Connexin 26 (GJB2) gene-related deafness and speech intelligibility after cochlear implantation.

HYPOTHESIS: Speech intelligibility in children after cochlear implantation may depend on their deafness cause, including connexin 26 (GJB2) gene-related deafness. BACKGROUND: There is significant variability in the degree of intelligibility, or clarity, of children's speech after cochlear implantation. GJB2 gene-related deafness may be a factor, as preliminary data suggest that pathologic changes do not affect the spiral ganglion cells, which are the neural elements stimulated by the implant, thus favoring better results. METHODS: In an observational retrospective cohort study of pediatric cochlear implantees, 38 patients with nonsyndromic deafness of unknown cause and 1 with keratitisichthyosis-deafness syndrome underwent GJB2 mutation analysis using polymerase chain reaction amplification and direct sequencing. The primary outcome measure assessed was Speech Intelligibility Rating score from postoperative Year 1 (n = 39) to Year 5 (n = 17). Educational setting was considered as a secondary outcome measure. Statistical analysis was double-blinded, with patients and assessors of outcome unaware of GJB2 status. RESULTS: Fourteen patients had GJB2-related deafness and 25 had GJB2-unrelated deafness. Comparisons at Year 3 (n = 31) revealed intelligible speech achieved by 9 of 11 with GJB2-related deafness, compared with only 6 of 20 with GJB2-unrelated deafness (p = 0.017). Ordinal logistic regression analysis on Speech Intelligibility Rating scores found statistically significantly better scores in children with GJB2-related deafness (p < 0.05) both before and after adjustment for confounding variables. A larger proportion with GJB2-related deafness also attended mainstream school (p = 0.01). CONCLUSION: In pediatric cochlear implantees, GJB2-related deafness is a predictor of good speech intelligibility.     

Audiological features of GJB2 (connexin 26) deafness

OBJECTIVE: The aim of the present study was to characterize audiological profiles in patients with GJB2 deafness DESIGN: We screened DNA from 399 individuals with nonsyndromic deafness for mutations in the connexin 26 gene (GJB2) by sequence analysis. A total of 77 (19%) of these deaf individuals were biallelic GJB2 mutations (either homozygous or compound heterozygous mutations) (GJB2 deafness). Using the audiological classification criteria of genetic deafness proposed by the European Workshop on Genetic Hearing Loss, we analyzed audiograms of these patients to characterize audiological features of the GJB2 deafness. In addition, we reviewed audiological data of 411 deafness cases from the literature providing details of audiological data (including 157 with GJB2 deafness). RESULTS: All categories of hearing loss severity were found, with significant differences in the findings from GJB2 cases: 1 (4.5%) of 22 individuals with mild hearing loss, 10 (13.3%) of 75 with moderate loss, 14 (14.9%) of 94 with severe loss, and 52 (25%) of 208 with profound deafness (Chi-square test, 3 df, p = 0.016). 81.6% of patients with GJB2 mutations had severe to profound loss, 18.4% with mild to moderate loss (Chi-square test, p = 0.014). The 235delC mutation was always associated with profound deafness. The main audiogram shapes found were residual/sloping (72.7%) and flat (23.4%). There were no differences in the severity and audiogram shapes of the hearing impairment between homozygous and compound heterozygous GJB2 deafness (Chi-square test, p > 0.05). CONCLUSIONS: Our study shows that the probability of finding biallelic GJB2 mutations increases with the severity of hearing loss. Audiograms associated with GJB2 deafness were usually nonspecific. Patients with unknown causes of severe or profound hearing loss should be routinely tested for GJB2 mutations, but due to the variability in hearing loss, individuals with lesser degrees of hearing loss should not be precluded from testing.     

Better speech performance in cochlear implant patients with GJB2-related deafness.

OBJECTIVE: We applied mutation screening in seven cochlear implant users to identify those persons with GJB2-related deafness to determine whether etiology of deafness was predictive of speech performance after implantation. METHODS: Direct sequence of GJB2 was conducted over seven cochlear implant users with prelingual hearing impairment and their speech, language and cognitive performance was examined. RESULTS: The three persons with GJB2-related deafness had a mean vocabulary of 1243 words compared to a mean vocabulary of 195 words in the four children with GJB2-unrelated deafness, although the number of patients examined here was limited. The developmental quotient (DQ) of cognitive ability also was higher in those children with GJB2-related deafness. CONCLUSIONS: These preliminary results suggest that better speech performance after cochlear implantation may be observed in persons with GJB2-related deafness. In the future, detailed phenotypic studies and mutation screening for non-syndromic hearing loss may play an important role in the preoperative assessment of prelingually-deafened children.     

Connexin-associated deafness and speech perception outcome of cochlear implantation

OBJECTIVE: To compare performance after cochlear implantation in children with mutations in connexin (Cx) 26 (GJB2) or Cx30 (GJB6) and children with deafness of unknown etiology. DESIGN: Genetic analysis and speech perception evaluation was performed in the children with and without Cx mutations who had undergone cochlear implantation. Speech perception performance was retrospectively analyzed 6, 12, 24, 36, and 48 months after implantation. Test material was selected according to the child's age and cognitive and language abilities. SETTING: The study took place at speech and hearing and genetic centers of a hospital in the central part of Israel and the genetics departments of 3 additional centrally located hospitals. PATIENTS: A total of 30 children who had undergone cochlear implantation were selected for the study, with control patients matched according to age at implantation, duration of implant use, and mode of communication. There was no evidence for additional disabilities or handicaps in either group. MAIN OUTCOME MEASURES: Speech perception measurements included a questionnaire, as well as closed and open-set tests. RESULTS: Overall, the 2 groups showed significant improvement in speech perception results after implantation. Four years after implantation, both groups achieved mean open-set speech perception scores of approximately 60%, 75%, and 90% for monosyllabic, 2 syllables, and words in sentences tests, respectively. CONCLUSIONS: There were no apparent differences in speech perception performance after implantation between the children with Cx mutations and children with deafness of unknown etiology. These data have important implications as a prognostic indicator when counseling candidates for cochlear implantation.     

Hearing impairment in Dutch patients with connexin 26 (GJB2) and connexin 30 (GJB6) mutations

OBJECTIVE: Despite the identification of mutations in the connexin 26 (GJB2) gene as the most common cause of recessive nonsyndromic hearing loss, the pattern of hearing impairment with these mutations remains inconsistent. Recently a deletion encompassing the GJB6 gene was identified and hypothesized to also contribute to hearing loss. We hereby describe the hearing impairment in Dutch patients with biallelic connexin 26 (GJB2) and GJB2+connexin 30 (GJB6) mutations. METHODS: The audiograms of patients who were screened for GJB2 and GJB6 mutations were analysed retrospectively. Standard statistical testing was done for symmetry and shape, while repeated measurement analysis was used to assess the relation between mutation and severity. Progression was also studied via linear regression analysis. RESULTS: Of 222 hearing-impaired individuals, 35 exhibited sequence variations; of these 19 had audiograms for study. Hearing loss in patients with biallelic "radical" (i.e. deletions, nonsense and splice site) mutations was significantly worse than in the wild type and heterozygotes (SAS proc GENMOD, p=0.013). The presence of at least one missense mutation in compound heterozygotes tends to lead to better hearing thresholds compared to biallelic radical mutations (p=0.08). One patient with the [35delG]+[del(GJB6-D13S1830)] genotype was severely impaired. Non-progressive hearing impairment was demonstrated in five 35delG homozygotes in individual longitudinal analyses. However a patient with the [299A>C]+[416G>A] genotype showed significant threshold progression in the lower frequencies. Findings on asymmetry and shape were inconclusive. CONCLUSIONS: Our data support the hypothesis that severity is a function of genotype and its effect on the amino acid sequence. A bigger cohort is required to establish non-progressivity more definitively.     

Auditory responses in cochlear implant users with and without GJB2 deafness

OBJECTIVE/HYPOTHESIS: It is reasonable to suppose that the pattern of sensorineural damage along the length of the cochlea depends on the etiology of a hearing loss (HL). In GJB2-related deafness, we hypothesize that gap junction deficits are uniformly distributed and will result in similar damage along the length of the cochlea as compared with non-GJB2 subjects. We assessed this by measuring patterns of neural activity and hearing from apical versus basal cochlear implant electrode regions. STUDY DESIGN: This was a prospective, blind, controlled study. METHODS: Blood from 301 pediatric cochlear implant users was analyzed for mutations in GJB2 by direct sequencing. After exclusion of patients with monoallelic GJB2 mutations, associated syndromes, or risk factors for HL that were not congenital, 39 children with biallelic GJB2 mutations and 58 without GJB2 mutations were evaluated. Hearing was measured before implantation at frequencies ranging from 250 Hz to 8 kHz. After implantation, neural activity at the apical and basal ends of the implanted array was measured using electrically evoked compound action potentials of the auditory nerve (ECAPs) and evoked stapedius reflexes (ESRs). RESULTS: GJB2 and non-GJB2 groups were not significantly different with respect to sex, age at implantation, duration of auditory deprivation, hearing aid use, duration of aided hearing, ear implanted, implant model, or depth of insertion (P>.05). Children with GJB2-related HL had greater similarities between low- and high-frequency residual hearing and between neural activity electrically evoked at apical and basal regions of the cochlea as compared with children with non-GJB2-related HL who demonstrated larger deficits in basal regions. CONCLUSION: Results suggest more consistent spiral ganglion survival along the length of the cochlea in GJB2-related HL as compared with non-GJB2-related HL, which appears to involve a decreasing gradient of spiral ganglion survival from the apex to the base of the cochlea. Our findings support our premise that in GJB2-related HL, dysfunction of gap junctions likely occurs to a similar degree in the apical and basal regions of the cochlea. This knowledge might be used to customize implantable devices for patients with HL in the future.     

Longitudinal phenotypic analysis in patients with connexin 26 (GJB2) (DFNB1) and connexin 30 (GJB6) mutations

In 15 Belgian subjects with prelingual sensorineural hearing impairment, the connexin 26 (GJB2) gene and the connexin 30 (GJB6) gene were analyzed for the presence of the 35delG mutation and the delta(GJB6-D13S1830) deletion first described by del Castillo et al in 2002. Seven patients were found to be homozygous for the 35delG mutation; 7 were combined heterozygotes for the 35delG mutation and the GJB6 deletion. In 11 subjects, phenotype and genotype were correlated. Significant, transient progression, in the range of 1.7 to 2.7 dB/y, was only found in 2 patients in the first part of the second decade of life. Hearing impairment was otherwise stable, with mean thresholds of 75, 90, and 100 dB at 0.125, 0.25, and 0.5 kHz, respectively, and 100 dB or higher at 1 to 4 kHz. There was no significant difference in hearing impairment between the patients with the homozygous 35delG mutation in GJB2 and those who are heterozygous for both the 35delG mutation and the deletion encompassing part of GJB6.     

Speech perception and speech intelligibility in children after cochlear implantation

OBJECTIVE: This study aimed to evaluate the long-term speech perception and speech intelligibility of congenitally and prelingually deaf children after cochlear implantation. It was a longitudinal study following 63 congenitally or prelingually deaf children up to 5 years after implantation. They each received a nucleus multichannel cochlear implant before they were 10 years old. METHODS: Perception is evaluated using the Test for the Evaluation of Voice Perception and Production (TEPP) and concerns closed- and open-set word and sentence perception without lip-reading. The intelligibility is classified according to the Speech Intelligibility Rating (SIR). The evaluations have been made every 3 months for 1 year, then at 18 months, 2 years, 3 years and 5 years after the cochlear implantation. RESULTS: After 5 years of implantation, the median percentage of closed-words speech perception (CSW) is 95.5%-93.67% for closed-sentence speech perception (CSS) and 76.3% for open-sentence speech perception (OSS); the median Speech Intelligibility Rating is 3.83. CONCLUSIONS: Congenitally and prelingually deaf children who receive cochlear implant before the age of 10 years develop speech perception and speech intelligibility abilities. The closed-set perception progresses quickly and seems to reaching a plateau at 5 years post implantation. The improvement of open-sentence perception is not significant until the first year post implantation. The speech intelligibility improves regularly the five first year post implantation.     

Auditory neuropathy in systemic sclerosis: a speech perception and evoked potential study before and after cochlear implantation

We report the results of speech perception and electrophysiological evaluation of the auditory periphery performed before and after cochlear implantation in a 18-year-old girl with systemic sclerosis (SS) who presented the clinical picture of auditory neuropathy. Transtympanic electrocochleography (ECochG) in response to 0.1 ms clicks was recorded 1 month before cochlear implantation on both sides while the electrically evoked neural response was obtained intraoperatively in the right ear through cochlear implant stimulation. The ECochG recordings revealed the presence of the cochlear microphonic with normal amplitude and threshold on both sides. A compound action potential was only detected in the left ear at high stimulation intensity, while the electrically evoked neural response was clearly identifiable at all the recording sites during neural response telemetry. Standardized speech perception tests were performed 1 month before cochlear implantation and several times after cochlear implant connection. Speech perception scores were close to chance before cochlear implantation while they showed a remarkable improvement thereafter. The results of this study show that subjects affected by SS could present the clinical picture of auditory neuropathy which is possibly underlain by lesions involving the distal portion of auditory nerve fibers and/or synapses with inner hair cells. The restoration of synchronous neural discharge could be achieved by electrical stimulation through cochlear implant.     

Duration of unilateral auditory deprivation is associated with reduced speech perception after cochlear implantation: A single-sided deafness study

Objective: Examine the relationship between duration of unilateral deafness and speech perception outcomes after cochlear implantation in adults with single-sided deafness.

Methods: A systematic review of PubMed articles containing individual speech perception and duration of deafness data from single-sided deaf adults. Studies were selected for detailed review and duration of deafness and speech perception outcomes were extracted, with speech scores reported as percent correct. A linear regression as a function of study and length of deafness was performed.

Results: A statistically significant negative effect of duration of unilateral deafness on speech perception was found, but there was substantial uncertainty regarding the strength of the effect.

Discussion: Existing data make it difficult to either support or reject a hard 5- or 10-year unilateral auditory deprivation limit on cochlear implant (CI) candidacy for patients with single-sided deafness. This is because the totality of available data are consistent with a very small effect, perhaps negligible in practical terms, and just as consistent with a very large effect. Regardless of effect size, the present results have important basic implications. They suggest that unilateral sound deprivation may have a deleterious effect on auditory processing even though more central parts of the auditory system have continued to receive input from a contralateral normal ear.

Conclusions: Speech perception scores in SSD patients are negatively correlated with duration of deafness, but the limited amount of data from cochlear implant users with long-term single-sided deafness leads to substantial uncertainly, which in turn precludes any strong clinical recommendations. Further study of SSD CI users with long-term deafness will be necessary to generate evidence-based guidelines for implantation criteria in this population.     

Ethnicity and mutations in GJB2 (connexin 26) and GJB6 (connexin 30) in a multi-cultural Canadian paediatric Cochlear Implant Program

OBJECTIVE: To determine the relationship between ethnicity and mutations in the GJB2 and GJB6 genes in multi-cultural patients enrolled in a Canadian paediatric Cochlear Implant Program. METHODS: Blood was analyzed from 65 paediatric cochlear implant users by direct sequencing of the coding region and intron/exon boundaries of the GBJ2 gene. Individuals heterozygous for one mutation in GJB2 or in whom mutations in GJB2 were not detected were analyzed for the common 342 kb deletion mutation D13S1830 in the GJB6 gene. Information regarding ethnicity of patients' families was obtained from patient records and/or interview. RESULTS: GJB2 mutations were found in 36.9% of paediatric cochlear implant users tested. Nine different GJB2 mutations were identified among individuals from 14 different countries of origin. Seventy-eight percent of all identified pathogenic GJB2 mutations were 35delG. Biallelic GJB2 mutations were found in 16 cochlear implant users (66.7% of GJB2 mutations). Three novel GJB2 sequence changes were identified: (1) a missense mutation T107C (L36P) in an individual of African decent; (2) a missense mutation G475T (D159Y) in an individual of Caribbean decent; (3) a regulatory region change 1-34C to T in an individual of African decent. GJB6-D13S1830 mutations were not found in any of the patients tested. Individuals of African, Caribbean and East Indian decent had different GJB2 mutations than the remainder of individuals tested. Patients of Asian, Italian, Spanish, Polish and Armenian decent were not found to carry mutations in GJB2 or the common GJB6-D13S1830 mutation. CONCLUSIONS: This study represents the largest number of biallelic GJB2 mutations isolated in a group of paediatric cochlear implant users to date. Numerous and diverse GJB2 mutations were found in this multi-cultural group of children. Even though GJB2 mutations have been widely reported in the literature, this discussion represents the first report of GJB2 mutations in a multi-ethnic population (Canadian), as compared with previous studies that investigated fairly homogeneous populations. The diversity of GJB2 mutations identified reinforces the importance of testing for changes in GJB2 by direct sequencing of the entire coding region rather than testing only for common mutations.     

语后聋成人人工耳蜗植入后言语感知能力的测评

目的通过对植入人工耳蜗的语后聋成人听力言语感知能力的测评,探讨人工耳蜗对语后聋成人言语康复的作用.方法受试者为14名语后聋成人患者,男性9例,女性5例;耳蜗植入年龄22岁～67岁,平均46岁;耳聋时间6年-42年,平均16年.在人工耳蜗植入6个月、12个月及24个月时,进行开放性单词和短句言语感知测试.分别在三种模式下进行:只听模式(开放人工耳蜗)、听觉加视觉模式(开放人工耳蜗加唇读)及视觉模式(关闭人工耳蜗只用唇读).结果在听觉模式及听觉加视觉模式下,患者对单词和句子的正确感知随人工耳蜗使用时间而不断改善.术后6个月,听觉模式下的开放性单词和短句的正确感知率分别是38%和54%;听觉加视觉模式下的开放性单词和短句的正确感知率分别是70%和76%.术后24个月,听觉模式下的开放性单词和短句的正确感知率分别是65%和72%;听觉加视觉模式下的开放性单词和短句的正确感知率分别是84%和88%.结论人工耳蜗植入能显著改善语后聋成人的言语感知能力,并随着人工耳蜗使用时间的增加,言语感知能力逐渐得到提高.     

Predicting speech perception outcomes following cochlear implantation in adults with unilateral deafness or highly asymmetric hearing loss

Objective: Unilateral deafness and highly asymmetric hearing loss can impair listening abilities in everyday situations, create substantial audiological handicap, and reduce overall quality of life. Preliminary evidence suggests that cochlear implantation may be effective in reversing some of these detrimental effects. Patient-level data from existing studies were re-analysed to explore potential factors that may be predictive of improved speech perception scores following implantation.

Methods: Logistic regression modelling examined whether improved speech perception following implantation under various listening conditions was related to the duration of deafness of the severe-to-profoundly deaf ear and/or the level of hearing in the better ear.

Results: Patients with a shorter duration of deafness were more likely to improve in listening conditions that created a less favourable SNR at the implanted ear than the non-implanted ear. Those with more residual hearing in the better ear were more likely to improve in the listening condition that created a less favourable SNR at that ear.

Discussion: The analysis suggests that characteristics of both ears may be relevant when seeking to identify those candidates who are likely to obtain benefit to speech perception following cochlear implantation.     

Auditory cortical activation and speech perception in cochlear implant users

Cochlear implantation is generally accepted as a successful means of restoring auditory sensation to profoundly deaf individuals. Although most patients can expect a satisfactory outcome following implantation, some have poor speech perception outcomes. This investigation used [18F]-fluorodeoxyglucose positron emission tomography to measure cortical activity resulting from auditory stimulation in seven 'good' and four 'poor' cochlear implant recipients. Activations were significantly greater in both the primary and association cortices in the good compared with the poor implant users. We suggest that the ability to access the more specialised speech processing abilities of the auditory association cortices helps determine outcome following cochlear implantation.     

Auditory rehabilitation with cochlear implantation in patients with neurofibromatosis type 2

Conclusions: New technological developments will most probably improve the efficiency of auditory brainstem implantation (ABI). Meanwhile, cochlear implantation in patients who have undergone prior reductive surgery, and who have maintained a positive electric stimulation, is an excellent alternative for rehabilitating complete and bilateral hearing loss in patients with neurofibromatosis type 2 (NF2). Auditory results are far better than those reported after ABI. Long-term follow-up will be necessary to demonstrate the validity of this strategy. Objectives: ABIs restore some degree of auditory perception in NF2 patients with bilateral and complete hearing loss, but results are often inadequate for maintaining social and professional activities. The aim of this study was to report the results of auditory rehabilitation by cochlear implantation in three cases of NF2. Patients and methods: This was a retrospective study undertaken in a tertiary referral center. The first patient had undergone previous surgery for a left grade III vestibular schwannoma (VS) and then underwent irradiation for a right grade I VS. Two years after irradiation, he suddenly lost his remaining hearing. Electric promontory stimulation was positive and cochlear implantation was performed. The second patient had undergone surgery for a left grade III VS and followed for a right grade II VS. She suddenly lost her remaining hearing. A cytoreductive surgery was performed and the cochlear nerve was preserved. Postoperative electric stimulation was positive. She was then implanted with a cochlear implant. The third patient presented with a right stage III and a left stage I VS. She first underwent a subtotal removal of the left VS with immediate cochlear implantation. She then underwent removal of the right VS stage III with no possible preservation of the cochlear nerve. Results: All three patients had excellent postoperative speech performance and were back to work 3 months after implantation. Imaging follow-ups at 4, 2, and 1 year, respectively, do not show any evolution of the tumor.     

GJB2及SLC26A4基因突变患儿耳蜗植入效果分析

目的探讨GJB2及SLC26A4基因突变的患儿人工耳蜗植入(cochlear implantation,CI)术后的效果。方法根据耳聋基因检测结果,将40名单侧CI患儿分成3组:GJB2组包括15名GJB2基因突变患儿,SLC26A4组包括8名SLC26A4基因突变患儿,对照组组包括17名未发现GJB2、SLC26A4及线粒体基因突变患儿。术后效果采用听觉意义整合量表(Meaningful Auditory Integration Scale,MAIS)、听觉行为分级标准(Categories of Auditory Performance,CAP)、规范学语时期出现时间、言语可懂度分级标准(Speech Intelligibility Rating,SIR)进行评估,比较3组术后1年效果差异的统计学意义。结果 GJB2基因突变组在MAIS及CAP两项评估中均明显优于其他两组,其差异有统计学意义。GJB2组的规范学语出现时间及SIR相较于另外两组也具有一定优势,但差异无统计学意义。SLC26A4组略优于非基因突变组,尽管统计学分析显示各项评估结果无显著差异。结论因病变部位在耳蜗,GJB2相关性耳聋患儿人工耳蜗植入术后效果较好,SLC26A4相关性耳聋术后是否存在优势有待进一步证实。     

Changes in educational placement and speech perception ability after cochlear implantation in children

OBJECTIVE: The purpose of this study was to evaluate the effect and relationship of paediatric cochlear implantation on educational placement and speech perception ability and to determine the effect of a multilingual background on educational placement and speech perception ability after cochlear implantation. DESIGN: This study consisted of a retrospective chart review of 83 implanted patients and a questionnaire sent to parents of 80 implanted children. SETTING: This study was conducted in a cochlear implant program at a tertiary care centre. METHODS AND OUTCOME MEASURES: From the chart review, the educational placements and speech perception scores of implanted children were determined before and after implantation. In the questionnaire, parents were asked about their preferred educational placement for their child, the language spoken at home, and their impressions of the chosen school program for their child. RESULTS: Of the children who were in nonmainstream school programs at implantation (n = 30), 50% moved toward mainstream with 9 (30%) reaching mainstream placement. Of the children who were preschool at implantation (n = 34), 24 (70%) were placed or planned to be placed in mainstream after implantation. The rate of improvement in speech perception ability was significantly higher in those children who moved toward or remained in mainstream than those who stayed at the same nonmainstream educational placement or moved away from mainstream. Children from a multilingual background were able to achieve similar educational placements and similar rates of progress of speech perception outcome as the only English-speaking children. CONCLUSIONS: Children with cochlear implants have increased educational opportunities, with those children in mainstream and those who have moved toward mainstream demonstrating improved progress in speech perception ability.     

Approach to communication, speech perception and intelligibility after paediatric cochlear implantation

The aim of this study was to explore the relationship between approach to communication, speech perception and speech intelligibility after cochlear implantation of young children with profound early deafness. A prospective speech perception and speech intelligibility assessment was undertaken on a consecutive group of implanted children. There were 46 children at the three-year, 26 at the four-year and 20 at the five-year intervals. All had been born deaf or deafened before the age of three and received cochlear implants before the age of seven. Their speech perception ability and the intelligibility of their speech were measured before cochlear implantation and annually thereafter. The children's communication had been classified by their teachers of the deaf at each interval into one of two categories: those using an oral approach and those using a signing approach. Results revealed that at all intervals, those children classified as using oral communication significantly exceeded those using signed communication on measures of speech perception and intelligibility (p<0.05). When those children who had changed from signed to oral communication were compared at the three-year interval with those who used oral communication throughout, there was no significant difference in their results. However, it remains to be explored whether children use oral communication after cochlear implantation because they are doing well, or whether they do well because they are using oral communication.     

Auditory cortical activation and speech perception in cochlear implant users: effects of implant experience and duration of deafness

This study aimed to investigate the relationship between outcome following cochlear implantation and auditory cortical activation. It also studied the effects of length of implant use and duration of deafness on the auditory cortical activations. Cortical activity resulting from auditory stimulation was measured using [(18)F]FDG positron emission tomography. In a group of 18 experienced adult cochlear implant users, we found a positive correlation between speech perception and activations in both the primary and association auditory cortices. This correlation was present in a subgroup of experienced implant users but absent in a group of new implant users with similar speech perception abilities. There was a significant negative correlation between duration of deafness and auditory cortical activation. This study gives insights into the relationship between implant speech perception and auditory cortical activation and the influence of duration of preceding deafness and implant experience.