Full text
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| Author(s): |
Thaís Peres Vanzella
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD) |
| Defense date: | 2006-08-04 |
| Examining board members: |
Jose Carlos Pereira;
Ruy Barboza;
Aparecida de Cassia Guerra
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| Advisor: | Jose Carlos Pereira |
| Abstract | |
The voice is one of the most direct expressions of our personality and feelings. In the childhood the use of voice is intense mainly by their need to exteriorize the knowledge acquired in a so rapidly manner. The child larynx has a conic shape with tiny cartilages and loose ligaments. The epithelial tissues are dense, abundants and more vascularized, which can cause edemas and obstruction. Considering its characteristics, a child larynx is an excellent tool for breathing, swallowing and for protection of superior aerial via, however its not well adapted for phonation due to its short vertical dimension, small resonance, capability and restricted vertical movement. The acoustic analysis of the human voice has been quite useful to quantify acoustic parameters of voice as well as in the studies of physiological mechanism of voice apparatus. The aim of this work is to establish a larger acoustic profile of childrens voice, during natural daily activities, compared to the actual literature. One hundred and eighty two voice signal samples of sustained vowel /a/ from brazilian portuguese, in normal conversation level, were acquired from children at public and particular schools of São Carlos city, both male and female, ranging in age from 07 to 10 years old. Voice signals were recorded at 22,05 KHz sampling rate during 5 seconds and digitalized in a personal computer through Análise de Voz 5.0 software. The acoustic parameters evaluated were: fundamental frequency (F0), jitter; shimmer; spectral flatness of the residue (SFR); spectral flatness of the filter (SFF); pitch amplitude (PA) and excess coefficient (EX). The results show the following mean values: FO = 237,15 Hz; jitter = 1.21%; shimmer = 7.01%; SFR = -9.53 dB; SFF = -11.09 dB; PA = 0.55 and EX = 7.46 dB. The suggested thresholds values for this age are: jitter = 1%; shimmer = 8%; SFR = -6 dB; SFF = - 6 dB; PA = 0.3 and EX = 2.0 dB. From these proposed values, three of them agree with normal adult thresholds, namely shimmer, PA and EX. The jitter and spectral flatness parameters, SFR and SFF, varied showing the physiological differences between children and adults. The results found here bring some important knowledge about childrens voices and would be useful in voice therapy and could provide programs to prevent voice dysfunction. Another important result is the establishment of acoustic profile of the children voices. (AU) | |