A longitudinal study of the bilateral benefit in children with bilateral cochlear implants

Objective: To study the development of the bilateral benefit in children using bilateral cochlear implants by measurements of speech recognition and sound localization. Design: Bilateral and unilateral speech recognition in quiet, in multi-source noise, and horizontal sound localization was measured at three occasions during a two-year period, without controlling for age or implant experience. Longitudinal and cross-sectional analyses were performed. Results were compared to cross-sectional data from children with normal hearing. Study sample: Seventy-eight children aged 5.1–11.9 years, with a mean bilateral cochlear implant experience of 3.3 years and a mean age of 7.8 years, at inclusion in the study. Thirty children with normal hearing aged 4.8–9.0 years provided normative data. Results: For children with cochlear implants, bilateral and unilateral speech recognition in quiet was comparable whereas a bilateral benefit for speech recognition in noise and sound localization was found at all three test occasions. Absolute performance was lower than in children with normal hearing. Early bilateral implantation facilitated sound localization. Conclusions: A bilateral benefit for speech recognition in noise and sound localization continues to exist over time for children with bilateral cochlear implants, but no relative improvement is found after three years of bilateral cochlear implant experience.     

The role of the promontory stimulation test in cochlear implantation

Abstract

To date, 290 adults have been implanted in the cochlear implant programme in Sydney (Australia), where the promontory stimulation test (PST) is routinely used to assess implant candidacy. There has been much controversy over the exact role and value of this test. Pre- and postoperative speech comprehension tests of 150 implantees were analysed, and scores were compared with preoperative PST performances. Eighty-nine per cent of the patients perceived sound when the promontory was stimulated electrically. This group of implantees scored 81% on CID speech tests at 12 months postoperatively, compared to the minority who lacked preoperative promontory stimulability, who scored 42%. The PST is therefore predictive of greater speech benefits after implantation. It also provides an important psychophysical experience of hearing electrical sound.     

听障幼儿人工耳蜗植入术后追赶发育实施效果

目的探讨运用健听小儿听能言语发育进程规律,加速听障幼儿人工耳蜗术后的感知觉发育进程。方法选择1.5～3岁人工耳蜗植入幼儿33例。进行为期5～6个月的听觉言语训练后,考察其追赶发育实施效果。结果听觉感受能力、语言表达能力均有显著改善。结论运用小儿生长发育规律,对听障幼儿实施追赶发育,可缩短开机后听能感知时间,使其尽快在大脑中形成听觉记忆。     

中国人工耳蜗植入儿童前语言交流能力发育研究

目的:探讨中国人工耳蜗植入儿童前语言交流能力的发展规律,为早期预测康复效果及制定合理的康复训练计划提供依据.方法:30例接受人工耳蜗植入手术的语前聋儿童参与本次研究,术前均为极重度聋.所有患儿使用人工耳蜗的时间均在12个月以内,平均5.8个月.使用录像分析法对患儿的轮流交流、主动交流、视觉交流及听觉注意等4项前语言交流能力进行分析和评估.结果:患儿的轮流交流能力呈快速增长趋势,其中有声回应能力也以相同的方式增长,而以肢体动作进行的回应则呈缓慢降低趋势.患儿主动交流和适时的视觉交流能力得分较低,呈缓慢增长,听觉注意能力呈逐步增长趋势.结论:随着人工耳蜗使用时间的增加,患儿初步建立起了"听/说"的交流模式,并越来越倾向于以发声的方式进行交流.录像分析法可用于评估中国人工耳蜗植入患儿前语言期交流能力.     

Modulation Enhancement in the Electrical Signal Improves Perception of Interaural Time Differences with Bimodal Stimulation

Interaural timing cues are important for sound source localization and for binaural unmasking of speech that is spatially separated from interfering sounds. Users of a cochlear implant (CI) with residual hearing in the non-implanted ear (bimodal listeners) can only make very limited use of interaural timing cues with their clinical devices. Previous studies showed that bimodal listeners can be sensitive to interaural time differences (ITDs) for simple single- and three-channel stimuli. The modulation enhancement strategy (MEnS) was developed to improve the ITD perception of bimodal listeners. It enhances temporal modulations on all stimulated electrodes, synchronously with modulations in the acoustic signal presented to the non-implanted ear, based on measurement of the amplitude peaks occurring at the rate of the fundamental frequency in voiced phonemes. In the first experiment, ITD detection thresholds were measured using the method of constant stimuli for five bimodal listeners for an artificial vowel, processed with either the advanced combination encoder (ACE) strategy or with MEnS. With MEnS, detection thresholds were significantly lower, and for four subjects well within the physically relevant range. In the second experiment, the extent of lateralization was measured in three subjects with both strategies, and ITD sensitivity was determined using an adaptive procedure. All subjects could lateralize sounds based on ITD and sensitivity was significantly better with MEnS than with ACE. The current results indicate that ITD cues can be provided to bimodal listeners with modified sound processing.     

A longitudinal study of electrical stimulation levels and electrode impedance in children using the Clarion cochlear implant

Conclusions. Electrical stimulation levels and electrode impedance values (EIVs) in children using the Clarion cochlear implant (CI) programmed with CIS strategy stabilized after 3 months of implant use. The data presented here may be useful as a general guideline for the programming of infants and young children and may further be of help for the identification of patients who fall outside the “average” range. Objectives. The purpose of the present study was to evaluate changes in electrical stimulation levels, i.e. threshold (T) levels, comfortable (M) levels, dynamic range (DR), and EIVs during the first 18 months of implant use, in children using the Clarion CI. Materials and methods. The maps of 18 pre-lingual children (mean age at implantation 4.2 years; range 1–8), using the Enhanced Bipolar 1.2 or Bipolar standard electrode with the S-Series speech processor programmed with CIS strategy, were examined at five time points: connection, and 3, 6, 12, and 18 months post-initial stimulation. T levels, M levels, DR and EIVs were analyzed according to four cochlear segments: apical, apical-medial, medial-basal, and basal. Results. During the first 3 months of implant use T levels increased to some extent, whereas M levels and DR increased significantly. From 3 months and through the entire follow-up, T and M levels as well as DR were stable. EIVs of current carrying electrodes decreased significantly from connection to the 3-month visit; thereafter a stabilization of values was evident. Electrical stimulation levels and EIVs did not differ among the cochlear segments during the entire follow-up.     

Comparison of the development of early auditory and preverbal skills in Mandarin-Speaking children with cochlear implants with and without additional disabilities

Abstract

Background: Few studies had assessed the auditory and preverbal skills of very young cochlear implant (CI) children with additional disabilities (AD) over a long period, especially in China.

Aims/Objectives: The aim of this study was to compare the early auditory and preverbal developmental trajectories in CI children with and without AD.

Material and Methods: The LittlEARS^® Auditory Questionnaire (LEAQ) was employed. 29 typically developing (TD) children and 17 with AD were involved (age at implantation less than 2?years).

Results: All children showed significant improvement in total LEAQ scores with CI use. Children with cerebral palsy (CP), developmental delay (DD) and white matter lesions (WML) scored lower than TD children since 3?months of CI use; a decreasing trend was observed from 24, 18 and 18?months of CI use, respectively. Children with higher nonverbal developmental quotients exhibited superior early auditory and preverbal skills.

Conclusions and significance: The development of early auditory and preverbal skills among CI-using children progressed more slowly in those with AD (CP, DD or WML) than in TD children, but the differences between the two groups gradually diminished over time. Nonverbal cognitive status has a positive effect on early auditory and preverbal abilities.     

The relationships among verbal ability,executive function,and theory of mind in young children with cochlear implants

Abstract

This study aims to examine the complex relationships among verbal ability (VA), executive function (EF), and theory of mind (ToM) in young Chinese children with cochlear implants (CCI). All participants were tested using a set of nine measures: one VA, one non-VA, three EF, and four ToM. Our study cohort comprised 82 children aged from 3.8 to 6.9?years, including 36 CCI and 46 children with normal hearing (CNH). CNH outperformed CCI on measures of VA, EF, and ToM. One of the EF tasks, inhibitory control, was significantly associated with ToM after controlling for VA. VA was the primary predictor of EF, while inhibitory control significantly predicted ToM. Our findings suggest that inhibitory control explains the association between EF and ToM, thereby supporting the hypothesis that EF may be a prerequisite for ToM.     

The development of hearing in prelingually deaf children with white matter changes in the first year after cochlear implantation

Abstract

Background: The development of hearing and plasticity of brain after cochlear implantation (CI) for prelingually deaf children with white matter changes (group A) is unclear.

Objective: To investigate the development of hearing for children in group A during 1 year after CI activation, compared with non-complicated peers (group B).

Materials and methods: Twenty-one and 22 children (average age is about 5 years old) were included in groups A and B, respectively. Questionnaires were used to assess the hearing ability at pre-CI, 1, 6 and 12 months after CI activation (called Mpre, M1, M6, M12 for short). In addition, MMRs to pure tones were investigated at the same three time points after CI.

Results: There is no significant difference in scores on questionnaires, MMR incidence, latency or amplitude between children in two groups. Scores on questionnaires showed a significant progressive improvement in two groups during the first year after CI. Furthermore, MMR incidence at M6 was significantly higher than that at M1, and MMR latency at M12 was significantly shorter than that at M1.

Conclusions and significance: Prelingually deaf children with white matter changes achieved rapid development and comparable outcomes with CI peers over the first year after CI.     

A comparison of the speech recognition and pitch ranking abilities of children using a unilateral cochlear implant, bimodal stimulation or bilateral hearing aids

Objective

The present study compared the speech recognition and pitch ranking abilities of normally hearing children (n = 15) to children using a cochlear implant (CI) alone (n = 8), bilateral hearing aids (HAs) (n = 6), or bimodal stimulation (BMS) (n = 9). It was hypothesised that users of BMS would score higher on tasks of speech and pitch perception than children using a CI alone, but not children using HAs.

Methods

Participants were assessed on tasks of monosyllabic word recognition in quiet, sentence recognition in quiet and noise (10 dB signal-to-noise ratio), and a pitch ranking task using pairs of sung vowels one, half, and a quarter of an octave apart.

Results

There were no significant differences between the mean percentage-correct scores of the four participant groups for either words in quiet or sentences in quiet and noise. However, the proportion of bimodal users who scored >80% correct (80%) was significantly greater than the proportion of high-scoring unilateral CI (25%) or bilateral HA users (17%). Contrary to expectations, there was also no significant difference between the pitch ranking scores of users of BMS and users of a CI alone for all three interval sizes (p < 0.05, RM-ANOVA). However participants using only acoustic hearing (i.e. the NH and HA groups) scored significantly higher than participants using electrical stimulation (i.e. the CI and BMS groups) on the pitch ranking task (p < 0.05; RM-ANOVA).

Conclusions

Contrary to findings in postlingually deafened adults, we found no significant bimodal advantage for pitch perception in prelingually deafened children. However, the performance of children using electrical stimulation was significantly poorer than children using only acoustic stimulation. Further research is required to investigate the contribution of the non-implanted ears of users of BMS to pitch perception, and the effect of hearing loss on the development of pitch perception in children.