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.     

Evaluation of auditory development in infants and toddlers who received cochlear implants under the age of 24 months with the LittlEARS Auditory Questionnaire

Background and Aims

Newborn hearing screening and early intervention for congenital hearing loss have created a need for tools assessing the hearing development of very young children. A multidisciplinary evaluation of children's development is now becoming standard in clinical practice, though not many reliable diagnostic instruments exist. For this reason, the LittlEARS^® Auditory Questionnaire (LEAQ) was created to assess the auditory skills of a growing population of infants and toddlers who receive hearing instruments. The LEAQ relies on parent report, which has been shown to be a reliable way of assessing child development. Results with this tool in a group of children who received very early cochlear implantation are presented.

Methods

The LEAQ is the first module of the LittlEARS^® comprehensive test battery for children under the age of two who have normal hearing (NH), cochlear implants (CIs) or hearing aids (HAs). The LEAQ is a parent questionnaire comprised of 35 “yes/no” questions which can be completed by parents in less than 10 min. Sixty-three children who received unilateral CIs at a young age were assessed longitudinally and their performance was compared to that of a NH group.

Results

All CI children reached the maximum possible score on the LEAQ on average by 22 months of hearing age, i.e. 38 months of chronological age. In comparison, the NH group reached the maximum score by 24 months of age demonstrating that auditory skills of CI children often develop quicker than those of NH children. In the two comparison groups of children aged (a) younger and older than 12 months, and (b) between 6-9 and 21-24 months at first fitting, the early implanted children reached the highest scores faster than the later implanted children. Furthermore, three children with additional needs were tested. They showed slower growth over time but also received benefits from early implantation.

Conclusions

The LEAQ is a quick and effective tool for assessing auditory skills of very young children with or without hearing loss. In our study, the auditory skills of children with CI progressed very quickly after implantation and were comparable with those of NH peers.     

Auditory evoked magnetic fields in children with functional hearing loss

Objectives

Abnormal cortical responses in patients with functional hearing loss were evaluated by magnetoencephalography, which can better separate bihemispherical activity than electroencephalography.

Methods

Auditory evoked fields in response to 1 kHz or 2 kHz tone bursts at 80 dB sound pressure level were measured by a helmet-shaped magnetoencephalography system in 22 patients with functional hearing loss (18 females, mean age 13.2 years) as well as 5 control subjects under 10 years old. Waveform, latency, and equivalent current dipole of N100m responses were used to evaluate activity in the bilateral auditory cortices.

Results

Abnormal N100m of the contralateral response to the stimulated ear, either absence or delayed latency in comparison to normal adult subjects, was found in 6 of the 7 patients with functional hearing loss aged 9 years or younger, but in only 3 of the 15 patients aged 10 years or older. However, such abnormalities were also observed in younger control subjects.

Conclusion

Auditory evoked field may be applied to objectively evaluate cortical auditory function in patients with functional hearing loss, but the normal findings for young children have not yet been established.     

Validation of the LittlEARS Auditory Questionnaire in children with normal hearing

Objectives

With more children receiving cochlear implants during infancy, there is a need for validated assessments of pre-verbal and early verbal auditory skills. The LittlEARS^® Auditory Questionnaire is presented here as the first module of the LittlEARS^® test battery. The LittlEARS^® Auditory Questionnaire was developed and piloted to assess the auditory behaviour of normal hearing children and hearing impaired children who receive a cochlear implant or hearing aid prior to 24 months of age. This paper presents results from two studies: one validating the LittlEARS^® Auditory Questionnaire on children with normal hearing who are German speaking and a second validating the norm curves found after adaptation and administration of the questionnaire to children with normal hearing in 15 different languages.

Methods

Scores from a group of 218 German and Austrian children with normal hearing between 5 days and 24 months of age were used to create a norm curve. The questionnaire was adapted from the German original into English and then 15 other languages to date. Regression curves were found based on parental responses from 3309 normal hearing infants and toddlers. Curves for each language were compared to the original German validation curve.

Results

The results of the first study were a norm curve which reflects the age-dependence of auditory behaviour, reliability and homogeneity as a measure of auditory behaviour, and calculations of expected and critical values as a function of age. Results of the second study show that the regression curves found for all the adapted languages are essentially equal to the German norm curve, as no statistically significant differences were found.

Conclusions

The LittlEARS^® Auditory Questionnaire is a valid, language-independent tool for assessing the early auditory behaviour of infants and toddlers with normal hearing. The results of this study suggest that the LittlEARS^® Auditory Questionnaire could also be very useful for documenting children's progress with their current amplification, providing evidence of the need for implantation, or highlighting the need for follow-up in other developmental areas.     

Cochlear implantation under the first year of age—The outcomes. A critical systematic review and meta-analysis

Objective

To review the current knowledge on cochlear implantation in infancy, regarding auditory perception/speech production outcomes.

Study-design

Meta-analysis. EBM level: II.

Methods

Literature-review from Medline and database sources. Related books were also included.

Results

The number of cohort-studies comparing implanted infants with under 2-year-old children was five; three represented type-III and two type-II evidence. No study was supported by type I evidence. Overall, 125 implanted infants were identified. Precise follow-up period was reported in 82. Median follow-up duration ranged between 6 and 12 months; only 17 children had follow-up duration equal or longer than 2 years. Reliable outcome measures were reported for 42 infants; 15 had been assessed with open/closed-set testing, 14 with developmental rating scales, and 13 with prelexical speech discrimination tools.Ten implanted infants assessed with open/closed-set measures had been compared with under 2-year-old implanted children; 4 had shown better performance, despite the accelerated rate of improvement after the first postoperative year.

Conclusion

Neuroplasticity/neurolinguistic issues have led cochlear implant centers to implant deaf children in infancy; however, widespread policies regarding the aforementioned issue are still not justified. Evidence of these children's outperformance regarding auditory perception/speech production outcomes is limited. Wide-range comparisons between infant implantees and under 2-year-old implanted children are lacking. Longer-term follow-up outcomes should be also made available. There is a need to develop and validate robust measures of monitoring implanted infants. Potential factors of suboptimal outcomes (e.g. misdiagnosis, additional disorders, device tuning, parental expectations) should also be weighted, when considering cochlear implantation in infancy.     

Maturation of auditory function related to hearing threshold estimations using the auditory brainstem response during infancy

Objective

The objective of this study was to quantify the maturation of the Auditory Brainstem Response (ABR) at discrete periods during infancy and to provide a means to appropriately estimate hearing thresholds when the ABR is immature.

Methods

A longitudinal study was designed to measure the in situ ABR thresholds of infants using air-conduction tone bursts of 500, 2000 and 4000 Hz. Thresholds were measured using an eardrum-level microphone to eliminate the bias related to coupler-referenced scales such as the dB nHL scale used for adult assessments.

Results

The study found that the in situ thresholds of a sample of normally developing infants decreased significantly during the first 6 months of life. A comparison of these in situ thresholds with those of normal-hearing adults revealed that the ABR response reached maturity in these infants between 4 and 6 months of age for the frequencies 500 and 2000 Hz but remained immature, or elevated, at 6 months of age for 4000 Hz.

Conclusions

The maturation of the ABR should be considered during the estimation of an infant's audiogram and subsequent diagnosis.     

Does auditory tube angle really affect childhood otitis media and size of the mastoid?

Objective

To assess the cross-sectional area of mastoid air cells and auditory tube angles (ATA), which were defined as the angles between the longitudinal line bisecting the transverse length of the external auditory canal and the longitudinal axis of the auditory tube (AT), both in healthy ears and diseased ears in patients with unilateral chronic otitis media (COM).

Methods

25 patients who had unilateral COM were included in the study. Assessment was performed using a quantitative digital image processing computer tomography (CT) program.

Study design

Prospective study with institutional review board approval including adult patients who had otological symptoms since their childhood period.

Results

Mastoid areas were greater on the healthy side than on the diseased side (p < 0.05). ATA were not significantly different among groups (p > 0.05). When we compared ATA with mastoid area in each group; there were no significant correlations in both healthy group and COM group (p > 0.05). Mastoid size in COM group was smaller than in the healthy group.

Conclusion

We suggest that middle ear inflammations in childhood may affect mastoid size but, the anatomic relationships of the auditory tube, mastoid and middle ear that form a functional unit may not be significantly important in chronic ear disease.     

Evaluation of musical skills in children with a diagnosis of an auditory processing disorder

Impaired musical skills are reported in parental questionnaires to be present in children with an auditory processing disorder (APD).

Objectives

To formally assess musical skills in children with a diagnosis of APD.

Methods

We used a validated musical test battery with extensive normative pediatric data, the Gordon's Musical Aptitude Profile and the tests of metre and melody in particular, in order to assess the musical skills of 8 children with a previously given diagnosis of APD (APD group) and 8 normal controls (control group) aged 7-15 years old. The two groups were well matched for age, sex, handedness, socio-economic factors and musical training.

Results

The APD group had significantly lower metre percentile scores than normal children (mean difference 28.9, p = 0.003). Melody scores tended to be lower in the APD group than in the controls, but this did not reach significance, possibly due to low power of the study.

Conclusion

This is the first study that systematically assesses musical skills in children with a formal diagnosis of APD in the absence of other developmental disorders. The APD group did significantly worse than the control group in judging metre. Musical skills assessment in children with APD may help constrain our understanding of this heterogeneous condition and possibly inform the management plan for these children.     

Articulation skills in Turkish speaking children with cochlear implant

Objective

The benefits of using cochlear implant (CI) on speech perception and production have been documented. The aim of this study is to investigate the effect of age of cochlear implantation performed and length of auditory experience with CI on the development of articulation skills in prelingual children with CI.

Methods

For this purpose, 14 children with CI were administered through the standardized articulation test named AAT (Ankara Articulation Test). In order to evaluate the development of articulation skills, AAT was applied to each child with CI at the first and the fourth years of CI. The test group was selected among those congenitally hearing impaired children who had used hearing aids bilaterally before the age of one and a half, and received intervention after fitting hearing aids. The test group was divided into two subgroups: Group 1 consisted of the children implanted at and below the age of 3 and Group 2 consisted of the children implanted after the age of 3. Evaluations of articulation skills between groups and within groups were performed in the first and fourth years of implantation. In the study, nonparametric statistics have been used to compare the test scores. Mann-Whitney U-test and Wilcoxon test have been used in the comparisons made between groups and within groups, respectively.

Results

While there has not been observed any statistically significant difference between the first year articulation skills of children with CI at and below the age of three and children with CI above the age of 3, for the fourth year this difference has been found to be statistically significant.

Conclusions

The results demonstrate the importance of the early application of CI and length of auditory experience with CI in the development of articulation skills.     

Congenital incudostapedial anomalies in adult stapes surgery: a case-series review

Objectives

The management of developmental anomalies of the ossicular chain and otic capsule in stapes surgery tests the otologist's diagnostic skills and flexibility in technique and prosthesis choice. We review our experience in managing various incudostapedial developmental anomalies discovered during middle ear exploration for suspected otosclerosis in adult patients.

Design

A retrospective case-series review was used.

Setting

The study was set at a military tertiary referral center.

Patients and other Participants

A review of 185 stapes procedures yielded 8 cases of identified congenital anomalies of the stapes or incudostapedial complex including congenital absence of the oval window with malformed incus and stapes, columellar-type stapes with promontory fixation, stapes superstructure fixation to the fallopian canal, and malformed incus with stapes superstructure fixation to the promontory.

Interventions

The developmental anatomy and surgical technique in each case were reviewed. The surgical technique used in each case varied depending on the specific ossicular abnormality found and whether both the stapes and incus were affected.

Main outcome measures

Comparison of preoperative and postoperative audiometric testing results was performed.

Results

All 8 ears (7 patients) that underwent a stapes procedure for either an isolated congenital stapes anomaly or a combined incudostapedial anomaly had a favorable hearing outcome, with 7 ears improving to within 10-dB and 1 ear to within 13-dB air-bone gap on postoperative audiometry.

Conclusions

Despite unanticipated findings of congenital anomalies of the stapes and incus during middle ear exploration for conductive hearing loss, a flexible management approach can lead to successful hearing outcomes.     

Prevalence of auditory neuropathy (AN) among infants and young children with severe to profound hearing loss

Auditory neuropathy is a challenging disorder and needs special habilitative/rehabilitative approach. This study aimed to detect its prevalence among infants and young children with severe to profound hearing loss. 112 infants and young children with age ranged 6-32 months were examined and diagnosed as having severe to profound hearing loss and were referred for hearing aid fitting. Those infants were reassessed in our centers for detecting cases with auditory neuropathy. The study group was subjected to immittancemetry, behavioral observation audiometry, ABR and cochlear microphonics.

Results

15 patients were found to have auditory neuropathy according to our criteria for diagnosis.

Conclusions

The prevalence of AN in the study group was 13.4%. CM were recommended to be tested routinely during ABR assessment whenever abnormal results are obtained.     

Infants versus older children fitted with cochlear implants: performance over 10 years

Objectives

To investigate the efficacy of cochlear implants (CIs) in infants versus children operated at later age in term of spoken language skills and cognitive performances.

Method

The present prospective cohort study focuses on 19 children fitted with CIs between 2 and 11 months (X = 6.4 months; SD = 2.8 months). The results were compared with two groups of children implanted at 12-23 and 24-35 months. Auditory abilities were evaluated up to 10 years of CI use with: Category of Auditory Performance (CAP); Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS); Peabody Picture Vocabulary Test (PPVT-R); Test of Reception of Grammar (TROG) and Speech Intelligibility Rating (SIR). Cognitive evaluation was performed using selected subclasses from the Griffiths Mental Development Scale (GMDS, 0-8 years of age) and Leiter International Performance Scale-Revised (LIPS-R, 8-13 years of age).

Results

The infant group showed significantly better results at the CAP than the older children from 12 months to 36 months after surgery (p < .05). Infants PPVT-R outcomes did not differ significantly from normal hearing children, whereas the older age groups never reached the values of normal hearing peers even after 10 years of CI use. TROG outcomes showed that infants developed significantly better grammar skills at 5 and 10 years of follow up (p < .001). Scores for the more complex subtests of the GMDS and LIPS-R were significantly higher in youngest age group (p < .05).

Conclusion

This study demonstrates improved auditory, speech language and cognitive performances in children implanted below 12 months of age compared to children implanted later.     

Landau-Kleffner syndrome: a rare auditory processing disorder series of cases and review of the literature

Objective

To describe the clinical presentation and treatment of 3 children with an Auditory Processing Disorder with an identifiable neurological cause: Landau-Kleffner syndrome [3]. This classical syndrome is well recognized in pediatric neurology but the diagnosis is less well known to Pediatric Otolaryngology, Speech Language Pathology and Audiology services.

Methods

Retrospective chart review of three patients with Landau-Kleffner syndrome.

Results

In all cases, pharmacological intervention led to clinical and electroencephalographic improvement, but all patients had long-term difficulty with understanding sounds in a noisy environment. Magnetic Resonance Imaging (MRI) of the brain was normal in all three patients. Their language disturbance improved over time. Speech language intervention was helpful in addressing communication difficulties arising from the auditory processing/receptive and expressive language disorder.

Conclusion

A multidisciplinary assessment is the key for early diagnosis, treatment and follow-up in patients with this syndrome.     

Random Gap Detection Test (RGDT) performance of individuals with central auditory processing disorders from 5 to 25 years of age

Objective

The aim of the present study was to assess the auditory temporal resolution ability in individuals with central auditory processing disorders, to examine the maturation effect and to investigate the relationship between the performance on a temporal resolution test with the performance on other central auditory tests.

Methods

Participants were divided in two groups: 131 with Central Auditory Processing Disorder and 94 with normal auditory processing. They had pure-tone air-conduction thresholds no poorer than 15 dB HL bilaterally, normal admittance measures and presence of acoustic reflexes. Also, they were assessed with a central auditory test battery. Participants who failed at least one or more tests were included in the Central Auditory Processing Disorder group and those in the control group obtained normal performance on all tests. Following the auditory processing assessment, the Random Gap Detection Test was administered to the participants. A three-way ANOVA was performed. Correlation analyses were also done between the four Random Gap Detection Test subtests data as well as between Random Gap Detection Test data and the other auditory processing test results.

Results

There was a significant difference between the age-group performances in children with and without Central Auditory Processing Disorder. Also, 48% of children with Central Auditory Processing Disorder failed the Random Gap Detection Test and the percentage decreased as a function of age. The highest percentage (86%) was found in the 5-6 year-old children. Furthermore, results revealed a strong significant correlation between the four Random Gap Detection Test subtests. There was a modest correlation between the Random Gap Detection Test results and the dichotic listening tests. No significant correlation was observed between the Random Gap Detection Test data and the results of the other tests in the battery.

Conclusion

Random Gap Detection Test should not be administered to children younger than 7 years old because other reduced capacities might influence their performance. Also, Random Gap Detection Test assesses a specific auditory ability, different than the one evaluated with the other auditory tests. Finally, it is suggested to test individuals at only one frequency of the Random Gap Detection Test because results provide similar information than when assessing them on all subtests.     

Auditory function in women with autoimmune inner ear diseases and their offspring

Objective

The precise cause of congenital sensorineural hearing loss (CSNHL) is unclear in many cases. In a previous study we found that offspring from guinea pigs with autoimmune sensorineural hearing loss (ASNHL) exhibited signs of SNHL. Here we studied women with autoimmune inner ear diseases (AIED) and their offspring. Our aim was to determine if autoimmune damage may be one of the causes of CSNHL.

Methods

Thirty-eight pregnant women with AIED were recruited. Thirty-three had ASNHL; one with autoimmune delayed endolymphatic hydrops (ADEH) and four with autoimmune Meniere's disease (AIMD). The following were assessed in all women: audiogram, auditory brain stem response (ABR), otoacoustic emission (OAE), vestibular function test and presence of inner ear antigens. The following were assessed in offspring from these women: OAE, ABR and presence of inner ear antigens.

Results

Five of the 38 children born to women with AIED had SNHL (an incidence much higher than normal). OAEs were not inducible in these children shortly after birth or within 46-100 days after birth. Abnormal ABR findings were apparent in these five children and inner ear antigens were detected in three of the five children (the mother's of these children were also positive for inner ear antigens).

Conclusions

These preliminary findings suggest that the prevalence of congenital ASNHL may be increased in offspring born to women with AIED.     

Effect of age at cochlear implantation on auditory and speech development of children with auditory neuropathy spectrum disorder

Objective

To evaluate the auditory and speech abilities in children with auditory neuropathy spectrum disorder (ANSD) after cochlear implantation (CI) and determine the role of age at implantation.

Methods

Ten children participated in this retrospective case series study. All children had evidence of ANSD. All subjects had no cochlear nerve deficiency on magnetic resonance imaging and had used the cochlear implants for a period of 12–84 months. We divided our children into two groups: children who underwent implantation before 24 months of age and children who underwent implantation after 24 months of age. Their auditory and speech abilities were evaluated using the following: behavioral audiometry, the Categories of Auditory Performance (CAP), the Meaningful Auditory Integration Scale (MAIS), the Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS), the Standard-Chinese version of the Monosyllabic Lexical Neighborhood Test (LNT), the Multisyllabic Lexical Neighborhood Test (MLNT), the Speech Intelligibility Rating (SIR) and the Meaningful Use of Speech Scale (MUSS).

Results

All children showed progress in their auditory and language abilities. The 4-frequency average hearing level (HL) (500 Hz, 1000 Hz, 2000 Hz and 4000 Hz) of aided hearing thresholds ranged from 17.5 to 57.5 dB HL. All children developed time-related auditory perception and speech skills. Scores of children with ANSD who received cochlear implants before 24 months tended to be better than those of children who received cochlear implants after 24 months. Seven children completed the Mandarin Lexical Neighborhood Test. Approximately half of the children showed improved open-set speech recognition.

Conclusion

Cochlear implantation is helpful for children with ANSD and may be a good optional treatment for many ANSD children. In addition, children with ANSD fitted with cochlear implants before 24 months tended to acquire auditory and speech skills better than children fitted with cochlear implants after 24 months.     

The genetic basis of auditory neuropathy spectrum disorder (ANSD)

Objective

Auditory neuropathy is a hearing disorder where outer hair cell function within the cochlea is normal, but inner hair cell and/or the auditory nerve function is disrupted. It is a heterogeneous disorder which can have either congenital or acquired causes. Furthermore, the aetiology of auditory neuropathy is vast, which may include prematurity, hyperbilirubinaemia, anoxia, hypoxia, congenital brain anomalies, ototoxic drug exposure, and genetic factors. It is estimated that approximately 40% of cases have an underlying genetic basis, which can be inherited in both syndromic and non syndromic conditions. This review paper provides an overview of the genetic conditions associated with auditory neuropathy spectrum disorders (ANSDs) and highlights some of the defective genes that have been found to be linked to the pathological auditory changes.

Method

Literature search was conducted using a number of resources including textbooks, professional journals and the relevant websites.

Results

The largest proportion of auditory neuropathy spectrum disorders (ANSDs) is due to genetic factors which can be syndromic, non-syndromic or mitochondrial related. The inheritance pattern can include all the four main types of inheritances such as autosomal dominant, autosomal recessive, X-linked and mitochondrial.

Conclusion

This paper has provided an overview of mutation with some of the genes and/or loci discovered to be the cause for auditory neuropathy spectrum disorders (ANSDs). It has been noted that different gene mutations may trigger different pathological changes in patients with this disorder. These discoveries have provided us with vital information as to the sites of pathology in auditory neuropathy spectrum disorders (ANSDs), and the results highlight the heterogeneity of the disorder.     

Day-case pediatric middle ear surgery: From myringoplasty to bilateral cochlear implantation

Objective

In the English speaking literature there is very little evidence demonstrating safe and effective tympanomastoid day case surgery in pediatric practice. At a time when there is ongoing pressure for trusts to meet financial government targets and our care provision revolves around a patient centred approach, could otolaryngologists perform more pediatric middle ear surgery on a day case basis? We report our experience with a series of 52 pediatric middle ear day cases.

Method

Prospective study from a London tertiary referral centre of 52 consecutive children undergoing tympanomastoid surgery. There were 6 categories of surgical procedure, ranging from myringoplasty to cochlear implantation. Post-operative recovery was monitored. The duration of anaesthesia was compared with the length of post-operative ward stay.

Results

The correlation co-efficient r = −0.2203, showing that there was no association between length of anaesthetic and duration of post-operative ward stay.

Conclusions

Despite minor post-operative problems including pain, bleeding, and nausea and vomiting all patients in this series were discharged on the day of surgery. For tympanoplasty our series adds weight to already available evidence. It is the first series showing that mastoid surgery, whether combined approach, traditional mastoidectomy or cochlear implantation can be performed safely as day cases in a pediatric population.     

Behavioral and electrophysiological measures of auditory change detection in children following late cochlear implantation: A preliminary study

Objective

The purpose of the current study was to longitudinally assess the development of automatic sound feature discrimination and compare it to behavioral discrimination in late-implanted cochlear implant users.

Methods

Scalp-recorded auditory evoked potentials (AEPs) and behavioral discrimination of frequency, duration and intensity differences within an oddball paradigm using complex stimuli were recorded in three late-implanted cochlear implant subjects beginning on turn-on day.

Results

Variable results were obtained in behavioral and AEPs that were consistent with the amount of pre-implant auditory experience each subject had. The best user showed rapid development of neurophysiologic indices of change detection along with improvement in behavioral and real-world auditory skills. In contrast, there were no recordable AEPs in the poorer CI user and there was little change in behavioral outcomes.

Conclusion

There is evidence of utilization of usual auditory processing pathways in the AEPs of some children who receive cochlear implants late in their childhood. Some plasticity in the auditory cortical pathways may be present despite prolonged auditory deprivation in school-aged children who are late-implanted cochlear implant recipients.     

An initial overestimation of sensorineural hearing loss in NICU infants after failure on neonatal hearing screening

Objective

Infants admitted to neonatal intensive care units have a higher incidence of significant congenital hearing loss. We classified audiologic diagnoses and follow-up in infants who had been admitted to our neonatal intensive care unit.

Methods

We included all infants admitted to the neonatal intensive care unit at Sophia Children's Hospital between 2004 and 2009 who had been referred for auditory brainstem response measurement after failing neonatal hearing screening with automated auditory brainstem response. We retrospectively analyzed the results of auditory brainstem response measurement.

Results

Between 2004 and 2009 3316 infants admitted to our neonatal intensive care unit had neonatal hearing screening. 103 infants failed neonatal hearing screening: 46 girls and 57 boys. After first auditory brainstem response measurement we found 18% had normal hearing or a minimal hearing loss. The remainder had a type of hearing loss, distributed as follows: 15% conductive, 32% symmetric sensorineural, 14% asymmetric sensorineural, and 21% absent auditory brainstem responses. Repeated auditory brainstem response measurement showed a shift in hearing outcome. The main difference was an improvement from symmetric sensorineural hearing loss to normal hearing. However, in a small percentage of children, the hearing deteriorated.

Conclusions

As many as 58% of infants in this high-risk population who failed the neonatal hearing screening were diagnosed with sensorineural hearing loss or absent auditory brainstem responses. An initial overestimation of sensorineural hearing loss of about 10% was seen at first auditory brainstem response measurement. This may be partially explained by a conductive component that has resolved. Finally, in a small percentage of children the hearing deteriorated.