http://repub.eur.nl/res/aut/9732/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/32773/ 2012-06-27T00:00:00Z OBJECTIVE: To determine the prevalence of hearing loss in school-age children who have undergone neonatal extracorporeal membrane oxygenation (ECMO) treatment and to identify any effects of hearing loss on speech- and language development. DESIGN: Prospective longitudinal follow-up study within the framework of a structured post-ECMO follow-up program. SETTING: Outpatient clinic of a level III university hospital. RESULTS: Tone audiometry was performed by standardized protocol in 136 children aged 5 to 12 years. Hearing loss was considered clinically significant when >20dB. Hearing was normal in 75.7% of children. Five children (3.7%) had bilateral sensorineural or combined hearing loss; 3 of them received special audiological care (2.2% of total sample). Of the 24 children with congenital diaphragmatic hernia, 19 (79.2%) had normal hearing; and only 2 (8.3%) had mild SNHL, unilateral in one of them. Follow-up at 24 months of age had shown normal verbal and non-verbal developmental scores. Language development and intelligence median (range) scores at 5 years of age were also normal: receptive language development 104 (55-133); syntactical development 104 (68-132); and lexical development 101 (50-141) for 89 children; intelligence quotient was 104 (68-132) in 106 children. Scores did not differ between those with normal hearing, and those with mild hearing loss, or those with moderate to severe hearing loss (p=0.800, p=0.639, p=0.876, and p=0.886, for the respective developmental tests). CONCLUSIONS: We found normal language development and intelligence in a cohort of neonatal ECMO survivors. The prevalence of bilateral sensorineural hearing loss was in accordance with that of larger series in the United States – which exceeds the prevalence in the normal population. http://repub.eur.nl/res/pub/33284/ 2011-10-01T00:00:00Z Objectives/Hypothesis: Analysis of auditory brainstem response (ABR) in very preterm infants can be difficult owing to the poor detectability of the various components of the ABR. We evaluated the ABR morphology and tried to extend the current assessment system. Study Design: Prospective cohort study. Methods: We included 28 preterm very low birth weight infants admitted to the neonatal intensive care unit of Sophia Children's Hospital. ABRs were measured between 26 and 34 weeks postconceptional age. The presence of the following ABR parameters was recorded: the ipsilateral peaks I, III and V, the contralateral peaks III and V, and the response threshold. Results: In 82% of our population, a typical "bow tie" response pattern was present as a sign of early auditory development. This bow tie pattern is the narrowest part of the response wave and is predominantly characterized by the ipsilateral negative peak III. This effect may be emphasized by the contralateral peak III. The bow tie pattern is seen approximately 0.1 milliseconds before the ipsilateral peak III. From 30 weeks postconceptional age onward, a more extensive morphologic pattern is recorded in 90% of the infants. A flow chart was designed to analyze the ABR morphology of preterm infants in an unambiguous stepwise fashion. Conclusions: A typical bow tie pattern preceding peak III seems to be the earliest characteristic of the developing ABR morphology in preterm infants. As ABR characteristics will improve with increasing age, neonatal hearing screening should be postponed until after 34 weeks. Copyright http://repub.eur.nl/res/pub/33475/ 2011-04-01T00:00:00Z Objectives: To evaluate independent etiologic factors associated with auditory neuropathy spectrum disorder (ANSD) in infants who have been admitted to the neonatal intensive care unit (NICU) compared to normal-hearing controls. Study Design: Case-control study. Methods: We included all infants (n = 9) with the ANSD profile admitted to the NICU of Sophia Children's Hospital between 2004 and 2009. Each patient was matched with four normal-hearing controls of the same gender and postconceptional age. The following possible risk factors were studied: birth weight, dysmorphic features, APGAR scores (at 1, 5, and 10 minutes), respiratory distress (IRDS), cytomegalovirus (CMV) infection, sepsis, meningitis, cerebral bleeding, hyperbilirubinemia requiring phototherapy, peak total bilirubin level, furosemide, dexamethason, vancomycin, gentamycin, and tobramycin administration. Results: Nine infants met the ANSD criteria in one or both ears. IRDS (P =.02), meningitis (P =.04), and vancomycin administration (P =.009) were significantly increased in infants with ANSD compared to controls. Conclusions: In high-risk NICU infants IRDS, meningitis and vancomycin administration are associated with auditory neuropathy spectrum disorder. http://repub.eur.nl/res/pub/33713/ 2011-02-01T00:00:00Z 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. http://repub.eur.nl/res/pub/20057/ 2010-10-01T00:00:00Z Little information is available regarding the auditory function in Pompe patients. Hearing loss has been reported in classic infantile patients, but it is still unknown whether central nervous system involvement interferes with auditory function and whether enzyme replacement therapy can improve hearing. Auditory function has not been studied in children with milder forms of the disease. We analyzed repetitive auditory brainstem response measurements and pure tone audiometry in 24 children with Pompe disease. Only 1 of 13 patients with milder phenotypes showed recurrent conductive hearing loss, while 10 out of 11 classic infantile patients had sensorineural hearing defects. These patients also had a high prevalence of conductive hearing loss. Five patients showed evidence of mild retrocochlear pathology, suggestive of glycogen accumulation in the central nervous system. Hearing loss persisted during therapy in all patients. The results emphasize the need for careful monitoring of auditory function in classic infantile Pompe patients, and for early implementation of hearing aids to protect speech and language development. http://repub.eur.nl/res/pub/28215/ 2010-10-01T00:00:00Z The purpose of this study was to present a simple and powerful fitting model that describes age-dependent changes of auditory brainstem responses (ABR) in a clinical population of normal hearing children. A total of 175 children (younger than 200 weeks postconceptional age) were referred for audiologic assessment with normal ABR results. ABR parameters of normal hearing children between 2003 and 2008 were included. The results of the right ears recorded at 90 dB nHL were analyzed. A simple and accurate fitting model was formulated based on these data. A very similar age-dependent effect was found for peaks III and V, and I-III and I-V intervals; latencies decrease as postconceptional age increases. It shows that the total age-dependent effect will be completed after 1.5-2 years. The age-dependent effect can be modeled by a relatively simple and accurate exponential function. This fitting model can be easily implemented to analyze ABR results of infants in daily clinical practice. We speculate about the underlying physiological processes. http://repub.eur.nl/res/pub/20911/ 2010-09-01T00:00:00Z Objectives: To evaluate independent etiologic factors associated with sensorineural hearing loss in infants who have been admitted to the neonatal intensive care unit compared to normal hearing controls. Method: Between 2004 and 2009, 3366 infants were admitted to the neonatal intensive care unit of Sophia Children's Hospital, of which 3316 were screened with AABR. A total of 103 infants were referred for auditory brainstem response analysis after failure on neonatal hearing screening. We included all infants diagnosed with sensorineural hearing loss. Each patient was matched with two normal hearing controls from the neonatal intensive care unit of the same gender and postconceptional age. The following risk factors were studied: birth weight, dysmorphic features, APGAR scores (at 1, 5 and 10. min), respiratory distress (IRDS), CMV infection, sepsis, meningitis, cerebral bleeding, cerebral infarction, hyperbilirubinemia requiring phototherapy, peak total bilirubin level, furosemide, dexamethason, vancomycin, gentamycin and tobramycin administration. Results: Fifty-eight infants were diagnosed with sensorineural hearing loss: 26 girls and 32 boys. The incidence of dysmorphic features (P= 0.000), low APGAR score (1. min) (P= 0.01), sepsis (P= 0.003), meningitis (P= 0.013), cerebral bleeding (P= 0.016) and cerebral infarction (P= 0.000) were significantly increased in infants with sensorineural hearing loss compared to normal hearing controls (n= 116). Conclusion: Dysmorphic features, low APGAR scores at 1. min, sepsis, meningitis, cerebral bleeding and cerebral infarction are associated with sensorineural hearing loss independent of neonatal intensive care unit admittance. http://repub.eur.nl/res/pub/21378/ 2010-01-01T00:00:00Z Infants admitted to neonatal intensive care units (NICUs) have a higher incidence of perinatal complications and delayed maturational processes. Parameters of the auditory brainstem response (ABR) were analyzed to study the prevalence of delayed auditory maturation or neural pathology. The prevalence of prolonged I-V interval as a measure of delayed maturation and the correlation with ABR thresholds were investigated. All infants admitted to the NICU Sophia Children's Hospital between 2004 and 2009 who had been referred for ABR measurement after failing neonatal hearing screening with automated auditory brainstem response (AABR) were included. The ABR parameters were retrospectively analyzed. Between 2004 and 2009, 103 infants were included: 46 girls and 57 boys. In 58.3% (60 infants) of our population, the I-V interval was recordable in at least one ear at first diagnostic ABR measurement. In 4.9%, the I-V interval was severely prolonged. The median ABR threshold of infants with a normal or mildly prolonged I-V interval was 50 dB. The median ABR threshold of infants with a severely prolonged I-V interval was 30 dB. In conclusion, in case both peak I and V were measurable, we found only a limited (4.9%) incidence of severely prolonged I-V interval (≥0.8 ms) in this high-risk NICU population. A mild delay in maturation is a more probable explanation than major audiologic or neural pathology, as ABR thresholds were near normal in these infants. http://repub.eur.nl/res/pub/6759/ 2005-06-02T00:00:00Z Hearing-aid users often continue to have problems with poor speech understanding in difficult acoustical conditions. Another generally accounted problem is that certain sounds become too loud whereas other sounds are still not audible. Dynamic range compression is a signal processing technique that may be used in hearing aids to compensate for these remaining disabilities. Its main function is to provide sufficient amplification at low input levels without overloading the auditory system at high input levels. The time constants define the time needed by the compressor to realize a change in amplification. When using relatively large time constants, the compressor only reduces differences in overall level. This type of compression is known as Automatic Gain Control (AGC) or Automatic Volume Control (AVC).With short time constants the compressor also reduces the dynamic range of a fast-fluctuating signal like speech. This last type of system is therefore often called a syllabic or a phoneme compressor. The main goal of using phoneme compression is to optimize speech intelligibility by improving the detection of weak speech cues. We developed a phoneme compression system to improve the perception of high-frequency speech cues in hearing impaired listeners. The basic mechanism is a continuously changing balancing between low- and high-frequency amplification, steered by the input level of each speech part. As a consequence, the system should provide a relatively high amount of amplification to weak high-frequency speech cues. A specific configuration was developed to additionally reduce the negative effect of low-frequency amplification on the detection of high-frequency cues. This type of configuration is called anti-USOM processing as it is meant to compensate for “Upward-Spread-Of-Masking” (USOM) of high-frequency information by low-frequency signal parts. The main goal of the present thesis was to evaluate the effect of the different compression configurations on speech intelligibility in a group of hearing-impaired listeners with moderate-to-severe perceptive high-frequency losses (chapters 4 to 7). Additionally, we have investigated the effect of various types of compression on amplitude-modulated signals and speech(-like) signals (chapters 2 and 3). The acoustical measurements in chapters 2 and 3 provided a good insight in the effect of compression on modulating signals like speech. Speech can be considered as a stream of sounds with a continuously varying spectrum. These spectral differences lead to fluctuations of the envelope of the signal within individual frequency bands. The modulation depth is a measure for the amount of fluctuations. Phoneme compression will normally reduce the amount of fluctuations, resulting in a smaller modulation depth. By comparing the modulation depth in a signal before and after compression, the effective amount of compression can be obtained. This method was applied using an amplitude-modulated signal (chapter 2) and using speech(-like) signals (chapter 3). Another method compared the average level distributions of speech with and without compression (chapter 2). The results show that relatively short time constants were needed to affect the range of modulations that are relevant to speech intelligibility. Furthermore, an effective reduction of intensity differences within separate frequency channels was only possible if the compression was applied within independent frequency channels as well. Interestingly, the results were not only influenced by the compressor settings but also by the acoustical properties of the test signal. Intensity differences were reduced more effectively for speech in a stationary background noise compared to speech only. Chapters 4 and 6 describe the effects of different types of phoneme compression on speech intelligibility in hearing-impaired listeners. Phoneme scores were obtained in conditions with and without background noise. We evaluated the difference in performance between phoneme compression and a linear reference condition near comfortable presentation levels. This implies that the results could not be influenced by differences in overall level between the various conditions. The results described in chapter 4 show that hearing-impaired listeners may benefit from our type of phoneme compression in conditions without background noise. Consonant perception was improved by phoneme compression whereas the anti-USOM processing had an additional positive effect on vowel perception. Unfortunately, no such positive effects were found in conditions with background noise. Even substantially negative effects were found with the anti-USOM configuration that gave the best performance in quiet. The use of a more moderate type of anti-USOM in chapter 6 also resulted in a negative effect on phoneme recognition in background noise. No benefit was found for other types of phoneme compression in background noise. The use of a compression ratio of 4 resulted even in negative effects (chapter 4). This means that the performance in background noise gets poorer with an increasing amount of phoneme compression. The temporal behaviour of the background noise did not influence the results (chapter 6). We hoped to find positive effects from phoneme compression in a fluctuating background noise, but no such improvement was found. The results of chapter 5 can be used to understand the measured effects of compression on speech intelligibility. Two methods were used to analyse the perceptual confusions of chapter 4. INDSCAL was used to identify and visualise the most relevant differences in phoneme perception. However the interpretation of these differences was not always easy because the perceptual dimensions could be related to several perceptual features. Therefore, SINFA was used as a second method. The advantage of using this method was that the various effects could be separated for the different predefined articulatory features. In quiet, positive effects were found on the perception of features containing mainly high-frequency information. This is according to our original goal to improve the identification of high-frequency cues by phoneme compression. However, the perception of high-frequency cues appeared to be highly deteriorated at critical background noise conditions. As a consequence, the features containing low-frequency information had become of major importance. The use of anti-USOM processing removed low-frequency information that appeared to be relevant for the perception of low-frequency cues. Additionally, we evaluated three phoneme compression conditions in a small field study using an experimental body-worn hearing aid (chapter 7). The phoneme compression configurations were embedded in a slow-acting non-linear system to compensate for differences in overall level. The listeners used the system for a period of six weeks next to the own hearing aids. The performance with the various compression programs was measured every week. The main question was if the performance could be influenced by a frequent use of the system. In general, the results were similar to that in previous experiments. The performance in background noise tended to be poorer than the performance in quiet. Interestingly, the overall recognition score with phoneme compression improved over time. However, a large part of this improvement was also found for the reference condition. The tendency for a small additional improvement with phoneme compression may be attributed to acclimatization to the speech processing. The experiences of the hearing-impaired listeners with the phoneme compression programs differed between listeners and depended of the difference in performance with the own hearing aids. Generally they had no problems with the sound of the new programs.