Titel Deelnemers "Korte inhoud" "Hearing configuration in children with cCMV infection and proposal of a flow chart for hearing evaluation" "Ina Foulon, Leen Vleurinck, Kristin Kerkhofs, Frans Gordts" "OBJECTIVE: This study had three main goals: (1) to determine the hearing configuration in hearing-impaired children born with a congenital CMV (cCMV) infection, (2) to see whether auditory neuropathy spectrum disorder (ANSD) was present, and (3) to propose a flow chart for the follow-up of hearing in children with cCMV. DESIGN: Hearing configuration and the presence of ANSD in cCMV infected children was analysed. Selection criteria were: hearing-impaired children with a regular audiometric follow-up for at least 36 months, no other major risk factors for hearing loss, a normal middle-ear status, and an appropriate behavioral response to the given pure-tone stimuli. STUDY SAMPLE: Out of a cohort of 206 cCMV infected children, 18 hearing-impaired children were selected. RESULTS: Audiograms of all children showed a flat configuration of SNHL: the slope between octave bands was never greater than 10 decibels. None of the 18 children were found to have ANSD. CONCLUSIONS: Hearing impairment in cCMV infants affected all frequencies equally and ANSD does not appear to be a feature of cCMV infection. A flow chart for hearing follow-up in children with cCMV infection was suggested in order to provide guidance, improve uniformity in follow-up, and to make results easier to compare." "Left-Right and Front-Back Spatial Hearing with Multiple Directional Microphone Configurations in Modern Hearing Aidsf" "Evelyne Carette, Tim Van den Bogaert, Jan Wouters" "BACKGROUND: Several studies have demonstrated negative effects of directional microphone configurations on left-right and front-back (FB) sound localization. New processing schemes, such as frequency-dependent directionality and front focus with wireless ear-to-ear communication in recent, commercial hearing aids may preserve the binaural cues necessary for left-right localization and may introduce useful spectral cues necessary for FB disambiguation. PURPOSE: In this study, two hearing aids with different processing schemes, which were both designed to preserve the ability to localize sounds in the horizontal plane (left-right and FB), were compared. RESEARCH DESIGN: We compared horizontal (left-right and FB) sound localization performance of hearing aid users fitted with two types of behind-the-ear (BTE) devices. The first type of BTE device had four different programs that provided (1) no directionality, (2-3) symmetric frequency-dependent directionality, and (4) an asymmetric configuration. The second pair of BTE devices was evaluated in its omnidirectional setting. This setting automatically activates a soft forward-oriented directional scheme that mimics the pinna effect. Also, wireless communication between the hearing aids was present in this configuration (5). A broadband stimulus was used as a target signal. The directional hearing abilities of the listeners were also evaluated without hearing aids as a reference. STUDY SAMPLE: A total of 12 listeners with moderate to severe hearing loss participated in this study. All were experienced hearing-aid users. As a reference, 11 listeners with normal hearing participated. DATA COLLECTION AND ANALYSIS: The participants were positioned in a 13-speaker array (left-right, -90°/+90°) or 7-speaker array (FB, 0-180°) and were asked to report the number of the loudspeaker located the closest to where the sound was perceived. The root mean square error was calculated for the left-right experiment, and the percentage of FB errors was used as a FB performance measure. RESULTS were analyzed with repeated-measures analysis of variance. RESULTS: For the left-right localization task, no significant differences could be proven between the unaided condition and both partial directional schemes and the omnidirectional scheme. The soft forward-oriented system and the asymmetric system did show a detrimental effect compared with the unaided condition. On average, localization was worst when users used the asymmetric condition. Analysis of the results of the FB experiment showed good performance, similar to unaided, with both the partial directional systems and the asymmetric configuration. Significantly worse performance was found with the omnidirectional and the omnidirectional soft forward-oriented BTE systems compared with the other hearing-aid systems. CONCLUSIONS: Bilaterally fitted partial directional systems preserve (part of) the binaural cues necessary for left-right localization and introduce, preserve, or enhance useful spectral cues that allow FB disambiguation. Omnidirectional systems, although good for left-right localization, do not provide the user with enough spectral information for an optimal FB localization performance." "Integrating a heat pump into a 4th generation district heating (4GDH) system – Two-mode configuration inputting operational data" "Stanislav V. Chicherin" "The aim is to examine integrating a heat pump (HP) into a district heating (DH) system versus potential savings in the separate scenario. It takes into account all the properties of both DH system and a HP operation, and gives the understanding of temperature, pressure and enthalpy of refrigerant at each cycle point. Contribution to the pool of knowledge is considering a novel configuration, which allows to get rid of a heat exchanger between the water-source HP and the network. Scenarios of (i) separate operation of a HP, and (ii) integrating it into a DH system and inputting design data only, or (iii) utilizing operational data have been analyzed. Multiple thermal simulations have been performed. We also allow traditional coverage of heat demand with the help of a supply line of high-temperature DH (HTDH), thus elaborated what happens when the outdoor air temperature drops below lower threshold. Hence, the model identifies two stages of operating a HP integrated into a DH system. Starting from it, the temperature of the supply water should be 50 °C and above, so it is more effective to use supply water directly until the outdoor temperature rises again. This outdoor temperature implies change of operational mode, which leads to the following results. On cold winter days, the available amount of heat is lower than the energy consumption, therefore, energy from a supply line of HTDH is utilized, which gives overall energy saving effect of about 14 %. Mass flow rates through the configuration suggested are identical during moderate-cold fall and spring days, since the control logic is established with the help of variation of supply temperature only. Single HP has the lowest efficiency because of high temperatures needed: with a nominal temperature difference of 25 °C, the coefficient of performance (COP) rises to 5.0 only. At the break-even point, HP in each configuration has COP ranging between 3.51 and 4.43, while the rest of the time COP is just above 2. In different cases, the lowest threshold of HP's performance is 2.4, 2.6, and 2.89, respectively. The DH-assisted scenario, where peak energy demand was covered by DH system directly, clearly outperformed separate installation, where a HP was the only thing responsible to provide the necessary supply temperatures. For this case, lower COP stipulates less energy is supplied from the DH system, and therefore a lower share of consumption is supplied directly from supply line, which decreases the overall seasonal COP. Scenario (iii) of inputting DH operational data has the highest seasonal COPs, reasoned to higher than design return temperatures. Given the low performance of a HP raising water temperature to 55 °C (the lowest threshold acceptable in winter) a single HP with no backup capacity accounts for 23 % more energy use. Supported by a coal-fired combined heat-and-power plant, distribution of primary energy consumption is more favorable, i.e. coal-fired generation covers the peak. The positive effect is expanded by converting a part of heat demand from HP operation to cheaper HTDH operation." "Design and cost comparison of district heating and cooling (DHC) network configurations using ring topology : a case study" "Joseph Stalin Maria Jebamalai, Kurt Marlein, Jelle Laverge" "District heating systems are evolved from steam systems (1st generation) to low temperature water based systems (4th generation) and pilot projects are coming out on ultra-low temperature systems along with building side heat pumps (5th generation). Some of the notable features of future (4th and 5th generation) district heating and cooling (DHC) networks are the integration of distributed low-temperature sources, combined DHC systems, integrated heat and cold storage, and usage of heat pumps at building side. The design of large-scale DHC networks with all these features poses many challenges. In this paper, a method to design 3-pipe DHC networks and ultra-low temperature DHC networks using a ring network configuration will be described and their network costs are compared. The developed method is implemented as a proof of concept in the DHC design tool, Comsof Heat and a case study is developed to design and compare these two configurations and study the effect on the network cost. Based on the case study results, the network deployment cost of ultra-low temperature DHC ring networks is around 23% costlier than the 3rd generation ring networks. Moreover, the ultra-low temperature (5th generation) networks are economically attractive only if there is a free low temperature waste heat source." "The clinical value of the multiple-frequency 80-Hz auditory steady-state response in adults with normal hearing and hearing loss" "Wendy D'Haenens, Hannah Keppler, Birgit Philips, Freya Swinnen" "Objectives: To determine the ability of the air-conduction multiple-frequency auditory steady-state response (ASSR) technique to diagnose normal hearing (NH) and mild and moderate degrees of sensorineural hearing loss (SNHL), to assess patients with conductive hearing loss (CHL), to evaluate flat and sloping configurations of hearing impairment, and to provide sensitivity and specificity values for various ASSR cutoff criteria. Design: A comparative study between ASSR and criterion-standard behavioral thresholds. Setting: Ear, nose, and throat department at a university hospital. Patients: The study population comprised 40 adults with NH, 17 with SNHL, and 7 with CHL. Main Outcome Measures: The measure of interest was the difference between ASSR and behavioral thresholds at 0.5, 1.0, 2.0, and 4.0 kHz. The sensitivity, specificity, positive predictive value, negative predictive value, and efficiency were calculated for several ASSR cutoff criteria. Results: The ASSR technique clearly distinguished moderate SNHL from NH, but the ""mild SNHL and NH"" and ""mild SNHL and moderate SNHL"" differentiation was particularly difficult at 0.5 and 2.0 kHz, respectively. Air-conduction ASSR thresholds accurately predicted behavioral thresholds in CHL. The ASSR system precisely reflected the flat and sloping configurations. Finally, the most appropriate ASSR cutoff point for normality seems to be the 30-dB-or-lower criterion. Conclusions: In adults, the multiple-frequency 80-Hz ASSR technique can be used to determine the degree and configuration of hearing loss. Although air-conduction ASSR thresholds accurately predicted behavioral thresholds in CHL, future research with bone-conduction ASSRs is necessary to establish the type of hearing loss. Furthermore, the applicability of these findings still needs to be confirmed for infants." "Incidence of congenital CMV in children at a hearing rehabilitation center." "I Courtmans, V Mancilla, C Ligny, SD Le Bon , Anne Naessens, Ina Foulon" "OBJECTIVE: This study had three main goals: (1) to determine the hearing configuration in hearing-impaired children born with a congenital CMV (cCMV) infection, (2) to see whether auditory neuropathy spectrum disorder (ANSD) was present, and (3) to propose a flow chart for the follow-up of hearing in children with cCMV. DESIGN: Hearing configuration and the presence of ANSD in cCMV infected children was analysed. Selection criteria were: hearing-impaired children with a regular audiometric follow-up for at least 36 months, no other major risk factors for hearing loss, a normal middle-ear status, and an appropriate behavioral response to the given pure-tone stimuli. STUDY SAMPLE: Out of a cohort of 206 cCMV infected children, 18 hearing-impaired children were selected. RESULTS: Audiograms of all children showed a flat configuration of SNHL: the slope between octave bands was never greater than 10 decibels. None of the 18 children were found to have ANSD. CONCLUSIONS: Hearing impairment in cCMV infants affected all frequencies equally and ANSD does not appear to be a feature of cCMV infection. A flow chart for hearing follow-up in children with cCMV infection was suggested in order to provide guidance, improve uniformity in follow-up, and to make results easier to compare." "Nonmuscle Myosin Heavy Chain IIA Mutation Predicts Severity and Progression of Sensorineural Hearing Loss in Patients With MYH9-Related Disease" "Eva J J Verver, Vedat Topsakal, Henricus P M Kunst, Patrick L M Huygen, Paula G Heller, Nuria Pujol-Moix, Anna Savoia, Marco Benazzo, Tiziana Fierro, Wilko Grolman, Paolo Gresele, Alessandro Pecci" "OBJECTIVES: MYH9-related disease (MYH9-RD) is an autosomal- dominant disorder deriving from mutations in MYH9, the gene for the nonmuscle myosin heavy chain (NMMHC)-IIA. MYH9-RD has a complex phenotype including congenital features, such as thrombocytopenia, and noncongenital manifestations, namely sensorineural hearing loss (SNHL), nephropathy, cataract, and liver abnormalities. The disease is caused by a limited number of mutations affecting different regions of the NMMHC-IIA protein. SNHL is the most frequent noncongenital manifestation of MYH9-RD. However, only scarce and anecdotal information is currently available about the clinical and audiometric features of SNHL of MYH9-RD subjects. The objective of this study was to investigate the severity and propensity for progression of SNHL in a large series of MYH9-RD patients in relation to the causative NMMHC-IIA mutations.DESIGN: This study included the consecutive patients diagnosed with MYH9-RD between July 2007 and March 2012 at four participating institutions. A total of 115 audiograms were analyzed from 63 patients belonging to 45 unrelated families with different NMMHC-IIA mutations. Cross-sectional analyses of audiograms were performed. Regression analysis was performed, and age-related typical audiograms (ARTAs) were derived to characterize the type of SNHL associated with different mutations.RESULTS: Severity of SNHL appeared to depend on the specific NMMHC-IIA mutation. Patients carrying substitutions at the residue R702 located in the short functional SH1 helix had the most severe degree of SNHL, whereas patients with the p.E1841K substitution in the coiled-coil region or mutations at the nonhelical tailpiece presented a mild degree of SNHL even at advanced age. The authors also disclosed the effects of different amino acid changes at the same residue: for instance, individuals with the p.R702C mutation had more severe SNHL than those with the p.R702H mutation, and the p.R1165L substitution was associated with a higher degree of hearing loss than the p.R1165C. In general, mild SNHL was associated with a fairly flat audiogram configuration, whereas severe SNHL correlated with downsloping configurations. ARTA plots showed that the most progressive type of SNHL was associated with the p.R702C, the p.R702H, and the p.R1165L substitutions, whereas the p.R1165C mutation correlated with a milder, nonprogressive type of SNHL than the p.R1165L. ARTA for the p.E1841K mutation demonstrated a mild degree of SNHL with only mild progression, whereas the ARTA for the mutations at the nonhelical tailpiece did not show any substantial progression.CONCLUSIONS: These data provide useful tools to predict the progression and the expected degree of severity of SNHL in individual MYH9-RD patients, which is especially relevant in young patients. Consequences in clinical practice are important not only for appropriate patient counseling but also for development of customized, genotype-driven clinical management. The authors recently reported that cochlear implantation has a good outcome in MYH9-RD patients; thus, stricter follow-up and earlier intervention are recommended for patients with unfavorable genotypes." "Acquisition of subcortical auditory potentials with around-the-Ear cEEGrid technology in normal and hearing impaired listeners" "Markus Garrett, Stefan Debener, Sarah Verhulst" "Even though the principles of recording brain electrical activity remain unchanged since their discovery, their acquisition has seen major improvements. The cEEGrid, a recently developed flex-printed multi-channel sensory array, can be placed around the ear and successfully record well-known cortical electrophysiological potentials such as late auditory evoked potentials (AEPs) or the P300. Due to its fast and easy application as well as its long-lasting signal recording window, the cEEGrid technology offers great potential as a flexible and 'wearable' solution for the acquisition of neural correlates of hearing. Early potentials of auditory processing such as the auditory brainstem response (ABR) are already used in clinical assessment of sensorineural hearing disorders and envelope following responses (EFR) have shown promising results in the diagnosis of suprathreshold hearing deficits. This study evaluates the suitability of the cEEGrid electrode configuration to capture these AEPs. cEEGrid potentials were recorded and compared to cap-EEG potentials for young normal-hearing listeners and older listeners with high-frequency sloping audiograms to assess whether the recordings are adequately sensitive for hearing diagnostics. ABRs were elicited by presenting clicks (70 and 100-dB peSPL) and stimulation for the EFRs consisted of 120 Hz amplitudemodulated white noise carriers presented at 70-dB SPL. Data from nine bipolar cEEGrid channels and one classical cap-EEG montage (earlobes to vertex) were analysed and outcome measures were compared. Results show that the cEEGrid is able to record ABRs and EFRs with comparable shape to those recorded using a conventional capEEG recording montage and the same amplifier. Signal strength is lower but can still produce responses above the individual neural electrophysiological noise floor. This study shows that the application of the cEEGrid can be extended to the acquisition of early auditory evoked potentials." "Spatial speech perception benefits in young children with normal hearing and cochlear implants" "Lieselot Van Deun, Astrid van Wieringen, Jan Wouters" "OBJECTIVES: Several studies have demonstrated better speech perception performance in children using two rather than one cochlear implant (CI). The extent to which bilaterally implanted children benefit from binaural cues to segregate speech and noise in a spatial configuration is less clear. Although better-ear effects are expected to be similar to adults, it is unknown whether electrical stimulation allows true binaural processing of speech signals in noise. Moreover, little data are available on the binaural hearing abilities of normal-hearing children. This study aimed at (1) developing and evaluating a speech test based on numbers to determine speech reception thresholds (SRTs) fast and accurately in young children, (2) evaluating a setup for measuring benefits of speech perception in a spatial configuration in young children and determining normative values of normal-hearing children, and (3) measuring spatial speech benefits in cochlear-implanted children with good sound localization abilities.DESIGN: The speech test was conducted using the Leuven Intelligibility Number Test (LINT) data base. The test was limited to the numbers 1 to 10 spoken by one female speaker (""LittleLINT""). The LINT speech-weighted noise was used as a masker. Perception of this speech material was evaluated at fixed signal-to-noise ratios (SNRs) through monaural presentation via headphones in 34 normal-hearing children of 4 and 5 yrs of age and 20 normal-hearing adults. Subsequently, spatial speech perception benefits were measured in 50 normal-hearing children between 4 and 8 yrs of age, 15 normal-hearing adults, and eight children with bilateral CIs. An adaptive procedure was used for estimating unilateral and bilateral SRTs for different spatial configurations of speech and noise. Speech was always presented at 0 degrees azimuth (the front) and noise at the front, 90 degrees to the right, or 90 degrees to the left.RESULTS: Unilateral headphone SRTs for the LittleLINT were higher for children (-9 dB SNR) than for adults (-13 dB SNR) and were lower than those for the LINT (-10 dB SNR for adults). Slopes (12 to 14%/dB) were comparable with that of the LINT (15%/dB), suggesting equal efficiency for the limited set of numbers. Normal-hearing subjects demonstrated several benefits of two-ear listening in spatial configurations (spatial release from masking [SRM], head shadow, summation, and squelch). Only SRM was influenced by age. Implanted children clearly benefited from bilateral implantation, as shown by SRM (3 dB) and head shadow effects (4 to 6 dB) comparable with normal-hearing children, but no summation or binaural squelch was established. The first CI seemed to contribute most to spatial speech perception.CONCLUSIONS: The steep slope, the familiarity to children, and the repeatability of lists make the LittleLINT suitable for fast and accurate SRT estimation in children. Spatial speech perception benefits were observed in normal-hearing subjects from the age of 4 yrs. Cochlear-implanted children showed better-ear effects but there was no evidence of true binaural processing." "Spatial speech perception benefits in young children with normal hearing and cochlear implants" "Lieselot Van Deun, Astrid van Wieringen, Jan Wouters" "OBJECTIVES: Several studies have demonstrated better speech perception performance in children using two rather than one cochlear implant (CI). The extent to which bilaterally implanted children benefit from binaural cues to segregate speech and noise in a spatial configuration is less clear. Although better-ear effects are expected to be similar to adults, it is unknown whether electrical stimulation allows true binaural processing of speech signals in noise. Moreover, little data are available on the binaural hearing abilities of normal-hearing children. This study aimed at (1) developing and evaluating a speech test based on numbers to determine speech reception thresholds (SRTs) fast and accurately in young children, (2) evaluating a setup for measuring benefits of speech perception in a spatial configuration in young children and determining normative values of normal-hearing children, and (3) measuring spatial speech benefits in cochlear-implanted children with good sound localization abilities. DESIGN: The speech test was conducted using the Leuven Intelligibility Number Test (LINT) data base. The test was limited to the numbers 1 to 10 spoken by one female speaker (""LittleLINT""). The LINT speech-weighted noise was used as a masker. Perception of this speech material was evaluated at fixed signal-to-noise ratios (SNRs) through monaural presentation via headphones in 34 normal-hearing children of 4 and 5 yrs of age and 20 normal-hearing adults. Subsequently, spatial speech perception benefits were measured in 50 normal-hearing children between 4 and 8 yrs of age, 15 normal-hearing adults, and eight children with bilateral CIs. An adaptive procedure was used for estimating unilateral and bilateral SRTs for different spatial configurations of speech and noise. Speech was always presented at 0 degrees azimuth (the front) and noise at the front, 90 degrees to the right, or 90 degrees to the left. RESULTS: Unilateral headphone SRTs for the LittleLINT were higher for children (-9 dB SNR) than for adults (-13 dB SNR) and were lower than those for the LINT (-10 dB SNR for adults). Slopes (12 to 14%/dB) were comparable with that of the LINT (15%/dB), suggesting equal efficiency for the limited set of numbers. Normal-hearing subjects demonstrated several benefits of two-ear listening in spatial configurations (spatial release from masking [SRM], head shadow, summation, and squelch). Only SRM was influenced by age. Implanted children clearly benefited from bilateral implantation, as shown by SRM (3 dB) and head shadow effects (4 to 6 dB) comparable with normal-hearing children, but no summation or binaural squelch was established. The first CI seemed to contribute most to spatial speech perception. CONCLUSIONS: The steep slope, the familiarity to children, and the repeatability of lists make the LittleLINT suitable for fast and accurate SRT estimation in children. Spatial speech perception benefits were observed in normal-hearing subjects from the age of 4 yrs. Cochlear-implanted children showed better-ear effects but there was no evidence of true binaural processing."