Leo De Raeve

Sound localization, sound lateralization, and binaural masking level differences in young children with normal hearing.

Objectives: In this study, procedures for measuring sound localization, sound lateralization, and binaural masking level differences (BMLDs) in young children were developed. Sensitivity for these tasks was assessed in large groups of children between 4 and 9 yr of age to investigate potential developmental trends. Design: Sound localization was measured in the sound field, with a broadband bell-ring presented from one of nine loudspeakers positioned in the frontal horizontal field. A group of 33 children between 4 and 6 yr of age and 5 adults took part in this experiment. Sound lateralization based on interaural time differences was measured with headphones in 49 children between 4 and 9 yr of age and 10 adults. A low-frequency stimulus containing harmonics 2 to 5 from a click train with a rate of 160 Hz was used. In the BMLD test, the same filtered click train was presented diotically or dichotically (phase reversed or time delayed) in a broadband (200 to 1000 Hz) frozen noise to 23 children between 4 and 6 yr of age and 10 adults. For comparison with literature, additional measurements with a 500-Hz sinusoid were administered to adults. All tasks were adapted to the interest and attention span of young children. Results: Children of 5 yr of age did not perform significantly different from adults on the sound localization task, but mean absolute errors were larger for the 4-yr-olds. Also on the BMLD task, 5-yr-old children performed at the adult level, whereas the 4-yr-old children obtained significantly less binaural unmasking compared with the adults. Concerning sound lateralization, a small but significant difference between adults and children existed, but no age effects were apparent in the 4- to 9-yr-old group. Overall, the variation was relatively large in the 4-yr-old group, with some of the children performing at adult level, in all three tasks. Conclusions: The results of this study show that the modified procedures are suitable for testing children from the age of 4 to 5 yr. Furthermore, it seems that binaural hearing capacities of the 5-yr-olds are similar to those of adults. Several observations led to the hypothesis that the observed age differences between 4-yr-olds and older subjects on localization and BMLD or between those 4- to 9-yr old and adults on lateralization, were attributable to both a development in binaural hearing and to nonauditory factors, such as task comprehension, attention, and testing conditions. It is possible that the developmental process is more obvious and prolonged in other aspects of binaural hearing, which require more dynamic or more central processing.

Expressive Vocabulary, Morphology, Syntax and Narrative Skills in Profoundly Deaf Children after Early Cochlear Implantation.

Practical experience and research reveal generic spoken language benefits after cochlear implantation. However, systematic research on specific language domains and error analyses are required to probe sub-skills. Moreover, the effect of predictive factors on distinct language domains is unknown. In this study, outcomes of 70 school-aged children with cochlear implants were compared with hearing peers. Approximately half of the children with cochlear implants achieved age-adequate language levels. Results did not reveal systematic strong or weak language domains. Error analyses showed difficulties with morphological and syntactic rules and inefficient narrative skills. Children without additional disabilities who received early intervention were raised with one spoken language, and used a second cochlear implant or contralateral hearing aid were more likely to present good language skills.

Emotion Understanding in Deaf Children with a Cochlear Implant

It is still largely unknown how receiving a cochlear implant affects the emotion understanding in deaf children. We examined indices for emotion understanding and their associations with communication skills in children aged 2.5-5 years, both hearing children (n = 52) and deaf children with a cochlear implant (n = 57). 2 aspects of emotion understanding were examined: (a) emotion recognition in facial expressions and (b) emotion attribution in a situational context. On all emotion-understanding tasks, children with a cochlear implant were less proficient than children with normal hearing. In children with normal hearing, performance and language skills were positively associated. In children with cochlear implants, language was positively associated only with tasks in which a verbal demand was made on children. These findings indicate that hearing loss in children, despite a cochlear implant, affects all aspects of emotion understanding measured in this study, including their nonverbal emotion-understanding skills.

Impact of newborn hearing screening: comparing outcomes in pediatric cochlear implant users.

To evaluate the impact of a newborn hearing screening program on the management and outcome of deaf children and to identify underlying factors that may be responsible for the differences between high and low performing implanted children.

Bilateral cochlear implants in children: binaural unmasking.

Bilateral cochlear implants (CIs) may offer deaf children a range of advantages compared to unilateral CIs. However, speech perception in noise is mainly facilitated by better-ear effects and much less by interaural comparisons or true ‘binaural’ hearing. Little is known about the development of the binaural auditory system with CIs provided at a young age. It is possible that, as with adults, binaural sensitivity exists but is not accessed due to technical limitations in electrical stimulation methods. In this paper, we present results on binaural hearing in children with bilateral CIs. Binaural masking level differences (BMLDs) were measured for a 180-degree phase shift in a 125-Hz sinusoid, presented in a 50-Hz-wide noise band and modulating a 1000-pps carrier pulse train. Stimuli were presented to a single electrode in the middle of the electrode array at both ears. Eight children between 6 and 15 years of age participated in this study. Six children had a significantly better detection threshold when the signal was out of phase (dichotic) between two ears than when it was in phase (diotic), with a mean difference (BMLD) of 6.4 dB. The present results show that children with bilateral CIs are sensitive to binaural cues in electrical stimuli, similar to adults, even when implants are provided at a later age and with a longer delay between implantations.

Functional outcome of sequential bilateral cochlear implantation in young children: 36 months postoperative results §

OBJECTIVE To examine the effects of sequential bilateral cochlear implantation (CI) on the life of young children after 36 months of bilateral implant use. METHOD Thirty-five children were assessed prior to and 3 until 36 months after activation of the second CI. Main outcome measures were: the Categories of Auditory Performance (CAP), Speech Intelligibility Rating (SIR), communication mode, classroom placement, parent reports and the Würzburg questionnaire. Results were analysed separately for children younger and older than 6 years at the time of the second implantation. RESULTS At the 3-year test interval, 80% of the younger children attended mainstream schools and were comprehensible for all listeners. They all used oral communication and almost 70% of them could have a conversation over the telephone. After 3 years of bilateral implant use less than 50% of the older children obtained the highest score on the SIR and CAP. Approximately 70% of them was integrated in mainstream schools and used oral communication. All parents reported a more natural communication and an improved quality of life. CONCLUSIONS Sequential bilateral implantation seems to offer a wide range of participation benefits to all children and facilitates the social intercourse with their hearing environment.

Three-Year Postimplantation Auditory Outcomes in Children With Sequential Bilateral Cochlear Implantation

Objectives: We report on the auditory abilities and speech performance in quiet and noise of 35 children with sequential bilateral cochlear implantation after 3 years of bilateral implant use. Methods: Testing was done in bilateral and both unilateral listening conditions. The assessments took place before the second implantation and at several time intervals after fitting. As different auditory tests were used, the children were categorized by their age at the second implantation: Younger or older than 6 years. Results: The pure tone averages for the bilateral condition were significantly better than those for either unilateral condition after 12 months of bilateral implant use and remained so from that test interval onward. The speech recognition outcomes in quiet and noise also improved significantly for almost all children after 36 months, although a linear regression analysis showed a beneficial effect of younger age at first implantation on the speech-in-noise results. Conclusions: Bilateral cochlear implantation offered advantages to all children in comparison with the first implant — Even the children who received the second implant after the age of 6 years. Compared to the younger children, the older children needed a longer adjustment period to gain bilateral benefit. However, they obtained similar results after 2 years of bilateral implant use.

Narrative spoken language skills in severely hearing impaired school-aged children with cochlear implants

Cochlear implants have a significant positive effect on spoken language development in severely hearing impaired children. Previous work in this population has focused mostly on the emergence of early-developing language skills, such as vocabulary. The current study aims at comparing narratives, which are more complex and later-developing spoken language skills, of a contemporary group of profoundly deaf school-aged children using cochlear implants (n=66, median age=8 years 3 months) with matched normal hearing peers. Results show that children with cochlear implants demonstrate good results on quantity and coherence of the utterances, but problematic outcomes on quality, content and efficiency of retold stories. However, for a subgroup (n=20, median age=8 years 1 month) of deaf children without additional disabilities who receive cochlear implantation before the age of 2 years, use two implants, and are raised with one spoken language, age-adequate spoken narrative skills at school-age are feasible. This is the first study to set the goals regarding spoken narrative skills for deaf children using cochlear implants.

Anxiety in children with hearing aids or cochlear implants compared to normally hearing controls

The objectives of this study were to examine the levels of anxiety in hearing‐impaired children with hearing aids or cochlear implants compared to normally hearing children, and to identify individual variables that were associated with differences in the level of anxiety.

Subjective benefits of sequential bilateral cochlear implantation in young children after 18 months of implant use

Objective: To investigate the subjective benefits of bilateral cochlear implantation in 33 young children after 18 months of second implant use. Method: The Würzburg questionnaire inquiring into a range of hearing functions was filled out by the parents. Additional data concerning the daily life and well-being of the children were gathered with an open-ended questionnaire and the Categories of Auditory Performance. Results were analyzed separately for children younger and older than 6 years at the time of the second implantation. Results: After 18 months of bilateral implant use 30% of the younger and 6% of the older children made the transition to an auditory-oral communication. In this period, 15% of all children switched to mainstream schools. The parents reported an evolution of their children’s auditory abilities, which included a better sound and speech perception. Multiregression analysis revealed that early hearing aid fitting and the age at the second cochlear implantation significantly contributed to the variance of the Würzburg results. Conclusions: The results indicate a wide range of positive subjective changes associated with bilateral cochlear implantation, even in older children. This progress led to a better and easier communication and a better integration in the normal-hearing world.