The relation between age at the time of cochlear implantation and long-term speech perception abilities in congenitally deaf subjects

Outcomes of cochlear implantation in Usher syndrome: a systematic review

PURPOSE

This study is a systematic review of the literature which seeks to evaluate auditory and quality of life (QOL) outcomes of cochlear implantation in patients with Usher syndrome.

METHODS

Systematic review of studies indexed in Medline via PubMed, Ovid EMBASE, Web of Science, CENTRAL and clinicaltrials.gov was performed up to March 9th 2022, conducted in accordance with the PRISMA statement. Patient demographics, comorbidity, details of cochlear implantation, auditory, and QOL outcomes were extracted and summarized.

RESULTS

33 studies reported over 217 cochlear implants in 187 patients with Usher syndrome, comprising subtypes 1 (56 patients), 2 (9 patients), 3 (23 patients), and not specified (99 patients). Auditory outcomes included improved sound detection, speech perception, and speech intelligibility. QOL outcomes were reported for 75 patients, with benefit reported in the majority.

CONCLUSIONS

Many patients with Usher syndrome develop improved auditory outcomes after cochlear implantation with early implantation being an important factor.

Systematic Review on Late Cochlear Implantation in Early-Deafened Adults and Adolescents: Predictors of Performance

OBJECTIVES

Early-deafened, late-implanted adolescents and adults constitute a unique group of cochlear implant (CI) users, showing a large variability in outcomes. The current systematic review aimed to determine which preimplantation factors are relevant in predicting postoperative outcomes in this patient group.

DESIGN

A systematic search for studies published between 2000 and September 2017 was performed in five electronic databases (PubMed, Embase, the Cochrane library, CINAHL, and PsycInfo). Prognostic studies that assessed the relation between patient-related factors and CI outcomes in early-deafened but late-implanted adolescent and adult CI users were included. Study quality was assessed with the Quality In Prognosis Studies (QUIPS) tool.

RESULTS

The systematic search and subsequent full-text evaluation identified 13 studies that had a clear prognostic study goal. Eight out of these 13 studies had a high risk of bias for at least one of the five QUIPS domains. Analysis of the outcomes identified that communication mode (in childhood), preoperative speech intelligibility, and preoperative speech recognition scores were significantly related to speech perception outcomes for this group of CI users. A number of additional factors considered worth for further investigation were also identified.

CONCLUSIONS

The analysis of the studies assessing the effect of a number of patient-related factors on outcome with CI in early-deafened adolescents and adults identified three potential prognostic factors and a number of additional factors to be incorporated in future research. More high-quality prognosis studies in the investigated patient population are still needed.

Systematic Review on Late Cochlear Implantation in Early-Deafened Adults and Adolescents: Clinical Effectiveness

OBJECTIVES

Cochlear implantation in early-deafened patients, implanted as adolescents or adults, is not always advised due to poor expected outcomes. In order to judge whether such reluctance is justified, the current systematic review aimed to gather all available evidence on postoperative outcomes obtained by early-deafened patients using a state-of-the art cochlear implant (CI).

DESIGN

Five electronic databases (PubMed, Embase, the Cochrane library, CINAHL, and PsycInfo) were systematically searched for studies in English, French, German, or Dutch, published between 2000 and September 2017. Studies that reported pre- and postoperative outcomes on any measure of speech or sound perception, audiovisual or subjective benefit (quality of life) were included. Study quality was assessed with the Institute of Health Economics quality appraisal tool for case series studies.

RESULTS

The systematic search and subsequent full-text evaluation identified 38 studies meeting the inclusion criteria. Only a limited number of studies were judged to be of high quality according to the Institute of Health Economics tool, with lack of (clear) presentation of relevant study information being a recurring problem. Twenty-five studies presented viable outcomes on open-set speech understanding in quiet: mean postoperative scores obtained with CI remained below 50% for the vast majority of studies; significant postoperative improvements were found in 16 studies, although this number might have been higher if appropriate statistical testing had been performed in all studies. Eight studies observed increased audiovisual performance after implantation, which was statistically significant in six studies. A validated measure of hearing-related quality of life was used in only 5 of the 16 studies assessing subjective outcomes, showing significant postoperative improvements for most questionnaire domains. The relation between auditory and subjective outcomes was assessed in two studies, with contradictory results.

CONCLUSIONS

The current review showed that late cochlear implantation in early-deafened subjects resulted in significantly improved open-set speech perception, audiovisual speech perception, and (hearing-related) quality of life in the majority of the studies involved. Nonetheless, more and especially higher-quality research is needed in order to gain a more detailed understanding of the outcomes of cochlear implantation in this population.

The Effect of Age at Cochlear Implantation on Speech and Auditory Performances in Prelingually Deaf Children

To understand the effect of age at implantation on speech and auditory performances of 74 prelingually deaf Indian children after using cochlear implants for 3, 6 and 12 months. We also evaluate the causes of late implantation in this population. Seventy four children who underwent cochlear implantation from December 2013 to December 2015 in the Department of Otorhinolaryngology and Head Neck Cancer in SMS Medical College, Jaipur were participated in this study. To compare the efficacy of cochlear implant, candidates are classified into 2 groups according to the age at the time of implantation: 1-4 years and 4.1-7 years. The sample size is 37 in both age groups. Their auditory performance and speech intelligibility were rated using the Revised Categories of Auditory Perception scales, Speech Intelligibility Rating scales and Meaningful Auditory Integration Scale. The evaluations were made before implantation and 3, 6 and 12 months after implantation. The scores when compared in both the groups revealed that the results were comparable and significant after 12 months of follow up while the scores were not significant after 3 and 6 months. The results were statistically significant when baseline is compared with different postoperative stages. The children implanted before the age of 4 years had significantly better auditory and linguistic performances. At least 12 months of audio-verbal rehabilitation and speech and language therapy are required to compare the effects of cochlear implant in any set of children. Our study shows that hearing impaired children who receive cochlear implantation below 4 years of age acquires better auditory ability for developing language skills.

Long-Term Conductive Auditory Deprivation During Early Development Causes Irreversible Hearing Impairment and Cochlear Synaptic Disruption

Conductive hearing loss is a prevalent condition globally. It remains unclear whether conductive hearing loss that occurs during early development disrupts auditory peripheral systems. In this study, a mouse model of conductive auditory deprivation (CAD) was achieved using external auditory canal closure on postnatal day 12, which marks the onset of external ear canal opening. Short-term (2 weeks) and long-term (6 weeks) deprivations involving external ear canal closure were conducted. Mice were examined immediately, 4 weeks, and 8 weeks after deprivation. Short-term deprivation induced reversible auditory brainstem response (ABR) threshold and latencies of ABR wave I, whereas long-term deprivation caused irreversible ABR thresholds and latencies of ABR wave I. Complete recovery of ribbon synapses and latencies of ABR wave I was observed in the short-term group. In contrast, we observed irreversible ABR thresholds, latencies of ABR wave I, and quantity of ribbon synapses in the long-term deprivation group. Positive 8-hydroxy-2'-deoxyguanosine signals were noted in cochlear hair cells in the long-term group, suggesting that long-term auditory deprivation could disrupt auditory maturation via mitochondrial damage in cochlear hair cells. Conversely, no significant changes in cellular morphology were observed in cochlear hair cells and spiral ganglion cells in either short- or long-term groups. Collectively, our findings suggest that long-term conductive hearing deprivation during early stages of auditory development can cause significant and irreversible disruption that persists into adulthood.

Late Cochlear Implantation in Early-Deafened Adults: A Detailed Analysis of Auditory and Self-Perceived Benefits

OBJECTIVES

It is known that early-deafened cochlear implant (CI) users are a very heterogeneously performing group. To gain more insight into this population, this study investigated (1) postoperative changes in auditory performance over time based on various outcome measures, focusing on poor performers, (2) self-perceived outcomes, (3) relations between auditory and self-perceived outcomes, and (4) preimplantation factors predicting postoperative outcomes.

METHODS

Outcomes were assessed prospectively in a group of 27 early-deafened, late-implanted CI users, up to 3 years after implantation. Outcome measures included open-set word and sentence recognition, closed-set word recognition, speech tracking and a questionnaire on self-perceived outcomes. Additionally, the relative influence of 8 preimplantation factors on CI outcome was assessed with linear regression analyses.

RESULTS

Significant improvements were found for auditory performance measures and most of the questionnaire domains. Significant changes of the closed-set word test, speech tracking and questionnaire were also found for a subgroup of poor performers. Correlations between auditory and self-perceived outcomes were weak and nonsignificant. Preoperative word recognition and preoperative hearing thresholds, both for the implanted ear, were significant predictors of postoperative outcome in the multivariable regression model, explaining 63.5% of the variation.

CONCLUSIONS

Outcome measurement in this population should be adjusted to the patients' individual performance level and include self-perceived benefit. There is still a need for more knowledge regarding predictors of CI outcomes in this group, but the current study suggests the importance of the preoperative performance of the ear to be implanted.

Impact of socioeconomic factors on paediatric cochlear implant outcomes

OBJECTIVES

The study was aimed at evaluating the impact of certain socioeconomic factors such as family income, level of parents' education, distance between the child's home and auditory verbal therapy clinic, and age of the child at implantation on postoperative cochlear implant outcomes.

METHODS

Children suffering from congenital bilateral profound sensorineural hearing loss and a chronologic age of 4 years or younger at the time of implantation were included in the study. Children who were able to complete a prescribed period of a 1-year follow-up were included in the study. These children underwent cochlear implantation surgery, and their postoperative outcomes were measured and documented using categories of auditory perception (CAP), meaningful auditory integration (MAIS), and speech intelligibility rating (SIR) scores. Children were divided into three groups based on the level of parental education, family income, and distance of their home from the rehabilitation-- auditory verbal therapy clinic.

RESULTS

A total of 180 children were studied. The age at implantation had a significant impact on the postoperative outcomes, with an inverse correlation. The younger the child's age at the time of implantation, the better were the postoperative outcomes. However, there were no significant differences among the CAP, MAIS, and SIR scores and each of the three subgroups. Children from families with an annual income of less than $7,500, between $7,500 and $15,000, and more than $15,000 performed equally well, except for significantly higher SIR scores in children with family incomes more than $15,000. Children with of parents who had attended high school or possessed a bachelor's or Master's master's degree had similar scores, with no significant difference. Also, distance from the auditory verbal therapy clinic failed to have any significantimpact on a child's performance.

DISCUSSION

These results have been variable, similar to those of previously published studies. A few of the earlier studies concurred with our results, but most of the studies had suggested that children in families of higher socioeconomic status had have better speech and language acquisition.

CONCLUSIONS

Cochlear implantation significantly improves auditory perception and speech intelligibility of children suffering from profound sensorineural hearing loss. Younger The younger the age at implantation, the better are the results. Hence, early implantation should be promoted and encouraged. Our study suggests that children who followed the designated program of postoperative mapping and auditory verbal therapy for a minimum period of 1 year seemed to do equally well in terms of hearing perception and speech intelligibility, irrespective of the socioeconomic status of the family. Further studies are essential to assess the impact of these factors on long-term speech acquisition andlanguage development.

Fitting prelingually deafened adult cochlear implant users based on electrode discrimination performance

OBJECTIVE

This study investigated the hypotheses that (1) prelingually deafened CI users do not have perfect electrode discrimination ability and (2) the deactivation of non-discriminable electrodes can improve auditory performance.

DESIGN

Electrode discrimination difference limens were determined for all electrodes of the array. The subjects' basic map was subsequently compared to an experimental map, which contained only discriminable electrodes, with respect to speech understanding in quiet and in noise, listening effort, spectral ripple discrimination and subjective appreciation.

STUDY SAMPLE

Subjects were six prelingually deafened, late implanted adults using the Nucleus cochlear implant.

RESULTS

Electrode discrimination difference limens across all subjects and electrodes ranged from 0.5 to 7.125, with significantly larger limens for basal electrodes. No significant differences were found between the basic map and the experimental map on auditory tests. Subjective appreciation was found to be significantly poorer for the experimental map.

CONCLUSIONS

Prelingually deafened CI users were unable to discriminate between all adjacent electrodes. There was no difference in auditory performance between the basic and experimental map. Potential factors contributing to the absence of improvement with the experimental map include the reduced number of maxima, incomplete adaptation to the new frequency allocation, and the mainly basal location of deactivated electrodes.

Fetal Central Auditory System Metabolic Response to Cochlear Implant Stimulation

OBJECTIVES: The purpose of this study was to examine the effects of profound auditory deprivation and its treatment by cochlear implantation and stimulation on the metabolic activity of the central auditory system in fetal sheep.

METHODS: Six ovine fetuses at 85% to 90% gestation were bilaterally deafened by kanamycin perfusion and unilaterally implanted with cochlear electrode arrays. Half of the implanted animals were stimulated with an extrauterine sound processor, and half were not. Four animals served as hearing controls. One week postoperatively, central nervous system metabolic activity was evaluated in ambient laboratory noise by quantitative autoradiography using 14C-deoxyglucose.

RESULTS: Kanamycin perfusion deafened all treated animals as verified by auditory brainstem response and scanning electron microscopy. Glucose utilization in the inferior colliculus was markedly lower in deafened and unstimulated animals relative to hearing controls. Glucose utilization in implanted-stimulated animals was similar to normal controls.

CONCLUSIONS: Changes in central auditory system metabolic activity associated with congenital deafness may be minimized by prompt auditory habilitation.

Delayed prelingual cochlear implantation in childhood and puberty

OBJECTIVE

To evaluate the results of delayed cochlear impantion performed in childhood and puberty in the light of speech language pathology assessments.

METHODS

Totally 49 children with prelingual profound hearing loss were included in the study. All children received a cochlear implant between the ages of 5 and 19 years (Group 1 aged between 5 and 9 years, group 2 aged between 10 and 14 years, group 3 aged between and 15 and 19 years). The MAIS, MUSS and PLS-4 scores of children were evaluated one month before, and one year and two years after the operation. The descriptive statistics included several independent variables; age of implantation; gender; trade name of the implant; preoperative duration of hearing aid use; preoperative special education, family support and additional handicap. These variables were categorical variables. We used repeated measures analysis of variance to test improvements in MAIS, MUSS and PLS scores, and whether this improvement depend on the independent variables. In addition, we also tested the interaction between time and the independent variables.

RESULTS

The preoperative MAIS, MUSS and language scores were significantly higher in older children compared to younger children (p<0.01). After two years these scores were similar between the all age groups (p>0.4). There was a significant age and time interaction (p=0.005). That is, improvement continued in all age groups in a parallel way and group 2 reached to the level of group 1 after two years. However, group 3 almost reached to a plateau level after two years. The family support was associated with the MAIS, MUSS and language scores of the patients (p=0.01), and there was a family support-time interaction (p<0.0001). In group 1 and 2, the way of communication shifted from total communication (lip reading, sign language, auditory) to auditory-verbal communication in a significant number of the patients (p<0.01). However, that change in the way of communication was not statistically significant in group 3 (p>0.05).

CONCLUSION

The decision of delayed cochlear implantation in children can be made in the light of following parameters. A good family support is most important. The patients must be wearing hearing aids regularly since early childhood, and preferably use the auditory verbal communication. Evaluation of the patient with MAIS, MUSS and PLS is important to understand the level of receptive and expressive communication level.

Audiovisual spoken word training can promote or impede auditory-only perceptual learning: prelingually deafened adults with late-acquired cochlear implants versus normal hearing adults

Training with audiovisual (AV) speech has been shown to promote auditory perceptual learning of vocoded acoustic speech by adults with normal hearing. In Experiment 1, we investigated whether AV speech promotes auditory-only (AO) perceptual learning in prelingually deafened adults with late-acquired cochlear implants. Participants were assigned to learn associations between spoken disyllabic C(=consonant)V(=vowel)CVC non-sense words and non-sense pictures (fribbles), under AV and then AO (AV-AO; or counter-balanced AO then AV, AO-AV, during Periods 1 then 2) training conditions. After training on each list of paired-associates (PA), testing was carried out AO. Across all training, AO PA test scores improved (7.2 percentage points) as did identification of consonants in new untrained CVCVC stimuli (3.5 percentage points). However, there was evidence that AV training impeded immediate AO perceptual learning: During Period-1, training scores across AV and AO conditions were not different, but AO test scores were dramatically lower in the AV-trained participants. During Period-2 AO training, the AV-AO participants obtained significantly higher AO test scores, demonstrating their ability to learn the auditory speech. Across both orders of training, whenever training was AV, AO test scores were significantly lower than training scores. Experiment 2 repeated the procedures with vocoded speech and 43 normal-hearing adults. Following AV training, their AO test scores were as high as or higher than following AO training. Also, their CVCVC identification scores patterned differently than those of the cochlear implant users. In Experiment 1, initial consonants were most accurate, and in Experiment 2, medial consonants were most accurate. We suggest that our results are consistent with a multisensory reverse hierarchy theory, which predicts that, whenever possible, perceivers carry out perceptual tasks immediately based on the experience and biases they bring to the task. We point out that while AV training could be an impediment to immediate unisensory perceptual learning in cochlear implant patients, it was also associated with higher scores during training.

Timing of surgical intervention with cochlear implant in patients with large vestibular aqueduct syndrome

Objectives

(1) To report the speech perception and intelligibility results of Mandarin-speaking patients with large vestibular aqueduct syndrome (LVAS) after cochlear implantation (CI); (2) to compare their performance with a group of CI users without LVAS; (3) to understand the effects of age at implantation and duration of implant use on the CI outcomes. The obtained data may be used to guide decisions about CI candidacy and surgical timing.

Methods

Forty-two patients with LVAS participating in this study were divided into two groups: the early group received CI before 5 years of age and the late group after 5. Open-set speech perception tests (on Mandarin tones, words and sentences) were administered one year after implantation and at the most recent follow-up visit. Categories of auditory perception (CAP) and Speech Intelligibility Rating (SIR) scale scores were also obtained.

Results

The patients with LVAS with more than 5 years of implant use (18 cases) achieved a mean score higher than 80% on the most recent speech perception tests and reached the highest level on the CAP/SIR scales. The early group developed speech perception and intelligibility steadily over time, while the late group had a rapid improvement during the first year after implantation. The two groups, regardless of their age at implantation, reached a similar performance level at the most recent follow-up visit.

Conclusion

High levels of speech performance are reached after 5 years of implant use in patients with LVAS. These patients do not necessarily need to wait until their hearing thresholds are higher than 90 dB HL or PB word score lower than 40% to receive CI. They can do it “earlier” when their speech perception and/or speech intelligibility do not reach the performance level suggested in this study.

An Usher syndrome type 1 patient diagnosed before the appearance of visual symptoms by MYO7A mutation analysis

Usher syndrome type 1 (USH1) appears to have only profound non-syndromic hearing loss in childhood and retinitis pigmentosa develops in later years. This study examined the frequency of USH1 before the appearance of visual symptoms in Japanese deaf children by MYO7A mutation analysis. We report the case of 6-year-old male with profound hearing loss, who did not have visual symptoms. The frequency of MYO7A mutations in profound hearing loss children is also discussed. We sequenced all exons of the MYO7A gene in 80 Japanese children with severe to profound non-syndromic HL not due to mutations of the GJB2 gene (ages 0-14 years). A total of nine DNA variants were found and six of them were presumed to be non-pathogenic variants. In addition, three variants of them were found in two patients (2.5%) with deafness and were classified as possible pathogenic variants. Among them, at least one nonsense mutation and one missense mutation from the patient were confirmed to be responsible for deafness. After MYO7A mutation analysis, the patient was diagnosed with RP, and therefore, also diagnosed with USH1. This is the first case report to show the advantage of MYO7A mutation analysis to diagnose USH1 before the appearance of visual symptoms. We believed that MYO7A mutation analysis is valid for the early diagnosis of USH1.

Categories of auditory performance and speech intelligibility ratings of early-implanted children without speech training

OBJECTIVE

To assess whether speech therapy can lead to better results for early cochlear implantation (CI) children.

PATIENTS

A cohort of thirty-four congenitally profoundly deaf children who underwent CI before the age of 18 months at the Sixth Hospital affiliated with Shanghai Jiaotong University from January 2005 to July 2008 were included. Nineteen children received speech therapy in rehabilitation centers (ST), whereas the remaining fifteen cases did not (NST), but were exposed to the real world, as are normal hearing children.

METHODS

All children were assessed before surgery and at 6, 12, and 24 months after surgery with the Categories of Auditory Performance test (CAP) and the Speech Intelligibility Rating (SIR). Each assessment was given by the same therapist who was blind to the situation of the child at each observation interval. CAP and SIR scores of the groups were compared at each time point.

RESULTS

Our study showed that the auditory performance and speech intelligibility of trained children were almost the same as to those of untrained children with early implantation. The CAP and SIR scores of both groups increased with increased time of implant use during the follow-up period, and at each time point, the median scores of the two groups were about equal.

CONCLUSIONS

These results indicate that great communication benefits are achieved by early implantation (<18 months) without routine speech therapy. The results exemplify the importance of enhanced social environments provided by everyday life experience for human brain development and reassure parents considering cochlear implants where speech training is unavailable.

Speech intelligibility as a predictor of cochlear implant outcome in prelingually deafened adults

OBJECTIVES

Among adult patients with prelingual deafness, interindividual variability in speech perception outcome after cochlear implantation is generally large. It was hypothesized that the intelligibility of the patient's own speech may be predictive of speech perception with a cochlear implant. The objectives were (1) to provide a validation of a new test battery as a measurement tool for intelligibility using a group of prelingually deafened patients; (2) to investigate the validity of the test battery as a predictor of postimplant speech perception, based on preliminary data with a cochlear implant from a subgroup of patients; and (3) to investigate the validity of the test battery as a predictor of postimplant health-related quality of life (HRQoL) for the same subgroup of patients.

DESIGN

Twenty-five adult cochlear implant candidates with prelingual deafness participated in this study. Average age at onset of deafness was 8 mos (range 0 to 4 yrs). Speech samples from the participants were recorded and presented to two normal-hearing listeners. Results from the seven intelligibility tests in the battery were subjected to analyses of reliability and validity. Furthermore, the multiple test outcomes were submitted to a Principal Component Analysis to investigate the possibility of summarizing the data. Subsequently, from the group of 25 participants, 9 participants with above-average intelligibility were selected for implantation. Speech perception data with a cochlear implant from the nine implantees were collected at 12 mos postimplantation, as well as HRQoL data. Predictive validity of the intelligibility test battery was determined, using the postimplant data as the criterion.

RESULTS

Results from the 25 participants averaged over listeners showed that all tests in the battery had good reliability and validity as measures of intelligibility. Principal Component Analysis showed that the multiple test outcomes could be summarized by a single underlying variable. Despite the early age at onset of deafness, the subgroup of nine participants who received a cochlear implant included several good performers in terms of speech perception with the implant. The intelligibility test battery summary score had good validity as a predictor of postimplant outcome: the more intelligible the participant's speech, the better his or her speech perception outcome with the cochlear implant. Availability of effective auditory input in early life may be the fundamental factor underlying the potential for speech perception with a cochlear implant in later life. The intelligibility test battery can be reduced to a single test to minimize testing time without negatively affecting its predictive validity. Predictive validity of the intelligibility test battery can be generalized to HRQoL outcomes of cochlear implantation, provided these outcomes are concerned with speech processing abilities.

CONCLUSIONS

The new test battery (or its reduced version), used as a measure of intelligibility, is a promising tool for guiding cochlear implant candidacy decisions and counseling for individual patients with prelingual deafness. Because intelligibility has superior predictive power in comparison to age at onset of deafness, the latter should be discarded as an exclusion criterion for cochlear implantation.

Delayed cochlear implantation in adults with prelingual severe-to-profound hearing loss

OBJECTIVES

To evaluate the results of late cochlear implantation in prelingually deaf patients with significant residual hearing loss and to evaluate patient factors relevant to postoperative auditory outcomes in this patient group.

STUDY DESIGN

Analysis of results of cochlear implantation using postoperative speech perception test scores per each condition.

SETTING

Tertiary referral center.

PATIENTS

Thirty-two subjects with severe to profound hearing loss that developed before the age of 4.

INTERVENTIONS

Subjects were implanted at a mean age of 24.8 years (range, 16-44) with Nucleus CI24 (n = 18, 56%), Clarion HiRes 90K (n = 11, 34%), and Medel PULSA (n = 3, 10%) device. Details of etiology, duration of deafness, hearing aid history, hearing thresholds before operation, communication mode, and educational environment were investigated. Speech perception tests were performed preoperatively and 12 months after the operation.

MAIN OUTCOME MEASURES

Postoperative speech perception test scores between different options within patient group.

RESULTS

: The results showed significant improvement in open set speech perception (sentence) scores after the implantation (mean scores from 7.0 to 46.7, p < 0.05). Preoperative hearing of better ear and preoperative speech perception scores correlated with postoperative performances (r = -0.70 and r = 0.46, respectively, p < 0.05). Education and communication mode were also closely related to postoperative performances. In the group with poorer performances, preoperative hearing thresholds were significantly worse than those with better performances, and a larger portion of those patients attended special schools and used sign language.

CONCLUSION

We found that residual auditory capacity in the better ear is an important factor in predicting outcomes after cochlear implantation in patients with prelingual hearing loss.

[Correlation of auditory-verbal skills in patients with cochlear implants and their evaluation in positone emission tomography (PET)]

INTRODUCTION

An assumption was taken that in central nervous system (CNS) in patients above 15 years of age there are possible mechanisms of neuronal changes. Those changes allow for reconstruction or formation of natural activation pattern of appropriate brain structures responsible for auditory speech processing.

AIM

The aim of the study was to observe if there are any dynamic functional changes in central nervous system and their correlation to the auditory-verbal skills of the patients.

MATERIAL AND METHODS

Nine right-handed patients between 15 and 36 years of age were examined, 6 females and 3 males. All of them were treated with cochlear implantation and are in frequent follow-up in the Department of Otolaryngology at the Medical University of Warsaw due to profound sensorineural hearing loss. In present study the patients were examined within 24 hours after the first fitting of the speech processor of the cochlear implant, and 1 and 2 years subsequently. Combination of performed examinations consisted of: positone emission tomography of the brain, and audiological tests including speech assessment. In the group of patients 4 were postlingually deaf, and 5 were prelinqually deaf.

RESULTS

Postlingually deaf patients achieved great improvement of hearing and speech understanding. In their first PET examination very intensive activation of visual cortex V1 and V2 (BA17 and 18) was observed. There was no significant activation in the dominant (left) hemisphere of the brain. In PET examination performed 1 and 2 years after the cochlear implantation no more V1 and V2 activation region was observed. Instead particular regions of the left hemisphere got activated. In prelingually deaf patients no significant changes in central nervous system were noticeable neither in PET nor in speech assessment, although their hearing possibilities improved.

CONCLUSIONS

Positive correlation was observed between the level of speech understanding, linguistic skills and the activation of appropriate areas of the left hemisphere of the brain in postlingually deaf patients treated with cochlear implants. No such correlation was noted in prelingualy patients treated with the same method.

Cochlear implantation in patients with prelingual hearing loss

CONCLUSION

The average age at the time of cochlear implantation is progressively being reduced. While cochlear obstruction and perilymph/cerebello-spinal fluid gusher were found in some cases, preoperative MRI and CT scans were predictive of such occurrences. The preoperative developmental quotient in the Cognitive-Adaptive Area was strongly correlated to the postoperative development in the Language-Social Area.

OBJECTIVE

To summarize the background, implant devices, intraoperative findings, and postoperative developmental quotients of prelingually deafened patients who underwent cochlear implantation.

METHODS

We conducted a retrospective chart review of 134 prelingually deafened cochlear implant recipients.

RESULTS

The median age at implantation was 3 years and 5 months. Most patients were born deaf without any known etiologies. In most cases, the transmastoid facial recess approach was utilized. Cochlear obstruction was identified in four patients, all of whom lost their hearing as a result of meningitis. Perilymph/cerebello-spinal fluid gusher was observed in six patients with inner ear anomalies. The preoperative developmental quotient for the Cognitive-Adaptive Area showed significant correlation with the postoperative developmental quotient in the Language-Social Area with a correlation coefficient of 0.71.

Cochlear implantation in late-implanted adults with prelingual deafness

PURPOSE

The purpose of this study was to examine the effect of cochlear implantation (CI) on prelingually deafened participants who were implanted as adults. The effect of the CI was examined with regard to the following variables: communication, family, social skills, education, and work satisfaction with one's life, loneliness, and self-esteem.

MATERIALS AND METHODS

Thirty-eight adults participated. Four self-report questionnaires were used at 2 points in time: before and after CI.

RESULTS

The research findings show significant differences in the reports of most variables before and after implantation. The participants felt better with regard to communication, social skills, education, and work and satisfaction with one's life after implantation in comparison to their feelings before implantation. Furthermore, they felt less lonely after implantation. However, there were no significant differences before and after implantation regarding their feelings within the family and regarding their self-esteem.

CONCLUSIONS

The results demonstrated the need to evaluate the benefits resulting from the CI not only with traditional clinical measures but with additional measures as well. Furthermore, they demonstrated the benefit of the CI on the positive psychosociological implications of prelingually deafened adults.

Bilateral effects of unilateral cochlear implantation in congenitally deaf cats

Congenital deafness results in synaptic abnormalities in auditory nerve endings. These abnormalities are most prominent in terminals called endbulbs of Held, which are large, axosomatic synaptic endings whose size and evolutionary conservation emphasize their importance. Transmission jitter, delay, or failures, which would corrupt the processing of timing information, are possible consequences of the perturbations at this synaptic junction. We sought to determine whether electrical stimulation of the congenitally deaf auditory system via cochlear implants would restore the endbulb synapses to their normal morphology. Three and 6-month-old congenitally deaf cats received unilateral cochlear implants and were stimulated for a period of 10-19 weeks by using human speech processors. Implanted cats exhibited acoustic startle responses and were trained to approach their food dish in response to a specific acoustic stimulus. Endbulb synapses were examined by using serial section electron microscopy from cohorts of cats with normal hearing, congenital deafness, or congenital deafness with a cochlear implant. Synapse restoration was evident in endbulb synapses on the stimulated side of cats implanted at 3 months of age but not at 6 months. In the young implanted cats, postsynaptic densities exhibited normal size, shape, and distribution, and synaptic vesicles had density values typical of hearing cats. Synapses of the contralateral auditory nerve in early implanted cats also exhibited synapses with more normal structural features. These results demonstrate that electrical stimulation with a cochlear implant can help preserve central auditory synapses through direct and indirect pathways in an age-dependent fashion.

Perception of speech by prelingual pre-adolescent and adolescent cochlear implant users

This study was undertaken to assess the speech perception benefits, 24 months after cochlear implantation (CI), in 20 young people (age at CI, 8-18.5 years) with prelingual profound hearing loss, in addition to the use of a proposed CI candidacy assessment profile. Speech perception was evaluated in terms of word and sentence perception before CI, and at six-monthly intervals for two years after CI. Before undergoing CI, all participants were tested on a pre-implantation assessment profile. Compared to the pre-CI findings, group results over 24 months post-CI demonstrated improved speech perception abilities reaching, on average, 46% for word recognition, 71.3% for sentences in quiet, and 33.6% for sentences in noise. Pre-CI profile scores correlated significantly with all speech perception results obtained 24 months after CI. Thus, despite their relatively late ages at implantation, all participants showed gradually improving performance in speech perception. The results showed a high variability in the outcomes of the participants. The pre-CI profile appeared to be useful in formulating realistic expectations of CI outcome during pre-implantation consultations, suggesting that expectations can and should be managed according to each patient's pre-implantation assessment.

The effects of age at cochlear implantation and hearing aid trial on auditory performance of Chinese infants

CONCLUSION

Most of the infants demonstrated rapid improvement in the three different auditory skills within the first year after switch-on. Infants undergoing hearing aid trial and habilitation demonstrated a significant positive effect on the development of auditory skills in comparison with infants without trial and habilitation.

OBJECTIVE

This paper aims to evaluate the auditory performance of infants of different age at cochlear implantation, emphasize the importance of the hearing aid trial and habilitation before implant, and provide baseline data of auditory development.

METHODS

In all, 259 infants with prelingually profound hearing loss participated in this study. The Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) was used to assess auditory skills in infants at different intervals.

RESULTS

The mean scores for the auditory skills improved significantly over time. The mean scores of three skills for each group at each interval were significantly different. The mean scores of the auditory skills were significantly superior for infants undergoing hearing aid trial and habilitation in comparison with those of infants without hearing aid trial and habilitation.

Cochlear implants and spoken language processing abilities: review and assessment of the literature

Cochlear implants (CIs) process sounds electronically and then transmit electric stimulation to the cochlea of individuals with sensorineural deafness, restoring some sensation of auditory perception. Many congenitally deaf CI recipients achieve a high degree of accuracy in speech perception and develop near-normal language skills. Post-lingually deafened implant recipients often regain the ability to understand and use spoken language with or without the aid of visual input (i.e. lip reading). However, there is wide variation in individual outcomes following cochlear implantation, and some CI recipients never develop useable speech and oral language skills. The causes of this enormous variation in outcomes are only partly understood at the present time. The variables most strongly associated with language outcomes are age at implantation and mode of communication in rehabilitation. Thus, some of the more important factors determining success of cochlear implantation are broadly related to neural plasticity that appears to be transiently present in deaf individuals. In this article we review the expected outcomes of cochlear implantation, potential predictors of those outcomes, the basic science regarding critical and sensitive periods, and several new research directions in the field of cochlear implantation.

Speech perception in children using cochlear implants: prediction of long-term outcomes

A group of 102 children using the Nucleus multichannel cochlear implant were assessed for open-set speech perception abilities at six-monthly intervals following implant surgery. The group included a wide range of ages, types of hearing loss, ages at onset of hearing loss, experience with implant use and communication modes. Multivariate analysis indicated that a shorter duration of profound hearing loss, later onset of profound hearing loss, exclusively oral/aural communication and greater experience with the implant were associated with better open-set speech perception. Developmental delay was associated with poorer speech perception and the SPEAK signal coding scheme was shown to provide better speech perception performance than previous signal processors. Results indicated that postoperative speech perception outcomes could be predicted with an accuracy that is clinically useful.

Developmental constraints on language development in children with cochlear implants

Research on pediatric cochlear implantation has frequently shown that speech perception, speech production, and language outcomes are better for children who are implanted earlier in life than later. These findings are often explained on the grounds that earlier implantation takes advantage of a critical or sensitive period. This paper reviews the literature concerning sensitive periods within the framework of speech and language development. It particularly emphasizes two alternate mechanisms proposed for these periods: an experience-independent mechanism, and an experience-dependent mechanism. Based on this literature review we proposed that research in the field of pediatric cochlear implantation needs to carefully define what kind of evidence is needed to reflect a sensitive period for speech and language learning. The field also needs to consider designing studies that allow the viability of these two mechanisms to be tested. An example of such a study is provided within.

What can be expected from a late cochlear implantation?

OBJECTIVE

Verify if late cochlear implantation allows pre-lingual deafs to convert from visual to oral communication mode only.

METHOD

Thirteen pre-lingual profoundly deaf patients implanted the ages of 8 and 22 years were included in the study. Before cochlear implantation, none of the patients used the oral language. Six patients used cued speech and seven used the sign language to communicate. Evaluations were made with measures of hearing thresholds, phoneme identification, categories of auditory performance and rating of the intelligibility of speech before and after implantation. Changes in principal mode of communication (i.e. oral, cued speech or sign language) were also monitored.

RESULTS

The former users of cued speech benefited significantly more from cochlear implantation than the sign language users for phoneme identification and categories of auditory performance, although all had similar hearing thresholds before and after cochlear implantation. After a mean implant use of 4.5 years, four out of six cued speech users converted to exclusive use of the oral language, while only one out of seven former users of the sign language converted to the use of the oral language.

DISCUSSION

It is possible for pre-lingual or congenital deafs to convert totally from a visual to an oral communication mode even in case of late cochlear implantation. Previous awareness of the structure of the oral language, even without hearing (e.g. via cued speech) influences positively the outcome of delayed implantations. We recommend the adoption of oral communication with the cued speech code in cases where a late cochlear implantation is envisioned.

Reading comprehension of deaf children with cochlear implants

The reading comprehension and visual word recognition in 50 deaf children and adolescents with at least 3 years of cochlear implant (CI) use were evaluated. Their skills were contrasted with reference data of 500 deaf children without CIs. The reading comprehension level in children with CIs was expected to surpass that in deaf children without implants, partly via improved visual word recognition. Reading comprehension scores of children with implants were significantly better than those of deaf children without implants, although the performance in implant users was substantially lagging behind that in hearing children. Visual word recognition was better in children with CIs than in children without implants, in secondary education only. No difference in visual word recognition was found between the children with CIs and the hearing children, whereas the deaf children without implants showed a slightly poorer performance. The difference in reading comprehension performance of the deaf children with and without CIs remained present when visual word recognition was controlled for. This indicates that other reading-related skills were also contributing to the improved reading comprehension skills of deaf children with CIs.

Effect of age at cochlear implantation on open-set word recognition in Mandarin speaking deaf children

OBJECTIVE

The purpose of this study was to determine whether age at cochlear implantation influences open-set speech perception in children after long-term use of the implant device.

METHOD

Twenty-eight congenitally deafened children, receiving implants of Nucleus CI24M devices, were divided into two groups: (1) CI < 3: those who received implants before 3 years of age and (2) CI > 3: those who received implants after 3 years of age. We compared open-set speech perception in CI < 3 and CI > 3 after 4-5 years of device use. Speech perception tests were conducted using the Mandarin Lexical Neighborhood Test (M-LNT). Unpaired t-test was applied for statistical analysis, and p < 0.05 was considered significant.

RESULTS

In CI < 3, the average of percent correct was 80.0 +/- 8.8 and 70.5 +/- 9.2% on, respectively, the easy and hard versions of the M-LNT. By contrast, in CI > 3, the average percent correct was 62.5 +/- 19.9 and 59.1 +/- 15.2%, respectively. Regardless of the M-LNT version used, CI < 3 performed significantly better than CI > 3 (easy, p = 0.005 versus hard, p = 0.022).

CONCLUSION

The present investigation demonstrated that age at implantation influences open-set speech perception of cochlear implanted children 4-5 years after device connection. Implantation before 3 years of age promotes the development of open-set speech perception abilities in congenitally deafened children.

Is there a critical period for cochlear implantation in congenitally deaf children? Analyses of hearing and speech perception performance after implantation

A range of basic and applied studies have demonstrated that during the development of the auditory system, early experimental manipulations or clinical interventions are generally more effective than those made later. We present a short review of these studies. We investigated this age-related plasticity in relation to the timing of cochlear implantation in deaf-from-birth children. Cochlear implantation is a standard intervention for providing hearing in children with severe to profound deafness. An important practical question is whether there is a critical period or cutoff age of implantation after which hearing outcomes are significantly reduced. In this article, we present data from prelingually deaf children (mostly congenitally deaf) implanted at ages ranging from 1 to 15 years. Each child was tested with auditory and speech understanding tests before implantation, and at regular intervals up to 8 years postimplantation. We measured the improvement in performance of speech understanding tests in younger implanted children and compared it with the results of those implanted at a later age. We also used a binary partitioning algorithm to divide the data systematically at all ages at implant to determine the optimum split, i.e., to determine the age at implant which best separates performance of early implanted versus later implanted children. We observed distinct age-of-implant cutoffs, and will discuss whether these really represent critical periods during development.

Cochlear implantation in adults with prelingual deafness. Part II. Underlying constraints that affect audiological outcomes

OBJECTIVES/HYPOTHESIS

To discuss the underlying physiological and anatomical constraints on audiological performance of late-implanted prelingually deafened adult cochlear implant patients.

STUDY DESIGN

Retrospective review.

METHODS

Published literature on the topic of auditory pathway responses to prolonged congenital deafness was reviewed. In particular, the authors sought to identify the anatomical and physiological changes that take place in both the peripheral and central auditory pathways in response to prolonged deafness, as well as how they are altered by chronic electrical stimulation.

RESULTS

The currently available evidence suggests that the colonization of the auditory cortex by other sensory modalities is the main limiting factor in postimplantation performance, not the pathological degenerative changes of the auditory nerve, cochlear nucleus, or auditory midbrain.

CONCLUSION

The reviewed evidence, although circumstantial, suggests that emphasizing aurally based educational programs before (with hearing aids) and after cochlear implantation could reduce the cortical colonization phenomenon and potentially improve postimplantation audiological performance of patients with long-term prelingual deafness.

Cochlear implantation in adults with prelingual deafness. Part I. Clinical results

OBJECTIVES/HYPOTHESIS

To examine the hypothesis that the newer generations of cochlear implants could provide considerable speech understanding to late-implanted, prelingually deaf adult patients.

STUDY DESIGN

Retrospective review.

METHODS

Speech perception scores of 103 patients with long-term prelingual deafness obtained from the recent clinical trials were compared with other previously published results.

RESULTS

Unlike patients receiving implants in early childhood, the audiologic performance of most patients with long-term prelingual deafness rapidly approached asymptotic levels within 1 year after implantation. Beginning at 3 months postimplantation, statistically significant improvement was noted in their speech perception scores compared with their preimplant levels. However, the average performance plateau achieved by this group of patients was significantly below the levels published for postlingual patients. No statistically significant differences were observed between the test scores at any testing interval among patients with different devices.

CONCLUSIONS

Most patients with long-term prelingual deafness achieve their performance plateau within 1 year after implantation. The results suggest that patient characteristics, rather than device properties, are likely to be the major contributing factor responsible for the observed audiologic outcomes.

Pediatric Cochlear Implant Patient Performance as a Function of Age at Implantation

OBJECTIVE

The objective of this study was to examine the effect that age at implantation has on performance of children who received multichannel cochlear implants.

STUDY DESIGN

This is a retrospective study of 295 children who were broken down into 5 age groups based on age at implantation: 1-3 years, 3-5 years, 5-7 years, 7-9 years, and 9-11 years. Speech perception test scores obtained 12, 24, and 36 months postactivation were compared for the 5 groups using repeated-measures analysis of variance.

SETTING

This study was carried out at a tertiary academic medical center.

PATIENTS

Subjects consisted of 295 children who ranged in age from 12 months to 10 years 11 months at the time they obtained their cochlear implant.

INTERVENTION

All patients received their cochlear implant at a single implant facility.

MAIN OUTCOME MEASURES

Performance on several speech perception tests was compared 12, 24, and 36 months postactivation. Performance was evaluated as a function of age at implantation.

RESULTS

Patients in all 5 groups demonstrated improved scores when compared with scores obtained preoperatively with hearing aids. Repeated-measures analysis of variance (ANOVA) revealed a significant group by time interaction for 3 of the 5 measures. For all three of these measures, children implanted at younger ages demonstrated greater gains in speech perception over time than children implanted at older ages.

CONCLUSIONS

These results are in agreement with those of previous studies indicating that early implantation facilitates improved development of speech perception skills in profoundly deaf children.

Usher syndrome and cochlear implantation

OBJECTIVE

To evaluate the symptoms leading to diagnosis and the quality of rehabilitation after cochlear implantation in Usher syndrome.

STUDY DESIGN

Retrospective cohort study.

SETTING

ENT department of a tertiary referral hospital.

PATIENTS

Among 210 patients given an implantation in the Ear, Nose, and Throat department, 185 were congenitally deaf and 13 had Usher syndrome (7.0%). Five had a family history of Usher, and eight were sporadic cases. Eleven cases were Usher type I, one was Usher type III, and one was not classified. The age at implantation ranged from 18 months to 44 years (mean, 6 years 1 month). The mean follow-up was 52 months (range, 9 months to 9 years).

MAIN OUTCOME MEASURES

All patients had audiophonological and clinical examination, computed tomography scan of the temporal bones, ophthalmologic examination with fundoscopy, and an electroretinogram. Cerebral magnetic resonance imaging and vestibular examination were performed in 9 of 13 and 10 of 13 cases, respectively. Logopedic outcome measured preimplant and postimplant closed- and open-set word recognition and oral expression at follow-up.

RESULTS

The most frequent initial sign of Usher syndrome was delayed walking, with a mean age of 20 months. Among the 172 other congenitally deaf children with implants, when deafness was not associated with other neurologic disorders, the mean age at walking was 14 months (p < 0.001). The fundoscopy was always abnormal after the age of 5 years, and the electroretinogram was abnormal in all cases. Vestibular function was abnormal in all but one case (nonclassified). The computed tomography scan and the magnetic resonance imaging were always normal. Logopedic results with cochlear implants showed good perception skills in all but one case. The best perceptive results were obtained in children implanted before the age of 9 years. Oral language had significantly progressed in 9 of 13 at follow-up. There was no relation between the visual acuity and the logopedic results.

CONCLUSION

The earliest clinical sign associated with deafness evoking Usher syndrome is late walking. The electroretinogram is the only reliable examination to enable the diagnosis. When severe profound deafness is associated with late walking, the electroretinogram should be systematically proposed. Logopedic results are linked to precocity of implantation, and early Usher's diagnosis contributes to optimize speech therapy.

Speech perception of Mandarin Chinese speaking young children after cochlear implant use: effect of age at implantation

OBJECTIVE

The purposes of this study were to examine (1). whether the benefit of cochlear implants in Mandarin-speaking congenitally deaf children persists over a 2-year follow-up period, and (2). whether the age of the child at implantation affects the acquisition of speech perception by young deafened children.

METHOD

Sixteen congenitally deaf children received implants of Nucleus CI24M devices. Speech perception tests were conducted using the Mandarin Auditory Perception Test Battery at 6-month intervals after connection of the device. We determined the benefit of cochlear implants by monitoring percent correct scores between 12 and 24 months after implantation. Regression analysis was used to correlate the measures of progress and the age at implantation.

RESULTS

In the comparison of performance at 12 and 24 months post-connection, subjects performed significantly better at 24 than at 12 months in spondee, vowel, and consonant tests (P<0.05). In phrase and sentence tests, the mean score improved over time with device use, but the difference was not significant (P=0.066 and 0.067, respectively). However, no obvious improvement in average score was found in tone tests (P=0.386). Progress (improvement in speech perception) at 12 and 24 months had moderate negative correlations with age at implantation in spondee, vowel, phrase and sentence tests (P<0.05), but no correlation with age in consonant (P=0.20) and tone tests (P=0.26).

CONCLUSION

The result, in accordance with the reports on Western language-speaking children, showed cochlear implants increasingly benefit Mandarin-speaking congenitally deaf children over a 2-year post-implantation period. Because age at implantation negatively correlates with improved speech perception after implantation, congenitally affected children with profound deafness (if they cannot obtain enough benefit from hearing aids) should receive implants as early as possible.

Binary partitioning for continuous longitudinal data: categorizing a prognostic variable

We investigate a binary partitioning algorithm in the case of a continuous repeated measures outcome. The procedure is based on the use of the likelihood ratio statistic to evaluate the performance of individual splits. The procedure partitions a set of longitudinal data into two mutually exclusive groups based on an optimal split of a continuous prognostic variable. A permutation test is used to assess the level of significance associated with the optimal split, and a bootstrap confidence interval is obtained for the optimal split.

Evaluation of cochlear implant benefit with auditory cortical evoked potentials

Endogenous P300 and exogenous slow vertex potentials were obtained with tone and speech stimuli in a group of five children using a cochlear implant (CI) with poor speech recognition (group A) and compared with those from another group of five children using a CI with good speech recognition (group B). The responses were also compared to those of children with normal hearing (n= 14) and a group of adult CI users (n=9). N1 and P2 latencies of CI group A and group B were prolonged compared to those of normally-hearing children. In group A, P300 was present when contrasts with tone stimuli were used. When speech stimuli were used, P300 potentials were absent or delayed. P300 potentials obtained in group B were no different from those obtained in normally-hearing children. It is suggested that the poor results evoked with speech stimuli in contrast to those evoked with pure-tone stimuli in group A are due to the immaturity of (sub) cortical generators associated with acoustical and phonetic processing. In contrast to the children in group B, all children in group A suffered from congenital deafness.

Speech perception outcomes in older children who use multichannel cochlear implants: older is not always poorer

Speech perception outcomes for early-deafened children who undergo implantation as teenagers or young adults are generally reported to be poorer than results for young children. It is important to provide appropriate expectations when counseling adolescents and their families to help them make an informed choice regarding cochlear implant surgery. The considerable variation of results in this group makes this process more difficult. This study considered a number of factors in a group of 25 children who underwent implantation in Melbourne between the ages of 8 and 18 years. Each subject completed open-set speech perception testing with Bamford-Kowal-Bench sentences before and after implantation and preoperative language testing with the Peabody Picture Vocabulary Test. Data were collected regarding the type of hearing loss, age at implantation, age at hearing aid fitting, audiometric details, and preoperative and postoperative communication mode. Results were submitted to a stepwise multiple linear regression analysis with postoperative open-set sentence scores as the dependent variables. The analysis suggested that 3 factors have a significant predictive value for speech perception after implantation: preoperative open-set sentence score, duration of profound hearing loss, and equivalent language age. These 3 factors accounted for 66% of the variance in this group. The results of this study suggest that children who have useful speech perception before implantation, and higher age-equivalent scores on language measures, would be expected to do well with a cochlear implant. Consistent with other studies, a shorter duration of profound hearing loss is also advantageous. The mean sentence score for this group, 47%, was not significantly different from the mean result across all children in the Melbourne program.

Influence of age at implantation and of residual hearing on speech outcome measures after cochlear implantation: binary partitioning analysis

The goal of this study was to evaluate speech understanding outcomes in prelingually deaf children who use a cochlear implant device. Specifically, we discuss investigations on 2 prognostic variables--age at implantation and degree of residual hearing--and use a novel method: binary partitioning analysis. Our outcome measures are standard speech perception evaluations, including the Word Intelligibility by Picture Identification (WIPI) test, the Phonetically Balanced-Kindergarten (PBK) test, and the Glendonald Auditory Screening Procedure (GASP). Regarding age at implantation, we definitely showed that growth rates of speech understanding do relate to age at implantation, but not in a simple fashion. We used binary partitioning in an attempt to find the age at implantation that best separates the performances of children with younger versus older ages at implantation. We found that there is no one "critical age"; much appears to depend on the nature and difficulty (eg, whether open- or closed-set) of the test used. Regarding residual hearing, binary partitioning analysis was unable to show that the amount of residual hearing (as shown by preimplantation audiometric data) has any significant bearing on speech outcome measures in congenitally or prelingually deaf children.

Variation in speech perception scores among children with cochlear implants

OBJECTIVE

The objective of this study was to identify common factors affecting speech perception scores in children with cochlear implants.

DESIGN

Speech perception data for 167 implanted children were collected at two cochlear implant centres in Melbourne and Sydney. The data comprised audition-alone scores on open-set word and sentence tests. Children were selected on the basis that they had a Nucleus 22-electrode cochlear implant. The average age of the children was 5 yr. Information was also collected about 12 factors that may have influenced speech perception scores for each child. Analysis of covariance was used to identify factors that significantly affected speech perception scores. Pearson pairwise correlation coefficients were also calculated for all factors analyzed.

RESULTS

The analyses in this study identified factors that accounted for 51%, 34%, and 45% of the variance in phoneme, word and sentence perception scores. Scores decreased by 1.4 to 2.4% per year of profound deafness prior to implantation. Children who normally use oral communication scored significantly higher than children normally using sign or simultaneous oral and sign communication. Children implanted in Sydney scored higher on average than children implanted in Melbourne.

CONCLUSIONS

The results show that a significant part of the variation in speech perception scores is systematically related to audiological and environmental factors for each child. The reasons for significant differences between children using different communication modes or from different clinics were not identified.

Progressive hearing loss in hearing impaired children: immediate results of antiphlogistic--rheologic infusion therapy

OBJECTIVE

The question whether progressive sensorineural hearing loss during childhood is the fateful course of a main illness has been discussed controversially over 60 years. No medicamentous therapy with satisfactory results has been described in the literature. The goal of this study was to determine whether an infusion therapy, developed for the treatment of sudden hearing loss in the elderly, can induce recovery after progression in sensorineural hearing loss during childhood.

METHODS

Out of 20 children suffering from acute progression in sensorineural hearing loss, seven children were treated with an infusion therapy containing prednisolone, pentoxifylline and a plasma expander (group I), and 13 children were not treated (group II). All children were advised not to use hearing aids for 6 weeks.

RESULTS

In group I, we observed partial to complete restoration of hearing threshold towards the original hearing threshold given by previous routine controls in 6/7 children. In group II, only three children recovered, with the state of ten children's' hearing loss remaining unchanged. The long-term follow-up, however, showed no distinct difference in either group.

CONCLUSION

Infusion therapy can be helpful when treating acutely progressing sensorineural hearing loss during childhood. The benefit for communicative competence has to be discussed. Further studies should be conducted.

Audiophonological results after cochlear implantation in 40 congenitally deaf patients: preliminary results

The aim of this study is to evaluate the prognostic factors of audiophonological results in cochlear implant in congenitally deaf patients. Between 1991 and 1996. 40 congenitally deaf children underwent cochlear implantation in our department, at an average age of 7 years (median: 5 years). The results of speech therapy were evaluated with a mean follow-up of 2 years and were classified according to four criteria: perception of sound, speech perception, speech production and the level of oral language. For each criterion, a score was established ranging from zero to four. These scores were weighted according to age such that the results before and after implantation only reflected the changes related to the implantation. The prognostic factors for good results were: a good level of oral communication before implantation, residual hearing, progressive deafness and implantation at a young age. On the other hand, poor prognostic factors were: the presence of behavioral disorders and poor communication skills prior to implantation. Overall, the major prognostic factor for a good outcome appeared to be the preoperative level of oral language, even if this was rudimentary.

Cochlear implantation in the very young child

Children younger than 2 years of age were initially excluded from cochlear implant candidacy for a variety of reasons. Reasons ranged from concerns about the reliability of the diagnosis of a profound hearing loss in very young children, to concerns about surgical safety and long-term durability of the device in a growing child. Results from several recent studies have shown that children younger than 2 years of age can safely and successfully be implanted. Provided this success, and the general agreement that early remediation of a hearing loss provides a greater potential for speech and language development, implantation of very young children may soon become the norm rather than the exception. This article discusses the issues related to the implantation of young children and the need for special tools and protocols to use with this population.

The role of a graded profile analysis in determining candidacy and outcome for cochlear implantation in children

Assessment of candidacy for cochlear implantation in children continues to present a challenge to cochlear implant programs. The efficacy of implantation depends on a number of factors and as a result a multidisciplinary approach has been adopted. At the Cochlear Implant Program at The Hospital for Sick Children, Toronto, we use a graded profile analysis (GPA) which has been adapted from the Children's Implant Profile (CHIP) developed by Hellman (S.A. Hellman, P.M. Chute, R.E. Kretschmer, M.E., Nevins, S.C. Parisier, L.C. Thurston, The development of a Children's Implant Profile, Am. Ann. Deaf. 136 (1991) 77-81). This structured assessment allows each potential candidate to be 'scored' in each category of assessment giving a potential range of -14 to +14. In this retrospective study of 109 candidates we examine the relationship between GPA scores and decision to implant. For those patients who were implanted, the relationship between GPA score and speech perception outcomes was also evaluated. Three distinct groups of children emerged from the analysis. The first group had scores less than 5 and were not considered to be suitable for implantation. Within the second group who scored between 5 and 8, there was no clear relationship between decision to implant and score. The last group, who scored 9-14, was considered to be generally suitable for implantation provided that there were no medical contraindications and the parents consented to implantation. There was a significant association between rate of improvement of speech perception and GPA score. Those patients with scores of 9 to +14 improved at a faster rate than group 5-8 (P < 0.05). The implications of these findings are discussed.

Age at implantation: its importance in pediatric cochlear implantation

OBJECTIVE

To assess the influence of age at implantation on speech perception and speech intelligibility following pediatric cochlear implantation.

STUDY DESIGN

A prospective study was undertaken on a consecutive group of 126 congenital and prelingually deaf children up to 4 years after implantation. The study group was confined to prelingually deaf children less than 7 years of age at the time of implantation. All had implantation with the same multichannel cochlear implant system. No child was lost to follow-up, and there were no exclusions from the study.

METHODS

The Iowa Matrix Closed Set Sentence test, connected discourse tracking, categories of auditory performance, and speech intelligibility rating were used to assess the speech perception (closed and open set) and speech intelligibility of the children with implants. Regression analysis and Spearman rank correlation coefficients were used to assess the correlation between the outcome measures with age at implantation. The setting was a tertiary referral pediatric cochlear implant center in the United Kingdom.

RESULTS

Age at implantation positively correlated with preimplantation assessment performance and with most of the outcome measures up to 24 months following implantation. However, at the 3-and 4-year intervals following implantation, age at implantation was found to be a strong negative predictor of all the outcomes studied (correlation coefficients ranging from -0.44 to -0.58, all statistically significant [P<.05]).

CONCLUSIONS

The results of the present study provide strong evidence that prelingually deaf children should receive implants as early as possible to facilitate the later development of speech perception skills and speech intelligibility and thus maximize the health gain from the intervention. However, because of the wide variation in individual outcomes, age alone should not be used as a criterion to decide implant candidacy.