mejora acustica post fonocirugia

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Indian J Otolaryngoi Head Neck Surg(April-June 2010)62(2): 131-137; DOI: 10.1007/s 12070-010-0024-6

O r ig i n a l A r t ic l e

O b j e c tiv e a c o u s t ic a n a iy s iso fv o i c e im p r o v e m e n t a f te r p h o n o s u rg e r

Piyush Verma Manisha Pal Anoopraj

Abstrac t

Objective To evaluate voice improvement after phonosur-gery by objective acoustic analysis.

Material and methods This prospective study was con-ducted in Maulana Azad Medical college New Delhi fromDecember 2002 to 2008. In this study 100 subjects wereincluded comprising of all age groups and either sex. Allthese patients with organic voice disorder underwent speechanalysis using VAUGMI speech analysis program beforeand after phonosurgery.

Result All the parameter of voice analysis were derangedbefore the treatment but after surgery all the parametersshould improvement most significant change was seen inthe jitter.

Conclusion After doing this study we found that theanalysis of hoarse voice using various parameters ofacoustic analysis like fundamental frequency, harmonics tonoise ratio, jitter, shimmer, S/z ratio helped us in identifyingthe degree of hoarseness and the severity related to it. Someparameters like jitter and shimmer were able to detect thecomponent of hoarseness in perceptually normal voice andthus patient was helped by doing surgery and voice therapyat the appropriate time.

Keywords PhonosurgeryOrganic voice disorder

Voice analysis

R Verma' M. PaP AnoopRaj''Department of ENT,-Department ofPaediatrics,Maulana Azad Medical CollegeNew Delhi, India

P Verma (M )

E -mail: [email protected]

introduction

Hoarseness is the cardinal symptom of laryngeal disease;considerable emphasis had been placed on this symptom.

Several approaches, including acoustic, cinematographicaerodynamic and electrophysiologic had been utilized toexplore the mechanism and pathophysiology of hoarse voiceproduction. However, the evaluation of hoarseness (theestimation ofthe degree and the quality of hoarseness) wasmade chiefly on the basis of clinicians subjective percep tion.The basic protocol [1,2] for functional assessment of voicepathology, especially for assessing the efficacy of treatmentincluded:

Perception,wh ich includedroughness andbreathiness

The severity of hoarseness was quantified under theparame ter G (Grade) for the GR AB AS scale [3 ]. The maincomponents of hoarseness were: Rough ness or hoarseness (R): Audible impression

of irregular glottal pulses, abnormal functions 1fundamental frequency and separately perceivedacoustic imp ulses due to irregular vocal fold vibration s.The other parameters like asthenicity (A) and stream(S) were less reliable and were omitted.

Breathiness (B): Audible impression of turbulent airleakage through an insufficient glottic closure, which

included short aphonie movements.Grading scale was made for the reporting purposes:

Norm al or absence of deviation Slight deviation Mo derate deviation Severe deviation.

Video strodoscopic ev aluation

It had been the main clinical tool for etiological diagnosisof voice disorders. It was also used assessing the quality

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132Indian J Otolaryngol Head Neck

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of vocal fold vibrations and thus studying the effectivenessof the treatment. Basic parameters of stroboscopy included-glottal closure.

Longitudinal: Over the whole length of the glottis andwithout sufficient adduction.

Dorsal: Posterior and triangular chink (it normal in 60%of the middle aged healthy wom en) ventral irregular.

Oval: Over the whole length of the gloftis but with adorsal closure hourglass shaped [11].

Rating of the glottal closure was found to be very reliableregularity:

Quantitative rating of the degree of irregular slowmotion. Mucosal wave/quantitative rating of the qualityof the mucosal wave, accounting for the physiology of thelayered structures of the vocal folds [12 ].

Symmetry: Quantitative rating of the mirror motion of

both the vocal cords.Aerodynamics, which included: Phonation quotient orthe maximum phonation time.

Acoustic measurement [4, 5], which included: Funda-mental Frequency/Fo, Harmonics to Noise Ratio, Jitter,Shimmer, etc.

S u b j e c t iv e e v a l u a t i o u

Acoustic analysis: It provided objective and non-invasivemeasures of vocal function.

Fundamental frequency/Fo [6] - It is the number ofvibrations of the vocal folds per second. Fo is the habitualpitch most often used by the individual. The normal valuefor males lies between 80-180 Hz and for females it is180-280 Hz. A high-pitched voice is seen in spasticdysphonia, puberphonia and in laryngeal webs. A low-pitched voice is seen in case of vocal fold thickening ormass on vocal folds.

Fundamental frequency range - It is the differencebetween the lowest and the highest frequency. The normalrange lies between 1-1.5 octaves for males and 2-2.5octaves for females.

Optimal frequency - It is the best suitable frequencyfor an individual which is marked maximum loudness withminimum physiological effort. It can be labeled as a fre-quency which is 1/3 of the fi"equency range. Ideally Fo =Optimal frequency.

Harmonics Harmonics-to-noise (H/N) ratio [7, 8, 16] -when the vocal folds are in the state of vibration, besidesgenerating fundamental frequency, they also generateharmon ics which are multiples of fundamental frequency.The energy of harmonics decreases as their frequencyincreases. Noise is produced when there is no firm closingof the glottis due to which there is ttirbulent air escape. The

ratio of harmonics to noise intensity should always be >1.

In conditions of slackness of vocal folds seen in paralnodule or reduced gloftic chink, the noise is greater caua reduction in H/N ratio.

Number of harmonics - This parameter can be detened by long term average spectrum (LTAS) at low frequ

(0-2000 Hz). Number of harmonics visible should beon LTAS. In case of increased noise level, the noise mthat higher harmonics resulting in a decrease in the nuof visible harm onics.

A study was conducted by Nieto et al. [9] in 199which LTAS and HNR were taken as the basic parameterpreoperative and postoperative evaluation of voice. Besurgery LTAS revealed weak harmo nics. After surgery values and harmonic energy was shown to be increPreoperative and postoperative changes were signif(p < 0.05). Improved glottic closure after surgery imprboth the LTAS and HNR parameters.

S/z ratio - Gam boa et al. [10], in 1995 cond uacoustic analysis by taking S/z ratio as the basic paramfor 72 patients with laryngeal pathology. This is definethe ratio of the maximum phonation time for which soucan be sustained for the maximum phonation time for wthat sound/z/can be phonated. This study concluded tha normal speaking subject it was nearly 1.0. When glclosure defect was present, the ratio was over 1.4.organ ic lesion where there was difficult glottic closure, was decreased airflow resistance and therefore, a shortphonation time of vow el and thus increased S/z ratio.

Jifter - It is the cycle to cycle variation in frequduring vibrations of the vocal folds. Variation in frequby 3 Hz is considered to be normal.

Shimmer - It is the cycle to cycle variation in intenVariation in intensity over 3 dB is considered normal.

Small variations (perturbations) in amplitude and petime from cycle to cycle in the speech w aveform are knto be the natural ingredients in normal speech (Liber1961). In fact, such perturbations were important fonatural quality of speech synthesis (Holmes, 1962). Tvariations in pitch and amplitude were probably due tperiodicity of the neuromuscular phonatory control sy(Shultz-Coulon, Batamar and Fedder, 1979). It was known that large magnitude perturbations gave rise "rou gh" voice quality (Coleman, 1971). Large perturbareflected aherations in the nonnal pattern of vocal vibrations (von Leden, 1960), and were associated laryngeal dysfunction (Hecker, 1971).

Liberman in 1961 performed pitch perturbation anaand defined a pitch perturbation factor as the percenoccurrence of pitch period perturbation larger than 0.5 a vocal segment ofa connected speech and this perturbafactor was useful in determining the laryngeal diseases

Koike in 1973 studied voice of 30 subjects with laryn

diseases and 30 normal subjects. In contrast to Liberm


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Indian J Otolaryngol Head Neck Surg(April-June 2010) 62(2):131-137 133

measurements, in which perturbations exceeding the fixedabsolute factor were included, Koike registered the relativepitch perturbation. Using the measures on sustained v owels,he was able to discriminate between patients with tumors,vocal cord paralysis, and normal subjects.

Rabinov et al. [11] conducted a study, in 1995

comparing the reliability of perceptual rating of roughnesswith acoustic measure ofjitter. This parameter was takenwas taken for comparison because it was extensivelystudied, widely available in commercial kits and easy tocompare and calculate. The results suggested that acousticmeasures of jitter had advantages over perceptual measuresof roughness for discriminating among normal voices, thatis, measures of jitter may resolve very small aperiodicitiesthat are presumably near or below listener's perceptualthresholds. This study also suggested that measured jitterwas the function of both signals and algorithms.

Subjective evaluation: This evaluation of voice although

subjective was very important. The basic aim was todifferentiate the deviance of voice quality and the severityof the disability in daily and professional life. A voicehandicap index [12] was computed on the basis of patient'sresponse to a carefully selected list of questions. A score of'o ' (extreme left) meant normal voice (no deviance) on thefirst scale and no disability or handicap (related to voice) indaily life on the second scale, while '100' (extreme right)meant extreme voice deviation on the first scale and extremedisability in daily social activities, as rated by the patienthimself.

A new handicap index called the voice handicap index-10 [13] which is an abbreviated form of voice handicapindex has been developed.

Voice related quality-of-life (V-ROOL) 14 scale com-prises 10 items divided into physical functioning and social-emotional fun ctioning subscale. Each item is scored on a fivepoint interval scale that reflects the degree of problem. Forthe subscales and the total score, 100 is the highest possiblescore and reflect the highest quality-of-life.

Another index called the glottal function index [17] isbeing used these days which is a simple self administered4-item battery, which is specifically aimed at identifying thepresence and the degree of symptoms of glottal dysfunction.The scale ranges from 0 (asymp tomatic) to20. The questionsincluded like speaking taking extra effort, throat discomfortwhile speaking, vocal fatigue, voice cracks.

Movem ent of vocal foids and anatomy of spe ecii

The vocal folds [15] usually vibrate at 100-300 Hz duringnormal conversation and even at 1000 Hz or even moreduring singing. In quiet respiration, the inter-membranouspart of the glottis is triangular and the inter-cartilaginous

part is rectangular as the medial surfaces ofthe arytenoidsare parallel.

In forced respiration, the vocal folds undergo extremeabduction; the arytenoids cartilages are pulled laterally andtheir vocal processes are pulled widely apart, changes inlength and tension o fthe vocal folds control the pitch ofth evoice and are produced normally only w hen the vocal foldsare in contact for phonation. Three following forces act tobring the vocal folds in contact with each other.

I Tension in the foldsII The decrease in sub-g lottic air pressureIII The sucking effect ofthe escaping air (Bernoulli'seffect).

The result ofthe rapidly repeating cycles of opening andclosing at the glottis releases small puffs from the sub-g lotticair column, which form sound waves. Frontal tomographyshow ed that the areas of vocal fold surface in contact vary inaccording to pitch. At low pitch the cross-sectional area ofthe vocal fold increases but as the pitch rise the vocal foldsbecome thinner.

Stroboscopy allows observation and description offundamental frequency, symmetry of bilateral mo vement ofthe vocal fold, regularity, glottal closure, amplitude, mucosalwave and non-vibrating portion. In the normal vocal foldsthe mucosal wave travels on the mucosa from its inferiorto superior surface. This is observed during vibrationsexcept for falsetto voice and is a function of soft and pliantsuperficial layer of the lamina propria. The function of the

vocal folds is to produce sounds varying only in intensityand pitch. This is modified by various resonating chambersabove and below the larynx and is ultimately converted tophonemes by the articulating action ofthe pharynx, tongue,palate, teeth and lips.

Spectral analysis shows that the vocal tract (larynx.Pharynx, mouth and nasal cavity) acts as an intricatelyselective filter and resonator, which propagates a remarkablysimilar pattern irrespective of fundamental frequency.This is essential to speech as it ensures that in spite of acontinuous variation in tone, a constant quality of timbre ismaintained.

iNateriaisandmetiiods

The objective acoustic analysis of voice improvementafter phonosurgery was conducted in the Department ofOtorhinolaryngology and Head and Neck surgery, MaulanaAzad Medical College and Lok Nayak and associatedhospitals from December 2 00 2-2 00 8. A total of 100patients were selected for various pho nosurgical p rocedureslike micro laryngeal surgery and medialization thyroplasty


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and the results were compared between preoperative andpostoperative voice evaluation.

P a U e n t s

Patients with organic voice disorders like vocal nodules,vocal polyps, Rinkes edema, and unilateral vocal cordparalys is were included in the study. Patients with functionalcauses of voice change and malignancy of the larynx wereexcluded from the study.

i H a t e r i a i s

Operating equipment for microlaryngeal surgery andthyroplasty speech analysis software program - VAGHMI,digital tape recorder personal computer with windows9 8 , 2000, Me, Xp, and other hardware like amplifier,micropho ne, and laser printer.

i H e t h o d s

In this prospective study all patients were taken up forobjective acoustic analysis, before and after phonosurgery,by VAGHMI software program. Audio recording was themost useful basic tool for voice assessm ent. The high qualityvoice recordings were made on digital tape recorder andwere later subjected to acoustic analysis. All the recordingswere done in a quiet room with ambient noise of


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Indian J Otolaryngoi Head Neck Surg(April-June 2010)62 (2): 131-137 135

ProperativePostoperativeCorrelation

Mean:Mean:0.266

11.817.5

cord palsy and in cases of Rinkie's edema.

Std. Dev.: 2.4Std. Dev.: 2.15p value 0.155

4. Jitter (%): It is the cycle-to-cycle variation infrequency during vibration of the vocal fold. Thenormal range is 0.33 to 7.52. It was above the normalvalues before surgery and became normal aftersurgery.


Mean: 14.3Mean: 6.50.586


5. Shimmer (dB): It is the cycle-to-cycle variation inintensity.The no rmal values ranges from 0.12 to 1.12dB . In our study it was found to abnormal or highersideof normal.But after surgery it was found to bewithinthe normalrange.


Mean: 0.76Mean: 0.490.371


Number of harmonics: It is the numb er ofvisiblepeaksin the LTAS graph. It should be >1 8 to be co nsidered to bewithinnormal limit. In case of increased noise level, thenoisemasks the higher harm onics resulting in a decrease inthe number of visible harmonics.In thispostoperativeperiodafterreceiving voice therapy the nu mber ofharmonicshasincreased.


Mean:Mean:0.194

5.613.1

Std.Dev.:1.73Std.Dev.:2.21p value 0.30

6. S/z ratio: It is the ratioof timefor which the sound /s /can be sustained to the sound/z/can be phonated.Normalvalue ranges from 0.9 to1.1 sec.In this studythisparameter improved with surgery in most of thepatients.


Mean:Mean:0.149

1.271.04

Std.Dev.:0.Std.Dev.:0.p value0.43

1512

7. Maximum phonat ion dura t ion: It is the time forwhichone can continue ph onation after a deep breath.Thenormal range is from 12 to 15sees.It was no rmalin both properative and postoperative periods, but itimprovedto high er values after surgery. The values

were really for patients with unilateral vocal paralysis.

ProperativePostoperative

Correlation

Mean: 12Mean: 15.3

0.112

Std. Dev.: 2.16Std. Dev.: 2.12

p value 0.55

Discussion

In this study of 100 patients, with age ranging10-55 years with a mean age of 33 years, various causes of hoarseness like vocal nodule and polyp, edema, vocal cord palsy and papilomatosis were takconsideration. There were total of 38 female patie62 male patients includ ing 1 to 10-year-old girl a10 year old boy. The reason for this discrepancy re

sex distribution could be attributed to the fact thaare more involved in outdoor activities and smokidrinking is also more p revalent in this sex.

AH the 100 patients underwent objective acanalysis both preoperatively and postoperatively. acoustic parameters measured were fundamental frefrequency range, jitter, shimmer, e tc. 92 patients undmicrolaryngeal surgery for various benign vocal foldand 08 patients underwent medialisation thyroplastkki type I) who were diagnosed with idiopathic unvocal cord paralysis. After 4 weeks of surgery, durinpatient was given voice therapy, acoustic analys

repeated again for the same parameters.It was observed that before surgery and voice therthe parameters of voice like fundamental frequency, frequency, jitter, S/z ratio, shimmer, harmonic to no inumber of harmonics, were having abnormal valuafter treatment and voice therapy all the values werto be within normal values but only jitter was statissignificant.

In our study it was observed that fundamental frewas relatively high for patients with benign vocalesions than for vocal cord palsy. This finding could be attributed to the fact that, due to the non-closure

glottic chink there was escape of air and thus decvocal cord vibration. Optimal frequency was also deafter the surgery. Various cases like laryngeal papillocomparatively less postoperative changes as compvocal nodule or m edialization thyroplasty similarly case with Rinke's edema (Fig.1 ).

The results showed that there were abnormallyvalues of jitter and shimmer before surgery, this be attributed to the fact that, when there was a susphonation, there was relatively longer open phase the vibratory cycle ofthe vocal cords and a shorter phase and thus increased vocal fold vibration lead

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Indian J Otolaryngol H ead Neck Su(April-June 2010) 62(2): 131-1

Fo preoperative Fo postoperative HNR preop erative

HNR operative J itterp reo pe rativ e Ji t terpostoperat ive

Shimmer preoperative 2 Shimmer posto perative

18 0 180

150 140

16 16

Polyp

160

17 24

0.6 0.

30 20

0.6 0.3

TVC pa lsy Papilomatosis

Fig. 1 Comparison of preoperative and postoperative acoustic analysis

these abnormal values. These changes in perturbationvalues could also be due to the contraction of the vocalismuscle, which is the primary agent for monitoring the stablephonation. It might be hypothesized that as the frequencyand intensity increases, the muscular forces exerted by the

vocalis and cricothyroid muscle gets misbalanced and thuscausing unstablising effect leading on to the change in thevibratory pattern of the vocal folds.

Acoustic analysis is a convenient, non-invasive methodof detecting aperiod icity in the speech w ave form, bu t it doesnot give definitive infonnation concerning the physiologiccauses of aperiodic performance of the vocal organ. Thenature of aperiodicity must be determined primarily bydirect observation of the larynx. The is a close cotinectionbetween the degree of perceived roughness and degree ofirregularity in the vocal fold vibration, that is, the degreeof irregularity increased with the increased amotrnt ofperceived roughness in voice. Because direct examinationof the larynx could interfere with the normal phonation andcauses discomfort to the patient, it is always better to utilizeacoustic measures for hoarseness.

S u m m aryand conclusion

The aim of the study was objective acoustic analysis ofvoice after phonosurgery. The analysis was done beforethe surgery and after 4 weeks of stirgery during which timespeech therapy was given to the patient. After doing thisstudy we found thatthe analysis of hoarse voice u sing various

parameters of acoustic analysis like ftindam ental frequenharmonics to noise ratio, jitter, shimmer, S/z ratio helpus in identifying the degree of hoarseness and the severelated to it. Some parameters like jitter and shimmer wable to detect the component of hoarseness in perceptuanormal voice and thus patient was helped by doing surgand voice therapy at the appropriate time.

As we found the ad vantages of this acoustic analysis,found the shortcomings of this measurement; that it conot predict the pathology causing dysphonia which coonly be confirmed on direct visualization ofthe vocal cordby either doing direct or indirect laryngoscopy; but direxamination of the larynx could interfere with the normphonation and causes discomfort to the patient, thus italways better to utilize acoustic measures for hoarsenalong with the other investigations.

Voice analysis should be d one on regular basis as par

the routine workup of the patient with hoarse voice, bucannot substitute other parameters like perceptual analyof voice, videostroboscopy, and direct and indirect largoscopy. It can work as complementary test for voice amainly for research pu rposes, the main outcome will alwbe subjective evaluation voice by the patienthimself.

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inctional assessment of voice pathology, especially forinvestigating the efficacy of phonosurgical treatments andevaluating new assessment techniques: Eur Arch Otorhinol258:77-82

3. Dejonckere PH, Remade M, Fresnell EE (1996) Differen-tiated perceptual evaluation of pathological voice quality;

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pathological voice: Acta Otolaryngol (Stock) 105:432-4385. Nieto A, Del Palacio AJ, Lorezo FJ (1995) Computer use

in voice analysis: Clinical applications: Acta Otorhinol Esp46(4):214-245

6. Maryloy P (1995) Fundam ental frequency, intensity andvowel selection; effect on measures of phonatory stability.J Speech Hearing 38:1189-1198

7. Nieto A, Cobeta 1, Gam boa FJ (1996) Harmonics to noiseratio and spectrographic analysis in vocal abuse pathology.Acta Otorhinol Esp 47(5):370-376

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graphic analysis in vocal abuse pathology. Acta OtorhinolEsp47(5):370-376

10. Gamboa FJ, Nieto A, del Palacio (1995) S/z ratio in gclosure defects. Acta Otorhinol Esp 46(1 ) :4 5 ^8

11. Rabinov, et al. (1995) Comparing reliability of pertcerating of roughness and acoustic measures of jitter shimmer. J Speech Hearing Res 38 :26-32

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and validation ofthe voice handicap index-10. Laryngo114(9): 1549-1556

14. Hogikyan ND, Sethuraman G (1999) Validation of an iment to measure voice related quality of life (V-RQOVoice 13:557

15. Hammarberg B, Fritzel G, Sunderberg J (1980) Perceand acoustic correlation of abnormal voice quality: Otorhinol 90:441^51

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