[The application of the screening questionnaires for the diagnostics of the central auditory processing disorders in the pediatric practice]. / Ispol'zovanie skriningovykh anket dlia vyiavleniia tsentral'nykh slukhovykh rasstroistv v pediatricheskoi praktike.

Identification and diagnostics of auditory processing disorders (APD) in the children continues to be a challenge. Screening tools help to decide the need for evaluation. However, none of them are used routinely in Russia, nor are there thus far auditory checklist questionnaires in the Russian language. The aim of his study was to approve Children's Auditory Performance Scale (CHAPS) and Fisher's Auditory Checklist in Russian for the children at the age of 5-10 years. The study included 52 children at the age from 5 to 11 years. All of them were native Russian speakers. Pure tone audiometry, immitancemetry, and the Simplified RuMatrix test were performed for all the children. All of them had normal hearing thresholds, speech and language development, and normal academic achievement at school. The parents filled in the CHAPS and Fisher's Auditory Checklist questionnaires in Russian. The mean value of Fisher's Auditory Checklist was 85.7 ± 9.3, the mean value of CHAPS questionnaire was equal to 0.08 ± 0.26. The results obtained with the use of the Russian language questionnaires are in excellent agreement with the test data yielded by the respective English language versions. It is recommended that the clinical assessment for APD should be performed for children with the result of the Fisher questionnaire less than 67 points and with the result of the CHAPS questionnaire less than -1 point. It is concluded that Fisher's questionnaire was more convenient for the parents to fill in.

Auditory system dysfunction in Alzheimer disease and its prodromal states: A review.

Recent findings suggest that both peripheral and central auditory system dysfunction occur in the prodromal stages of Alzheimer Disease (AD), and therefore may represent early indicators of the disease. In addition, loss of auditory function itself leads to communication difficulties, social isolation and poor quality of life for both patients with AD and their caregivers. Developing a greater understanding of auditory dysfunction in early AD may shed light on the mechanisms of disease progression and carry diagnostic and therapeutic importance. Herein, we review the literature on hearing abilities in AD and its prodromal stages investigated through methods such as pure-tone audiometry, dichotic listening tasks, and evoked response potentials. We propose that screening for peripheral and central auditory dysfunction in at-risk populations is a low-cost and effective means to identify early AD pathology and provides an entry point for therapeutic interventions that enhance the quality of life of AD patients.

Una estrategia de teleducación sobre la salud auditiva y vocal en Brasil / A teleducation strategy on hearing and vocal health in Brazil

La teleducación interactiva viene fortaleciéndose y sosteniendo proyectos cuyos objetivos son alcanzar la promoción de la salud utilizando tecnologías de información y comunicación. Entre ellos, está el Proyecto Joven Doctor que se propone capacitar agentes multiplicadores del conocimiento. De esta forma, la presente investigación tiene como objetivo crear una red de aprendizaje colaborativa entre los alumnos sobre las temáticas de salud auditiva y vocal. Los alumnos son entrenados por medio de clases presenciales, acceso al cibertutor y talleres sobre la salud auditiva y vocal. Al término de las actividades, los alumnos capacitados se transformarían en «jóvenes doctores», y de este modo transmitirían el conocimiento adquirido a la comunidad. El proyecto fue realizado en los años 2008 y 2009, contando con la participación de 31 alumnos de enseñanza primaria y secundaria, que recibieron conocimiento sobre los temas de comunicación. Concluida la capacitación, los «jóvenes doctores» multiplicaron la información a 1.750 personas, entre alumnos de la escuela, profesores, padres y comunidad en general. De esta forma, se observó que las acciones realizadas con la metodología del Proyecto Joven Doctor sobre los temas de salud auditiva y salud vocal ayudaron a establecer una cadena productiva del saber (AU)

Interactive teleducation is gaining in strength and is being used to carry out projects aiming to promote health by using information and communication technologies. Among these projects is the Young Doctor Project, which aims to train knowledge multipliers. Thus, the goal of this project is to create a collaborative learning network among students on issues related to hearing and vocal health. Students are trained through classes, cybertutor access, and workshops on auditory and vocal health. At the end of the activities, trained students become «young doctors» and transmit the acquired knowledge to the community. The project was conducted in 2008 and 2009 with the participation of 31 students in primary and secondary education who received training on communication issues. After the training, the «young doctors» transmitted the knowledge gained to 1,750 people, including school students, teachers, parents, and the community. Thus, the methodology used in the Young Doctor Project on hearing and vocal health helped to establish a chain of knowledge (AU)

Auditory dysfunction in patients with cerebrovascular disease.

Auditory dysfunction is a common clinical symptom that can induce profound effects on the quality of life of those affected. Cerebrovascular disease (CVD) is the most prevalent neurological disorder today, but it has generally been considered a rare cause of auditory dysfunction. However, a substantial proportion of patients with stroke might have auditory dysfunction that has been underestimated due to difficulties with evaluation. The present study reviews relationships between auditory dysfunction and types of CVD including cerebral infarction, intracerebral hemorrhage, subarachnoid hemorrhage, cerebrovascular malformation, moyamoya disease, and superficial siderosis. Recent advances in the etiology, anatomy, and strategies to diagnose and treat these conditions are described. The numbers of patients with CVD accompanied by auditory dysfunction will increase as the population ages. Cerebrovascular diseases often include the auditory system, resulting in various types of auditory dysfunctions, such as unilateral or bilateral deafness, cortical deafness, pure word deafness, auditory agnosia, and auditory hallucinations, some of which are subtle and can only be detected by precise psychoacoustic and electrophysiological testing. The contribution of CVD to auditory dysfunction needs to be understood because CVD can be fatal if overlooked.

Importancia de la salud auditiva / Importance of hearing health

Se realiza un estudio sobre la exposición al ruido, sus efectos nocivos y la situación actual de lesiones auditivas en la juventud por el empleo excesivo de reproductores, así como exposición a niveles altos de ruido en discotecas. Se informa de la posibilidad de lesión auditiva en los músicos, técnicos de sonido y disk jockeys. Conscientes de esta problemática la Fundación Pedro Salesa Cabo está realizando un estudio conjuntamente con la Mutua Intercomarcal y la sociedad de prevención Prevint para el estudio de este problema y sus posibles soluciones. Este estudio «Impacto sonoro de la música en sus intérpretes y técnicos» comporta la realización de diversas pruebas auditivas en las personas afectadas (AU)

A study is made on the exposure to noise, on its harmful effects and the current situation on hearing problems in young people due to the excessive use of music players and to the exposure to high levels of noise in discotheques. Information is provided about possible hearing damage in musicians, sound technicians, and disk jockeys. The Pedro Salesa Cabo Foundation is aware of this problem and is conducting an extensive study, together with Mutua Intercomarcal and the society Prevint, to evaluate the problem and its possible solutions. This study "Impacto sonoro de la música en sus intérpretes y técnicos" is supported by different audiological tests in the people affected (AU)

Cuidados de salud en el adulto con síndrome de Down / Health cares in the adult with Down’s syndrome

Superada la alta mortalidad perinatal e infantil que años atrás presentaban las personas con síndrome de Down, en la actualidad se enfrentan al reto de la vida adulta e incluso de la ancianidad, con la expectativa de superar los 60 años. La salud del adulto viene condicionada por las patologías frecuentemente asociadas al síndrome de Down, tanto por las previas adquiridas en la infancia como por otras propias de la edad adulta. En general, su diagnóstico y tratamiento difieren poco de los del resto de la población. Otro condicionante importante es el envejecimiento precoz que padecen las personas con síndrome de Down. Mención especial merece la atención a su salud mental por las dificultades que hay a la hora de hacer el diagnóstico diferencial de los procesos neuropsiquiátricos, por la falta de pruebas específicas y por su complejidad. Las entidades implicadas en síndrome de Down apoyan a los profesionales con sus Programas de Salud y otras publicaciones especializadas (AU)

Having overcome the high perinatal and infant mortality that persons with Down’s syndrome had years earlier, there is currently the challenge of the adult life and even the elderly age, with life expectancy exceeding 60 years. The adult’s health is conditioned by diseases frequently associated to Down’s syndrome, both because of those previously acquired in childhood as well as others characteristic of the adult age. In general, their diagnoses and treatment differs little from that of the rest of the population. Another important conditioning factor is the early aging that persons with Down’s syndrome have. Their mental health merits special mention because it is hard to make the differential diagnosis regarding the neuropsychological processes because of the lack of specific tests and due to its complexity. The entities involved in Down’s syndrome support the professionals with their Health Programs and other specialized publications (AU)

Desarrollo de una hoja de cálculo del impedimento auditivo usando Microsoft EXCEL / Developement of a spreadsheet for hearing impairment using Microsoft Excel

En nuestra actividad profesional diaria es habitual que necesitemos calcular el impedimento auditivo, para realizar informes médicos o para informar a nuestros pacientes. Hasta ahora hemos utilizado tablas y sistemas de cálculo manual que lo facilitan. Para simplificar y hacer más preciso este cálculo hemos desarrollado un sistema utilizando el programa Microsoft Excel y las fórmulas de cálculo de la American Academy of Otolaryngology. Respecto a otros sistemas, el programa de cálculo que describimos aporta 2 ventajas. La primera es su capacidad para corregir el error asociado a la aplicación directa de la fórmula de cálculo del impedimento monoaural, que con valores audiométricos normales (<25dB)da resultados negativos y en caso de hipoacusia profunda (>90dB), resultados superiores al 100%. La segunda ventaja es que no se tiene que indicar cuál es el oído mejor antes de realizar el cálculo binaural hecho que evita la introducción de los valores de «oído mejor» «oído peor» en 2 celdas y supone el ahorro de alrededor de un 20% de tiempo total de cálculo. En conclusión, consideramos que en nuestras especialidades, la hoja de cálculo de Excel adaptada para la valoración del impedimento auditivo, resulta muy adecuada, reproduce los resultados de cualquier sistema de cálculo manual y minimiza la posibilidad de error, por lo que puede aportar un ahorro de tiempo y una mayor seguridad (AU)

In daily clinical practice, the results of audiometric tests often need to be converted into the percentage of hearing impairment in order to prepare health reports or to provide information requested by patients. Until now, manual systems have been used to calculate this percentage. To simplify and add precision to this calculation, we developed a spreadsheet using Microsoft Excel software and the American Academy of Otolaryngology's formula to determine hearing handicap. Compared with other systems, our spreadsheet provides two main advantages. First, it corrects the intrinsic problem of the original formula, which gives negative results in the presence of normal audiometries (values under 25dB) or results over 100 in the case of severe hypoacusis (values over 90dB). The second advantage is that there is no need to specify the best ear in order to calculate the global hearing handicap, thus avoiding the introduction of two values and saving 20% of the overall calculation time. In conclusion, we consider that the Excel spreadsheet, adapted for the evaluation of hearing handicap, could save time and be more accurate than manual methods, thus reducing the possibility of making mistakes (AU)

Repeated antenatal corticosteroid treatments adversely affect neural transmission time and auditory thresholds in laboratory rats.

Antenatal corticosteroid (AC) treatment is given to pregnant women at risk for preterm birth to reduce infant morbidity and mortality by enhancing lung and brain maturation. However, there is no accepted regimen on how frequently AC treatments should be given and some studies found that repeated AC treatments can cause growth retardation and brain damage. Our goal was to assess the dose-dependent effects of repeated AC treatment and estimate the critical number of AC courses to cause harmful effects on the auditory brainstem response (ABR), a sensitive measure of brain development, neural transmission and hearing loss. We hypothesized that repeated AC treatment would have harmful effects on the offspring's ABRs and growth only if more than 3 AC treatment courses were given. To test this hypothesis, pregnant Wistar rats were given either a high regimen of AC (HAC), a moderate regimen (MAC), a low regimen (LAC), or saline (SAL). An untreated control (CON) group was also used. Simulating the clinical condition, the HAC dams received 0.2mg/kg Betamethasone (IM) twice daily for 6 days during gestation days (GD) 17-22. The MAC dams received 3 days of AC treatment followed by 3 days of saline treatment on GD 17-19 and GD 20-22, respectively. The LAC dams received 1 day of AC treatment followed by 5 days of saline treatment on GD 17 and GD 18-22, respectively. The SAL dams received 6 days of saline treatment from GD 17 to 22 (twice daily, isovolumetric to the HAC injections, IM). The offspring were ABR-tested on postnatal day 24. Results indicated that the ABR's P4 latencies (neural transmission time) were significantly prolonged (worse) in the HAC pups and that ABR's thresholds were significantly elevated (worse) in the HAC and MAC pups when compared to the CON pups. The HAC and MAC pups were also growth retarded and had higher postnatal mortality than the CON pups. The SAL and LAC pups showed little or no adverse effects. In conclusion, repeated AC treatment had harmful effects on the rat offspring's ABRs, postnatal growth and survival. The prolonged ABR latencies reflect slowed neural transmission times along the auditory nerve and brainstem auditory pathway. The elevated ABR thresholds reflect hearing deficits. We concluded that repeated AC treatment can have harmful neurological, sensory and developmental effects on the rat offspring. These effects should be considered when weighing the benefits and risks of repeated AC treatment and when monitoring and managing the prenatally exposed child for possible adverse effects.

Central auditory nervous system dysfunction in infants with non-syndromic cleft lip and/or palate.

OBJECTIVE: Peripheral hearing loss has been commonly reported in children with non-syndromic cleft lip and/or palate (NSCLP) but few studies have provided information about central auditory nervous system (CANS) functioning for this group. The main objective of this study was to explore CANS functioning in infants with NSCLP through analysis of auditory evoked potentials (AEPs). METHODS: AEPs including auditory brainstem response (ABR), middle latency response (MLR), and mismatch negativity (MMN) recordings were conducted in 34 infants of Chinese ethnicity with NSCLP and an equivalent number of normal controls. RESULTS: There was no significant difference in ABR (all measurements, including wave I, III, V latencies, I-V inter-wave latency, and wave V amplitude), or MLR (recordable components, Na, Pa latencies, and Na-Pa amplitude) findings between the two groups. However, infants with NSCLP had a significantly smaller MMN response than their normal controls, using MMN strength as the measurement. CONCLUSIONS: Significant abnormal auditory evoked potential findings at the cortical level suggest that infants with NSCLP may be at risk of central auditory discrimination dysfunction. Further effort is needed to determine auditory processing abilities in infants with NSCLP.

Central auditory dysfunction as a harbinger of Alzheimer dementia.

OBJECTIVE: To confirm that central auditory dysfunction (CAD) may be a precursor to the onset of Alzheimer dementia (AD). DESIGN: Cohort study. SETTING: Research study center. PARTICIPANTS: Two hundred seventy-four volunteers from a dementia surveillance cohort were followed up for as long as 4 years after undergoing complete audiometric assessment. Twenty-one received a consensus diagnosis of AD after a hearing test. INTERVENTION: The following 3 central auditory tests were performed: the Dichotic Sentence Identification, the Dichotic Digits, and the Synthetic Sentence Identification With Ipsilateral Competing Message. MAIN OUTCOME MEASURES: A new diagnosis of AD using the National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer Disease and Related Disorders Association criteria at a consensus conference. RESULTS: The mean scores on each CAD test were significantly poorer in the incident dementia group. Cox proportional hazards models with age as the time scale were used to estimate the hazard ratio for incident dementia based on CAD test results. After adjusting for educational level, the hazard ratio for incident dementia in people with severe CAD based on a Dichotic Sentence Identification in free report mode of less than 50% was 9.9 (95% confidence interval, 3.6-26.7). CONCLUSIONS: Central auditory dysfunction is a precursor to AD. We recommend evaluation with CAD tests in older adults who report hearing difficulty. Those with severe CAD should receive a modified rehabilitation program and be considered for referral for neurologic evaluation.

Cochlear implantation in children with auditory neuropathy spectrum disorder.

OBJECTIVE: To report the patient's characteristics, preoperative audiological profiles, surgical outcomes, and postoperative performance for children with auditory neuropathy spectrum disorder (ANSD) who ultimately received cochlear implants (CIs). DESIGN: Prospective, longitudinal study of children with ANSD who received CIs after a stepwise management protocol that included electrophysiologic and medical assessment, documentation of behavioral audiometric thresholds and subsequent fitting of amplification according to Desired Sensation Level targets, auditory-based intervention with careful monitoring of skills development and communication milestones, and finally implantation when progress with the use of acoustic amplification was insufficient. RESULTS: Of 140 children with ANSD, 52 (37%) received CIs in their affected ears (mean duration of use of 41 mos). Many of these children were born prematurely (42%) and impacted by a variety of medical comorbidities. More than one third (38%) had abnormal findings on preoperative magnetic resonance imaging of the brain and inner ear, and 81% had a greater than severe (>70 dB HL) degree of hearing loss before implantation. Although 50% of the implanted children with ANSD demonstrated open-set speech perception abilities after implantation, nearly 30% of them with >6 months of implant experience were unable to participate in this type of testing because of their young age or developmental delays. No child with cochlear nerve deficiency (CND) in their implanted ear achieved open-set speech perception abilities. In a subgroup of children, good open-set speech perception skills were associated with robust responses elicited on electrical-evoked intracochlear compound action potential testing when this assessment was possible. CONCLUSIONS: This report shows that children with ANSD who receive CIs are a heterogeneous group with a wide variety of impairments. Although many of these children may ultimately benefit from implantation, some will not, presumably because of a lack of electrical-induced neural synchronization, the detrimental effects of their other associated conditions, or a combination of factors. When preoperative magnetic resonance imaging reveals central nervous system pathology, this portends a poor prognosis for the development of open-set speech perception, particularly when CND is evident. These results also show that electrical-evoked intracochlear compound action potential testing may help identify those children who will develop good open-set speech perception. Instead of recommending CI for all children with electrophysiologic evidence of ANSD, the stepwise management procedure described herein allows for the identification of children who may benefit from amplification, those who are appropriate candidates for cochlear implantation, and those who, because of bilateral CND, may not be appropriate candidates for either intervention.

Neuropatía auditiva, diagnóstico y manejo audiológico / Auditory neuropathy / dyssychrony, assessment and audiologic management

Los hallazgos clínicos que definen una neuropatía/des sincronía (NA/DA) son la integridad de las células ciliadas evidenciado, mediante la presencia de emisiones otoacústicas evocadas (EOAe) y/o la presencia de potenciales microfónicos cocleares (PMIC), junto con la ausencia de actividad neural evocada a nivel del VIII par craneano (potencial de acción compuesto) y tronco cerebral (potencial evocado auditivo de tronco (PEAT)). Las condiciones clínicas relacionadas con una NA/DA incluyen a la hiperbilirrubinemia, enfermedades neurovegetativas (ejemplo ataxia de Friedreich), síndrome de Charcot-Marie-Tooth así como otras neuropatías sensoriomotoras, desórdenes mitocondriales y neuropatías isquémica-hipóxicas como resultados de asfixia. El desarrollo de las habilidades auditivas y comunicacionales pueden estar comprometidas en forma importante en los niños con aparición prelingual de una NA/DA, mayor es aún este compromiso al no existir un perfil pronóstico preestablecido del desarrollo y resultados en el tratamiento de este desorden. En la actualidad existen múltiples estudios en donde se ha observado que hasta 50 por ciento de los pacientes con NA/DA presentan algún grado de beneficio al usar audífonos por lo que se sugiere que sistemas de amplificación como los audífonos o incluso implante coclear deberían ser el primer paso en el proceso de (re)habilitación.

The clinical findings that define an auditory neuropathy/dyssynchrony (AN/Dys) are the integrity of the outer hair cells demonstrated by the presence of evoked otoacoustics emissions (OAEe) and/or the presence of cochlear microphonic potential (CMP) along with the absence of neural activity evoked at level of VIII nerve (action potential compound) and brainstem (Auditory Brainstem Response, ABR). The clinical conditions related to an AN they include hiperbilirrubinemia, neurodegenerative diseases (eg ataxia of Friedreich), Charcot-Marie-Tooth syndrome as well as other sensoriomotor neuropathies, mitocondrial disorders and hypoxic neuropathy as perinatal asphyxia. The development of the auditory and communicational abilities can be compromise in children with prelingual onset of an AN/Dys, the development and results of treatment of this disorder is still this commitment when not existing a profile prognosis. At the present time multiple studies have been observed that until a 50 percent of the patients with AN present some degree of benefit using hearing aids, reason why it suggests amplification systems as the hearing aids or even cochlear implant would have to be the first step in the process of (re) habilitation of these patients.

Central auditory impairment in unilateral diencephalic and telencephalic lesions.

The extent of perceptual impairment following unilateral lesions in the auditory cortex, its thalamic or callosal afferents was studied with psychoacoustic tests. Thresholds for the discrimination of signal frequency, intensity and duration were acquired under three different conditions of headphone stimulation ('monaural', 'interaural', and 'dichotic signal/noise tests') using the three-alternative forced-choice procedure. The different test alternatives generated distinct auditory percepts, which is in accordance with the assumption of specific signal processing at the level of the auditory brainstem and at thalamocortical auditory areas. Twenty-one patients from neurology were studied who suffered from unilateral lesions in the auditory cortex, the auditory thalamus, or the acoustic radiation. Location and extent of the lesions were assessed by magnetic resonance imaging. Monaural tests of either ear revealed no deficits in auditory performance. The patients showed impaired discrimination of signal frequency, intensity and duration in the dichotic signal/noise tests, when the signals were presented to the ear contralateral and the noise ipsilateral to the lesion. With inverted signal and noise stimulation, however, the thresholds were in the range of age-matched controls. All patients were able to master the interaural tests, which indicates the preserved ability to lateralize sound sources to the left and to the right with either one of the auditory cortices left intact. Another 24 patients were studied who had lesions mostly close to but sparing the before-mentioned auditory structures. All of them showed unimpaired performance in all test alternatives. The results indicate the specificity of the dichotic signal/noise tests for the identification of unilateral lesions in thalamocortical auditory structures. In addition, the results also point to the capacity of each telencephalic hemisphere to process the full range of auditory lateralization from left to right.

Brain abnormalities in language disorders and in autism.

It has been speculated that autism and specific language impairment share common underlying neural substrates because of the overlap in language impairment issues and evidence suggesting parallels in other domains and implying a possible shared genetic risk. Anatomically the two sets of disorders have generally been studied using different methodologies, but when identical methodologies have been used substantial similarities have been noted. Functionally there is a growing body of literature suggesting sensory perception abnormalities that have parallels in both conditions and that may be upstream of language abnormalities. Finding upstream mechanisms that impact language and non-language abnormalities in autism and specific language impairment would impact the orientation taken by translational attempts to use science to design treatments.

Speech perception in noise for children with auditory neuropathy/dys-synchrony type hearing loss.

OBJECTIVE: To evaluate the effect of background noise on speech perception in children with auditory neuropathy/dys-synchrony (AN/AD) type hearing loss. DESIGN: Open and closed-set speech perception abilities were assessed in 12 school-age children who had been diagnosed with AN/AD in infancy. Data were also obtained from a cohort of subjects with sensorineural (SN) hearing loss and from a group of normal-hearing children. RESULTS: Closed-set speech understanding was more affected by the presence of a competing signal in the hearing impaired than in the normal-hearing subjects. The mean S/N ratio required to identify a spondee in noise was -11.5 +/- 2.0 dB for the normal group, whereas the ratio required for the SN group was -5.4 +/- 5.1 dB and for the AN/AD group was -2.5 +/- 4.7 dB. Closed-set perception in noise was not significantly different for the AN/AD children and their SN counterparts although there was a trend toward poorer performance in the AN/AD group. The effect of background noise on open-set speech perception was also similar across hearing-impaired subjects although again, the AN/AD cohort tended to show greater difficulties in noise than their SN peers. CONCLUSIONS: Listening in background noise was more difficult for our group of children with AN/AD-type hearing loss than for their normal-hearing peers. However, the noise effects were not consistent across subjects and some children demonstrated reasonable perceptual ability at low signal-to-noise ratios. The ways in which speech understanding is affected by competing signals may be different for different types of hearing deficit, but the results of this investigation indicate that significant perceptual disruption occurs both in children with auditory neuropathy/dys-synchrony and sensorineural type hearing loss.

Risk factors for auditory neuropathy/auditory synaptopathy.

AIMS: It was the aim of this study to describe risk factors in auditory neuropathy/auditory synaptopathy (AN/AS). METHODS: Between 1997 and 2005, we diagnosed 37 children with AN/AS. They underwent a critical chart review for risk factors and etiological coincidences in this idiosyncratic disorder. RESULTS: Eighteen neonates had a history of prematurity and low birth weight. Hyperbilirubinaemia was present in 13 children. Three patients had evidence of infection during pregnancy, and AN/AS was associated with complex syndromal diseases in 2 cases. A congenital, familial pattern was seen in 2 siblings. Seven patients had idiopathic AN/AS. CONCLUSION: Rather than being a single etiological entity, AN/AS comprises a spectrum of risk factors and associated problems affecting the cochlea and the auditory pathway. This study shows that the majority of AN/AS in children is the result of perinatal problems and is not genetic in origin. Hyperbilirubinaemia is a common and etiologically significant finding in infants suffering from AN/AS. Thus, early hearing screening for AN/AS including transient evoked otoacoustic emissions and auditory brainstem response assessment among neonates with risk factors for AN/AS is crucial in order to better manage patients suffering from this disorder.

Tinnitus and neural plasticity of the brain.

OBJECTIVE: To describe the current ideas about the manifestations of neural plasticity in generating tinnitus. DATA SOURCES: Recently published source articles were identified using MEDLINE, PubMed, and Cochrane Library according to the key words mentioned below. STUDY SELECTION: Review articles and controlled trials were particularly selected. DATA EXTRACTION: Data were selected systematically, scaled on validity and comparability. CONCLUSION: An altered afferent input to the auditory pathway may be the initiator of a complex sequence of events, finally resulting in the generation of tinnitus at the central level of the auditory nervous system. The effects of neural plasticity can generally be divided into early modifications and modifications with a later onset. The unmasking of dormant synapses, diminishing of (surround) inhibition and initiation of generation of new connections through axonal sprouting are early manifestations of neural plasticity, resulting in lateral spread of neural activity and development of hyperexcitability regions in the central nervous system. The remodeling process of tonotopic receptive fields within auditory pathway structures (dorsal cochlear nucleus, inferior colliculus, and the auditory cortex) are late manifestations of neural plasticity. The modulation of tinnitus by stimulating somatosensory or visual systems in some people with tinnitus might be explained via the generation of tinnitus following the nonclassical pathway. The similarities between the pathophysiological processes of phantom pain sensations and tinnitus have stimulated the theory that chronic tinnitus is an auditory phantom perception.

Prevalence and audiological characteristics in individuals with auditory neuropathy/auditory dys-synchrony.

The objectives of this study were to (a) estimate the prevalence of auditory dys-synchrony in Mysore, a city of one million population in Southern India and, (b) present the results of audiological testing of this clinical population as well as the relationship between these figures. A register-based study design was employed wherein the results of audiological tests of all patients who visited the Department of Audiology, All India Institute of Speech and Hearing between January 2000 and December 2003 were reviewed. Results showed that the prevalence of auditory dys-synchrony was around 1 in 183 in individuals with sensory neural hearing loss. Behavioural thresholds and speech identification scores were variable. Around 60% of the individuals had no measurable speech identification scores. There was no relation between the hearing thresholds and speech identification scores or between otoacoustic emissions and speech identification scores. These results indicate that auditory dys-synchrony is not an extremely rare disorder.

A comparison of higher order auditory processes in younger and older adults.

The authors conducted 3 experiments investigating the effects of aging on higher order auditory processes. They compared younger and older adults with respect to (a) their auditory channel capacity, (b) the extent of their top-down control over auditory gain, and (c) their ability to focus attention on a narrow band of frequencies. To ensure that subclinical cochlear processing deficits in older adults (e.g., higher thresholds, poorer discrimination of frequency and intensity differences) did not limit performance, the authors used only stimuli that were perfectly discriminable by all participants. No age differences were found in any of these experiments, suggesting that some higher order auditory processes (e.g., top-down control over auditory gain, auditory attention) are preserved in normal aging, despite numerous age-related declines in peripheral auditory functionality.

Auditory neuropathy/auditory dys-synchrony in school children with hearing loss: frequency of occurrence.

OBJECTIVE: The frequency of occurrence of a recently identified hearing disorder, auditory neuropathy/auditory dys-synchrony (AN/AD), was investigated in children with hearing impairment in Hong Kong. METHODS: In this study, 56 students, aged 7-18 years, attending primary divisions in schools for the hearing impaired were screened using otoacoustic emission procedures. RESULTS: One student in the study group was found to have intact outer hair cell function. A detailed diagnostic assessment of this case strongly suggested AN/AD was involved. Combining the study results with those of a previously conducted survey in Hong Kong, the frequency of occurrence of AN/AD in children attending schools for the hearing impaired was estimated to be 2.44% (3 out of 123 children screened). Estimates of the frequency of occurrence of AN/AD in various other educational settings in Hong Kong were also derived. CONCLUSIONS: The study indicates that AN/AD is not an extremely rare disorder. Educational audiologists and other health care professionals need to be actively involved in the identification and management of AN/AD. Research should be directed at technological innovations that may help to overcome the limitations of present screening procedures, in order to more accurately identify the disorder.