RESUMO Objetivo analisar o efeito do mascaramento estável e modulado no Potencial Evocado Auditivo Cortical com estímulo de fala em adultos-jovens. Método participaram 14 indivíduos com idades entre 19 e 28 anos de ambos os sexos e sem perda auditiva. O exame de Potencial Evocado Auditivo Cortical foi realizado com estímulo de fala sintética /ba/ simultâneo ao ruído Speech Shaped Noise apresentado em três condições: ruído estável com intensidade de 30 dB NPSpe (ruído estável fraco), ruído estável com intensidade de 65 dB NPSpe (ruído estável forte) e ruído modulado em intensidade de 30 dB NPSpe e 65 dB NPSpe em 25Hz e com período de modulação de 40 ms. Resultados foram observadas maiores latências nos componentes corticais, exceto P2, na condição de ruído estável forte e medidas mais robustas de amplitude dos componentes corticais P1, N1 e P2 na condição de ruído modulado com diferença estatística significativa na comparação com a condição de ruído estável forte. Houve pior morfologia na condição de ruído estável forte, quando comparado aos demais registros. Os limiares eletrofisiológicos médios para as condições de ruído estável forte e ruído modulado foram 60 dB NPSpe e 49 dB NPSpe, respectivamente, mostrando 11,7 dB de diferença média. Conclusão podemos inferir que houve um menor efeito mascarante do ruído modulado, comparado à condição de ruído estável forte, nas medidas de amplitude dos componentes corticais e uma diferença média de 11,7 dB entre os limiares eletrofisiológicos (interpretado como a medida do Benefício do Mascaramento Modulado).

ABSTRACT Purpose To analyze the effect of masking on the Cortical Auditory Evoked Potential with speech stimulus in young adults. Methods Fourteen individuals aged between 19 and 28 years of both sexes with no hearing loss participated in the study. The Cortical Auditory Evoked Potential examination was performed with synthetic speech stimulus /ba/ simultaneous to Speech Shaped Noise presented under three conditions: steady noise with a 30 dB SPLep intensity (weak steady noise), steady noise with a 65 dB SPLep intensity o (strong steady noise) and modulated noise with 30 dB SPLep and 65 dB SPLep intensities at 25Hz and modulation period of 40 ms. Results Higher latencies were observed in the cortical components, except P2, in the condition of strong steady noise and more meaningful measures of amplitude of the cortical components P1, N1 and P2 in the condition of modulated noise with statistically significant difference in comparison to the strong steady noise condition. There was worse wave morphology in the condition of strong steady noise, when compared to the other records. The average electrophysiological thresholds for the conditions of strong steady noise and modulated noise were 60 dB SPLep and 49 dB SPLep, respectively, showing a 11.7 dB mean difference. Conclusion We could infer that there was a lower masking effect of modulated noise when compared to the strong steady noise condition, in the amplitude measurements of the cortical components and an average difference of 11.7 dB between the electrophysiological thresholds (interpreted as the measure of the Masking Release).

Abstract Introduction Idiopathic sudden sensorineural hearing loss (ISSHL) is a disabling otologic urgency whose ethiopathogenesis is still controversial. Only in recent years metabolic syndrome (MetS) has been implicated as a possible aggravating factor in the prognosis of recovery from ISSHL. Objective To assess whether the preexistence of MetS interferes on hearing recovery levels. Methods Retrospective cohort study composed of adult (> 18 years old) ISSHL patients admitted for treatment between January 2015 and December 2019. To diagnose ISSHL, we used pure-tone audiometry, and identified MetS patients based on the criteria of the United States National Cholesterol Education Program Adult Treatment Panel III (NCEPATP III). The treatment protocol comprised hospitalization for five days for the intravenous administration of dexamethasone, audiometric surveillance, imaging and blood analyses, and, based on recovery, the planning of rescue treatments (intratympanic administration of dexamethasone and/or hyperbaric oxygen). The Siegel criteria were used to evaluate the hearing outcomes. Results The final sample was composed of 81 patients, 48 without MetS (nMetS) and 33 with MetS. Regarding the Siegel recovery category, the nMetS group had significantly better results (p = 0.001), with 44% of complete recoveries against 6% in the MetS, and 58% of the MetS patients had the worst outcome, contrasting with 27% in the nMetS group. The nMetS group had an overall better evolution in terms of hearing recovery and had a significant improvement in the median hearing gain (20.6 dB versus 8.8 dB; p = 0.008). Additionally, the multivariate analysis revealed that the presence of MetS is a significant risk factor for a worse outcome (odds ratio [OR] = 0.30; 95% confidence interval [95%CI] = 0.10–0.85). Conclusion Regardless of age, gender, the initial audiometry threshold, and autoimmunity, MetS is a clear risk factor for a worse outcome regarding the recovery of hearing after ISSHL.

ABSTRACT Purpose: to compare cortical auditory evoked responses using two speech stimuli, /ma/ and /da/, in normally hearing young adults. Methods: a cross-sectional, observational and analytical study, with a sample composed of nineteen normally hearing young adults, recruited by convenience, ages between 18 and 25 years old, from both genders, participated in the study. Cortical auditory evoked potentials (CAEP) were monaurally recorded in two conditions: 1) with a pair of speech stimuli /ba/ and /da/, and 2), with a pair of speech stimuli /ba/ and /ma/. The order of the experiments was randomized in a proportion of 50% for each of the two stimuli, totaling 100 stimuli for each experiment. Speech sounds were presented at 70 dB SPL. Descriptive and analytical statistical tests were performed. Results: mean latency values of the complex P1, N1, P2, N2 and P3 were lower for the /ma/ when compared to those of /da/ (p <0,05). There was no difference in amplitude values between responses evoked using /ma/ and /da/. Conclusion: cortical auditory evoked potentials, elicited by the speech stimulus /ma/ had, on average, lower latency peaks of P1-N1-P2-N2 and P3, when compared to those of speech stimulus /da/.

RESUMO Objetivo: investigar o reconhecimento auditivo da fala intermitente em função de diferentes taxas de modulação e em função da idade. Métodos: participaram do estudo vinte jovens, vinte adultos de meia idade, e dezesseis idosos, todos com limiares auditivos iguais ou menores que 25 dB NA até a frequência de 4000 Hz. Os participantes foram submetidos a testes de reconhecimento da fala intermitente apresentada em três condições de modulação: 4 Hz, 10 Hz e 64 Hz. Percentuais de acerto foram comparados entre grupos etários e taxas de modulação. Para a investigação do efeito da taxa de modulação foi realizada ANOVA e testes Post Hoc, enquanto para a investigação do efeito da idade, utilizou-se o modelo de regressão linear misto (p<0,001). Resultados: sobre o efeito da idade, os dados mostram diferença significante entre jovens e idosos, e entre adultos de meia idade e idosos. Sobre o efeito da taxa de modulação, os índices de acerto da taxa mais lenta (4Hz) foram significantemente menores nos três grupos etários. Conclusão: foi verificado um efeito da idade no reconhecimento da fala intermitente: idosos apresentaram maior dificuldade. Percebeu-se também um efeito de taxa de modulação nos três grupos etários: quanto maior a taxa, melhor o desempenho.

ABSTRACT Purpose: to investigate the auditory recognition of intermittent speech in relation to different modulation rates and ages. Methods: 20 young people, 20 middle-aged adults, and 16 older adults, all of them with auditory thresholds equal to or lower than 25 dB HL up to the frequency of 4000 Hz. The participants were submitted to intermittent speech recognition tests presented in three modulation conditions: 4 Hz, 10 Hz, and 64 Hz. The percentages of correct answers were compared between age groups and modulation rates. ANOVA and post hoc tests were conducted to investigate the modulation rate effect, and the mixed linear regression model (p < 0.001). Results: regarding the age effect, the data showed a significant difference between young people and older adults, and between middle-aged and older adults. As for the modulation rate effect, the indexes of correct answers were significantly lower at the slower rate (4 Hz) in the three age groups. Conclusion: an age effect was verified on intermittent speech recognition: older adults have greater difficulty. A modulation rate effect was also noticed in the three age groups: the higher the rate, the better the performance.

ABSTRACT Computer models have been used to assess soil organic carbon (SOC) stock change. Commonly, models require to determine soil bulk density (Db), a variable that is often lacking in soil data bases. To partly overcome this problem, pedotransfer functions (PTFs) are developed to estimate Db from other easily available soil properties. However, only a few studies have determined the accuracy of these functions and quantified their effects on the final quality of the spatial variability maps. In this context, the objectives of this study were: i) to develop one PTF to estimate Db in soils of the Brazilian Central Amazon region; ii) to compare the performance of PTFs generated with three other models generally used to estimate Db in soils of the Amazon region; and iii) to quantify the effect of applying these PTFs on the spatial variability maps of SOC stock. Using data from 96 soil profiles in the Urucu river basin in Brazil, a multiple linear regression model was generated to estimate Db using SOC, pH, sum of basic cations, aluminum (Al+3), and clay content. This model outperformed the three other PTFs published in the literature. The average estimation error of SOC stock using our model was 0.03 Mg C ha−1, which is markedly lower than the other PTFs (1.06 and 1.23 Mg C ha−1, or 15 % and 17 %, respectively). Thus, the application of a non-validated PTF to estimate Db can introduce an error that is large enough to skew the significant difference in soil carbon stock change.

RESUMO Introdução A capacidade em perceber os sons da fala possibilita ao ser humano comunicar-se de forma eficiente. Esse aspecto deve ser considerado na avaliação dos distúrbios da comunicação humana. O Hearing in Noise Test (HINT) foi adaptado para o português brasileiro e faz uso de sentenças para avaliar o reconhecimento de fala em silêncio e na presença de ruído competitivo. O teste pode ser uma ferramenta clínica importante, embora não se observe a utilização do HINT na prática clínica audiológica no Brasil. Um dos motivos dessa ausência pode estar relacionado com a falta de padronização em alguns aspectos do teste, incluindo o julgamento de respostas apresentadas durante sua aplicação. Objetivo Analisar os diferentes critérios de julgamento de respostas obtidas de indivíduos submetidos à pesquisa de limiares de reconhecimento das sentenças do HINT em português brasileiro. Método A pesquisa foi realizada com 30 adultos jovens (três grupos de 10 pessoas), entre 18 e 25 anos, de ambos os gêneros, com audição normal. Os indivíduos foram submetidos ao teste de reconhecimento de sentenças em presença de ruído competitivo com uso de sentenças do HINT, adaptado para o português brasileiro. Foram determinados limiares de reconhecimento de sentenças na presença de ruído, através da utilização de três critérios de julgamento publicados na literatura brasileira. Foi realizada uma análise de variação única para comparar as médias dos limiares entre os três grupos. A probabilidade máxima de erro para rejeitar a hipótese nula foi de 5%. Resultados As médias e os desvios padrão dos limiares de reconhecimento de sentenças, respectivamente, foram: 59,90 dB NPS ± 1,43; 59,60 dB NPS ± 0,53 e 59,95 dB NPS ± 0,6. Não houve diferença, estatisticamente significativa, entre as médias (F=0,398; p>0,05). Conclusão Independentemente do critério de julgamento utilizado, as respostas obtidas de indivíduos submetidos à pesquisa de limiares de reconhecimento de sentenças na presença de ruído, foram semelhantes.

ABSTRACT Introduction The ability to recognize the sounds of speech enables an efficient communication. This ability must always be considered when communication disorders are evaluated. In this study, sentences of the Hearing in Noise Test (HINT), originally developed in English and adapted to Brazilian Portuguese, were used to evaluate speech recognition in silence and in the presence of noise. Although this test can be an important clinical tool, it is noticed that it has not been used in audiological clinical practice in Brazil. One possible reason is the lack of standardization of some aspects of the test, including the methods adopted to analyze the patient’s answers. Purpose The aim of this study was to analyze different judgment criteria of individuals’ answers during sentence recognition thresholds measurement using the HINT in Brazilian Portuguese. Methods The study was conducted with 30 young adults (three groups of 10 people), between 18 and 25 years old, of both genders, with normal hearing. HINT sentences were adapted to Brazilian Portuguese and speech recognition thresholds were determined in the presence of noise by using three judgment criteria published in Brazilian literature. A single variation analysis was performed to compare the average threshold between the three groups. The maximum error probability to reject the null hypothesis was 5%. Results The mean and standard deviations of thresholds, respectively, were: 59.90 ± 1.43 dB SPL; 59.60 ± 0.53 dB SPL and 59.95 ± 0.6 dB SPL. There was no statistically significant difference between the means (F = 0.398; p> 0.05). Conclusion Regardless the judging criteria used, results obtained in all groups were equivalent.

ABSTRACT Salmonella species have been isolated from various kinds of food and are accountable for outbreaks of foodborne diseases in humans. This study aimed at identifying the similarities between the DNA profiles of Salmonella isolated from chicken feces, chicken products, and human feces in southern Brazil. Six hundred samples were collected (200 from chicken products, 200 from broiler chicken feces, and 200 from human feces) and tested for the presence of Salmonella. Isolates proven to be Salmonella compatible by biochemical and serological tests were tested by the Polymerase Chain Reaction. Their DNA profiles were then analyzed by PFGE and rep-PCR. Salmonella was isolated from 16 out of 600 analyzed samples, with Schwarzengrund serotype presenting the highest incidence, followed by Mbandaka in chicken meat and fecal samples, and Panama in human fecal samples. Some strains isolated from chicken fecal and product samples were indistinguishable by the molecular methods used in the study, suggesting that that the contamination of the broilers on the farm can be transmitted the processed products.

RESUMO INTRODUÇÃO: Um dos problemas observados na audiometria tonal é a variação nos resultados de testes de um mesmo indivíduo, sobretudo nas frequências de 4, 6 e/ou 8 kHz. A colocação indevida dos fones é um dos fatores que podem causar alterações nos resultados. OBJETIVO: Comparar as diferenças nos limiares auditivos com os fones posicionados pelo examinador e pelo paciente. MÉTODO: Estudo clínico e experimental realizado, em 2009, com 324 trabalhadores, com idade entre 19 e 61 anos, média de 29,33 anos e tempo médio de exposição ao ruído de 7,67 anos; todos familiarizados com os procedimentos da audiometria. Os limiares auditivos foram obtidos nas frequências de 0,25 a 8 kHz, com os fones colocados pelos examinadores; e nas frequências de 4, 6 e 8 kHz com os fones colocados pelos trabalhadores em posição de conforto, sob orientação do examinador. Os limiares obtidos nas duas situações foram comparados. RESULTADOS: As três frequências apresentaram melhores respostas com os fones colocados pelos próprios indivíduos (p < 0,001). Na frequência de 8 kHz foi encontrada a maior diferença (p < 0,001), com média de 13,89 dB e desvio padrão de 6,07 dB. CONCLUSÃO: A colocação dos fones de ouvido pelos próprios trabalhadores, sob supervisão dos examinadores, resulta na melhora dos limiares auditivos médios nas frequências de 4, 6 e 8 kHz, sendo esta última significativamente maior que as demais.

ABSTRACT INTRODUCTION: One of the problems observed in pure-tone audiometry tonal has been the variation in test results of a same individual, particularly at frequencies of 4 kHz, 6 kHz and/or 8 kHz. Improper placement of headphones is one of the factors that can cause alterations in results. OBJECTIVE: To compare differences in auditory thresholds using earphones positioned by the examiner and by the worker. METHODS: Clinical and experimental study conducted in 2009, with 324 workers aged between 19 and 61 years, with a mean of 33.29 years and mean exposure time of 7.67 years. All subjects were familiar with audiometry procedures. Auditory thresholds were obtained at frequencies of 0.25-8 kHz, with earphones positioned by the examiners, and at frequencies of 4, 6 and 8 kHz, with earphones placed by workers in a comfortable position, following the examiner's instructions. The thresholds obtained in these two situations were compared. RESULTS: The three frequencies exhibited better responses with earphones placed by the workers themselves (p < 0.001). At a frequency of 8 kHz a greater difference was found (p < 0.001), with a mean of 13.89 dB and standard deviation of 6.07 dB. CONCLUSION: Earphone placement by the workers themselves under supervision of the examiner results in improved mean auditory thresholds at frequencies of 4, 6 and 8 kHz, the last one significantly higher than the other two.

INTRODUÇÃO: Ainda não existe consenso quanto ao melhor estímulo acústico utilizado para a captação do potencial evocado miogênico vestibular (PEMV). Respostas amplas são observadas para estímulos de baixa frequência, porém estudos recentes ainda utilizam cliques. A reprodutibilidade dos traçados é um importante parâmetro de análise para observar a confiabilidade das respostas. OBJETIVO: Verificar a reprodutibilidade dos parâmetros ''latência e amplitude das ondas p13 en23'' do PEMV para estímulos com diferentes frequências de estímulos do tipo tone burst, e definir a melhor frequência de teste. MÉTODO: Estudo de coorte-transversal. Captou-se PEMV em 156 orelhas, no músculo esternocleidomastóideo, com 100 estímulos do tipo tone burst nas frequências de 250, 500, 1.000 e 2.000 Hz e nível sonoro 95 dB NAn, registrados três vezes de cada lado. RESULTADOS: Foram constatadas similaridades para latências de p13 e n23 do potencial estudado nos três momentos com estímulos tone burst em 250, 500, 1.000 Hz, e diferenças entre as captações desse potencial (p < 0,001) para a frequência de 2.000 Hz. A análise da amplitude de p13 e n23 se mostrou semelhante, no teste-reteste, para todas as frequências analisadas. CONCLUSÃO: Existe reprodutibilidade das latências e amplitudes de p13 e n23 do PEMV para estímulos tone burst nas frequências de 250, 500 e 1.000 Hz.

INTRODUCTION: There is still no consensus in the literature as to the best acoustic stimulus for capturing vestibular evoked myogenic potential (VEMP). Low-frequency tone bursts are generally more effective than high-frequency, but recent studies still use clicks. Reproducibility is an important analytical parameter to observe the reliability of responses. OBJECTIVE: To determine the reproducibility of p13 and n23 latency and amplitude of the VEMP for stimuli with different tone-burst frequencies, and to define the best test frequency. METHODS: Cross-sectional cohort study. VEMP was captured in 156 ears, on the sternocleidomastoid muscle, using 100 tone-burst stimuli at frequencies of 250, 500, 1000, and 2000 Hz, and sound intensity of 95 dB nHL. Responses were replicated, that is, recorded three times on each side. RESULTS: No significant difference was observed for p13 and n23 latencies of the VEMP, captured at three moments with tone-burst stimuli at 250, 500, and 1000 Hz. Only the frequency of 2000 Hz showed a difference between captures of this potential (p < 0.001). p13 and n23 amplitude analysis was also similar in the test-retest for all frequencies analyzed. CONCLUSION: p13 and n23 latencies and amplitudes of VEMP for tone-burst stimuli at frequencies of 250, 500, and 1000 Hz are reproducible.

OBJECTIVE: The aim of this study was to determine the effects of occupational noise on sound localization in different spatial planes and frequencies among normal hearing firefighters. METHOD: A total of 29 adults with pure-tone hearing thresholds below 25 dB took part in the study. The participants were divided into a group of 19 firefighters exposed to occupational noise and a control group of 10 adults who were not exposed to such noise. All subjects were assigned a sound localization task involving 117 stimuli from 13 sound sources that were spatially distributed in horizontal, vertical, midsagittal and transverse planes. The three stimuli, which were square waves with fundamental frequencies of 500, 2,000 and 4,000 Hz, were presented at a sound level of 70 dB and were randomly repeated three times from each sound source. The angle between the speaker's axis in the same plane was 45°, and the distance to the subject was 1 m. RESULT: The results demonstrate that the sound localization ability of the firefighters was significantly lower (p<0.01) than that of the control group. CONCLUSION: Exposure to occupational noise, even when not resulting in hearing loss, may lead to a diminished ability to locate a sound source.

Os potenciais evocados miogênicos vestibulares são reflexos vestíbulo-cervicais, decorrentes da estimulação do sáculo com sons de forte intensidade. São necessários parâmetros de normalidade para indivíduos jovens normais, utilizando-se estímulos a baixas frequências, as quais configuram a região de maior sensibilidade desse órgão sensorial. OBJETIVO: Realizar normatização do potencial evocado miogênico vestibular para baixas frequências de estimulação. MATERIAL E MÉTODO: Captou-se o potencial evocado miogênico vestibular em 160 orelhas, no músculo esternocleidomastoideo, de forma ipsilateral, por meio da promediação de 200 tone bursts, frequência de 250 Hz, intensidade de 95 dB NAn. FORMA DE ESTUDO: Estudo de coorte contemporânea com corte transversal. RESULTADOS: Aplicando-se o teste T de Student ou o Teste de Mann-Whitney, não foi constatada diferença significativa para parâmetros do potencial evocado miogênico vestibular entre os gêneros, para p <; 0,05. Verificamos, independente do gênero, latências de p13, n23 e interpicos p13-n23 iguais a 13,84ms (± 1,41), 23,81ms (±1,99) e 10,62ms (± 6,56), respectivamente. Observamos índices de assimetria iguais a 13,48% para mulheres e 3,81% para homens. CONCLUSÃO: Estímulos de baixa frequência geram respostas de potenciais evocados miogênicos vestibulares, com morfologia e amplitudes adequadas, sendo determinados, valores de normalidade para essa frequência, em indivíduos normais.

Vestibular evoked myogenic potentials are vestibulocervical reflexes resulting from sacculus stimulation with strong intensity sounds. Normality parameters are necessary for young normal individuals, using low frequency stimuli, which configure the most sensitive region of this sensory organ. AIM: To establish vestibular evoked myogenic potential standards for low frequency stimulation. MATERIAL AND METHOD: Vestibular evoked myogenic potential was captured from 160 ears, in the ipsilateral sternocleidomastoid muscle, using 200 averaged tone-burst stimuli, at 250 Hz, with an intensity of 95 dB NAn. CASE STUDY: Clinical observational cross-sectional. RESULTS: Neither the student's t-test nor the Mann-Whitney test showed a significant difference in latency or vestibular evoked myogenic potential amplitudes, for p <; 0.05. Irrespective of gender, we found latencies of p13-n23 and p13-n23 interpeaks of 13.84 ms (± 1.41), 23.81 ms (±1.99) and 10.62 ms (± 6.56), respectively. Observed values for amplitude asymmetry between the ears were equal to 13.48% for females and 3.81% for males. CONCLUSION: Low frequency stimuli generate vestibular evoked myogenic potentials, with adequate morphology and amplitude, thereby enabling the establishment of standard values for normal individuals at this frequency.

Thalassophryne nattereri (niquim) is a venomous fish responsible for numerous accidents involving fishermen in northern and northeastern Brazil. The aim of the present investigation was to evaluate the action of antivenom on renal effects caused by Thalassophryne nattereri venom. Isolated kidneys of Wistar rats were perfused with a previously dialyzed Krebs-Henseleit solution containing 6 g% bovine serum albumin. The antivenom action was studied through perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF) and glomerular filtration rate (GFR). The niquim venom (1 µg/mL), the antivenom alone (1 µg/mL) or the venom incubated with antivenom were added to the system 30 minutes after the beginning of each perfusion. Previous works have shown venom induced-alterations of renal function parameters. In the isolated rat kidney, T. nattereri venom (1 µg/mL) increased the perfusion pressure and renal vascular resistance at 60, 90 and 120 minutes. UF and GFR also increased at 60, 90 and 120 minutes when compared with the control group; however, no effects were observed on the percent of sodium (%TNa+control = 81.1 ±0.86; %TNa+60 = 78.04 ±1.18; %TNa+90 = 76.16 ±3.34; %TNa+120 = 79.49 ±0.87) and potassium (%TK+control = 72.29 ±1.12; %TK+60 = 75.41 ±0.65; %TK+90 = 71.23 ±2.55; %TK+120 = 76.62 ±1.04) tubular transport. The administration of the antivenom (1 µg/mL) incubated with venom (1 µg/mL) reduced the changes in PP, RVR, UF and GFR provoked by Thalassophryne nattereri venom. The group perfused with venom alone showed a moderate deposit of a proteinaceous material in the tubules and urinary space. The group perfused with the antivenom presented similar results to the control group. In conclusion, the antivenom was able to decrease the effects induced by T. nattereri venom in isolated rat kidney.

OBJETIVO: Esclarecer a relação das diferenças entre os limiares auditivos das orelhas direita e esquerda com o percentual de erros e acertos na localização de fontes sonoras em ambientes reverberantes. MÉTODOS: Foram examinados 56 voluntários, sendo 33 homens e 23 mulheres, média de idade de 26,6 anos, submetidos aos seguintes testes: otoscopia, audiometria tonal, imitanciometria e emissões otoacústicas. Todos os voluntários apresentaram audição dentro dos padrões de normalidade. Posteriormente, os indivíduos foram submetidos ao teste de localização sonora espacial, onde foram utilizadas ondas quadradas com freqüências fundamentais centradas em 500 Hz, 2000 Hz e 4000 Hz. Os estímulos foram apresentados quinze vezes em cada uma das treze posições espaciais do aparelho utilizado, em cada uma das freqüências escolhidas. Assim, foram apresentados 585 estímulos, no total, por pessoa. RESULTADOS: Na amostra estudada, encontrou-se como resultado, idade entre 18 e 50 anos, média da diferença dos limiares auditivos entre as orelhas de 6,81 dB e percentual de acertos na localização sonora dentro dos padrões normais. A correlação entre as diferenças interaurais e os acertos na localização, no entanto, não foi significativa. CONCLUSÕES: O presente estudo demonstrou que, em pessoas com audição normal, as variações dos limiares auditivos e as diferenças entre as orelhas até 10 dB não interferem na localização de fontes sonoras.

PURPOSE: To relate the differences between left and right ears' auditory thresholds and rate of correct/incorrect responses in sound localization tasks placed in reverberant environments. METHODS: The following tests were carried out: otoscopy, pure tone audiometry, impedanciometry and otoacoustic emissions. All 56 volunteers presented normal hearing results in all tests. After that, the volunteers were submitted to a sound localization test, in which square waves of 500 Hz, 2000 Hz and 4000 Hz were used. Stimuli were presented fifteen times in each one of the thirteen space positions of the device used, for each frequency tested. Therefore, a total number of 585 stimuli were presented for each subject. RESULTS: Data analysis showed that the sample had subjects with ages between 18 and 50 years, the average difference between right and left ears' auditory thresholds was 6,81 dB, and percentage of correct answers on the sound localization test was within normal values. No significant correlations were found between interaural differences and localization abilities. CONCLUSIONS: The present study showed that, for people with normal hearing, the auditory thresholds variations and interaural differences until 10 dB do not interfere on sound localization.