Peripheral hearing in Parkinson's disease: a systematic review.

OBJECTIVE: To investigate the implications of Parkinson's disease (PD) in the peripheral auditory system, a systematic survey of the scientific literature was conducted. DESIGN: Systematic review. STUDY SAMPLE: An electronic search of the non-gray literature in the last decade was conducted using the digital databases MEDLINE® (PubMed interface), LILACS® (Virtual Health Library), Web of Science® (CAPES publications portal), and SciELO®. Studies addressing peripheral auditory function as part of the range of nonmotor PD symptoms were selected for analysis. RESULTS: Pure tone audiometry data suggested that sensorineural hearing loss was more severe in the PD population than in the control groups. The effects of PD on cochlear function were evidenced by a decrease in the levels of otoacoustic emissions. CONCLUSIONS: Sensorineural hearing loss and cochlear impairment are more severe in the PD population than in the control groups. Additional studies are recommended to further understand the characteristics of the peripheral auditory system in PD patients, which constitutes an emerging subject in the scientific literature.

Influence of obstructive sleep apnea on auditory event-related potentials.

PURPOSE: To evaluate the influence of obstructive sleep apnea (OSA) on the P300 response of auditory event-related potentials (ERPs) and to correlate the electrophysiological findings with OSA severity. METHODS: Patients with no OSA and mild, moderate, and severe OSA according to polysomnography (PSG) with normal hearing and no comorbidities were studied. Individuals with a body mass index (BMI) ≥ 40 kg/m2, hypertension, diabetes, dyslipidemia, the use of chronic medications, and a risk of hearing loss were excluded. All patients underwent full PSG and auditory ERP measurement using the oddball paradigm with tone burst and speech stimuli. For P300 analysis (latencies and amplitudes), normal multiple linear regression models were adjusted with the groups (No OSA, Mild OSA, Moderate OSA, Severe OSA), age, BMI, and Epworth score as explanatory variables. RESULTS: We studied 54 individuals (47 males) aged 35 ± 8 years with a BMI of 28.4 ± 4.3 kg/m2. Patients were divided according to the apnea-hypopnea index (AHI) derived from PSG into no OSA (n = 14), mild (n = 16), moderate (n = 12), and severe OSA (n = 12) groups. Patients with severe OSA presented prolonged P300 latencies with tone burst stimuli compared to patients with no OSA and those with mild and moderate OSA. CONCLUSION: Severe OSA is associated with impairment of the P300 response of auditory ERPs, suggesting a decrease in the processing speed of acoustic information that may be mediated by the level of somnolence.

"Benefits of the pedicled osteoplastic flap as a surgical approach of mastoidectomy in cochlear implant surgery".

OBJECTIVE: To evaluate the esthetic and functional results of an osteoplastic flap for mastoid cavity closure in cochlear implant surgery. STUDY DESIGN: Double-blind, prospective, randomized clinical trial. SETTING: tertiary referral center. INTERVENTION(S): On hundred and twenty-six patients were randomized in 2 groups for cochlear implant surgery. Cases (n: 63) underwent simple mastoidectomy using an anteriorly pedicled osteoplastic flap for mastoid closure. In controls (n: 63), a traditional periosteal flap was used. Evaluation with the POSAS questionnaire was performed 1 year after surgery to assess surgical wound esthetics. Sixteen patients from each group had postoperative CT-scans and wideband tympanometry to assess mastoid aeration and middle ear absorbance. Gender and time after surgery were correlated. MAIN OUTCOME MEASURE(S): Evaluation of the quality of the surgical wound with the application of a questionnaire validated in the medical literature and translated into Portuguese language called POSAS, considering the perception of the blinded patient and doctor regarding the surgical technique proceeded. A lower POSAS score suggests better esthetics of the surgical wound. Secondary outcomes are volumetric measurement of aeration inside mastoid cavity using 3D computer tomography exam, which aims to analyze the influence of fibrocicatricial retraction in the surgical wound into the mastoid and the interference of its aeration volume in the absorption of sound in the middle ear, using the wideband tympanometry exam. RESULTS: The POSAS questionnaire in the Case group showed a lower level of local pain and itchiness, a skin color and thickness more similar to the surrounding skin and less irregularity and stiffness, with no influence from time after surgery and gender compared to the Control group. The median tomographic volume was 6.37 cc in the cases and 4.60 cc in controls. Wideband tympanometry showed general smaller sound absorbance in the Case group results, specially, at 1000 Hz frequency. No intraoperative or postoperative complications were observed with the osteoplastic flap. CONCLUSIONS: This technique is an effective and safe alternative to alleviate common problems of mastoid surgery for cochlear implantation. In addition to esthetic benefits, it has less interference in middle ear physiology of sound absorbance and less fibrous tissue into the mastoid cavity during the follow-up of more than 1 year.

Development of auditory perception in preschool children.

OBJECTIVE: The aim of this study was to determine whether the auditory skills presented by five-year-old children can predict their performance in auditory processing (AP) tests at seven years old. DESIGN: Thirty-five children were evaluated for AP at two different times. At evaluation 1, the children were between 5 years 2 months and 6 years 1 month of age, and at evaluation 2, they were between 7 years 1 month and 7 years 8 months of age. The interval between the evaluations ranged from 18 to 23 months. After evaluation 2, the 7-year-olds were classified according to their performance on central AP tests. The children were divided into three groups: GI included nine children with at least two AP tests that scored two standard deviations below the mean and the presence of a speech complaint; GII included 18 children with at least two AP tests that scored two standard deviations below the mean and no speech complaints; and GIII included eight children with no more than one test scored two standard deviations below the mean and no speech disorders complaint. The analysis was performed considering each test individually and as a battery of applied tests. From the results obtained, a discriminant analysis was performed to assess the differences in test performance between the groups when the children were 5 years old. RESULTS: The discriminant analysis showed that with the results obtained during evaluation 1, it was possible to predict which group 74.3% of the children would be classified into after evaluation 2. The percentage of correct classifications for each group was 77.8% for GI, 66.7% for GII and 87.5% for GIII. That is, 87.5% of the children who were classified as GIII after evaluation 2 had already demonstrated good auditory performance in the tests applied at 5 years of age. CONCLUSIONS: Children who exhibited lower scores on AP tests at 7 years of age had demonstrated poor auditory perception at 5 years of age. This finding is relevant because it offers the possibility of stimulating or training these auditory skills in preschoolers to foster their development.

Evaluation of peripheral auditory pathways and brainstem in obstructive sleep apnea / Avaliação da via auditiva periférica e do tronco encefálico na apneia obstrutiva do sono

Abstract Introduction Obstructive sleep apnea causes changes in normal sleep architecture, fragmenting it chronically with intermittent hypoxia, leading to serious health consequences in the long term. It is believed that the occurrence of respiratory events during sleep, such as apnea and hypopnea, can impair the transmission of nerve impulses along the auditory pathway that are highly dependent on the supply of oxygen. However, this association is not well established in the literature. Objective To compare the evaluation of peripheral auditory pathway and brainstem among individuals with and without obstructive sleep apnea. Methods The sample consisted of 38 adult males, mean age of 35.8 (±7.2), divided into four groups matched for age and Body Mass Index. The groups were classified based on polysomnography in: control (n = 10), mild obstructive sleep apnea (n = 11) moderate obstructive sleep apnea (n = 8) and severe obstructive sleep apnea (n = 9). All study subjects denied a history of risk for hearing loss and underwent audiometry, tympanometry, acoustic reflex and Brainstem Auditory Evoked Response. Statistical analyses were performed using three-factor ANOVA, 2-factor ANOVA, chi-square test, and Fisher's exact test. The significance level for all tests was 5%. Results There was no difference between the groups for hearing thresholds, tympanometry and evaluated Brainstem Auditory Evoked Response parameters. An association was observed between the presence of obstructive sleep apnea and changes in absolute latency of wave V (p = 0.03). There was an association between moderate obstructive sleep apnea and change of the latency of wave V (p = 0.01). Conclusion The presence of obstructive sleep apnea is associated with changes in nerve conduction of acoustic stimuli in the auditory pathway in the brainstem. The increase in obstructive sleep apnea severity does not promote worsening of responses assessed by audiometry, tympanometry and Brainstem Auditory Evoked Response.

Resumo Introdução A Apneia Obstrutiva do Sono provoca modificações na arquitetura normal do sono, fragmentando-o de forma crônica com hipóxias intermitentes levando, a longo prazo, a sérias consequências na saúde. Acredita-se que a ocorrência de eventos respiratórios durante o sono como apneia e hipopneia pode prejudicar a transmissão de impulsos nervosos ao longo da via auditiva que são altamente dependentes do fornecimento do oxigênio. Contudo, essa associação não se encontra bem estabelecida na literatura. Objetivo Comparar os achados da avaliação da via auditiva periférica e no tronco encefálico entre indivíduos portadores e não portadores de apneia obstrutiva do sono. Método A casuística foi composta por 38 adultos do sexo masculino, média de idade de 35,8 (±7,2); divididos em quatro grupos experimentais pareados por idade e índice da massa corpórea. Os grupos foram classificados com base na polissonografia em: controle (n = 10), apneia obstrutiva do sono leve (n = 11), apneia obstrutiva do sono moderada (n = 8) e apneia obstrutiva do sono grave (n = 9). Todos os sujeitos do estudo negaram história pregressa de risco para perda auditiva e foram submetidos à audiometria, timpanometria, pesquisa dos reflexos acústicos e Potenciais Evocados Auditivos de Tronco Encefálico. As análises estatísticas foram realizadas por meio de ANOVA 3-fatores, ANOVA 2-fatores, teste de Qui-quadrado e teste exato de Fisher. O nível de significância adotado para todos os testes foi de 5%. Resultados Não houve diferença entre os grupos para os limiares auditivos, timpanometria e parâmetros avaliados do Peate. Observou-se associação entre a presença da apneia obstrutiva do sono e alteração da latência absoluta da onda V (p = 0,03). Observou-se associação entre apneia obstrutiva do sono de grau moderado e alteração da latência da onda V (p = 0,01). Conclusão A presença de apneia obstrutiva do sono está associada à presença de alteração na condução nervosa do estímulo acústico na via auditiva em tronco encefálico. O aumento do grau de severidade da apneia obstrutiva do sono não promove piora das respostas avaliadas pela audiometria, timpanometria e Potenciais Evocados Auditivos de Tronco Encefálico.

Severe obstructive sleep apnea is associated with cochlear function impairment.

PURPOSE: The purpose of this study is to investigate the association between obstructive sleep apnea (OSA) with middle ear acoustic transference and cochlear function. METHODS: Male individuals with and without mild, moderate, and severe OSA according to standard criteria of full polysomnography and no co-morbidities were studied. Subjects with BMI ≥40 kg/m2, present or past treatment for OSA, with heart failure, diabetes, hypertension, dyslipidemia, stroke, use of chronic medications, and previous history of risk for hearing loss were excluded. All subjects were submitted to full polysomnography, evaluation of wideband acoustic immittance by energy of absorbance (EA), and distortion product otoacoustic emissions (DPOAE). RESULTS: We studied 38 subjects (age 35.8 ± 7.2 years, BMI 28.8 ± 3.8 kg/m2) divided into no OSA (n = 10, age 33.6 ± 6.4 years, BMI 26.9 ± 4.1 kg/m2), mild (n = 11, age 32.8 ± 2.9 years, BMI 28.5 ± 3.5 kg/m2), moderate (n = 8, age 34.1 ± 6.8 years, BMI 29.6 ± 3.3 kg/m2), and severe OSA (n = 9, age 41.2 ± 9.2 years, BMI 30.5 ± 3.8 kg/m2). EA was similar between groups. In contrast, patients with severe OSA presented significantly lower DPOAE amplitudes when compared to the control, mild, and moderate OSA groups (p ≤ 0.03, for all comparisons). CONCLUSIONS: Acoustic transference function of middle ear is similar in adults with and without OSA. Severe OSA is independently associated with cochlear function impairment in patients with no significant co-morbidities.

Medial olivocochlear function in children with poor speech-in-noise performance and language disorder.

OBJECTIVES: Contralateral masking of transient-evoked otoacoustic emissions is a phenomenon that suggests an inhibitory effect of the olivocochlear efferent auditory pathway. Many studies have been inconclusive in demonstrating a clear connection between this system and a behavioral speech-in-noise listening skill. The purpose of this study was to investigate the activation of a medial olivocochlear (MOC) efferent in children with poor speech-in-noise (PSIN) performance and children with language impairment and PSIN (SLI + PSIN). METHODS: Transient evoked otoacoustic emissions (TEOAEs) with and without contralateral white noise were tested in 52 children (between 6 and 12 years). These children were arranged in three groups: typical development (TD) (n = 25), PSIN (n = 14) and SLI + PSI (n = 13). RESULTS: PSIN and SLI + PSI groups presented reduced otoacoustic emission suppression in comparison with the TD group. CONCLUSION: Our finding suggests differences in MOC function among children with typical development and children with poor SIN and language problems.

Evaluation of peripheral auditory pathways and brainstem in obstructive sleep apnea.

INTRODUCTION: Obstructive sleep apnea causes changes in normal sleep architecture, fragmenting it chronically with intermittent hypoxia, leading to serious health consequences in the long term. It is believed that the occurrence of respiratory events during sleep, such as apnea and hypopnea, can impair the transmission of nerve impulses along the auditory pathway that are highly dependent on the supply of oxygen. However, this association is not well established in the literature. OBJECTIVE: To compare the evaluation of peripheral auditory pathway and brainstem among individuals with and without obstructive sleep apnea. METHODS: The sample consisted of 38 adult males, mean age of 35.8 (±7.2), divided into four groups matched for age and Body Mass Index. The groups were classified based on polysomnography in: control (n=10), mild obstructive sleep apnea (n=11) moderate obstructive sleep apnea (n=8) and severe obstructive sleep apnea (n=9). All study subjects denied a history of risk for hearing loss and underwent audiometry, tympanometry, acoustic reflex and Brainstem Auditory Evoked Response. Statistical analyses were performed using three-factor ANOVA, 2-factor ANOVA, chi-square test, and Fisher's exact test. The significance level for all tests was 5%. RESULTS: There was no difference between the groups for hearing thresholds, tympanometry and evaluated Brainstem Auditory Evoked Response parameters. An association was observed between the presence of obstructive sleep apnea and changes in absolute latency of wave V (p=0.03). There was an association between moderate obstructive sleep apnea and change of the latency of wave V (p=0.01). CONCLUSION: The presence of obstructive sleep apnea is associated with changes in nerve conduction of acoustic stimuli in the auditory pathway in the brainstem. The increase in obstructive sleep apnea severity does not promote worsening of responses assessed by audiometry, tympanometry and Brainstem Auditory Evoked Response.

Wideband reflectance in Down syndrome.

OBJECTIVE: Children with Down syndrome (DS) have a high incidence of middle ear disorders and congenital abnormalities of the external, middle and inner ear. Energy reflectance (ER), a wideband acoustic immittance (WAI) measurement parameter, can measure the sound energy reflected or absorbed in the ear canal over a wider range of frequencies more efficiently and faster than conventional single-tone 226 Hz tympanometry. The aim of the present study was to compare the WAI measurements of children with DS with those of typically developing, normal-hearing children according to their tympanometric findings. METHODS: Four groups of children with Down syndrome (age range: 2 years and 4 months to 16 years and 3 months; mean age: 8.5 yr) with normal tympanograms (19 ears), flat tympanograms (13 ears), mild negative pressure tympanograms (6 ears between -100 and -199 daPa at the admittance peak) and severe negative pressure tympanograms (4 ears at -200 daPa or lower at the admittance peak) were assessed. All findings were compared with data obtained from 21 ears of a healthy control group (age range: 3 years and 1 month to 13 years and 11 months; mean age: 7.9 yr). The subjects underwent tympanometry with a 226-Hz probe tone frequency and ER measurements along the 200-6,000 Hz range with a chirp stimulus using the Middle-Ear Power Analyzer (MEPA3 - HearID) by Mimosa Acoustics (Champaign, IL), software, version 3.3 [38]. RESULTS: Statistically significant differences were observed in the ER curves for some comparisons between the studied groups. There was also a negative correlation between the static acoustic admittance at the tympanic membrane level and ER measured with a chirp stimulus at 500 and 1,000 Hz. The discriminant analysis technique, which used a chirp stimulus at 1,000 and 1,600 Hz to classify the participants' data based on ER values, achieved a correct classification rate of 59.52% for participants with DS. CONCLUSION: While groups with abnormal middle ear status, as indicated by tympanometry, showed higher ER values compared to the DS tymp A group and the control group, similar reflectance curves were observed between control group and the DS tymp A group. WAI shows promise as a clinical diagnostic tool in investigating the impact of middle ear disorders in DS group. However, further research is required to investigate this issue in narrower age range group and a larger sample size.

Relationship Between Distortion Product - Otoacoustic Emissions (DPOAEs) and High-Frequency Acoustic Immittance Measures.

BACKGROUND Pathologies that alter the impedance of the middle ear may consequently modify the DPOAE amplitude. The aim of this study was to correlate information from 2 different clinical procedures assessing middle ear status. Data from DPOAE responses (both DP-Gram and DP I/O functions) were correlated with data from multi-component tympanometry at 1000 Hz. MATERIAL AND METHODS The subjects were divided into a double-peak group (DPG) and a single-peak group (SPG) depending on 1000 Hz tympanogram pattern. Exclusion criteria (described in the Methods section) were applied to both groups and finally only 31 ears were assigned to each group. The subjects were also assessed with traditional tympanometry and behavioral audiometry. RESULTS Compared to the single-peak group, in terms of the 226 Hz tympanometry data, subjects in the DPG group presented: (i) higher values of ear canal volume; (ii) higher peak pressure, and (iii) significantly higher values of acoustic admittance. DPOAE amplitudes were lower in the DPG group only at 6006 Hz, but the difference in amplitude between the DPG and SPG groups decreased as the frequency increased. Statistical differences were observed only at 1001 Hz and a borderline difference at 1501 Hz. In terms of DPOAE I/O functions, significant differences were observed only in 4 of the 50 tested points. CONCLUSIONS The 1000-Hz tympanometric pattern significantly affects the structure of DPOAE responses only at 1001 Hz. In this context, changes in the properties of the middle ear (as detected by the 1000 Hz tympanometry) can be considered as prime candidates for the observed variability in the DP-grams and the DP I/O functions.

The influence of (central) auditory processing disorder on the severity of speech-sound disorders in children.

OBJECTIVE: To identify a cutoff value based on the Percentage of Consonants Correct-Revised index that could indicate the likelihood of a child with a speech-sound disorder also having a (central) auditory processing disorder . METHODS: Language, audiological and (central) auditory processing evaluations were administered. The participants were 27 subjects with speech-sound disorders aged 7 to 10 years and 11 months who were divided into two different groups according to their (central) auditory processing evaluation results. RESULTS: When a (central) auditory processing disorder was present in association with a speech disorder, the children tended to have lower scores on phonological assessments. A greater severity of speech disorder was related to a greater probability of the child having a (central) auditory processing disorder. The use of a cutoff value for the Percentage of Consonants Correct-Revised index successfully distinguished between children with and without a (central) auditory processing disorder. CONCLUSIONS: The severity of speech-sound disorder in children was influenced by the presence of (central) auditory processing disorder. The attempt to identify a cutoff value based on a severity index was successful.

The influence of (central) auditory processing disorder on the severity of speech-sound disorders in children

OBJECTIVE: To identify a cutoff value based on the Percentage of Consonants Correct-Revised index that could indicate the likelihood of a child with a speech-sound disorder also having a (central) auditory processing disorder . METHODS: Language, audiological and (central) auditory processing evaluations were administered. The participants were 27 subjects with speech-sound disorders aged 7 to 10 years and 11 months who were divided into two different groups according to their (central) auditory processing evaluation results. RESULTS: When a (central) auditory processing disorder was present in association with a speech disorder, the children tended to have lower scores on phonological assessments. A greater severity of speech disorder was related to a greater probability of the child having a (central) auditory processing disorder. The use of a cutoff value for the Percentage of Consonants Correct-Revised index successfully distinguished between children with and without a (central) auditory processing disorder. CONCLUSIONS: The severity of speech-sound disorder in children was influenced by the presence of (central) auditory processing disorder. The attempt to identify a cutoff value based on a severity index was successful.

The influence of (central) auditory processing disorder in speech sound disorders / Influência do transtorno do processamento auditivo (central) no transtorno fonológico

ABSTRACT INTRODUCTION: Considering the importance of auditory information for the acquisition and organization of phonological rules, the assessment of (central) auditory processing contributes to both the diagnosis and targeting of speech therapy in children with speech sound disorders. OBJECTIVE: To study phonological measures and (central) auditory processing of children with speech sound disorder. METHODS: Clinical and experimental study, with 21 subjects with speech sound disorder aged between 7.0 and 9.11 years, divided into two groups according to their (central) auditory processing disorder. The assessment comprised tests of phonology, speech inconsistency, and metalinguistic abilities. RESULTS: The group with (central) auditory processing disorder demonstrated greater severity of speech sound disorder. The cutoff value obtained for the process density index was the one that best characterized the occurrence of phonological processes for children above 7 years of age. CONCLUSION: The comparison among the tests evaluated between the two groups showed differences in some phonological and metalinguistic abilities. Children with an index value above 0.54 demonstrated strong tendencies towards presenting a (central) auditory processing disorder, and this measure was effective to indicate the need for evaluation in children with speech sound disorder.

RESUMO INTRODUÇÃO: Considerando a importância das informações recebidas auditivamente para a aquisição e organização das regras fonológicas, a avaliação do processamento auditivo (central) traz contribuições significativas para o diagnóstico e direcionamento da intervenção fonoaudiologia das crianças com transtorno fonológico. OBJETIVO: Estudar as medidas fonológicas e o processamento auditivo (central) de crianças com transtorno fonológico. MÉTODO: Estudo clínico e experimental com 21 sujeitos com transtorno fonológico, entre 7,0 e 9,11 anos, separados em dois grupos: com e sem transtorno do processamento auditivo (central). Foram avaliadas as provas de fonologia, inconsistência de fala e habilidades metalinguísticas. RESULTADOS: O grupo com transtorno do processamento auditivo (central) apresentou maior gravidade do transtorno fonológico. O valor de corte obtido para o process density index foi o que melhor caracterizou a ocorrência dos processos fonológicos para crianças acima de sete anos. CONCLUSÃO: A comparação do desempenho das provas avaliadas nos dois grupos mostrou diferenças quanto a alguns aspectos fonológicos e metalinguísticas. As crianças com valor do índice acima de 0,54 demonstraram uma forte tendência a apresentar alteração no processamento auditivo (central), sendo que esta medida foi efetiva para indicar a necessidade de avaliação de crianças com transtorno fonológico.

The influence of (central) auditory processing disorder in speech sound disorders.

INTRODUCTION: Considering the importance of auditory information for the acquisition and organization of phonological rules, the assessment of (central) auditory processing contributes to both the diagnosis and targeting of speech therapy in children with speech sound disorders. OBJECTIVE: To study phonological measures and (central) auditory processing of children with speech sound disorder. METHODS: Clinical and experimental study, with 21 subjects with speech sound disorder aged between 7.0 and 9.11 years, divided into two groups according to their (central) auditory processing disorder. The assessment comprised tests of phonology, speech inconsistency, and metalinguistic abilities. RESULTS: The group with (central) auditory processing disorder demonstrated greater severity of speech sound disorder. The cutoff value obtained for the process density index was the one that best characterized the occurrence of phonological processes for children above 7 years of age. CONCLUSION: The comparison among the tests evaluated between the two groups showed differences in some phonological and metalinguistic abilities. Children with an index value above 0.54 demonstrated strong tendencies towards presenting a (central) auditory processing disorder, and this measure was effective to indicate the need for evaluation in children with speech sound disorder.

Effect of contralateral stimulation on acoustic reflectance measurements / Efeito da estimulação contralateral nas medidas de reflectância acústica

ABSTRACT INTRODUCTION: Acoustic reflectance is an important tool in the assessment of middle ear afflictions, and the method is considered advantageous in relation to tympanometry. There has been a growing interest in the study of contralateral acoustic stimulation and its effect on the activation of the efferent auditory pathway. Studies have shown that the introduction of simultaneous stimulation in the contralateral ear generates alterations in auditory response patterns. OBJECTIVE: To investigate the influence of contralateral stimulation on acoustic reflectance measurements. METHODS: Case study of 30 subjects with normal hearing, of both genders, aged 18-30 years. The test and retest acoustic reflectance was conducted in the frequency range 200-6000 Hz. The procedure was repeated with the simultaneous presence of contralateral white noise at 30 dBNS. RESULTS: The analysis of the conditions of test, retest, and test with contralateral noise showed statistical difference at the frequency of 2 kHz (p = 0.011 and p = 0.002 in test and retest, respectively) in the right ear. CONCLUSION: The activation of the auditory efferent pathways through contralateral acoustic stimulation produces alterations in response patterns of acoustic reflectance, increasing sound reflection and modifying middle ear acoustical energy transfer.

RESUMO Introdução: A reflectância acústica é citada como uma importante ferramenta na avaliação das afecções da orelha média, sendo um método considerado vantajoso em relação à timpanometria. Tem havido crescente interesse no estudo da estimulação acústica contralateral e seu efeito na ativação da via eferente auditiva. Estudos têm demonstrado que a introdução de estímulo simultâneo na orelha contralateral gera mudanças no padrão de respostas auditivas. Objetivo: Verificar a influência da estimulação contralateral nas medidas de reflectância acústica. Método: Estudo de casos de 30 sujeitos com audição normal, de os gêneros entre 18 a 30 anos. Foi realizado o teste e reteste de reflectância acústica no intervalo de frequência de 200 a 6000 Hz. O procedimento foi repetido com a presença simultânea de ruído branco contralateral à 30 dBNS. Resultados: A análise entre as condições de teste, reteste e teste com ruído contralateral apresentou diferença estatística na frequência de 2 kHz (p = 0,011 em teste e p = 0,002 em reteste) em orelha direita. Conclusão: A ativação da via auditiva eferente por meio da estimulação acústica contralateral produz mudanças nos padrões de respostas da reflectância acústica, aumentando a reflexão do som e, modificando a transferência de energia sonora da orelha média.

Efferent inhibition of otoacoustic emissions in preterm neonates / Inibição eferente das emissões otoacústicas em neonatos prematuros

ABSTRACT INTRODUCTION: Abnormalities in auditory function of newborns may occur not only because of preterm birth, but also from the use of medications and from diseases related to prematurity. OBJECTIVE: To analyze the inhibitory effect from stimulation of the olivocochlear efferent system on transient evoked otoacoustic emissions in preterm neonates, comparing these data with those from full-term neonates. METHODS: This was a prospective, cross-sectional, contemporary cohort study with 125 neonates, pooled into two groups: full-term (72 full-term neonates, 36 females and 36 males, born at 37-41 weeks of gestational age); and preterm (53 neonates, 28 males and 25 females, born at ≤36 weeks of gestational age, evaluated at the corrected gestational age of 37-41 weeks). Otoacoustic emissions were recorded using linear and nonlinear click-evoked stimuli, with and without contralateral stimulation. RESULTS: The inhibitory effect of the efferent pathway in otoacoustic emissions was different (p = 0.012) between groups, and a mean reduction of 1.48 dB SPL in full-term births and of 1.02 dB SPL in preterm births was observed for the non-linear click-evoked stimulus. CONCLUSION: The results suggest a reduced inhibitory effect of the olivocochlear efferent system on otoacoustic emissions in preterm neonates.

RESUMO Introdução: Alterações na função auditiva de recém-nascidos prematuros podem ocorrer não só devido ao nascimento antecipado, mas também pelo uso de medicamentos e por doenças relacionadas à prematuridade. Objetivo: Analisar o efeito inibitório da estimulação do sistema eferente olivo coclear sobre a amplitude das emissões otoacústicas evocadas transientes em recém-nascidos prematuros, comparando esses dados aos de recém-nascidos a termo. Método: Estudo prospectivo, de coorte contemporânea com corte transversal, com 125 recémnascidos, distribuídos em dois grupos: a termo (72 recém-nascidos a termo, 36 feminino e 36 masculino, nascidos entre 37-41 semanas de idade gestacional), e pretermo (53 recém-nascidos, 28 masculino e 25 feminino, nascidos com idade gestacional ≤ 36 semanas avaliados entre 37-41 semanas de idade gestacional corrigida). As emissões otoacústicas foram registradas a partir de estímulos clique lineares e não lineares, com e sem estimulação contralateral. Resultados: O efeito inibitório da via eferente nas otoemissões foi diferente (p = 0,012) entre os grupos, sendo observada uma redução média de 1,48 dB SPL nos nascimentos a termo e 1,02 dBSPL no grupo pretermo para o estímulo clique não-linear. Conclusão: Os resultados sugerem efeito inibitório do sistema eferente olivococlear reduzido sobre as emissões otoacústicas em recém-nascidos prematuros.

Efferent inhibition of otoacoustic emissions in preterm neonates.

INTRODUCTION: Abnormalities in auditory function of newborns may occur not only because of preterm birth, but also from the use of medications and from diseases related to prematurity. OBJECTIVE: To analyze the inhibitory effect from stimulation of the olivocochlear efferent system on transient evoked otoacoustic emissions in preterm neonates, comparing these data with those from full-term neonates. METHODS: This was a prospective, cross-sectional, contemporary cohort study with 125 neonates, pooled into two groups: full-term (72 full-term neonates, 36 females and 36 males, born at 37-41 weeks of gestational age); and preterm (53 neonates, 28 males and 25 females, born at ≤36 weeks of gestational age, evaluated at the corrected gestational age of 37-41 weeks). Otoacoustic emissions were recorded using linear and nonlinear click-evoked stimuli, with and without contralateral stimulation. RESULTS: The inhibitory effect of the efferent pathway in otoacoustic emissions was different (p=0.012) between groups, and a mean reduction of 1.48dB SPL in full-term births and of 1.02dB SPL in preterm births was observed for the non-linear click-evoked stimulus. CONCLUSION: The results suggest a reduced inhibitory effect of the olivocochlear efferent system on otoacoustic emissions in preterm neonates.

Effect of contralateral stimulation on acoustic reflectance measurements.

INTRODUCTION: Acoustic reflectance is an important tool in the assessment of middle ear afflictions, and the method is considered advantageous in relation to tympanometry. There has been a growing interest in the study of contralateral acoustic stimulation and its effect on the activation of the efferent auditory pathway. Studies have shown that the introduction of simultaneous stimulation in the contralateral ear generates alterations in auditory response patterns. OBJECTIVE: To investigate the influence of contralateral stimulation on acoustic reflectance measurements. METHODS: Case study of 30 subjects with normal hearing, of both genders, aged 18-30 years. The test and retest acoustic reflectance was conducted in the frequency range 200-6000Hz. The procedure was repeated with the simultaneous presence of contralateral white noise at 30dBNS. RESULTS: The analysis of the conditions of test, retest, and test with contralateral noise showed statistical difference at the frequency of 2kHz (p=0.011 and p=0.002 in test and retest, respectively) in the right ear. CONCLUSION: The activation of the auditory efferent pathways through contralateral acoustic stimulation produces alterations in response patterns of acoustic reflectance, increasing sound reflection and modifying middle ear acoustical energy transfer.

Middle ear muscle reflex measurement in neonates: comparison between 1000Hz and 226Hz probe tones.

INTRODUCTION: Middle ear muscle reflex (MEMR) evaluation assists in diagnosing hearing problems because normal responses depend on preconditions of a healthy auditory system. Studies in neonates recording the acoustic reflex with 226Hz probes have described high rates of absence. Other studies using a high frequency probe have found higher rates of presence in normal neonates. However, few studies have compared results between low and high frequency probes in the same newborns. OBJECTIVE: To comparatively assess the ipsilateral acoustic reflex recorded by 226Hz and 1000Hz probes in newborns. METHOD: A total of 77 newborns, with the presence of transient otoacoustic emissions, underwent tympanometry, wideband acoustic immittance, and ipsilateral reflex investigations with 226Hz and 1000Hz tone probes. RESULTS: The acoustic reflex was activated at a much lower intensity with all activating stimuli using the 1000Hz probe compared with the values of the 226Hz probe. There was a higher incidence of ipsilateral acoustic reflexes recorded by the 1000Hz tone probe compared to the 226Hz tone probe. There was no correlation between the acoustic reflex thresholds and otoacoustic emissions. CONCLUSION: In newborns, the acoustic reflex measurements obtained with the 1000Hz probe showed advantages over the 226Hz probe.

Mercury Exposure in a Riverside Amazon Population, Brazil: A Study of the Ototoxicity of Methylmercury

Introduction Mercury poisoning causes hearing loss in humans and animals. Acute and long-term exposures produce irreversible peripheral and central auditory system damage, and mercury in its various forms of presentation in the environment is ototoxic. Objective We investigated the otoacoustic emissions responses in a riverside population exposed to environmental mercury by analyzing the inhibitory effect of the medial olivocochlear system (MOCS) on transient otoacoustic emissions (TEOAE). Methods The purpose of the research was to evaluate the entire community independently of variables of sex and age. All of the participants were born and lived in a riverside community. After otolaryngologic evaluation, participants were received tympanometry, evaluation of contralateral acoustic reflexes, pure tone audiometry, and recording of TEOAEs with nonlinear click stimulation. Hair samples were collect to measure mercury levels. Results There was no significant correlation between the inhibitory effect of the MOCS, age, and the level of mercury in the hair. Conclusions The pathophysiological effects of chronic exposure may be subtle and nonspecific and can have a long period of latency; therefore, it will be important to monitor the effects of mercury exposure in the central auditory system of the Amazon population over time. Longitudinal studies should be performed to determine whether the inhibitory effect of the MOCS on otoacoustic emissions can be an evaluation method and diagnostic tool in populations exposed to mercury. .