Positron emission tomography in cochlear implant and auditory brainstem implant recipients

Positron emission tomography (PET) imaging was used to evaluate the brain's response to auditory stimulation, including speech. Five cases of adults illustrate the utility of PET to illuminate auditory processing with cochlear or brainstem implants. Subjects showed varying degrees of success in processing speech, which was reflected in the resulting PET images. Functional speech processing was associated with activation in areas classically associated with speech processing. In one patient who did not achieve functional speech processing, activation in frontal regions suggests that the subject used other cognitive strategies to assist auditory processing. Learning outcomes: As a result of this activity, the participant will be introduced to the principles of PET and the application of this technology to deaf patients who have received an implanted auditory prosthesis.     

REZ-1人工耳蜗电极植入方法的改进研究

目的 探讨使REZ-1人工耳蜗电极靠近蜗轴的植入方法.方法 22例尸头标本CT扫描测量耳蜗直径后,植入REZ-1人工耳蜗电极,完成植入后回撤1～2个电极环,耳蜗位摄片,测量蜗轴与电极环之间距离是否有所改变.测量60例CT扫描显示一侧中耳、内耳结构正常病例的耳蜗直径.结果 22例标本中3例植入27个电极环,19例植入28个电极环.回撤电极后,与回撤前相比17例标本中第12至第19个电极环与蜗轴的距离减小(配对t检验,P<0.01),该17例标本的耳蜗直径均小于9.50 mm;而耳蜗直径大于9.60 mm的5例标本均没有出现电极环靠近蜗轴的改变.17例电极回撤后靠近蜗轴的标本耳蜗直径为9.11(0.57)mm[中位数(四分位数间距),下同],另外5例标本耳蜗卣径为9.78(0.28)mm,二者差异具有统计学意义(Mann-Whitney秩和检验,P<0.001).60例正常耳蜗直径(x±s)为(9.04±0.45)mm,90%小于9.50 mm.结论 REZ-1人工耳蜗电极植入后回撤电极的植入方法可以使耳蜗直径小于9.50 mm的患者底回内部分电极环靠近蜗轴.术前CT扫描测量耳蜗直径可以为REZ-1人工耳蜗电极选择植入方法提供帮助.     

Patients' involvement in choosing a cochlear implant

Abstract

Objective

The study describes the procedure followed by the South of England Cochlear Implant Centre, Southampton in involving the patients in their choice of device and it also describes the reasons given by patients for choosing a particular device.

Methods

A retrospective service evaluation of 43 adults and 19 children was carried out and the data was analysed.

Results

A wide range of reasons for choosing a particular device were reported. However, it is notable that the single most common reason for choosing a particular device was related to the aesthetics.

Discussion

The data suggest that the main reason for choosing a particular device related more to the aesthetics and comfort of the device irrespective of the technical aspects.     

语后聋人工耳蜗患者音乐节奏与音色感知能力的评价

目的 评价成人语后聋人工耳蜗使用者感知音乐中节奏和音色的能力.方法 选取年龄与音乐经验相匹配的听力正常受试者与人工耳蜗使用者各12名,均为男5名,女7名.应用人工耳蜗音乐评估软件( Musical Sounds in Cochlear Implants,MuSIC)中的节奏辨别、乐器识别与乐器数辨别测试评价两组受试者的音乐节奏和音色感知能力.结果 12名人工耳蜗受试者平均节奏辨别率为84.4％,与听力正常受试者(85.1％)比较,差异无统计学意义(t=0.116,P＞0.05);人工耳蜗受试者平均乐器识别率为72.3％、乐器数辨别正确率为39.2％,均低于听力正常受试者平均88.3％和73.5％的正确率,差异具有统计学意义(t值分别为2.498和4.673,P值均＜0.05).结论 成人语后聋人工耳蜗使用者的节奏辨别能力与听力正常人相似,但音色感知能力明显差于听力正常人群.     

The role of post-operative imaging in cochlear implant surgery: A review of 220 adult cases

Abstract

Objectives

To determine the incidence of abnormal radiological findings after cochlear implantation and their effect on clinical outcomes.

Methods

Retrospective review of 220 adult cochlear implants. Clinical records and post-operative plain X-rays were reviewed and compared with pre-operative and 6-month post-operative City University of New York (CUNY) speech scores.

Results

There were no cases of extra-cochlear array misplacement. Imaging showed 20 cases of incomplete array insertion (9.2%), 3 cases of kinking of the array (1.4%), 2 cases of tip rollover (0.9%), and 1 case of apparent array fracture (0.5%). Patient management was not altered by abnormal imaging. Patients with abnormal radiological findings had slightly minor improvements (median 39 vs. 56%) in City University of New York (CUNY) speech discrimination scores at 6 months (Mann–Whitney U test, P = 0.043).

Conclusion

All abnormalities on post-operative imaging were minor and did not alter patient management. The future role of post-operative imaging is discussed.     

Systematic review of cochlear implantation in CHARGE syndrome

Objective: CHARGE syndrome presents with a collection of congenital anomalies affecting multiple organs. Ear and temporal bone anomalies, including hearing loss are highly prevalent.

We present an aid to management of this challenging condition and report the strategies and outcomes of cochlear implantation.

Methods: Systematic review of Medline, EMBASE, Web of Science, CENTRAL and clinicaltrials.gov was performed up to 21/10/2018

The review and meta-analysis of studies were performed according to the PRISMA statement.

Patient demographics, comorbidity, anatomical factors, details of cochlear implantation and audiological outcome were extracted and summarized. Anatomical and surgical factors were evaluated by meta-analysis. Audiological outcomes reported were too heterogeneous for meta-analysis.

All statistics were calculated with SPSS v23.0 (IBM, New York, USA).

Results: Thirty-one studies reported 165 cochlear implants in 156 patients with CHARGE syndrome. Temporal bone and facial nerve anomalies were common.

Discussion: The assessment and management of patients with CHARGE syndrome undergoing cochlear implantation is challenging. Outcomes may be affected by cochlear nerve deficiency, inner ear anomalies, and developmental delay. Surgery is almost invariably complicated by abnormal anatomy, and increased incidence of complications.

Conclusion: A careful, case-by-case assessment of an individual's requirements within a multi-disciplinary setup is essential for achieving the best possible outcome.     

Social hearing measured with the Performance Inventory for Profound and Severe Loss: a comparison between adult multichannel cochlear implant patients and users of acoustical hearing aids

The objective of this study was to investigate social hearing in successful users of multichannel cochlear implants (CIs) and to compare the scores with those of a group of hearing-impaired adults using acoustical hearing aids (HAs). Out of 88 patients who had undergone surgery, 75 CI users with a mean age of 55 years and a mean pre-operative hearing level of 113dB in the better ear were compared with 59 users of acoustical HAs with a mean age of 56 years and a mean hearing level of 82dB in the better ear. Seven CI patients were non-users and were excluded from the study. The Performance Inventory for Profound and Severe Loss, a questionnaire that measures different aspects of hearing handicap, was used. The CI group scored significantly better than the HA group in three of six evaluated categories, measuring subjective intensity of sounds, speech with visual cues, and response to auditory failure. Awareness of environmental sounds, speech with no visual cues and personal reactions did not differ significantly. The group of successful CI users scored higher on a self-report measure than did a group of users of acoustical HAs with moderate- severe-profound deafness. The best CI users scored better than the best HA users, and the worst CI users scored worse than the worst HA users.     

Mycobacterium abscessus infection of a cochlear implant insertion site

Infectious complications of cochlear implantation are unusual but can be severe, often requiring implant removal. We report a child who underwent cochlear implant revision and developed a post-operative infection with Mycobacterium abscessus complex. The patient's symptoms were refractory to empiric antibacterial therapy. After more than 2 weeks incubation, M. abscessus complex grew in culture. Resolution of the infection was achieved utilizing prolonged multi-drug therapy and device removal with the intra-cochlear leads remaining in place. Clinical signs of an infectious process with concomitant sterile bacterial cultures should raise concern for a potential mycobacterial infection in association with cochlear implantation.     

The long-term results of speech perception in elderly cochlear implant users

Objectives: To evaluate the speech discrimination performance of elderly post-lingually deafened cochlear implant (CI) users and the stability of performance over time relative to a control group of younger CI users.

Methods: The study group consisted of 20 native Dutch speaking, post-lingually deafened CI users, aged 70 or older at the time of implantation. Controls were patients aged 40–60 years at implantation and included according to the same inclusion criteria (except age). Linear mixed models assessed speech recognition scores between groups, the variability of their performance, and stability over time.

Results: 20 elderly and 37 controls were included. The mean follow-up was 4.4 and 5.3 years for elderly and controls, respectively. There was no significant difference in average speech discrimination between both groups. The elderly group had a larger intra-subject variability over time. There was no significant effect of follow-up on the speech discrimination, indicating a stable performance over time.

Discussion: This study has a longer follow-up than methodologically comparable previous studies. We found no difference in speech discrimination between elderly patients and controls and no deterioration of performance over time. The subjects in the elderly group exhibit a larger variability around their mean performance.

Conclusion: Speech recognition in both elderly and younger adult CI users is stable over time and is not significantly related to the age of implantation.     

Residual hearing in cochlear implant patients

Preservation of residual hearing should be a desirable outcome of implant surgery. Prevention of neural degeneration due to loss of residual hair cells, together with the continuous progress in cochlear implant technology should be able to preserve cochlear integrity as well as possible. The degree of hearing preservation may vary depending on surgical approach, maximum insertion depth and other factors not uniformly considered to date. The aim of this retrospective case controlled study is to evaluate residual hearing after cochlear implant surgery. In particular, we analyzed data obtained with use of two different kinds of electrode arrays, with and without rigid introductor (stylet). We report the results on 37 patients with measurable preoperative hearing thresholds, mean age of 28 years (5–70 years), having the following implants: seven Advanced Bionics^®, four Med-El^®, 24 Cochlear^®, two MXM^®; 19 of them were performed using the stylet and the other 18 without it. A minimally invasive surgical approach was performed with a short retroauricular incision and a 1.2 mm cochleostomy. A complete electrode array insertion was obtained in all patients. Responses to pure-tone stimuli were measured for each ear in pre-implantation conditions and 3–12 months after surgery. After implantation 14 patients (38%) showed no hearing threshold variation, 29 (78%) maintained an appreciable hearing threshold level in the implanted ear, 8 (22%) had a total loss of residual hearing. Median increases of threshold levels were, in all 37 studied patients, 5, 10, 10 and 5 dB HL, respectively, for 125, 250, 500 and 1 kHz. For the 18 patients having implants without the stylet median increases of threshold levels were 0, 10, 5 and 7 dB HL; in the stylet group, they were 10, 5, 5 and 10 dB HL. On a comparison between the stylet and the non-stylet group, no significant differences in mean hearing threshold worsening were found. Data seem to suggest that cochlear function is less sensitive to mechanical trauma during implant surgery than was thought. Besides, electrode array stiffness seems not to influence preservation of cochlear residual functional integrity. Finally, the authors hypothesize a direct spiral ganglion activation under strong mechanical stimulation.     

Computer modelling of the cochlea and the cochlear implant: A review

Abstract

In the last few decades, cochlear implants have experienced major developments with intensive studies carried out through experimental and computational analysis. With the rapid increase in computational resources available and the development of efficient computational techniques, computer models of the cochlea and the cochlear implant have become more sophisticated. It is now possible to analyze the micromechanics of the cochlea and the transient response of tissue to external stimulation. This study reviews the major developments in cochlear models, summarizes, and categorizes features of models used in different studies and makes recommendations for future development. The paper is classified into four sections detailing features of the cochlear models, electrodes, electrical stimulation, and software used in different studies. The paper highlights unexplored areas in the model design and suggests additions to develop a better computer model.     

Case report: Staphylococcus aureus biofilm formation on an explanted cochlear implant demonstrated using an ultrasonication technique

Abstract

Relevance

Biofilm forming microorganisms are responsible for the infection of a number of different indwelling medical devices including cochlear implants. The current definitive technique for proving biofilm infection is the use of scanning electron microscopy that is expensive and of limited availability.

Clinical presentation

A persistently infected cochlear implant was explanted. At operation it was surrounded by a fibrous capsule containing a glue-like substance, characteristic of biofilm formation that yielded Staphylococcus aureus after ultrasonication of the device.

Technique

The explanted cochlear implant was placed in a nutrient broth in an ultrasonic water bath. The implant was ultrasonicated for 5 minutes and the broth cultured on blood agar, incubated aerobically and anaerobically for 48 hours, and then incubated in air on Maconkey agar for 24 hours. This produced a heavy, confluent growth of S. aureus, in contrast to previous aspirates from a blister that lay over the infected implant that grew a coliform organism and Pseudomonas sp.

Conclusion

Ultrasonication is a widely available and relatively inexpensive technique that can be used to improve the recovery of biofilm-associated organisms from explanted cochlear implants.     

Pitch ranking of complex tones by normally hearing subjects and cochlear implant users

The ability of 10 normally hearing (NH) adults and eight cochlear implant (CI) users to pitch-rank pairs of complex tones was assessed. The acoustically presented stimuli differed in fundamental frequency (F0) by either one or six semitones (F0 range: 98 to 740 Hz). The NH group obtained significantly higher mean scores for both experiments: (NH: one semitone – 81.2%, six semitones – 89.0%; CI: one semitone – 49.0%, six semitones – 60.2%; p < 0.001). Prior musical experience was found to be associated with higher pitch-ranking scores for the NH subjects. Those with musical experience ratings <3 obtained significantly lower scores for both interval sizes (p < 0.001) than those with higher ratings. Nevertheless, the scores obtained by the musically inexperienced, NH adults were significantly higher than those obtained by the CI group for both the one-semitone (p = 0.022) and six-semitone (p = 0.018) intervals. These results suggest that the pitch information CI users obtain from their implant systems is less accurate than that obtained by NH listeners when listening to the same complex sounds. Furthermore, the relatively poor pitch-ranking ability of at least some CI users may be associated with a more-limited experience of music in general.     

Assessment of cochlear implant candidacy in patients with cochlear nerve deficiency using the P1 CAEP biomarker

Abstract

Objective

The goal of this report was to ascertain the efficacy of the P1 cortical auditory evoked potential (CAEP) biomarker as an objective tool to assist in the evaluation of cochlear implant (CI) candidacy in children with a radiological diagnosis of cochlear nerve deficiency (CND).

Methods

Retrospective case study review of audiological and radiological findings was performed in four pediatric patients identified with CND and severe-to-profound sensorineural hearing loss. Cortical auditory evoked potential testing was conducted, and the presence and latency of the P1 component were analyzed.

Results

Three out of four children demonstrated robust P1 CAEP responses, indicating activation of the central auditory pathways by auditory stimulation, despite the diagnosis of CND. These children were considered good candidates for cochlear implantation.

Discussion

Although cochlear implantation in children is a fairly routine procedure, cases exist for which implant candidacy is questionable. Among these cases are children with CND. In these children, cochlear implantation may be contraindicated due to the likelihood that the implant electrodes may not stimulate the VIII nerve adequately. Magnetic resonance imaging (MRI) is considered the gold standard in the assessment of CND, but this measure is not always sufficient to determine CI candidacy in cases of CND. The addition of the P1 CAEP measurement to the usual electrophysiological, audiometric, and radiological test battery may prove to be useful in determining CI options for children with CND.     

Pre-operative appraisal of cochlear implant results by means of electrical promontory stimulation: Preliminary report

Summary A test procedure based on the patient's understanding of acoustic material is presented. The score obtained in this test showed a highly significant correlation with the postoperative score evaluated by independent examiners 4 weeks after stimulator adjustment.     

多道人工耳蜗植入533例临床分析

目的 分析人工耳蜗植入患者的手术适应证、手术方法和术后效果。方法 533例(534耳)重度和极重度聋患者接受人工耳蜗植入手术。其中语前聋495例,语后聋38例。植入时年龄:1～3岁167例,～5岁77例,-7岁73例,-14岁136例,～17岁28例,>17岁52例。内耳中耳畸形共76例,其中Mondini畸形26例、共同腔畸形10例、前庭水管扩大综合征20例。术前纯音听阈(听力级)为105.5 dB,听性脑干反应阈>95 dB,40 Hz相关电位(500 Hz)>101.7 dB。使用装置:Nucleus 22M 27耳,24M 308耳,24R Contour 131耳,24RST 21耳;Med El C40 44耳;Clarion CI 3耳。常规手术采用面隐窝进路方法。共同腔畸形病例采用经水平半规管进路。部分病例行术后声场测听和听觉言语评估。结果 Mondini畸形26例中有20例术中出现脑脊液井喷。电极平均植入深度:耳蜗正常病例中Nucleus 30环,Med El为31 mm。Mondini畸形病例中Nucleus 28环。共同腔畸形病例中Necleus 26环。语后聋患者的平均开放言语识别率为71％,17岁以下语前聋的问卷调查满意度为94.7％。结论 人工耳蜗是使重度和极重度聋患者恢复听觉功能的有效方法,术前评估,手术和术后康复都是治疗效果的关键。