Portuguese Version

Year:  2004  Vol. 70   Ed. 1 - (4º)

Artigo Original

Pages: 30 to 34

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Correlation among stroboscopic, perceptual and acoustic analysis findings in adult subjects without vocal complaint

Author(s): Vera Regina Corazza 1,
Vanessa Figueiredo Custódio da Silva 1,
Débora S. Queija 1,
Rogério A. Dedivitis 2,
Ana Paula Brandão Barros 1,3

Keywords: voice, laryngoscopy, stroboscopy, perceptual evaluation, voice acoustic evaluation, vocal complaints

Abstract:
The great progress in understanding the vocal physiology and the scientific and technological development in the voice area allow transposing the therapeutic limit through the means for the precocious detection of vocal changes. Objective: to evaluate subjects without vocal complaint, and to correlate possible videostroboscopic, perceptual and acoustic analysis finding. Study Design: Observacional cohort with transversal cut. Patients and Methods: 21 men without vocal complaints were studied. Their ages ranged from 20 to 50 with median of 33. They were neither alcohol nor smoke users. The subjects underwent the videostroboscopic, perceptual and acoustic evaluations. Results: 57.15% of the subjects presented any alteration in one or more of the evaluated aspects. In the videostroboscopy it was observed posterior triangular gap in 4 subjects. Ten subjects presented a mild grade alteration in the perceptual analysis, in instability, hoarseness and breathiness parameters. Three subjects presented respectively hipernasal, cul de sac and pharyngolaryngeal resonance focus. The acoustic evaluation presented the following averages: f0 - 125.69 Hz; jitter - 0.22%; shimmer - 3.06%; NNE - -12.29 dB; HNR - 20.75 dB; tremor frequency - 2.09 Hz; tremor amplitude - 1.16 Hz. Some subjects presented shimmer% values and tremor frequency largest than the average. Conclusion: Alterations were detected in 57.15% of the evaluations of subjects without vocal complaints. Those changes could be variations of the normality, or they could indicate a predisposition to future glottic and vocal alterations in the course of the time. There was any acoustic aspect change in all the evaluations, which presented alteration.

INTRODUCTION

One of the main advances in vocal physiology is directly related to the fact that voice is not a product simply from the larynx and specifically from the vocal folds, but rather a complex function that interconnects different organic systems with different functions 1. As a result of scientific and technological development, voice professionals have the possibility of providing to patients complete and reliable vocal assessment, encompassing physiological, psychological and acoustic aspects 2. Expansion and enriching of acquired knowledge allowed us to go beyond the clinical-therapeutic limit, presenting means for early detection of vocal affections and their prevention.

The concept of normal voice is very much discussed and is constantly modified. It is widely influenced by the environment and the culture in which we live 3. Three issues can be taken into account when judging the normality of a voice: whether the voice is appropriate to provide speech intelligibility to the listener, whether the acoustic elements are esthetically acceptable and if it meets the occupational and social demands of speakers 4. These parameters can lead to description of vocal affections and/or difficulties by the subjects themselves or by others, which eventually leads to the so-called complaint 5. Some subjects may not refer vocal complaints, but it is not a reliable indicator of absence of laryngeal, perceptual-auditory and acoustic findings. The purpose of the present study was to assess subjects without vocal complaints and correlate laryngeal stroboscopic, auditory perceptive and acoustic data so as to detect occasional variations of the normal range.

MATERIAL AND METHOD

The research project was approved by the Research Ethics Committee, Universidade Metropolitana de Santos. It included 21 male volunteers ages ranging from 20 to 50 years and median of 33 years, who did not present complaints, vocal signs or symptoms, with no previous vocal therapy and free from inflammatory acute respiratory conditions at the time of the assessment. They were not smokers or alcohol abusers. All data were collected by previous history. Next, subjects were submitted to telelaryngeal-stroboscopy, perceptual-auditory and acoustic evaluations.

For the telelaryngeal-stroboscopic evaluation we used rigid laryngoscope 70o Storz®; digital stroboscope RLS 9100B, Kay Elemetrics®; microcamera Toshiba CCD IK-M41A; videocassette Sony Trinitron® model PVM-14N5U; microphone Leson® ML-8; and video monitor Sony SLV-60HFBR. We instructed them to produce deep breathing, comfortable production of sustained vowels /e/ and /i/, /hee/ /hee/ /hee/ and inspiratory phonation. The collected material was recorded in VHS tape and analyzed by a physician, following the protocol by Hirano and Bless (1997)6.

For the collection of perceptual-auditory and acoustic data, subjects stood up, arms along the body side, and they were instructed to breathe deeply and produce isolated and sustained oral open central vowel /a/ at habitual frequency and intensity.

Connected speech consisted of spontaneous speech sample, including complete name and date of birth and it was used only for perceptual-auditory assessment. The vocal assessment, based on scale GIRBAS7, in which G corresponds to grade of affection: 0 - absent or normal, 1 - mild, 2 - moderate; 3 - severe; identifying five independent parameters: I -instability; R - roughness; B -breathiness; A -asteny; and S -strain.

Resonance pattern was also assessed by sustained vowel production and connected speech, based on the following foci: nasal (hyponasal and hypernasal), pharyngeal, cul de sac, and laryngeal-pharyngeal8.

Acoustic analysis was conducted through the Vocal Assessment module by Dr. Speech software, version 3.0 of Tiger Electronics®, analyzing the following parameters: fundamental frequency (f0) Mean; f0 standard deviation; jitter % (frequency perturbation); shimmer % (amplitude perturbation); NNE-dB (glottic noise energy); HNR-dB (noise-to-harmonic ratio); frequency of tremor-Hz (long-term frequency instability); and amplitude of tremor-Hz (long-term amplitude instability).

RESULTS

Out of 21 assessed subjects, 12 (57.15%) presented some type of abnormality in the assessments. In telelaryngeal-stroboscopic assessment, we observed the presence of posterior triangular chink in 19% of the assessed subjects, being that it was the only significant finding in the exam.

Perceptual-auditory analysis detected affections in 10 subjects. Some of the assessed parameters were common in the same subject. We detected the following records in the production of sustained vowel: instability, hoarseness, and breathiness, all in discreet grades. Only the parameter breathiness was detected during connected speech (Table 1).

As to resonance in sustained vowels, three subjects had, respectively, hypernasal focus, cul de sac and laryngeal-pharyngeal resonance. In connected speech, these subjects maintained the same pattern, except for the one with laryngeal-pharyngeal resonance, which proved to be appropriate. Subjects with hypernasal and cul de sac resonance patterns presented fundamental frequency values that were higher than the mean, being respectively 158.95 and 159.42 Hz. The other acoustic parameters, as well as telelaryngoscopic images were not affected.

All the cases that presented some abnormality in the parameters also manifested acoustic analysis alterations (Table 2). Acoustic assessment presented the following results: mean f0 was 125.69Hz, being minimum value of 87.33 Hz and maximum value of 161.23 Hz, Mean standard deviation of f0 was 0.5 Hz. Values of jitter% and shimmer% had mean of 0.22% and 3.06%, respectively. Seven subjects had shimmer values much higher than the mean. NNE mean was -12.29 dB and for HNR it was 20.75 dB. The tremor frequency had mean of 2.09 Hz and tremor amplitude was 1.16 Hz. Some subjects presented tremor frequency higher than the mean (Table 3).

DISCUSSION

The first fact that attracts our attention in the data is the high number of abnormalities found in the assessments conducted, despite being mild, since the studied sample had no vocal complaints or history of dysphonia. In 30 subjects without complaints and/or history f dysphonia, only one female subject did not present any affection, indicating that when the perceptual-auditory analysis is carefully conducted it is possible to identify mild to moderate abnormalities 10.

One of the observed findings was the high number of posterior triangular chink in men, which is more frequently found in young women, since female glottis configuration is shorter in the ventral-dorsal direction. Among men, the most common pattern is complete glottic closure, however, it is possible to find incomplete closure in the posterior region in modal phonation in male patients11. The presence of posterior triangular chinks in men can be related to small-sized larynges, such as in women 12 and it is also important to point out that in the telelaryngoscopy exam the degree of incomplete closure can be higher, since the posture used is not physiological, with the tongue pulled in protrusion 13.

In all subjects with incomplete closure, posterior triangular chink was grade I. This piece of data would not make us consider hyperfunctional behavior, since posterior triangular chink grade II, known as medium-posterior, may be indicative of primary hypokinetic picture 8. Thus, these chinks would be only anatomical-physiological variations or the result of the posture in the test. However, we observed that in a series of 15 men, the presence of posterior triangular chink was detected in two cases and both had complete closure after tongue vibration technique 10. Thus, we could conclude that these chinks were the beginning of the development of a hyperkinetic picture.

Out of four cases in which we observed alterations of glottic coaptation, two had perceptual-auditory correlation (mild hoarseness and instability) and acoustic correlation (increased tremor frequency) and the other half had it only in the acoustic assessment (increased shimmer) (Table 4). Hoarseness is one of the auditory-perceptive affections expected in cases of isolated glottic chink equal or greater than 0.5mm 14, but in this sample, it was observed only in one case. In the other case, we observed instability, which had no direct correlation with incomplete glottic closure.

The auditory-perceptive parameter of breathiness was observed only in one subject, which had no other abnormal finding in the other assessments. The most frequent vocal quality abnormality was instability, differently from what was initially predicted, since in most situations this parameter is associated with aging, such as in presbyphonia 12 and neurological cases 15. In our sample, instability was present only during sustained vowel production. Phonation instability has already been related with jitter and shimmer increase in other studies 16. In the present study, half of the cases of instability presented shimmer increase and in the other 50% we observed vocal tremor frequency increase. These two findings were also observed in other studies 16, 17.

Vocal tremor refers to involuntary, rhythmic and sinusoid movements that affect some or many portions of the speech articulation support (breathing, phonation or articulation). It is considered long-term phonation instability since it affects vocal fold vibration in a time interval that is greater than the individual glottic cycle 3. It is also found in normal vocal production, such as in physiological tremor. The physiological tremor may get enhanced in situations of cold and anxiety 3.

We excluded the possibility of having instability related to articulation support, since during vocal sample collection, this factor was observed. As to glottic source, it was not possible to reach an objective conclusion, being that telelaryngological-stroboscopy data had no significant correlation with this finding and the respiratory support was not assessed.

As to acoustic analysis, the increase in tremor frequency is related with instability, but we did not detect any correlation with presence of hoarseness or presence of chink, as proposed by the literature. In the other cases, there was correlation between incomplete glottic closure and increase in shimmer. Shimmer affections tend to be correlated with glottic resistance 3. In the acoustic assessment, fundamental frequency means had values close to those reported in the literature. In a study in adult normal men, the mean values of f0 were 107 to 129 Hz9,18-22. For Brazilian Portuguese speakers, the normal range is 80Hz to 150Hz23. All the other parameters were within the normal range 3.

Acoustic parameter affections were detected in all cases that had some variation from normal range. It may have been due to greater sensitivity of the method comparing to the other two or we can question the real value of acoustic parameter affection when observed in isolation or in asymptomatic patients.

The high incidence of abnormalities found can be related to variation of normality. However, it is difficult to make any statement, since the number of studied subjects was small and the literature provides very few studies that compare the three measures together. It could also be an indicative of subjects who have greater predisposition to developing glottic affections, especially when exposed to unfavorable vocal agents and conditions. Such affections are silent, but as time goes by, they can become perceivable.

CONCLUSION

The present study detected abnormalities in telelaryngeal-stroboscopic, auditory perceptual and acoustic assessments in 57.15% of adult men without vocal complaints, defining correlations among findings. In all affected samples, acoustic parameter was equally compromised.

Table 1. Distribution of abnormalities in the auditory perceptual assessment.

I1: mild instability; S1: mild breathiness; R1: mild hoarseness; /a/: sustained vowel; /speech/: connected speech.


Table 2. Distribution of assessments that detected abnormalities.

TE: Telelaryngo-stroboscopic assessment; PA: perceptual-auditory assessment; A: acoustic assessment.


Table 3. Distribution of results of the acoustic assessment.

Control Group: study with a similar group (matched by age and gender), using Dr. Speech. (Saviolli, 1999)9


Table 4. Correlation of findings of glottic chink with other assessments.

R1/a/: mild hoarseness in sustained vowel; I1/a/: mild instability in sustained vowel; > freq. Tremor: (increase in value of tremor frequency; > shimmer: increase in value of shimmer.

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1 Speech Therapist, Division of Speech Therapy and Audiology, Discipline of Otorhinolaryngology and Head and Neck Surgery, Universidade Metropolitana de Santos (UNIMES), Santos.
2 Ph.D. in Medicine, Post-Graduation in Otorhinolaryngology and Head and Neck Surgery, UNIFESP - Escola Paulista de Medicina; Faculty Professor, Discipline of Otorhinolaryngology and Head and Neck Surgery, Universidade Metropolitana de Santos (UNIMES), Santos.
3 Master in Health Sciences, Medical School, University of Sao Paulo; Speech Therapist, Treatment and Research Center, Hospital do Câncer - A.C.Camargo, Sao Paulo.
Affiliation: Discipline of Otorhinolaryngology and Head and Neck Surgery, Universidade Metropolitana de Santos (UNIMES), Santos.
Address correspondence to: Rogério A. Dedivitis - Rua Olinto Rodrigues Dantas 343 conj.92 Santos SP 11050-220.
Tel/fax: (55 13) 3221-1514/ 3223-5550 - E-mail: dedivitis.hns@uol.com.br

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