Behavioral Observation Audiometry Research Articles

Comparison of Hearing Impairment among Healthy and High-risk Neonates at a Tertiary Care Hospital, Rajasthan, India: A Cross-sectional Study

Introduction: Hearing impairment is caused by damage in the inner ear (can be even birth defect), ear infection, ruptured eardrum and so on. It can be prevented using early detection thus, helps in avoiding severe psychosocial, educational, and linguistic repercussions. Infants, who are not diagnosed of hearing impairment before six months of age, will have delays in speech and language development. Aim: To determine the prevalence of hearing impairment in highrisk neonates and to establish the fact that, these neonates have higher prevalence of hearing impairment as compared to normal population. Materials and Methods: A cross-sectional study was conducted in the Department of Paediatrics at Jawaharlal Nehru Medical College and Hospital, Ajmer, Rajasthan, India. The duration of the study was six months, from December 2012 to May 2013. A total of 500 babies including 297 normal and 203 high-risk babies were enrolled into the study. All the neonates were screened using Behavioural Observation Audiometry (BOA) and Distortion Product Oto-acoustic Emission (DPOAE) preferably within three days of life. Those, who failed under this test, underwent for Brain stem Evoked Response Audiometry (BERA). Data was collected in the Microsoft Excel and analysis done by Statistical Package for Social Sciences (SPSS) version 23.0. Results: The mean age of the newborns on admission, was 3.86±4.25 days and the mean weight was 2560±510 g. Out of 500 newborns screened, 58 babies had abnormal results with the first screening test. When these 58 babies subjected to BERA, eight babies showed Hearing Loss (HL). Sepsis, Neonatal Intensive Care Unit (NICU) stay >5 days and use of aminoglycosides >7 days were the important risk factors associated with hearing impairment. Prevalence of hearing impairment in the present study was came out to be 16/1000. This finding was statistically significant with p-value<0.05. Conclusion: There was high prevalence of hearing impairment in high-risk newborns, majority of which were bilateral. The authors recommend multistage screening in all newborns at birth or within month’s time at all level of healthcare facility. Newborns with sepsis, NICU stay >5 days and use of aminoglycosides >7 days should have mandatory audiologic evaluation at discharge.

AUDITORY NEUROPATHY SPECTRUM DISORDER IN CHILDREN: ASSOCIATION BETWEEN PERINATAL RISK FACTORS AND RADIOLOGY

IntroductionRadiological assessment plays a vital role in identifying auditory neuropathy spectrum disorder (ANSD) in children. Identifying the neonatal risk factors and their association with radiological findings might facilitate the management of children with ANSD. The goal of the current work was to investigate the relationship between perinatal risk factors and radiological findings in children with ANSD.Material and methodsAltogether, 28 children with ANSD aged 1 to 6 were enrolled. Behavioural observation audiometry (BOA), otoacoustic emissions (OAEs), and auditory brainstem responses (ABRs) were conducted. High-resolution computed tomography (CT) and magnetic resonance imaging (MRI) were performed.ResultsThere was a statistically significant association between ANSD risk factors – hydrocephalus, preterm birth, hyperbilirubinemia, entry into newborn intensive care, and cerebral palsy – and white matter changes and cerebral/brainstem abnormalities.ConclusionsIn children with ANSD, certain cerebral/brainstem abnormalities and white matter changes were associated with the condition. To minimize the impact of hearing loss, radiological assessments should be conducted on all children having ANSD risk factors.

An audiological profiling in metachromatic leukodystrophy: a case study

<p class="abstract">Metachromatic leukodystrophy (MLD) is a lysosomal storage disease, which is characterized by damage of the myelin sheath that covers most of nerve fibers of the central and peripheral nervous systems. The disease occurs due to a deficiency of the lysosomal enzyme arylsulfatase A (ARSA) or its sphingolipid activator protein saposin B (SapB). Audiological test batteries were carried out, i.e.; behavioural observation audiometry (BOA), impedance audiometry, otoacoustic emission (OAE) and brainstem evoked response audiometry (BERA). Result showed there was no changes in behaviour towards the stimulus, has been noticed in BOA, bilateral A type tympanogram with absence of acoustic reflexes in all frequencies on Ipsi and contra-lateral stimulations and no wave Vth was found at 90 dBnHL in both ears even at repeated trials in BERA. Early identification of hearing loss offers children the opportunity to develop significantly improved language skills. Otologist and audiologist need to be taken care and to provide medical treatment as well as amplification device to the patients.</p>

Effectiveness of Bone Conduction Hearing Aids in Young Children with Congenital Aural Atresia and Microtia.

BackgroundThe aim of this study was to assess the effectiveness of bone conduction hearing aids in children under 2 years old who have congenital microtia and atresia.Material/MethodsThis prospective study involved 42 children under 2 years old with congenital microtia and atresia who were divided into 2 groups: 21 with unilateral defect and 21 with bilateral defect. All children were provided with bone conduction hearing aids on a softband. Air and bone auditory thresholds were assessed by auditory brainstem responses (ABRs). The LittlEARS questionnaire was used to evaluate auditory development at baseline and after 6 months of hearing aids use. Behavioral observation audiometry (BOA) was used to assess auditory thresholds and compare aided and unaided hearing.ResultsAfter 6 months of hearing aid use, the total score of the LittlEARS questionnaire in children with unilateral defect was 24±5.60, while children with bilateral defect achieved a result of 26.29±6.17. Hearing thresholds in both groups with bone conduction hearing aids improved significantly and approached the normal level.ConclusionsOur results confirm that bone conduction hearing aids provide an effective method of auditory rehabilitation for children with conductive and mixed hearing loss caused by microtia and atresia. Using bone conduction hearing aids in such children is crucial for proper hearing, speech, and language development.

Hearing Impairment in Children with Congenital Hypothyroidism

Background: There is increased risk of hearing impairment in children with congenital hypothyroidism (CH). Only a few studies have explored the prevalence of hearing impairment in CH and their results vary widely. There is no data of hearing impairment in Bangladeshi children with CH.
 Objectives: The aim of this study was to investigate the prevalence of hearing impairment in children with CH, and its relation with age of diagnosis and the dose of thyroxine (T4) they received.
 Methods: This study was conducted in Paediatric Endocrinology & Metabolic Disorder Department of Dhaka Shishu (Children) Hospital from July 2014 to December 2018. Hearing evaluation of 55 children diagnosed with CH was performed with a battery of tools that included Middle ear analysis, Pure Tone Audiometry (PTA), Behavioral Observation Audiometry (BOA) and Oto Acoustic Emissions (OAE). The choice of assessment tool was based on patient’s age.
 Results: The mean age at diagnosis and at inclusion into the study was 2.0±1.7 years and 3.2±2.3 years respectively. The etiological diagnosis was thyroid agenesis in 40(72.7%), ectopia in 3(5.5%), dyshormonogenesis in 7(12.7%) and hypothyroidism with eutopic gland in 5(9.1%%) patients. Middle ear analysis, PTA, BOA and OAE was done in 35, 28, 32 and 37 patients respectively. Sensorineural hearing loss was detected in 1 out of 55(1.8%) patients while conductive hearing loss was found in 3(5.4%) patients.
 Conclusion: Hearing loss was present in a small proportion of patients with permanent CH. Further larger studies are required to determine the exact prevalence of hearing impairment in Bangladeshi children with CH.
 DS (Child) H J 2020; 36(1) : 14-19

Auditory Steady-State Response (ASSR) in hearing-impaired children with absent Auditory Brainstem Response (ABR) waves

Objectives: The aim of this work was to evaluate the residual hearing in children with sensorineural hearing loss and absent ABR waves by ASSR to select the appropriate way for intervention either the use of hearing aid or cochlear implant. Patients and methods: Forty children (80 ears) were included in this study in the period from May 2019 up to April 2020. All children had detailed complete history taking, otoscopic examination, immittancemetry, hearing assessment to get an accurate frequency specific threshold with play audiometry, behavioral observation audiometry, and evoked audiometry including ABR, TEOAEs, and ASSR. Results: Forty hearing impaired children with ages ranged from 1 to 5 years old, 22 were males and 18 were female. ASSR response was obtained from 53 ears, and 27 ears showed no response. The ASSR showed a better response at low-frequency regions when compared to the high-frequency regions but with no statistically significant difference. Conclusions: The absence of click-ABR waves and behavioral free-field responses do not rule out the presence of residual hearing. ASSR was done to estimate the residual hearing mainly at low-frequency regions.

Auditory brainstem response to a chirp stimulus in infants with normal hearing

Background The CE-chirp stimulus shows promising results in auditory brainstem recording. The response to broad-band CE-chirp in normal infants and comparing it with the gold standard click stimulus is needed. Objective The purposes of this study were to (a) standardize auditory brainstem responses (ABR) in infant using chirp stimuli in normal hearing infants, (b) compare them with those evoked by click stimuli, (c) determine whether chirp-evoked response is easier to detect at near threshold values, and (d) analyze the amplitude growth function of chirp-evoked ABR as a function of stimulus intensity in infants. Patients and methods A total of 50 normal infants, with age ranging from 2 to 24 months, with normal hearing were included. The following procedures were done: a medical history, otologic examinations, behavioral observation audiometry, acoustic impedance, and ABR by click and CE-chirp. Results The chirp stimulus shows higher amplitude at all intensities and shorter latencies in comparison with click at high intensity and longer at low and threshold levels. The early waves are less frequent in chirp at high intensities. Conclusion The present study provides reference CE-chirp ABR values for infants. CE-chirp evokes lower threshold than click and easier peak identification at threshold, which is particularly helpful in infants.

Mapping of Paediatric Cochlear Implant Using Neural Response Threshold (NRT) and Behavioural Observation Audiometry (BOA).

To measure the correlation between neural response threshold (NRT) and most comfortable level for behaviouralresponse (MCLB) whichever is better for rehabilitation purpose and to calculate the impedance of the electrode in cochlear implant recipient. Mapping may be done by various methods here we did by NRT and behavioral observation audiometry (BOA). NRT is technique by which we measure the response from the auditory nerve using the hi-resolution bionic ear system. Neural response measurement depends on the-neural tissue, stimulus used and recording technique. BOA is used for observing motor response on presenting sound to the implanted child. Most comfortable level for behaviouralresponse (MCLB) is calculated for behavioural response. It measures the useful information about low frequency hearing, it provides more information about the hearing of neurologically immature babies giving indication of uncomfortable loudness levels. The NRT and MCLB is calculated for 2nd, 6th, and 11th electrode for all patients in our study. Auditory response threshold is better for rehabilitations then behavioural observation audiometry for Cochlear implant patients. Mean value and standard deviation of neural response threshold (NRT) (qu) are 10.23, 3.67; 11.27, 4.39; 10.71, 3.88 at 2nd, 6th, and 11th electrode respectively. Mean value and standard deviation of Most comfortable level for behavioral response (qu) are 20.49, 7.08; 21.26, 7.31; 21.01, 6.03 at 2nd, 6th and 11th electrode respectively. NRT is better for post-operative rehabilitations and MCL and threshold vary with different electrode and in different patients.

Neonatal screening for hearing loss and its risk factors at a tertiary hospital; A : Prospective Cross sectional study.

Background Hearing loss is one of the commonest childhood disabilities with a huge burden in developing countries like India. Detecting and rehabilitating neonates with hearing impairment is a healthcare priority. Prevalence of hearing impairment among neonates is high. Early identification and early rehabilitation is the key in addressing this disability. Behavioral observation audiometry is a dependable screening tool compared to Auditory Brainstem Response.Objectives 1. To screen neonates for hearing impairment using behavioral observation audiometry 2.To confirm hearing impairment using Auditory Brainstem Response among screen positive neonatesMethodology A cross sectional study was conducted among 160 randomly selected neonates. A questionnaire was administered followed by free field testing of Behavioral Observation Audiometry was done on all neonates. Risk factors for neonatal hearing loss was assessed among all neonates.Results The prevalence of hearing impairment on screening with BOA was found to be 2.5 . Risk factors for hearing impairment are more prevalent in our study. 27.5 of the neonates were born preterm being the most common risk factor followed by hyperbilirubinaemia 21.9 low birth weight 13.13 NICU admissions 9.4 and vaginal discharge in mothers during antenatal period being 6.9.Conclusions Prevalence of hearing impairment among newborns and its risk factors are high among normal newborns. Hence there is a need for a routine neonatal hearing screening program.

Hearing impairment in children with permanent congenital hypothyroidism: Data from Northwest India

Background: There is an increased risk of hearing impairment in permanent congenital hypothyroidism (CH). Only a few studies have explored the prevalence of hearing impairment in CH and their results vary widely. There is no data on hearing impairment in Indian children with CH. Setting and Design: Pediatric Endocrinology Clinic of a large tertiary care hospital located in Northwest India. Cross sectional study. Materials and Methods: Hearing evaluation of 77 children diagnosed with permanent CH was performed with a battery of tools that included Middle ear analysis, Pure Tone Audiometry (PTA), Behavioral Observation Audiometry (BOA) and Oto Acoustic Emissions (OAE). The choice of assessment tool was based on patient's age. Results: The mean age at diagnosis and at inclusion into the study was 3.0±2.7 years and 5.2±3.3 years respectively. The majority (63, 82%) of patients had symptoms suggestive of hypothyroidism; none complained of hearing loss. The etiological diagnosis was thyroid agenesis in 55 (71.4%), ectopia in 5 (6.5%), dyshormonogenesis in 9 (11.7%) and hypothyroidism with eutopic gland in 8 (10.3%) patients. Middle ear analysis, PTA, BOA and OAE was done in 48, 44, 43 and 53 patients respectively. Sensorineural hearing loss was detected in 1 out of 77 (1.2%) patients while conductive hearing loss was found in 5 (6.5%) patients. Conclusion: Hearing loss was present in a small proportion of patients with permanent CH. Further larger studies are required to determine the exact prevalence of hearing impairment in Indian children with permanent CH.

The audiological journey and early outcomes of twelve infants with auditory neuropathy spectrum disorder from birth to two years of age

Objective: To describe the audiological journey of a group of infants with auditory neuropathy spectrum disorder (ANSD) following the fitting of hearing aids, and to investigate the potential benefits of including cortical auditory-evoked potentials (CAEPs) and a measure of functional auditory behaviour during early audiological management. Design: Results from chart revision of estimated hearing threshold, early behavioural testing, parental observation, and functional auditory behaviour assessments were described, and compared to visual reinforcement audiometry (VRA) thresholds obtained at a mean corrected age of 10 months (SD 3). The relationship with CAEPs and functional performance was examined. Study sample: The study included 12 infants diagnosed with ANSD and fitted with amplification. Results: The estimated 4FA at a mean corrected age of four months (SD5) was within ± 10 dB of VRA results in 75% of infants when unaided and aided behavioural observation audiometry (BOA), together with unaided and aided parental observations was combined. Infants with a greater proportion of CAEPs present had higher PEACH scores. Conclusions: Delaying amplification until VRA results were available would have led to a significant period of auditory deprivation for infants in this study group. None of the assessments could accurately determine hearing thresholds when used in isolation, however when used in combination clinicians were able to obtain sufficient information to fit hearing aids early, and identify infants requiring closer monitoring.

Audiological assessment modalities in children with multiple handicaps and parents′ perception

Aim of the Study: Children with multiple disabilities have combination of various disabilities. Accurate hearing evaluation is difficult in this population. Audiologists generally employ a test battery approach, which includes combining findings of parent impression with behavioral observation audiometry (BOA) as well as auditory brainstem response (ABR) findings. Present study was done to find if there exists correlation among various steps in test battery for the children with multiple handicaps as well as to find out which disability is most common among this population. Materials and Methods: Total 103 numbers of children with multiple handicaps were chosen at random who were referred to CU Shah Institute of Audiology and Speech Therapy for audiological assessment. The three steps involved in assessment that is parental impression, BOA, and ABR findings were taken into account. The relationship was obtained using data analysis. Results: It was found that among children with multiple handicaps referred for audiological assessment, mental retardation (MR) was the most common (32.03%). Also, it was found that there were more contradictory findings between parent impression and ABR (48%) when compared with parent impression with BOA (38%). In between BOA and ABR, contradictory findings were found in 41% of cases. Conclusion: There are wide contradictions among various steps involved in assessment of children with multiple handicaps. Implication: Audiologist should use a test battery approach to assess hearing ability of this population and audiologists should interpret findings carefully at each level.

Clinical presentation and audiologic findings in pediatric auditory neuropathy

Aim: of the study was to rule out audiologic findings, related etiologies and its effect in pediatric patients having hearing deficits that are most likely due to a neuropathy of the eighth nerve. Study Design: Retrospective neo-natal hearing screening programme based. Subject and Methods: Subjects include 30 children aged from 0 yrs to 12 yrs, were tested with pure tone audiometry, behavioral observation audiometry, free-filed audiometry, speech audiometry, auditory brainstem response, and click evoked otoacoustic emissions. Results: Pure tone and free-field testing revealed 40 ears (66.67%, n = 60) with sloping type, sensorineural hearing loss, 20 ears (33.3%, n = 60) had flat configuration. Out of this 18 (6%, n = 30) subject showed bilateral similar configuration (either bilateral sloping type/ flat type of audiogram). Rest 12 (40%, n = 30) subject showed bilateral different pattern. 10 (33.3%, n = 30 children demonstrated fair to poor word discrimination scores and the other 2 (6.67%, n = 30) had fair to good word discrimination. For other rest of 18 (60%, n = 30) children speech test couldn't be performed because of age limit and poor speech and language development. Out of 30 subjects 28 (93.3%, n = 30) showed normal distortion product Otoacoustic emissions and 2(6.67%, n = 30) subjects showed absent emissions. Conclusions: All thirty children demonstrated absent or marked abnormalities of brainstem auditory evoked potentials which suggest cochlear outer hair cell function is normal; mostly lesion is located at the eighth nerve or beyond. Generally auditory neuropathy is associated with different etiologies and it is difficult to diagnose auditory neuropathy with single audiological test; sufficient test of battery is required for complete assessment and diagnosis of auditory neuropathy

Audiometric screening of a population with intellectual disability

Objective: Evaluation of pure-tone audiometry (PTA) in hearing screening of a population with mild to profound intellectual disability (ID). Design: PTA was performed at six frequencies at the screening level 20 dB HL. Referral criteria were threshold levels ≥ 25 dB HL at two or more frequencies for one ear or both. Study sample: 1478 participants aged 7–91 years were included. Results: 1470 (99.5%) people cooperated in screening of which 1325 (90%) could be tested on both ears at all six frequencies. A majority, 987 (66.8%), performed ordinary PTA, 234 (15.8%) conditioned play audiometry, and 249 (16.9%) behavioural observation audiometry. Six hundred and sixty-nine (45%) passed and 809 (55%) failed according to referral criteria. Of those failing, 441 (54.5%) accepted referral to clinical evaluation. Conclusions: PTA with slight modifications is applicable for screening of a population with mild to profound intellectual disability. The most challenging and time-consuming activity is to introduce the test procedure in a way that reduces anxiety and establishes trust.

Clinical and audiological evaluation of hearing impaired children

Daily activities, interpersonal relationship, employment, and general well being; among such skills, communication skills are essential to a successful life for all individuals. Such skills affect education, adequate hearing acuity is of paramount importance and acts as a prerequisite in the overall personality development of an individual. Hearing impairment at any age has serious effects on the day to day life of an individual and he/she feels handicapped socially, emotionally, and scholastically. A child stuck with this malady is a back bencher in the class, excommunicative, and absent-minded. This study was conducted in order to find out various causes of hearing impairment in children and to study role of various audiological and radiological tests in finding the cause of impaired hearing in children. Aims and Objectives: To assess the possible etiological causes of hearing impairment in children. Study role of various audiological tests in finding the cause of impaired hearing in children. Study Design: Prospective study. Materials and Methods: This study was conducted in the Department of ENT and HNS of government medical college Srinagar. A total of 150 children of age range 0-14 years visited our ENT Department with complaints of impaired hearing, but only 70 children who met the inclusion criteria of impaired hearing and defective/delayed speech were selected for this study. Results of initial evaluation by means of comprehensive clinical history and followed by proper thorough systemic physical examination from head to toe was performed. These hearing impaired children were subjected to various subjective and objective tests; pure tone audiometry and behavioral observation audiometry were performed for subjective tests and impedance audiometry, Oto-acoustic emissions (OAE), and brainstem evoked response audiometry (BERA) were performed for objective tests. Results: Possible etiological cause on the basis of history were birth anoxia (2.85%), premature (5.71%), low birth weight (4.28%), hyperbilirubinemia (4.28%), and consanguinity (42.86%). Possible cause revealed after proper systemic examination includes 2.85% children with craniofacial abnormalities, 2.85% children with Down's syndrome, and 1.42% with Usher's syndrome. OAE revealed 70% bilateral REFER and 30% bilateral PASS. Impedance audiometric results were mostly Type A tympanogram. Pure tone audiometric results were mostly on profound hearing loss (86.69%). BERA findings were mostly on profound hearing loss (85.79%). Conclusion: In this study large vestibular aqueduct (LVAQ) is most common cause of abnormality detected in hearing impaired children.

Genetic study of autosomal recessive nonsyndromic sensorineural hearing loss in Kuwaiti children

EnAbstract Background The prevalence of congenital hearing loss was found to be one in 1000 of live births. Fifty percent of the cause is genetic and autosomal recessive nonsyndromic sensorineural hearing loss (ARNSNHL) is responsible for 80% of the genetic causes. Study design Descriptive cross-sectional study. Objectives To study the genetic causes of ARNSNHL, mainly mutation in the gene encoding connexin26 (Cx26), and to correlate the identified gene and mutation with the degree and configuration of hearing loss, the progressiveness of hearing loss, as well as its relation to language development. Patients and methods One hundred children, age ranging from 6 months to 18 years, presenting with congenital ARNSNHL were chosen. Behavioral observation audiometry or pure tone audiometry to identify the hearing threshold level of the children was performed. Imittancemetry, otoacoustic emissions, auditory brainstem response, and computed tomography scan study were also undertaken. In addition, genetic tests to detect Cx26 mutations using a PCR and primers, as well as sequencing using different primers were also undertaken. Results Out of the total of 100 cases, 15 children were shown to have positive results for Cx26; nine of these were heterozygous and six were homozygous. Twelve participants (80%) among the Cx26 cases were due to 35delG. Out of the nine children who were heterozygous, six showed positive results for D1 (35delG), whereas three children were found to have positive results for D2 (G2A at location base 71). All the six homozygous cases were shown to be positive for D1 (35delG). Thus, the results revealed that 80% of the positive genetic results cases had 35delG. Conclusion Eighty percent of the cause of ARNSNHL in a Kuwaiti population was the 35delG mutation and 20% was due to G2A at location base 71. Of all the cases, 57% showed a positive family history of hearing loss. The homozygous cases presented with more severe clinical pictures compared with the heterozygous cases.

Testing Babies: You Can Do It! Behavioral Observation Audiometry (BOA)

Behavioral observation audiometry (BOA) is the only test protocol that provides a direct measure of hearing. This valuable technique can be used to monitor hearing and hearing aid benefit in infants who are not yet able to participate in visual reinforcement audiometry (VRA). In this article, I present a carefully developed protocol that uses changes in sucking, resulting in a reliable threshold measures. Key points include Auditory brainstem response (ABR) testing, auditory steady state response (ASSR) testing, and otoacoustic emissions (OAEs) testing provide critical information about the status of the auditory pathways but are not direct measures of hearing. Only behavioral testing provides a direct measure of hearing. Behavioral testing can be used to monitor hearing and performance with hearing technology. When carefully performed, using appropriate criteria including using changes in sucking as an indication of a response, behavioral observation audiometry can be used by clinicians to accurately measure thresholds in infants cognitively less than 6 months of age.

聴性行動反応検査(Behavioral Observation Audiometry: BOA)における検査者の技術的差異に関する予備的研究

聴性行動反応検査(Behavioral Observation Audiometry: BOA)における検査者の技術的差異に関する予備的研究

Behavioral observation audiometry (BOA) on babies less than 2 months old—Report on babies who underwent newborn hearing screening—

新生児聴覚スクリーニングにより月齢2ヵ月以前に受診した208例を対象に, 初診時に実施した1kHz, 3kHzの聴力レベル50, 70dB刺激による聴性行動反応聴力検査 (BOA) の結果を確定診断との比較により検討した。両側または片側の聴力が正常でもBOAの反応がなかった例がある程度認められた。50dBに反応があったほぼ全例, 70dBに反応があったうちの約90%の例は両側または片側の聴力が正常であった。反応があった例では高度難聴は極めて稀であった。また, 初診時以降の難聴進行が疑われる例があった。被検児の睡眠に関する状態別の検討では入眠時が覚醒時, 睡眠時に比べて反応が得られやすかった。月齢2ヵ月以前のBOAでは, 反応が得られない場合に難聴の有無や程度を推測するのは不可能であるが, 反応が得られれば精密検査や診断の参考になり, また保護者指導の際の有用な情報になると考えられた。

Hearing Threshold Prediction Using Auditory Brainstem Response and Auditory Steady-State Response in Infants and Young Children

Received June 21, 2011 Accepted July 15, 2011 Address for correspondence Lee-Suk Kim, MD, PhD Department of OtolaryngologyHead and Neck Surgery, College of Medicine, Dong-A University, 1 Dongdaesin-dong 3-ga, Seo-gu, Busan 602-715, Korea Tel +82-51-240-5428 Fax +82-51-253-0712 E-mail klsolkor@chol.com Between one and three of every 1,000 neonates have sensorineural hearing loss (SNHL). It is of utmost importance to minimize the duration of auditory deprivation between the onset of bilateral deafness and intervention using hearing devices such as hearing aids and cochlear implants for achieving the best speech percpetion ability. To fit amplification accurately for children with SNHL, hearing thresholds for frequencies in the range of human communication should be evaluated. However, infants and young children are difficult to test using conventional behavioral tests, and hearing thresholds of them can be predicted using auditory brainstem response (ABR) and auditory steady-state response (ASSR). ABR is best evoked by applying a click stimulus, which allows an estimate over a broad range of high frequencies. ABR elicited by tone burst stimulus provides frequency-specific audiometric information. However, it can be difficult to record and observe at near-threshold levels, especially at lower frequencies. ABR thresholds for click and tone burst stimuli are highly correlated with behavioral thresholds, and often give an idea of the shape of an audiogram. ASSR is an auditory evoked potential, elicited with modulated tones. It provides frequency-specific hearing thresholds across the audiometric frequencies, which are well correlated with behavioral thresholds. However, the accuracy of threshold prediction decreases directly with the decrease of degree of hearing loss, and hearing thresholds cannot be predicted for auditory neuropathy. ASSR is most useful for estimating auditory thresholds for patients with no evidence of auditory neuropathy by the click ABR and OAEs, and who have an ABR only at high intensities or no ABR at a maximum stimulus level. Even if hearing thresholds are predicted through ABR and ASSR, behavioral testing including behavioral observation audiometry, visual reinforcement audiometry, or play audiometry should be employed repeatedly to verify the predicted thresholds, becasue the thresholds of ABR and ASSR are not true measure of hearing acuity but just responses generated at the brainstem. Korean J Otorhinolaryngol-Head Neck Surg 2011;54:592-602