analysis values were classified according to the normal standards of the program, which are 0.6% for jitter, 6.5% for shimmer, above 0.5 GNE, and up to 2.5 noise rate. The minimum and maximum reference f0 means were respectively 226.52 and 261.71 Hz for males and 226.52 and 253.80 Hz for females^23-27.

The PVRQOL data were entered into Excel and analyzed with SPSS 19 statistical software. The children were stratified according to their sex for data analysis.

Normality was analyzed with the Shapiro-Wilk test, rejecting the hypothesis of the normal distribution when p < 0.05. The Mann-Whitney test was used to compare the acoustic values between the sexes, while Pearson’s chi-square test was used to verify the statistical association between the sex and changes in the acoustic analysis. In all of them, the significance level used was 5%.

Results

The normality test revealed that not all values of the variables studied had a normal distribution. Hence, the results were presented in medians and minimum and maximum values.

A total of 31 recordings of the students’ voices were made - 15 (48.38%) females and 16 (51.62%) males.

Table 1 shows the medians and minimum and maximum values of fundamental frequency (f0), jitter, shimmer, glottal-to-noise excitation ratio (GNE), and noise rate according to the children’s sex.

Table 1:
Median (minimum-maximum values) of the acoustic parameters of voice in relation to sex (N=31)

	f0 (Hz)	Jitter (%)	Shimmer (%)	GNE	Noise
Girls (n=15)	245.76 (230.17-280.09)	0.24 (0.11-2.91)	5.49 (1.93-18.11)	0.89 (0.39-0.98)	0.70 (0.32-2.77)
Boys (n=16)	235.22 (203.39-271.94)	0.50 (0.12-7.66)	8.88 (3.45-23.25)	0.86 (0.30-0.94)	0.84 (0.47-3.15)
p-valor*	0.040	0.089	0.502	0.342	0.343

• *Mann-Whitney test - 5% significance level
• Captions: f0: fundamental frequency; GNE: Glottal-to-Noise Excitation Ratio; n: number of subjects

There was a noticeable difference between the girls’ and boys’ groups in fundamental frequency (p = 0.040), whereas no significant difference was found regarding sex in the other acoustic parameters.

Table 2 shows the percentages regarding changed values of jitter, shimmer, GNE, and noise rate according to sex.

Table 2:
Percentage of children with changes in the acoustic measures in relation to sex (N=31)

Children	Jitter		Shimmer		GNE		Noise		PDD
	n	(%)	n	(%)	n	(%)	n	(%)	n	(%)
Girls (n=15)	3	9.7	7	22.6	1	3.2	1	3.2	6	19.3
Boys (n=16)	6	19.3	11	35.5	1	3.2	1	3.2	10	32.3
p-valor*	0.283		0.213		0.962		0.962		0.210

• * Pearson’s chi-square test - 5% significance level
• Captions: GNE: Glottal-to-Noise Excitation Ratio; PDD: phonatory deviation diagram; Normal: corresponds to the lower-left quadrant; Changed: corresponds to the lower-right, upper-right, or upper-left quadrants; n: number of subjects.

The shimmer values were found to be changed in most boys and almost half of the girls. As for PDD, more than half of the children’s results were outside normal limits. Also, of all the acoustic variables studied (jitter, shimmer, GNE, noise rate, and PDD), changes in PDD, jitter, and especially shimmer occurred more frequently in boys than girls, despite the absence of association between sex and frequency of change. Concerning GNE and noise rate, only one child of each sex had their values changed.

Figure 1 presents the mean values of the PVRQOL domains according to the children’s sex. The score in the three PVRQOL domains was close to 100% in both groups, with no difference regarding sex in the self-perceived voice-related quality of life.

Figure 1:
Mean values of the general, physical, and socioemotional domains of the Pediatric Voice-Related Quality of Life Survey in relation to sex (N=31)

Table 3 shows the correlation of the general, physical, and socioemotional PVRQOL scores with jitter, shimmer, GNE, and noise rate of the children assessed. There was no correlation between the PVRQOL domains and the acoustic parameters of voice.

Table 3:
Correlation between the scores of the Pediatric Voice-Related Quality of Life Survey and the acoustic parameters of voice (N=31)

Variables	Correlation	Jitter (%)	Shimmer (%)	GNE	Noise
Socioemotional	rho	0.07	0.14	0.12	0.12
	p	0.715	0.444	0.539	0.539
Physical	rho	0.23	0.17	0.06	0.06
	p	0.220	0.352	0.736	0.736
General	rho	0.23	0.22	0.12	0.12
	p	0.208	0.239	0.511	0.511

• rho: Spearman’s correlation coefficient
• Caption: GNE: Glottal-to-Noise Excitation Ratio

Discussion

Pediatric dysphonia is often overlooked by parents and teachers, despite its impact on the children’s quality of life^{3,13-15,22,23}. Also, the children’s auditory-perceptual self-analysis differs from the adults’ analysis because of the maturation of the systems involved in phonation during the development process²². Thus, resources used to screen schoolchildren’s voices can help promote vocal health and prevent vocal deviations in this population.

The acoustic measures are less subjective and furnish important information on voice function, while self-assessment provides essential complementary information regarding other assessment methods¹⁷. Hence, in combination, they are important resources in the identification of possible voice changes in children without voice complaints.

In this study, the acoustic variables were correlated with the self-reported voice-related quality of life of schoolchildren without voice complaints, enrolled at a municipal school where speech-language-hearing internship activities are carried out, focusing on educational speech-language pathology.

The acoustic analysis results revealed a difference in fundamental frequency between the girls’ and boys’ groups, which was not to be expected in an age group that is still far from the voice change²⁸. This difference at such an early age may be explained by changes in hormone production due to the children’s exposure to adult stimuli from a young age, besides variables such as overweight and low income^28,29. However, these variables were not controlled in this study, not allowing the hypothesis to be confirmed.

Furthermore, the chronological boundary of the beginning of puberty has been intensely discussed. An American study with 17,000 girls demonstrated that 27.3% of the African American girls and 6.7% of the white girls had entered puberty at 7 years old, suggesting an adjustment of the mean age when puberty begins³⁰. Future studies with a larger sample should investigate such sociobiological influences on children’s voice quality.

The acoustic results disagree with the reference values for boys of this age group, whereas they corroborate the reference shimmer values for girls¹. These results reveal the need to compare such data with the auditory-perceptual analysis to confirm the impact these changes have on pediatric voice quality⁸.

An aspect to be considered is the physiological difference between pediatric and adult vocal folds, as in children the vocal ligament and the layers in the lamina propria are not fully differentiated². Also considering the neuromuscular development, a greater change would be expected in jitter and shimmer in relation to the parameters expected for adults²⁷.

The percentages of change in the PDD should be approached considering this diagram’s limitations in terms of distinguishing healthy from changed voices, as well as the intensity of vocal deviation in the child population¹⁹. This may be explained by the fact that instability, strain, and breathiness are characteristics expected in pediatric voices, even in healthy ones.

However, considering the study sample (15 girls and 16 boys), the percentage of children with changes in the acoustic parameters was high, especially regarding shimmer and the PDD. Although the auditory-perceptual analysis was not carried out and despite the limitations of the acoustic analysis in isolated parameters,^18,19 the results obtained indicate possible voice changes in this population.

As for the PVRQOL, the scores in the three domains came close to 100% in both groups. This corroborates the results found in children without voice changes and contrasts with the results obtained in children with voice changes, whose scores were low in all the domains²⁸.

A study that used the VRQOL to compare the general, physical and socioemotional scores between the sexes did not show any difference between men and women. It indicates that the impact of voice changes on the quality of life is perceived similarly by both sexes²⁹, agreeing with the results in the present study.

It is important to point out that the children researched did not have difficulties filling out the PVRQOL, which corroborates the feasibility and importance of administering it to the child population as well, not only to their parents/guardians^14,15.

On the other hand, there was no correlation between the PVRQOL domains and the acoustic parameters. Such a result can be explained by the already expected instability of the pediatric voice^2,9,27, or else by the reference values established for the adult population, which are not compatible with the age group studied. To confirm this hypothesis, it is necessary to compare it with the auditory-perceptual analysis.

Also, younger children may have a less refined self-perception of voice quality than the older ones. Hence, further investigation is necessary for clinicians to better understand what is important for children of different ages and provide a personalized treatment according to their various social and educational experiences at the time of intervention^12,14.

One of the possible limitations of this study is the potentially complex PVRQOL questions to younger children. Nonetheless, this limitation was minimized in this study, as each question was explained in simpler terms to the children assessed.

The results of the protocol are compatible with the sample studied, which had no voice complaints. However, the importance of pediatric vocal health programs at schools must be emphasized, given the acoustic results obtained.

Thus, the study values the administration of the PVRQOL to schoolchildren with and without voice complaints, along with the use of voice screening instruments at schools. These results suggestively illustrate actions that promote vocal health and prevent dysphonia in children.

Furthermore, considering the difference between the reported prevalence of dysphonia and the one verified with voice assessment¹, it must be emphasized that the PDD of most children was changed, which may point to possible voice changes that must be investigated. Therefore, this study should be complemented with laryngeal and auditory-perceptual assessments of the voice quality of the children researched to obtain results in other parameters related to voice quality. Also, a study can be conducted to compare the different realities between public and private schools.

Conclusion

The schoolchildren without voice complaints self-reported a positive voice-related quality of life, despite the acoustic changes found in their voice. There was no correlation between the voice-related quality of life and the assessment of acoustic parameters in voice, in this studied group.

Acknowledgments

The present paper was carried out with support from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001.

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• Research support source: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001 and Postgraduate Dean - Federal University of Pernambuco, Recife, Pernambuco, Brazil. Announcement PROPG no. 03/2020.

Publication Dates

• Publication in this collection
  24 May 2021
• Date of issue
  2021

History

• Received
  11 Sept 2020
• Accepted
  30 Mar 2021