Audiological Follow-up Research Articles

Follow-up audiometry after bilateral myringotomy and tympanostomy tube insertion

ObjectiveThere are no evidence-based guidelines regarding timing of postoperative audiometric follow-up for children undergoing tympanostomy tube insertion. Given the variability of follow-up among physicians, we attempt to guide the timing of postoperative audiograms using objective data. Study designRetrospective chart review. MethodsAll pediatric patients undergoing primary bilateral myringotomy and tympanostomy tube insertion for otitis media with effusion who had audiometric data available at two follow-up times were identified from 2014. Patients were classified according to the type of audiometry performed and were further categorized into those who had tympanostomy tube insertion only and those who had concurrent adenotonsillectomies. Results34 patients were included in the study. Among patients assessed by sound field audiometry, the mean sound field threshold value was 29.2dB preoperatively and improved to 21dB 2 weeks postoperatively and 17.9dB 6 to 10 weeks postoperatively. The difference between the two postoperative means was significant (p<0.0001). For patients evaluated by pure-tone audiometry, the mean preoperative air–bone gap was 20.1dB; this improved to 10dB at the first postoperative visit and 7.3dB at the second visit. The difference between the two means was significant (p<0.0001). For the subgroups in which adjunct adenotonsillectomy was performed, the greater improvement at the later follow-up was still statistically significant. ConclusionsProgressive hearing improvement was demonstrated from 2 weeks to 6 to 10 weeks postoperatively. We recommend testing no fewer than 6 weeks after tympanostomy tube insertion. Earlier audiometry underestimates the degree of hearing improvement.

Management of hearing loss and the normal ear in cases of unilateral Microtia with aural atresia.

To identify the rate of hearing loss related to middle ear disease and the frequency of tympanostomy tube (TT) insertion in the contralateral ear of patients with unilateral microtia/aural atresia. Retrospective case series of patients less than 3 years of age with unilateral microtia/aural atresia treated at an urban, tertiary care children's hospital from 2008 to 2013. Clinical and audiologic data were reviewed. Statistical analysis was performed to determine the relative risk of TT insertion in the normal ear. A total of 72 patients were included for analysis. The average age of patients at their initial otolaryngology visit was 3.3 months (range 0.08-1.67 years); 38 (52.8%) patients were males. Aural atresia involved the right ear in 43 (59.7%) cases. Five (6.9%) patients were syndromic. Abnormal audiometric testing of the normal ear was noted in 12 (16.7%), and 14 (19.4%) underwent TT during the first 3 years of life. Twelve children (85.7%) who had a TT placed were nonsyndromic. When compared to published norms for TT placement in the general population (6.8% of children < 3 year of age), a greater proportion of children with unilateral microtia/aural atresia had TT placement in the normal ear (z = 4.26, P < 0.0001). Patients with unilateral microtia/aural atresia have increased rates of hearing loss and middle ear effusion leading to TT in their normal ear at a higher rate versus the general population. This information can help guide more vigilant care and audiologic follow-up in affected children. 4. Laryngoscope, 126:1470-1474, 2016.

Surgical Findings and Results of Stapes Surgery for Stapedial Fixation in Adults

Received January 24, 2015 Revised March 24, 2015 Accepted March 27, 2015 Address for correspondence Hong Ju Park, MD, PhD Department of Otolaryngology, Aasan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 138-736, Korea Tel +82-2-3010-3710 Fax +82-2-489-2773 E-mail dzness@amc.seoul.kr Background and ObjectivesZZStapes surgery has been reported to improve hearing for stapedial fixation. This study aimed to review the surgical findings and hearing results of stapes surgeries for 20 ears with stapedial fixation. Subjects and MethodZZWe reviewed the medical records and video recordings of 20 consecutive stapes surgeries between 2011 and 2014. Patient age ranged from 20 to 64 years, representing 5 males and 12 females. Mean audiologic follow-up duration was 11 months. Hearing improvement at the final pure-tone audiometry was determined to be successful when air-bone gap (ABG) was reduced to 20 dB or less, and excellent when ABG was reduced to 10 dB or less. Surgery-related deterioration of bone-conduction (BC) was determined to be positive when the difference between final and preoperative BC was more than 15 dB, and over-closure positive when final air-conduction (AC) was better than preoperative BC. ResultsZZPre-operative threshold frequency for BC and AC were 39.8±15.8 and 66.4±15.3 dB HL, respectively, and ABG was 26.6±10.2 dB. After the stapes surgery, the thresholds for BC and AC were 36.8±16.3 and 42.0±16.2 dB HL, respectively, and ABG was 5.2±6.5 dB during the last follow-up. After surgery, BC threshold was significantly improved at 2 kHz, whereas AC threshold improved at all frequencies. Excellent hearing improvement was accomplished in 16 ears (80%) and successful improvement in all ears (100%). Over-closure was observed in 7 ears (35%). There were no patients with surgery-related sensorineural hearing loss. ConclusionZZStapes surgery is effective for improving hearing for stapedial fixation. Operator should be able to cope with various situations during or after the stapes surgery. Korean J Otorhinolaryngol-Head Neck Surg 2015;58(7):469-74

Hearing loss and congenital CMV infection: a systematic review.

Hearing loss caused by congenital cytomegalovirus (cCMV) infection was first observed in 1964. Today cCMV is the most common cause of nonhereditary sensorineural hearing loss in childhood. Our objective was to provide an overview of the prevalence of cCMV-related hearing loss, to better define the nature of cCMV-associated hearing loss, and to investigate the importance of cCMV infection in hearing-impaired children. Two reviewers independently used Medline and manual searches of references from eligible studies and review articles to select cohort studies on children with cCMV infection with audiological follow-up and extracted data on population characteristics and hearing outcomes. Thirty-seven studies were included: 10 population-based natural history studies, 14 longitudinal cohort studies, and 13 retrospective studies. The prevalence of cCMV in developed countries is 0.58% (95% confidence interval, 0.41-0.79). Among these newborns 12.6% (95% confidence interval, 10.2-16.5) will experience hearing loss: 1 out of 3 symptomatic children and 1 out of 10 asymptomatic children. Among symptomatic children, the majority have bilateral loss; among asymptomatic children, unilateral loss predominates. In both groups the hearing loss is mainly severe to profound. Hearing loss can have a delayed onset, and it is unstable, with fluctuations and progression. Among hearing-impaired children, cCMV is the causative agent in 10% to 20%. Despite strict selection criteria, some heterogeneity was found between selected studies. This systematic review underscores the importance of cCMV as a cause of sensorineural hearing loss in childhood.

Pediatric hearing loss.

On the basis of strong research, universal newborn screening should be performed before age 1 month with repeat or follow-up testing for those who do not pass performed before age 3 months and intervention started before age 6 months. On the basis of strong research and consensus statement, tympanostomy tubes should be considered for individuals with bilateral persistent middle ear effusion for 3 months or greater and a documented conductive hearing loss. On the basis of consensus statement, all children with suspected hearing loss should have an age appropriate hearing test. On the basis of strong research, the most common form of congenital hearing loss is genetic. Most of this is nonsyndromic hearing loss.

Pseudohypacusis in children: Circumstances and diagnostic strategy

ObjectivesThe study attempts to specify the circumstances under which we should pay attention to children's pseudohypacusis. It evaluates the methods used to detect such cases and to determine hearing thresholds, according to the uni-or bilateralism of hearing loss. The study finally deals with the future of children diagnosed with pseudohypacusis. MethodsThe study was retrospective from January 1993 to November 2011 and prospective from December 2011 to April 2012. We included all the children between 3 and 16 years who were diagnosed with pseudohypacusis. We observed the reasons for them to consult, whether they had already been tested or had treatment, and what kind of hearing loss they displayed. All children were tested using standard pure tone audiometry and speech audiometry. Depending on the first results, other tests were conducted. They included transient evoked otoacoustic emissions (TEOEs), auditory brainstem responses (ABR) and auditory steady state responses. Families were finally contacted by phone over April 2012 in order to let them know about their child's results. ResultsFifty-four children were included: 19 boys and 35 girls, with an average age of 10 year-old (±3). The simulated hearing loss (HL) was bilateral (36), unilateral (18), of perception (37), moderate HL (33), cophosis (5). Fifteen cases were linked to a family or personal history of hearing loss, while 27 cases were due to important events like adoption, abuse, verbal aggression, school problems. Before diagnosing a pseudohypacusis, 13 children had had imaging studies, 3 had been treated with corticosteroids, and 5 had hearing aids. Most of the time the presence of pseudohypacusis was suspected a discrepancy between speech reception and air-conduction pure tone thresholds, as shown by the medical test (answer on whispered voice). The diagnosis was confirmed by ABR or TEOEs, except in cases where clinic was obvious. Then family's patient and patient were reassured and informed. An audiological follow-up during either 6 months or 1 year was proposed, as well as a psychological consultation. ConclusionComplementary examinations have to be performed to rule out a pseudohypacusis case before suggesting an invasive or expensive treatment (surgery or hearing aids) of children.

Differences in DPOAE and AABR in Noise‐Exposed Infants in the Neonatal Intensive Care Unit

Objectives: 1) Describe the differences in distortion product otoacoustic emissions (DPOAE) and automated auditory brainstem response (AABR) results in premature infants in the neonatal intensive care unit (NICU) with noise exposure. 2) Discuss optimal newborn hearing screen protocols for capturing at-risk NICU graduates. Methods: Prospective observational outcomes study from August to the present. Subjects: Admissions to the NICU, &lt;37 weeks gestational age. Setting: NICU. Outcome Measurements: DPOAE, AABR, and follow-up audiometry collected by the Oregon Early Hearing Detection and Intervention (EHDI) program. Independent variables: Sound pressure levels and cumulative sound dosage. Preliminary analyses: This dataset represents preliminary data from an ongoing study with a target enrollment of 150 over 12 months. Results: The average sound pressure level per individual admission ranged from 57.4 to 67.8 dBA. DPOAE demonstrated a greater rate of abnormalities in the high frequency range of 4000-10000 Hz (40-45%) compared to lower frequencies (10-15%). AABR generated only a 5% rate of referrals; however, 50% of DPOAEs obtained showed abnormal results in at least 2/3 of the high frequencies tested. Conclusions: All infants received sound exposures that substantially exceeded AAP guidelines. More abnormalities were found on DPOAE than AABR, with a significantly higher rate in the high frequencies compared to lower frequencies, consistent with possible noise-induced cochlear dysfunction. Neonatal intensive care units should consider adding DPOAE to their hearing screen protocols so that infants at risk for noise-induced hearing loss are not missed.

Audiological follow-up of 24 patients affected by Williams syndrome

Williams syndrome is a neurodevelopmental disorder associated with cardiovascular problems, facial abnormalities and several behavioural and neurological disabilities. It is also characterized by some typical audiological features including abnormal sensitivity to sounds, cochlear impairment related to the outer hair cells of the basal turn of the cochlea, and sensorineural or mixed hearing loss, predominantly in the high frequency range. The aim of this report is to describe a follow-up study of auditory function in a cohort of children affected by this syndrome. 24 patients, aged 5–14 years, were tested by means of air/bone conduction pure-tone audiometry, immittance test and transient evoked otoacoustic emissions. They were evaluated again 5 years after the first assessment, and 10 of them underwent a second follow-up examination after a further 5 years. The audiometric results showed hearing loss, defined by a pure tone average >15 dB HL, in 12.5% of the participants. The incidence of hearing loss did not change over the 5-year period and increased to 30% in the patients who underwent the 10-year follow-up. Progressive sensorineural hearing loss was detected in 20% of the patients. A remarkable finding of our study regarded sensorineural hearing impairment in the high frequency range, which increased significantly from 25% to 50% of the participants over the 5-year period. The increase became even more significant in the group of patients who underwent the 10-year follow-up, by which time the majority of them (80%) had developed sensorineural hearing loss. Otoacoustic emissions were found to be absent in a high percentage of patients, thus confirming the cochlear fragility of individuals with Williams syndrome. Our study verified that most of the young Williams syndrome patients had normal hearing sensitivity within the low-middle frequency range, but showed a weakness regarding the high frequencies, the threshold of which worsened significantly over time in most patients.

Failure of hearing screening in high-risk neonates does not increase parental anxiety

Objective: The aim of this study was to determine whether a failure of neonatal hearing screening affected the anxiety level of parents of high-risk infants.Methods: Two hundred and eighty-eight parents of infants included in the neonatal hearing screening protocol of our Institution were tested with the Spielberger State-Trait Anxiety Inventory and with an open-question questionnaire investigating parents’ attitude to hearing problems in their child, done at the time of audiological follow-up. 105 were parents of high-risk infants who had been discharged from neonatal intensive care unit (NICU) and 183 of low-risk infants discharged from well-baby nursery.Results: No differences in anxiety levels were seen between parents of high-risk infants passing and failing neonatal hearing screening using homogeneous case-control pairs. Additionally, no differences in the level of anxiety were found between parents of high- and low-risk infants failing neonatal auditory screening.Conclusions: Failure of neonatal auditory screening does not affect the anxiety levels of parents of high-risk infants at post discharge from NICU. This finding is a key factor to be considered when evaluating the costs and benefits of tests for universal neonatal hearing screening.

Providing Information to Families in Newborn Hearing Screening Follow-Up: Professional Challenges

Universal newborn hearing screening is effective only when it leads to audiological and educational follow-up. The purpose of our study was to detect the essential factors that contribute to a high-quality follow-up to families with referred babies after hearing screening in Norway. In-depth interviews of six families were performed, as well as a web-based survey focusing on information needs. Informants were families of children born from 2003 to 2009 who did not pass hearing screening. Our findings stress the importance of comprehensive information given at an early stage, although this also may be overwhelming to many families. From the point of screening and throughout audiological, medical, developmental, and educational follow-up, parents react to the quality of information, affecting their trust in professionals. This is particularly evident when decisions need to be made based on ambiguous information. Dilemmas and challenges for professionals providing information to families are explored, and factors contributing to a high-quality follow-up are described.

Early Identification of Young Children with Hearing Loss in Federally Qualified Health Centers

While newborn hearing screening has improved outcomes for children diagnosed with hearing loss, the screening protocol is incomplete in the critical early developmental years, particularly among underserved populations. To address this gap, 7 federally qualified health centers (FQHCs) implemented a periodic, objective infant-toddler hearing screening program during well-child visits. The study aimed to determine the ability of these primary care providers to implement the hearing screening protocol and to identify children in need of audiologic follow-up. This study represents a prospective chart review. Children aged 0 to 3 years presenting to participating clinics for well-child care visits were offered the hearing screen, which included a brief risk factor questionnaire, otoacoustic emissions (OAEs), and tympanometry. Main outcome measures were time to screen, accuracy of physician interpretation of the tympanogram results, and screening results requiring immediate audiology follow-up. Among 1965 OAE screens, 75% took <10 minutes, and 205 patients (10%) failed OAEs in at least 1 ear; based on tympanometry, middle ear effusions were present in 102 of these cases (50%), while 45 cases (22%) raised concerns for sensorineural hearing loss. Physicians accurately interpreted tympanogram results in 89% of cases. There were 5 patients identified with confirmed permanent sensorineural hearing loss. Findings demonstrate that infant-toddler hearing screening in FQHCs is feasible to conduct, and it may effectively identify cases of postnatal hearing loss. This is one of the first studies in a primary care setting using OAE technology coupled with tympanometry, allowing physicians to better triage patients for immediate audiology referral.

Cochlear implantation in patients with radical mastoid cavities

In the past, cochlear implantation was a contraindicated procedure in profoundly deaf patients with radical mastoid cavities. This was due to high risk of infection spread into the cochlea with possible destruction of the remainder surviving cochlear neural elements. We report on King Abdulaziz University Hospital, Riyadh, Saudi Arabia experience in managing, two postlingual profoundly deaf patients (both male and adult) with radical mastoid cavities due to chronic cholesteatomatous otitis media by cochlear implantation. Two different open techniques were used, cochlear implantation with (in the first patient) and without (in the second patient) obliteration of the pre-existing mastoid cavity. One patient (first) suffered infection of mastoid cavity with extrusion of electrode, 55 months post-implantation. The infection could not be controlled without explantation, so the patient was explanted. The other (second) patient suffered facial nerve twitching, ear discharge and later failure of the implant as proved by integrity testing, 22 months post-implantation. The infection subsided after explantation. We recommend regular clinical and audiological follow-up of such patients in the same cochlear implantation center to avoid any complications which may lead to implant failure or electrode extrusion. This is also useful to discover and treat early any potential recurrent infection or cholesteatoma. High-resolution computed tomography scan of temporal bone is a good tool in the follow-up of patient with post-implantation complications or those implanted with closed blind sac technique which may be a better alternative technique than the open technique.

Methadone Induced Sensorineural Hearing Loss

Background. Sudden sensorineural hearing loss (SSHL) caused by opiate abuse or overuse has been well documented in the medical literature. Most documented case reports have involved either heroin or hydrocodone/acetaminophen. Recently, case reposts of methadone induced SSHL have been published. Case Report. We present the case of a 31-year-old man who developed SSHL after a methadone overdose induced stupor. He was subsequently restarted on methadone at his regular dose. On follow-up audiometry exams, he displayed persistent moderately severe sensorineural hearing loss bilaterally. Discussion. This case is notable because unlike all but one previously reported case, the patient—who was restated on methadone—did not make a complete recovery. Conclusion. Methadone overuse in rare cases causes SSHL.

Hearing preservation in patients with vestibular schwannoma treated with Gamma Knife surgery

Hearing loss after Gamma Knife surgery (GKS) in patients with vestibular schwannoma has been associated with radiation dose to the cochlea. The purpose of this study was to evaluate serviceable hearing preservation in patients with VS who were treated with GKS and to determine if serviceable hearing loss can be correlated with the dose to the cochlea. Forty patients with vestibular schwannoma with serviceable hearing were treated using GKS with a median marginal dose of 12.5 Gy (range 12.5-13 Gy) to the 50% isodose volume. Audiometry was performed prospectively before and after GKS at 1, 3, and 6 months, and then every 6 months thereafter. Hearing preservation was based on pure tone average (PTA) and speech discrimination (SD). Serviceable hearing was defined as PTA less than 50 dB and SD greater than 50%. The median cochlear maximum and mean doses were 6.9 Gy (range 1.6-16 Gy) and 2.7 Gy (range 0.7-5.0 Gy), respectively. With a median audiological follow-up of 35 months (range 6-58 months), the 1-, 2-, and 3-year actuarial rates of maintaining serviceable hearing were 93%, 77%, and 74%, respectively. No patient who received a mean cochlear dose less than 2 Gy experienced serviceable hearing loss (p = 0.035). Patients who received a mean cochlear dose less than 3 Gy had a 2-year hearing preservation rate of 91% compared with 59% in those who received a mean cochlear dose of 3 Gy or greater (p = 0.029). Those who had more than 25% of their cochlea receiving 3 Gy or greater had a higher rate of hearing loss (p = 0.030). There was no statistically significant correlation between serviceable hearing loss and age, tumor size, pre-GKS PTA, pre-GKS SD, pre-GKS Gardner-Robertson class, maximum cochlear dose, or the percentage of cochlear volume receiving 5 Gy. On multivariate analysis there was a trend toward significance for serviceable hearing loss with a mean cochlear dose of 3 Gy or greater (p = 0.074). Local control was 100% at 24 months. No patient developed facial or trigeminal nerve dysfunction. With a median mean cochlear dose of 2.7 Gy, the majority of patients with serviceable hearing retained serviceable hearing 3 years after GKS. A mean cochlear dose less than 3 Gy was associated with higher serviceable hearing preservation.

A longitudinal study of hearing and middle ear status in adolescents with cleft lip and palate

To study longitudinal prevalence of otitis media with effusion (OME) in children between 7 and 16 years of age by cleft group, and hearing sensitivity across time and across frequencies. Retrospective and longitudinal. All children with cleft palate born from 1991 to 1993 were included in the study (n = 58). Audiological and otological data were reviewed at 7, 10, 13, and 16 years of age. The group was divided by cleft type (24 unilateral cleft lip and palate, 23 cleft palate only, and 11 bilateral cleft lip and palate). The prevalence of abnormal middle ear status decreased significantly with age. When comparing cleft types, the isolated cleft palate group presented with a significantly lower prevalence of abnormal middle ear status than the other groups at 7 and 16 years of age (21% as compared to 32% in the unilateral group and 38% in the bilateral group). The pure-tone average improved with age, while the high-frequency pure-tone average did not. When cleft types were compared, the bilateral group demonstrated significantly poorer hearing in the high frequencies than the other groups. Children with cleft palate need regular audiological and otological follow-up to ensure management is appropriate and timely. The increased hearing thresholds in the high frequencies may be due to the increased episodes of OME.

Audiological Follow-Up of Children with the m.1555A>G Mutation in Mitochondrial DNA

The age at onset and the severity of hearing impairment (HI) varies widely among subjects and within families with the m.1555A>G mutation in mitochondrial DNA. We examined prospectively the hearing of 19 children in three nuclear families of a pedigree with m.1555A>G during a period of 7.8 years. The children underwent an audiological examination annually. At the end of the follow-up, the children were 2–13 years old. The parents were asked about the exposure of the children to risk factors of HI. We found that the 19 children with m.1555A>G were born with normal hearing and that 10 of them had developed HI by the end of the follow-up. High frequencies were affected first. The median age at the onset of HI was 3.7 years. Both the severity of HI and the age of onset varied within and between families. Most commonly, audiograms revealed a sensorineural, progressive HI sloping towards high frequencies. We could not identify environmental factors which could modify the development of HI. In conclusion, we were able to pinpoint the time of onset of HI and to follow the progression of HI in childhood. Our results show that there are distinct phenotypes, but at present there are no means to predict which phenotype will develop. It is important to follow up the hearing of children in families with the m.1555A>G mutation, because these children generally pass the newborn hearing screening, and the age at onset or the phenotype of HI cannot be predicted.

Longitudinal analysis of hearing before and after radiosurgery for vestibular schwannoma

The aim of this study was to perform an accurate analysis of changes in hearing in patients with vestibular schwannoma (VS) who have undergone Gamma Knife surgery (GKS) and distinguish the impact of radiosurgery from the natural course of hearing deterioration due to the tumor itself. This study was a retrospective review of prospectively collected patient data. A group of 154 patients with unilateral nonsurgically treated VS was conservatively monitored for more than 6 months and then treated with GKS between July 1997 and September 2005. They were followed up with serial clinical examination, MRI, and audiometry. The annual hearing decrease rate (AHDR) was measured before and after radiosurgery, and the possible prognostic factors for hearing preservation were investigated. The mean dose prescribed to the tumor margins was 12.1 Gy. The mean radiological follow-up period after GKS was 60 months (range 7-123 months). The tumor control rate was 94.8%, and 8 patients underwent subsequent intervention due to tumor progression. The mean audiological follow-up times before and after GKS were 22 and 52 months, respectively. The mean AHDRs before and after GKS were 5.39 dB/year (95% CI 3.31-7.47 dB/year) and 3.77 dB/year (95% CI 3.13-4.40 dB/year), respectively (p > 0.05). The mean pre- and post-GKS AHDRs in patients who initially had Gardner-Robertson (GR) Class I hearing were -0.57 dB/year (95% CI -2.95 to 1.81 dB/year) and 3.59 dB/year (95% CI 2.52-4.65 dB/year), respectively (p = 0.007). The mean pre- and post-GKS AHDRs in patients who initially had GR Class II hearing were 5.09 dB/year (95% CI 1.36-8.82 dB/year) and 4.98 dB/year (95% CI 3.86-6.10 dB/year), respectively (p > 0.05). A subgroup of 80 patients had both early and late post-intervention AHDR assessment (with early referring to the period from GKS to the assessment closest to the 2-year follow-up point and late referring to the period from that assessment to the most recent one); in these patients, the mean early post-GKS AHDR was 5.86 dB/year (95% CI 4.25-7.50 dB/year) and the mean late post-GKS AHDR was 1.86 dB/year (95% CI 0.77-2.96 dB/year) (p < 0.001). A maximum cochlear dose of less than 4 Gy was found to be the sole prognostic factor for hearing preservation. The present study demonstrated the absence of an increase in AHDR after radiosurgery as compared with the preoperative AHDR. There was even a trend indicating a reduction in the annual hearing loss after radiosurgery over the long term. To fully elucidate a possible protective effect of radiosurgery, longer-term follow-up with a larger group of patients will be required.

Hearing Loss in Older Adults

Hearing Loss in Older Adults

Audiological Follow-up Results after Newborn Hearing Screening Program

ObjectivesTo investigate the validity of newborn hearing screening protocol using automated auditory brainstem response (AABR) with a confirmation method using click auditory brainstem response (ABR) and to evaluate changes in hearing status of infants with confirmed congenital hearing loss.MethodsNeonates in the well-baby nursery were screened by staged AABR. Subjects whose final AABR result was "refer" were tested by diagnostic click ABR and 226 Hz tympanometry within 3 months of age. Changes in hearing status of subjects with confirmed hearing loss were analyzed by follow-up ABR at 3-6 month intervals.ResultsOf the 12,193 healthy babies born during this period, 10,879 (89.22%) were screened by AABR. Of 10,879 neonates screened by AABR, 148 (1.36%) were "referred"; of these, 45 subjects showed ABR thresholds over 30 dB nHL in at least one ear. Thirty-four subjects underwent serial follow-up ABR tests, with 11 (32.4%) found to have normal ABR thresholds. Most subjects with mild to moderate hearing loss were found to be normal before 1 year of age, whereas all infants with severe or profound hearing loss were identified as having congenital hearing loss.ConclusionThe referral rate and the positive predictive value of our protocol were acceptable. We have also found here that substantial temporary hearing loss can be included in the first confirmative diagnosis. Temporary hearing loss of our study on follow-up give emphasis to need of further differentiation using the testing for bone conduction and middle ear status.

Pesquisa audiológica y molecular para pérdida auditiva por mutación 35delG en el gen de la conexina 26 e infección congénita por citomegalovirus

Hearing loss may be attributed to genetic and environmental factors. Mutations in the gene of the CX26 protein (connexin 26), are responsible for 30-80% of all cases of non-syndromic profound hearing loss. The 35delG is the most frequent variant in the caucasian population. As to environmental factors, the cytomegalovirus (CMV) is the main cause of congenital infection.To determine the prevalence of congenital CMV infection and the frequency of the 35delG mutation in newborns. To identify those at risk of suffering hearing loss in order to do an audiologic follow-up of detected cases.One thousand and twenty samples of dry blood spots corresponding to newborns were tested using conventional and real time PCR. Audiologic screening was performed to all newborns before hospital discharge.Fifteen out of 1020 subjects were heterozygous for the mutation. No homozygous patients were found. Six out of the samples tested positive for CMV (confirmed by a urine sample), out of which only one newborn was symptomatic. The auditory brainstem response was recorded in all these children. Hearing loss was found in three children with congenital CMV infection and two with 35delG mutation.The frecuency of 35delG mutation carriers in our population was 1.3% and the CMV congenital infection prevalence was 0.6%. Audiologic monitoring of these two populations allowed detection of hearing loss of late onset.