Optimizing vestibular implant electrode positioning using fluoroscopy and intraoperative CT imaging.

PURPOSE:  Vestibular implant electrode positioning close to the afferent nerve fibers is considered to be key for effective and selective electrical stimulation. However, accurate positioning of vestibular implant electrodes inside the semicircular canal ampullae is challenging due to the inability to visualize the target during the surgical procedure. This study investigates the accuracy of a new surgical protocol with real-time fluoroscopy and intraoperative CT imaging, which facilitates electrode positioning during vestibular implant surgery. METHODS:  Single-center case-controlled cohort study with a historic control group at a tertiary referral center. Patients were implanted with a vestibulocochlear implant, using a combination of intraoperative fluoroscopy and cone beam CT imaging. The control group consisted of five patients who were previously implanted with the former implant prototype, without the use of intraoperative imaging. Electrode positioning was analyzed postoperatively with a high-resolution CT scan using 3D slicer software. The result was defined as accurate if the electrode position was within 1.5 mm of the center of the ampulla. RESULTS: With the new imaging protocol, all electrodes could be positioned within a 1.5 mm range of the center of the ampulla. The accuracy was significantly higher in the study group with intraoperative imaging (21/21 electrodes) compared to the control group without intraoperative imaging (10/15 electrodes), (p = 0.008). CONCLUSION:  The combined use of intraoperative fluoroscopy and CT imaging during vestibular implantation can improve the accuracy of electrode positioning. This might lead to better vestibular implant performance.

High-resolution frequency tuning but not temporal coding in the human cochlea.

Frequency tuning and phase-locking are two fundamental properties generated in the cochlea, enabling but also limiting the coding of sounds by the auditory nerve (AN). In humans, these limits are unknown, but high resolution has been postulated for both properties. Electrophysiological recordings from the AN of normal-hearing volunteers indicate that human frequency tuning, but not phase-locking, exceeds the resolution observed in animal models.

Congenital CMV-Associated Hearing Loss: Can Brain Imaging Predict Hearing Outcome?

OBJECTIVES: Congenital cytomegalovirus (cCMV) infection is the leading cause of nonhereditary sensorineural hearing loss in childhood and is also associated with CNS abnormalities. The main objective is to investigate the prognostic value of neonatal cranial ultrasound (cUS) and cranial magnetic resonance imaging (cMRI) in predicting long-term hearing outcome in a large cohort of cCMV-infected symptomatic and asymptomatic patients. DESIGN: Data were prospectively collected from a multicentre Flemish registry of children with cCMV infection born between 2007 and 2016. Neonatal cUS and cMRI scans were examined for lesions related to cCMV infection. Audiometric results at different time points were analyzed. The imaging and audiometric results were linked and diagnostic values of cUS and cMRI were calculated for the different hearing outcomes. RESULTS: We were able to include 411 cCMV patients, of whom 40% was considered symptomatic at birth. Cranial ultrasound abnormalities associated with cCMV infection were found in 76 children (22.2% of the cUS scans), whereas cMRI revealed abnormalities in 74 patients (26.9% of the cMRI scans). A significant relation could be found between the presence of cUS or cMRI abnormalities and hearing loss at baseline and last follow-up. Cranial ultrasound and cMRI findings were not significantly correlated with the development of delayed-onset hearing loss. Specificity and sensitivity of an abnormal cUS to predict hearing loss at final follow-up were 84% and 43%, respectively compared with 78% and 39% for cMRI. Normal cUS and cMRI findings have a negative predictive value of 91% and 92%, respectively, for the development of delayed-onset hearing loss. CONCLUSIONS: Neuroimaging evidence of CNS involvement in the neonatal period is associated with the presence of hearing loss in children with a cCMV infection. Imaging abnormalities are not predictive for the development of delayed-onset hearing loss.

Vestibular dysfunction is a manifestation of 22q11.2 deletion syndrome.

The 22q11.2 deletion syndrome (22q11.2DS) is the second most common cause of developmental delay after Down syndrome. Impaired cognitive development is highly prevalent, but also motor abnormalities such as hypotonia and delays in achieving motor milestones are described. Instability is frequently detected in children, adolescents, and adults and is mostly attributed to their limited motor performance. Until now, vestibular function has not been investigated in these patients, despite the growing evidence that they often have inner ear malformations. The aim of this prospective study was to identify the presence and character of vestibular dysfunction in 22q11.2DS. We investigated 23 subjects with proven 22q11.2DS, older than the age of 12. We performed caloric testing and pendular rotation chair tests with videonystagmography, cervical vestibular-evoked myogenic potential (c-VEMP)-testing, and posturography. Additional otoscopy and audiometry were performed on all subjects. We found a unilateral caloric hypofunction in 55% of patients, a certain absent c-VEMP response in 15% of ears, an inconclusive c-VEMP response in 33% of ears, and abnormal posturography in 68% of patients, of whom 42% displayed a typical vestibular pattern. Remarkably, 90% revealed uni- or bilateral weak caloric responses, independent of caloric symmetry. Vestibular dysfunction is frequent in subjects with 22q11.2DS. This knowledge should be taken into account when assessing motor performance in these patients. Additional larger studies are needed to determine whether this dysfunction implicates a therapeutic potential.

A Role for Acoustic Stimulation in Advanced Otosclerosis: Direct Acoustic Cochlear Implant versus Cochlear Implant.

Recent findings support the efficacy of the direct acoustic cochlear implant (DACI) in patients with advanced otosclerosis whose rehabilitation is very challenging. Standard treatment consists of stapes surgery combined with hearing aids or a cochlear implant (CI). CI surgery, however, is often challenging depending on the grade of otosclerosis. This study aims to compare speech perception scores in quiet and noise of 6 DACI and 12 CI patients with advanced otosclerosis at 3 and 12 months after fitting. Preoperative computed tomographic scans of all patients were scored by experts using an existing otosclerosis grading system (stages 1-3). Speech perception in quiet was significantly better for DACI compared to CI users at 3 months after fitting. At 12 months, no difference was found between DACI and CI patients. Speech perception scores in noise were significantly better in the DACI group. In summary, a DACI system seems to provide an effective treatment option as the acoustic component can be preserved in patients with advanced otosclerosis.

Hearing in Children with Congenital Cytomegalovirus Infection: Results of a Longitudinal Study.

OBJECTIVES: To evaluate hearing outcome, to characterize the nature of symptomatic and asymptomatic congenital cytomegalovirus (cCMV) infection and associated hearing loss, and to compare results with data from previous studies. STUDY DESIGN: A prospective multicenter registry was set up in 2007. Six centers participated in the development of a standardized protocol for diagnosis, treatment, and follow-up. Data were gathered in an online registry. Children (n = 379) with a documented cCMV infection and at least 2 separate audiologic evaluations were included. Audiometric results from a multicenter cohort study of children with cCMV infection with longitudinal observation were examined. RESULTS: Results from 123 children with a symptomatic and 256 children with an asymptomatic cCMV infection were analyzed. In the group with symptomatic cCMV, 63% had hearing loss, compared with 8% in the group with asymptomatic cCMV. Delayed-onset hearing loss occurred in 10.6% of symptomatic cCMV and in 7.8% of asymptomatic cCMV. In the group with symptomatic cCMV, 29.3% of children used some kind of hearing amplification; 1.6% in the group with asymptomatic cCMV used hearing amplification. CONCLUSIONS: Symptomatic and asymptomatic cCMV infections are a major cause of hearing loss in childhood. Reliable estimates of the long-term outcome of cCMV infection are mandatory to increase vigilance, especially among pregnant women and to draw attention to preventive measures, vaccine development, and prenatal and postnatal therapy. Universal screening of newborns for cCMV infection should be initiated and combined with longitudinal audiometric follow-up.

A comparative study on speech in noise understanding with a direct acoustic cochlear implant in subjects with severe to profound mixed hearing loss.

The aim of this study was to investigate the efficacy of a direct acoustic cochlear implant (DACI) for speech understanding in noise in patients suffering from severe to profound mixed hearing loss (MHL) due to various etiologies compared to the preoperative best-aided condition. The study was performed at five tertiary referral centers in Europe (Belgium, Germany, Poland and Spain). Nineteen adult subjects with severe to profound MHL due to (advanced) otosclerosis, ear canal fibrosis, chronic otitis media, tympanosclerosis or previous cholesteatoma were implanted with a DACI (Codacs™ Investigational Device) combined with a conventional stapes prosthesis. Unaided and aided speech reception scores in quiet and in noise, preoperative and postoperative air and bone conduction thresholds and aided and unaided sound field thresholds were measured prospectively during the study. Subjective benefit analysis was determined through the Abbreviated Profile of Hearing Aid Benefit questionnaire. Quality of life was measured by the Health Utilities Index. All subjects were fitted preoperatively with hearing aids and/or a bone conduction implant on a headband before DACI implantation. This allows direct comparison between different hearing rehabilitation solutions. The mean speech reception threshold in noise improved significantly by 7.9 dB signal-to-noise ratio (SNR) after activation of the DACI compared to the preoperative best-aided condition. For all 19 subjects, a mean postoperative aided speech reception threshold of 2.6 dB SNR (standard deviation: 8.3 dB) was measured. On average, no significant shift in the bone conduction thresholds was noted 4-5 months after implantation. A mean sound field threshold improvement of 46 and 16 dB was measured compared to the preoperative unaided and best-aided condition, respectively. Speech perception tests in quiet showed a mean improvement of the word recognition scores by 65 and 48% at 65 dB SPL compared to the preoperative unaided and best-aided condition, respectively. In summary, DACI provides an effective improvement of the speech perception in noise compared to the best-aided condition in subjects suffering from severe to profound MHL.

Tophaceous Gout of the Middle Ear.

Tophaceous gout can rarely present in the middle ear as a mass-like lesion, causing conductive hearing loss. Noncontrast high-resolution computed tomography (HRCT) of the temporal bone plays a significant role in the diagnosis. Awareness of this condition among radiologists is important since it presents a distinctive appearance on HRCT. We present a case of tophaceous gout of the middle ear diagnosed with photon-counting computed tomography (PCCT). Teaching point: The presence of a partially calcified mass with a semolina-like appearance within the middle ear is highly suggestive of tophaceous gout, even in the presence of normal serum uric acid levels.

Long-term follow-up of otitis media with effusion in neonatal hearing screening.

OBJECTIVES: Increased neonatal referral rate of conductive hearing loss (CHL) related to otitis media with effusion (OME) following universal neonatal hearing screening (UNHS) may cause an unnecessary clinical, emotional, and financial burden. This study analyzes the long-term, audiological, and medical characteristics of CHL associated with OME in neonates in order to establish a standardized protocol following technology-driven improvements in detection and referral rates in UNHS. METHODS: A retrospective study of all neonates with OME-related CHL referred to the University Hospital of Leuven (Belgium) after failing UNHS with the MAICO devices between January 1, 2013 and December 31, 2021 was performed. Follow-up consultations, auditory tests, referral side, birth month, hearing loss degree, underlying pathologies and risk factors, time to normalization, and need for ventilation tubes were assessed. RESULTS: The incidence of CHL related to OME was stable between 2013 and 2021. Of all referred infants with OME, 52.3 % demonstrated spontaneous recovery. The average time to hearing normalization was significantly longer in children with underlying congenital pathologies compared to those without. Moreover, 74.4 % of these children received ventilation tubes compared to 32.0 % of children without underlying pathologies. No correlation was found between the incidence of OME-related CHL with either a hearing loss degree, admission to neonatal intensive care, or history of a nasogastric feeding tube. CONCLUSIONS: In children who failed UNHS due to OME, hearing recovers spontaneously without surgical intervention in 2/3 of the infants without underlying conditions within one year. In children with underlying congenital disorders, the time to hearing recovery is longer and the risk for surgical intervention is higher, underlining the need for implementing a UNHS standardized protocol.

Risk Factors for Natural Hearing Evolution in Newborns With Congenital Cytomegalovirus Infection.

Importance: Congenital cytomegalovirus (cCMV) is the major cause of congenital nonhereditary sensorineural hearing loss in children. Currently, criteria to identify infants at increased risk for unfavorable hearing outcome are lacking. Objective: To identify risk factors associated with cCMV-related hearing improvement, hearing deterioration, and late-onset hearing loss. Design, Setting, and Participants: This multicenter cohort study included patients from 6 secondary and tertiary hospitals enrolled in the Flemish CMV registry (Belgium). Newborns with untreated cCMV infection with at least 4-year audiological follow-up were included. Patients who presented with other possible causes of sensorineural hearing loss were excluded. Data were collected for 15 years (January 1, 2007, to February 7, 2022) and analyzed from September 26, 2022, to January 16, 2023. Main Outcomes and Measures: Primary outcome was hearing evolution (per-ear analysis; described as stable hearing, improvement, or deterioration). The association of gestational characteristics, clinical findings, timing of seroconversion, viral load, and hearing status at birth with hearing evolution was investigated using effect sizes (Cramer V, odds ratio [OR], or Hedges g). Results: Of the 387 children, 205 of 385 with nonmissing data were male (53.2%), 113 (29.2%) had a symptomatic infection, and 274 (70.8%) had an asymptomatic infection. Every child was 4 years or older at final hearing evaluation. A total of 701 of 774 ears (90%) showed stable hearing (normal hearing or stable hearing loss since birth) over time. Late-onset hearing loss (normal hearing at birth followed by hearing loss) was present in 43 of 683 ears (6.3%). Among children with hearing loss present at birth, 24 of 34 ears (70.6%) had hearing deterioration, and 6 of 91 ears (6.6%) had hearing improvement. Prematurity was associated with a higher chance of hearing improvement (OR, 12.80; 95% CI, 2.03-80.68). Late-onset hearing loss was more prevalent in a first trimester infection (OR, 10.10; 95% CI, 2.90-34.48). None of the 104 ears of children with a third trimester seroconversion developed late-onset hearing loss. Conclusions and Relevance: Findings of this cohort study support that ongoing audiological follow-up for untreated children with congenital hearing loss is important, as the majority of patients had hearing deterioration. The timing of seroconversion was associated with the risk of developing late-onset hearing loss. These insights can aid in parental counseling, patient stratification, and follow-up. Future research should focus on the effect of treatment, the influence of determined risk factors, and the study of eventual new risk factors in patients at high risk to develop hearing loss.

Early cochlear implantation supports narrative skills of children with prelingual single-sided deafness.

Prelingual single-sided deafness (SSD) not only affects children's hearing skills, but can also lead to speech-language delays and academic underachievement. Early cochlear implantation leads to improved spatial hearing, but the impact on language development is less studied. In our longitudinal study, we assessed the language skills of young children with SSD and a cochlear implant (CI). In particular, we investigated their narrative skills in comparison to two control groups: children with SSD without a CI, and children with bilateral normal hearing. We found that children with SSD and a CI performed in line with their normal-hearing peers with regard to narrative and verbal short-term memory skills. Children with SSD without a CI had worse narrative (group difference = - 0.67, p = 0.02) and verbal short-term memory (group difference = - 0.68, p = 0.03) scores than the implanted group. Verbal short-term memory scores and grammar scores each correlated positively with narrative scores across all groups. Early grammar scores (at 2-3 years of age) could partially predict later narrative scores (at 4-6 years of age). These results show that young children with prelingual SSD can benefit from early cochlear implantation to achieve age-appropriate language skills. They support the provision of a CI to children with prelingual SSD.

Risk Factors for Hearing Loss at Birth in Newborns With Congenital Cytomegalovirus Infection.

Importance: With a prevalence between 0.2% and 6.1% of all live births, congenital cytomegalovirus (cCMV) infection is a major cause of congenital nonhereditary sensorineural hearing loss. Despite the large amount of research on cCMV-related hearing loss, it is still unclear which newborns are at risk of hearing loss. Objective: To identify independent risk factors for cCMV-related congenital hearing loss and predictors of hearing loss severity at birth. Design, Setting, and Participants: This cross-sectional study of newborns with cCMV infection used data included in the Flemish CMV registry that was collected from 6 secondary and tertiary hospitals in Flanders, Belgium, over 15 years (January 1, 2007, to February 7, 2022). Data were analyzed March 3 to October 19, 2022. Patients were included in the study after confirmed diagnosis of cCMV infection and known hearing status at birth. Patients who presented with other possible causes of sensorineural hearing loss were excluded. Main Outcomes and Measures: Primary outcome was hearing status at birth. Clinical, neurological, and laboratory findings along with the timing of seroconversion and blood viral load were separately considered as risk factors. Binary logistic regression was performed to identify independent risk factors for congenital hearing loss in newborns with cCMV. Effect sizes were measured using Hedges g, odds ratio, or Cramer V. Results: Of the 1033 newborns included in the study (553 of 1024 [54.0%] boys), 416 (40.3%) were diagnosed with symptomatic cCMV infection and 617 (59.7%) with asymptomatic cCMV infection. A total of 15.4% of the patients (n = 159) presented with congenital hearing loss; half of them (n = 80 [50.3%]) had isolated hearing loss. The regression model revealed 3 independent risk factors for congenital hearing loss: petechiae at birth (adjusted odds ratio [aOR], 6.7; 95% CI, 1.9-23.9), periventricular cysts on magnetic resonance imaging (MRI; aOR, 4.6; 95% CI, 1.5-14.1), and seroconversion in the first trimester (aOR, 3.1; 95% CI, 1.1-9.3). Lower viral loads were seen in patients with normal hearing compared with those with congenital hearing loss (median [IQR] viral load, 447.0 [39.3-2345.8] copies per milliliter of sample [copies/mL] vs 1349.5 [234.3-14 393.0] copies/mL; median difference, -397.0 [95% CI, -5058.0 to 174.0] copies/mL). Conclusions and Relevance: Findings of this cross-sectional study suggest that newborns with cCMV infection and petechiae at birth, periventricular cysts on MRI, or a seroconversion in the first trimester had a higher risk of congenital hearing loss. Clinicians may use these risk factors to counsel parents in the prenatal and postnatal periods about the risk of congenital hearing loss. Moreover, linking clinical features to hearing loss may provide new insights into the pathogenesis of cCMV-related hearing loss. The importance of viral load as a risk factor for congenital hearing loss remains unclear.

Longitudinal auditory data of children with prelingual single-sided deafness managed with early cochlear implantation.

Individuals with single-sided deafness (SSD) have no access to binaural hearing, which limits their ability to localize sounds and understand speech in noisy environments. In addition, children with prelingual SSD are at risk for neurocognitive and academic difficulties. Early cochlear implantation may lead to improved hearing outcomes by restoring bilateral hearing. However, its longitudinal impact on the development of children with SSD remains unclear. In the current study, a group of young children with prelingual SSD received a cochlear implant at an early age. From the age of four, the children's spatial hearing skills could be assessed using a spatial speech perception in noise test and a sound localization test. The results are compared to those of two control groups: children with SSD without a cochlear implant and children with bilateral normal hearing. Overall, the implanted group exhibited improved speech perception in noise abilities and better sound localization skills, compared to their non-implanted peers. On average, the children wore their device approximately nine hours a day. Given the large contribution of maturation to the development of spatial hearing skills, further follow-up is important to understand the long-term benefit of a cochlear implant for children with prelingual SSD.

Three Years of Vestibular Infant Screening in Infants With Sensorineural Hearing Loss.

OBJECTIVES: Although vestibular deficits are more prevalent in hearing-impaired children and can affect their development on many levels, a pediatric vestibular assessment is still uncommon in clinical practice. Since early detection may allow for timely intervention, this pioneer project has implemented a basic vestibular screening test for each six-month-old hearing-impaired infant in Flanders, Belgium. This study aims to report the vestibular screening results over a period of three years and to define the most important risk factors for abnormal vestibular screening results. METHODS: Cervical Vestibular Evoked Myogenic Potentials with bone-conduction were used as a vestibular screening tool in all reference centers affiliated to the Universal Newborn Hearing Screening Program in Flanders. From June 2018 until June 2021, 254 infants (mean age: 7.4 months, standard deviation: 2.4 months) with sensorineural hearing loss were included. RESULTS: Overall, abnormal vestibular screening results were found in 13.8% (35 of 254) of the infants. The most important group at risk for abnormal vestibular screening results were infants with unilateral or bilateral severe to profound sensorineural hearing loss (20.8%, 32 of 154) (P < .001, odds ratio = 9.16). Moreover, abnormal vestibular screening results were more prevalent in infants with hearing loss caused by meningitis (66.7%, 2 of 3), syndromes (28.6%, 8 of 28), congenital cytomegalovirus infection (20.0%, 8 of 40), and cochleovestibular anomalies (19.2%, 5 of 26). CONCLUSIONS: The vestibular screening results in infants with sensorineural hearing loss indicate the highest risk for vestibular deficits in severe to profound hearing loss, and certain underlying etiologies of hearing loss, such as meningitis, syndromes, congenital cytomegalovirus, and cochleovestibular anomalies.

Prevalence of Otological Disease in Turner Syndrome: A Systematic Review.

INTRODUCTION: Girls and women with Turner syndrome (TS) present with multiple ear and hearing problems, ranging from external morphologic abnormalities to sensorineural or conductive hearing loss. The exact pathophysiology behind these otological diseases is not yet completely understood. The aim of this study is to provide a systematic review on the prevalence of otological disease in TS. METHODS: We conducted a systematic review according to the PRISMA guidelines. A database search was performed in PubMed, Embase, Web of Science, and Cochrane library. RESULTS: The prevalence of otological disease as external ear deformities (20-62%), recurrent otitis media (24-48%), and hearing loss (36-84%) is high in TS. The auditory phenotype in TS is complex and seems to be dynamic with CHL due to middle ear disease at young age and sensorineural hearing loss later in life. CONCLUSION: This systematic review of the literature confirms that otological disease is definitely part of the widely variable phenotype in Turner patients. Strong evidence is lacking on the exact prevalence numbers, emphasizing the need for more prospective data gathering. Growing insights in its pathophysiology will help in the understanding and management of hearing problems in TS across lifespan.

Assessment of Receptive and Expressive Language Skills Among Young Children With Prelingual Single-Sided Deafness Managed With Early Cochlear Implantation.

Importance: Pediatric single-sided deafness (SSD) can seriously affect development, causing impaired spatial hearing skills, speech-language delays, and academic underachievement. Early cochlear implantation likely improves hearing-related outcomes, but its association with language development remains unclear. Objective: To investigate whether early cochlear implantation is associated with language outcomes for children with prelingual SSD. Design, Setting, and Participants: The Cochlear Implant for Children and One Deaf Ear study was initiated in 2015 and recruited participants at 4 academic hospitals in Flanders, Belgium, through 2019. This cohort study included 3 groups of children aged 2 to 5 years: children with SSD and a cochlear implant, children with SSD without a cochlear implant, and a control group with normal hearing. Language and hearing skills were assessed 1 to 2 times per year until the age of 10 years. Study completion rates were high (82%). Data analysis was performed from October to December 2020. Exposure: Unilateral cochlear implant. Main Outcomes and Measures: Longitudinal vocabulary, grammar, and receptive language scores. The implanted group was hypothesized to outperform the nonimplanted group on all language tests. Results: During the recruitment period, 47 children with prelingual SSD without additional disabilities were identified at the participating hospitals. Fifteen of the 34 children with an intact auditory nerve received a cochlear implant (44%, convenience sample). Sixteen of the remaining children were enrolled in the SSD control group (50%). Data from 61 children (mean [SD] age at the time of enrollment, 2.08 [1.34] years; 26 girls [42%]) were included in the analysis: 15 children with SSD and a cochlear implant, 16 children with SSD without a cochlear implant, and 30 children with normal hearing. Children with SSD and a cochlear implant performed in line with their peers with normal hearing with regard to grammar. In contrast, children with SSD without a cochlear implant had worse grammar scores than the group with implants (-0.76; 95% CI, -0.31 to -1.21; P = .004) and the group with normal hearing (-0.53; 95% CI, -0.91 to -0.15; P = .02). The 3 groups had similar vocabulary and receptive language abilities. Conclusions and Relevance: These findings suggest that early cochlear implantation is associated with normal grammar development in young children with prelingual SSD. Although further follow-up will reveal the long-term outcomes of the cochlear implant for other skills, the current results will help clinicians and policy makers identify the best treatment option for these children.

Latencies of auditory steady-state responses recorded in early infancy.

Multiple-stimulus auditory steady-state responses (ASSRs) were assessed in 111 ears of 70 infants between -4 and 19 weeks of age at risk for hearing loss. ASSR thresholds obtained in infants with normal hearing (n = 69 ears) were compared with normal adult ASSR thresholds (n = 32 ears), and the linear relation between ASSR thresholds and behavioral thresholds (BHTs) was investigated in normal-hearing and hearing-impaired infants (n = 79 ears). Furthermore, latency estimates of significant responses to stimuli of 50 dB SPL were compared between the normal-hearing infants (n = 171 data points) and adults (n = 124 data points) and developmental changes in latency were evaluated within the infant group. Normal ASSR thresholds were on average 12 dB higher in infants compared with adults. Correlations between ASSR thresholds and BHTs were 0.75, 0.87, 0.87 and 0.79 for 500, 1000, 2000 and 4000 Hz, respectively. There was a significant effect of carrier frequency on ASSR latency, with higher carrier frequencies evoking shorter latencies in both infants and adults. Mean latencies in adults were 24.3 +/- 1.5, 22.3 +/- 1.1, 19.4 +/- 1.0 and 18.0 +/- 1.1 ms for 500, 1000, 2000 and 4000 Hz, respectively. Depending on the data fit of the infant latency estimates, mean latencies were 1.0 ms shorter or 9.5 ms longer in infants compared with adults. In infants, latencies were on average 2.0 ms longer in the youngest infant group (< or =0 weeks) relative to the oldest infant group (3-8 weeks). These age-related trends, together with other arguments, point to longer latencies in infants compared with adults. The results of this study are valuable as a clinical reference for interpreting ASSR results obtained in high-risk infants within their first months of life and indicate that developmental changes occur regarding ASSR latency.

Earlier intervention leads to better sound localization in children with bilateral cochlear implants.

We present sound localization results from 30 children with bilateral cochlear implants. All children received their implants sequentially, at ages from 6 months to 9 years for the first implant and 1.5-12 years for the second implant, with delays of 10 months to 9 years. Localization was measured in the sound field, with a broadband bell-ring presented from 1 of 9 loudspeakers positioned in the frontal horizontal plane. The majority of the children (63%) were able to localize this signal significantly better than chance level. Mean absolute error scores varied from 9 to 51 degrees (root mean square error scores from 13 to 63 degrees ). The best scores were obtained by children who received their first implant before the age of 2 years and by children who used hearing aids prior to implantation for a period of 18 months or longer. Age at second implantation was important in the group of children who did not use a contralateral hearing aid during the unilateral implant period. Additionally, children who attended a mainstream school had significantly better localization scores than children who attended a school for the deaf. No other child or implantation variables were related to localization performance. Data of parent questionnaires derived from the Speech, Spatial and Qualities of Hearing Scale were significantly correlated with localization performance. This study shows that the sound localization ability of children with bilateral cochlear implants varies across subjects, from near-normal to chance performance, and that stimulation early in life, acoustically or electrically, is important for the development of this capacity.

Vestibular Infant Screening (VIS)-Flanders: results after 1.5 years of vestibular screening in hearing-impaired children.

Due to the close anatomical relationship between the auditory and vestibular end organs, hearing-impaired children have a higher risk for vestibular dysfunction, which can affect their (motor) development. Unfortunately, vestibular dysfunction often goes unnoticed, as vestibular assessment in these children is not standard of care nowadays. To timely detect vestibular dysfunction, the Vestibular Infant Screening-Flanders (VIS-Flanders) project has implemented a basic vestibular screening test for hearing-impaired infants in Flanders (Belgium) with a participation rate of 86.7% during the first year and a half. The cervical Vestibular Evoked Myogenic Potentials (cVEMP) test was applied as vestibular screening tool to map the occurrence of vestibular (mainly saccular) dysfunction in this population. At the age of 6 months, 184 infants were screened. No refers on vestibular screening were observed in infants with permanent conductive hearing loss. In infants with permanent sensorineural hearing loss, a cVEMP refer rate of 9.5% was observed. Failure was significantly more common in infants with severe-profound compared to those with mild-moderate sensorineural hearing loss (risk ratio = 9.8). Since this is the first regional study with a large sample size and successful participation rate, the VIS-Flanders project aims to set an example for other regions worldwide.