Kevin Green

Factors Affecting Auditory Performance of Postlinguistically Deaf Adults Using Cochlear Implants: An Update with 2251 Patients

Objective: To update a 15-year-old study of 800 postlinguistically deaf adult patients showing how duration of severe to profound hearing loss, age at cochlear implantation (CI), age at onset of severe to profound hearing loss, etiology and CI experience affected CI outcome. Study Design: Retrospective multicenter study. Methods: Data from 2251 adult patients implanted since 2003 in 15 international centers were collected and speech scores in quiet were converted to percentile ranks to remove differences between centers. Results: The negative effect of long duration of severe to profound hearing loss was less important in the new data than in 1996; the effects of age at CI and age at onset of severe to profound hearing loss were delayed until older ages; etiology had a smaller effect, and the effect of CI experience was greater with a steeper learning curve. Patients with longer durations of severe to profound hearing loss were less likely to improve with CI experience than patients with shorter duration of severe to profound hearing loss. Conclusions: The factors that were relevant in 1996 were still relevant in 2011, although their relative importance had changed. Relaxed patient selection criteria, improved clinical management of hearing loss, modifications of surgical practice, and improved devices may explain the differences.

Pre-, Per- and Postoperative Factors Affecting Performance of Postlinguistically Deaf Adults Using Cochlear Implants: A New Conceptual Model over Time

Objective To test the influence of multiple factors on cochlear implant (CI) speech performance in quiet and in noise for postlinguistically deaf adults, and to design a model of predicted auditory performance with a CI as a function of the significant factors. Study Design Retrospective multi-centre study. Methods Data from 2251 patients implanted since 2003 in 15 international centres were collected. Speech scores in quiet and in noise were converted into percentile ranks to remove differences between centres. The influence of 15 pre-, per- and postoperative factors, such as the duration of moderate hearing loss (mHL), the surgical approach (cochleostomy or round window approach), the angle of insertion, the percentage of active electrodes, and the brand of device were tested. The usual factors, duration of profound HL (pHL), age, etiology, duration of CI experience, that are already known to have an influence, were included in the statistical analyses. Results The significant factors were: the pure tone average threshold of the better ear, the brand of device, the percentage of active electrodes, the use of hearing aids (HAs) during the period of pHL, and the duration of mHL. Conclusions A new model was designed showing a decrease of performance that started during the period of mHL, and became faster during the period of pHL. The use of bilateral HAs slowed down the related central reorganization that is the likely cause of the decreased performance.

Complications of bone-anchored hearing aid implantation

INTRODUCTION Bone-anchored hearing aid implantations have been performed in Manchester for over 20 years. This study examined a range of variables that can occur during the implantation process, and the effect they may have on successful outcome. METHOD Retrospective study and literature review. LOCATION Tertiary referral centre in central Manchester. RESULTS Details of 602 bone-anchored hearing aid implantation procedures were retrieved from the departmental database. The overall complication rate was 23.9 per cent. The rate of revision surgery was 12.1 per cent. CONCLUSION This study involved a significantly larger number of patients than any previously reported, similar study. Possible reasons for differences in outcomes, and recommendations for best practice, are discussed.

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.

Complications following adult cochlear implantation: experience in Manchester

Cochlear implantation is regarded as a safe and effective treatment for the profoundly deaf. However, a proportion of patients suffer complications after implant surgery. This paper examines the complications encountered in 240 adult cochlear implant operations performed in Manchester between June 1988 and June 2002. Minor complications were defined as those that either settled spontaneously or with conservative management. The total number of minor complications was 61 (25.4 per cent of cases). Non-auditory stimulation, which resolved with implant reprogramming, was present in 53 cases (22.1 per cent). Major complications were defined as those requiring further surgery, explantation or causing a significant medical problem, and occurred in 15 patients (6.25 per cent). These included implant extrusion, implant sepsis, electrode migration, flap-related problems, and persistent non-auditory stimulation. Nine of the 15 patients suffering a major complication required explantation. There were no post-operative deaths, cases of meningitis, nor persistent facial palsies in the series.

Stability, survival, and tolerability of a novel baha implant system: six-month data from a multicenter clinical investigation

Objective: Determination of the difference in implant stability between a novel Baha implant system (test) and the previous-generation implant system (control). Methods: In an open, randomized, prospective multicenter clinical investigation, 77 adult patients with Baha implants were included. Test and control implants were randomly assigned in proportions of 2:1. Implant stability quotient (ISQ) values were recorded using resonance frequency analysis at the time of implantation and at 10 days, at 4, 6, 8, and 12 weeks, and at 6 months after surgery. Skin reactions were evaluated according to the Holgers classification. Sound processor fitting was performed from 6 weeks after implantation. Results: Significantly higher mean ISQ values, measured between 0 and 6 months, were obtained for test compared to control implants (70.4 versus 65.4, p < 0.0001). Statistically significant differences were obtained for the study population as a whole and for the subgroup of patients loaded at 6 ± 1 weeks after implant surgery (63.6% of patients). Up to 12 weeks, Holgers rates were comparable, whereas at 6 months, more skin reactions (Grades 1 and 2) were observed in the control implant group. No reduction in mean ISQ values was observed after implant loading. Conclusion: The test implant showed higher mean ISQ values at the time of placement and over time. The level of osseointegration reached with the implants in adults as early as 6 weeks after implantation was sufficient to support the sound processor. The test implant system is expected to provide additional benefits related to the improvement of the degree of osseointegration, especially for patients with thin or compromised bone.

Cochlear implantation in children with cerebral palsy

OBJECTIVE Few studies have looked at the outcomes of children with complex needs following cochlear implantation. Increasing evidence supports the case for implantation in these children. To date there is very little evidence available evaluating the role of cochlear implantation in children with cerebral palsy. In this paper we look at the Manchester Cochlear Implant Programmes experience of implantation in 36 children with cerebral palsy. METHODS A retrospective review of prospectively collected data for all children with cerebral palsy was undertaken. Cognitive and physical disability was scored by members of the cochlear implant team. A modified version of Geers and Moogs 1987 Speech Reception Score was used to assess outcome. Data was analysed looking at the relationship between cognitive and physical impairment, age at implantation and the SRS outcomes. RESULTS This study demonstrated that children with cerebral palsy and a mild cognitive impairment do significantly better following implantation than those with a severe impairment (p=0.008). Children with mild physical impairment did not appear to do significantly better than those with moderate or severe impairments (mild versus severe p=0.13). Age at implantation was not a significant prognostic factor in this study group. CONCLUSIONS Children with complex needs are increasingly being referred for consideration of cochlear implantation. Further research is required to help guide candidacy, but each case must be considered individually. Higher functioning does appear to be the most important prognostic indicator regarding outcome but the effect of modest improvement in sound perception should not be underestimated.

Hearing preservation via a cochleostomy approach and deep insertion of a standard length cochlear implant electrode.

Objective The suggestion that the depth of insertion of the electrode into the cochlea is critical to hearing preservation has led to the development of a generation of short electrodes designed to minimize intracochlear trauma and avoid contact with the apical region of the cochlea. This study aims to describe our experience of hearing preservation surgery using a deeply inserted standard length electrode array covering the region of residual hearing. Study Design A retrospective case note review was performed identifying cases of attempted hearing preservation using standard length electrodes. Setting Study based at Manchester Royal Infirmary, a tertiary referral center. Patients Fourteen cochlear implants in 13 patients were identified for further analysis from the Manchester Cochlear Implant Programme database. Intervention(s) Each patient received the same design of implant using a “soft” surgical technique. Main Outcome Measure Preoperative and postoperative air conduction thresholds were compared to assess the degree of hearing preservation. Results Successful hearing preservation was demonstrated in 12 of 14 cases, and the postoperative residual hearing thresholds in 3 adolescents receiving a standard length electrode array were found to have improved. Preservation of speech recognition was not measured in this study, rather hearing was tested by pure tone audiogram. Follow-up at the time of this study ranged from 1 week to 23 months. Conclusion This study demonstrates that deep insertion of the electrode into the cochlea does not preclude successful hearing preservation. It also highlights that residual hearing can be consistently preserved using a “cochleostomy” approach.

A retrospective Multicenter Study comparing Speech Perception outcomes for Bilateral Implantation and Bimodal rehabilitation

Objectives: To compare speech perception outcomes between bilateral implantation (cochlear implants [CIs]) and bimodal rehabilitation (one CI on one side plus one hearing aid [HA] on the other side) and to explore the clinical factors that may cause asymmetric performances in speech intelligibility between the two ears in case of bilateral implantation. Design: Retrospective data from 2247 patients implanted since 2003 in 15 international centers were collected. Intelligibility scores, measured in quiet and in noise, were converted into percentile ranks to remove differences between centers. The influence of the listening mode among three independent groups, one CI alone (n = 1572), bimodal listening (CI/HA, n = 589), and bilateral CIs (CI/CI, n = 86), was compared in an analysis taking into account the influence of other factors such as duration of profound hearing loss, age, etiology, and duration of CI experience. No within-subject comparison (i.e., monitoring outcome modifications in CI/HA subjects becoming CI/CI) was possible from this dataset. Further analyses were conducted on the CI/CI subgroup to investigate a number of factors, such as implantation side, duration of hearing loss, amount of residual hearing, and use of HAs that may explain asymmetric performances of this subgroup. Results: Intelligibility ranked scores in quiet and in noise were significantly greater with both CI/CI and CI/HA than with a CI-alone group, and improvement with CI/CI (+11% and +16% in quiet and in noise, respectively) was significantly better than with CI/HA (+6% and +9% in quiet and in noise, respectively). From the CI/HA group, only subjects with ranked preoperative aided speech scores >60% performed as well as CI/CI participants. Furthermore, CI/CI subjects displayed significantly lower preoperative aided speech scores on average compared with that displayed by CI/HA subjects. Routine clinical data available from the present database did not explain the asymmetrical results of bilateral implantation. Conclusions: This retrospective study, based on basic speech audiometry (no lateralization cues), indicates that, on average, a second CI is likely to provide slightly better postoperative speech outcome than an additional HA for people with very low preoperative performance. These results may be taken into consideration to refine surgical indications for CIs.

Cerebrospinal fluid leak rate after the use of BioGlue in translabyrinthine vestibular schwannoma surgery: a prospective study.

Objective: To determine the effectiveness of BioGlue surgical adhesive in dural and middle ear closure after translabyrinthine vestibular schwannoma surgery. Study Design: A prospective study. Setting: Tertiary neurotological referral center. Patients: There were 24 patients in the BioGlue series. BioGlue was used in the same manner in all cases. All patients received similar postoperative care. Interventions: We studied the use of BioGlue and its possible effect on further reducing our departments cerebrospinal fluid leak rate for translabyrinthine vestibular schwannoma surgery. Main Outcome Measures: Postoperative events were documented that enabled us to determine the overall cerebrospinal fluid leak rate (including incidence of various leak routes and morbidity). Results: The overall cerebrospinal fluid leak rate was 62.5% (15 of 24). Rhinorrhoea was the commonest route (80%), followed by postaural wound leak (33.3%) and external auditory canal otorrhoea (33.3%). Forty percent of cases had more than one cerebrospinal fluid leak route; 73.3% of leak cases required lumbar drain insertion, 40% needed pressure bandaging, and 66.7% had to undergo formal surgical repair. Forty percent had recurrent leaks after the initial episode had completely ceased. The mean extra stay in hospital as a result of the cerebrospinal fluid leak was 13.3 days. Conclusion: Our preliminary prospective study of the use of BioGlue for dural and middle ear closure in translabyrinthine vestibular schwannoma surgery demonstrated poor results. The high cerebrospinal fluid leak rate associated with the unusual presentations and ensuing management difficulties in controlling these leaks lead us to recommend that BioGlue not be used in translabyrinthine vestibular schwannoma surgery. The manufacturers have noted our results and have considered adding our recommendation to the product data sheet.