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.     

The LAURA multichannel cochlear implant in a true Mondini dysplasia

A congenitally deaf child with bilateral Mondini dysplasias of the inner ear was successfully implanted with a LAURA multichannel cochlear prosthesis. This is the first report of a patient with a Mondini dysplasia in whom a LAURA multichannel cochlear prosthesis was successfully implanted. The cerebrospinal fluid leakage typically occurring after cochleostomy in similar patients was readily controlled, indicating that the deformity present was not a contra-indication for cochlear surgery. The audiological results obtained are described in detail. Since the internal unit of the LAURA prosthesis is very flexible, various speech processing strategies, such as continuous interleaved and phase-locked continuous interleaved strategies, can be tried and evaluated.     

Effects of a cochlear implant simulation on immediate memory in normal-hearing adults

This study assessed the effects of stimulus misidentification and memory processing errors on immediate memory span in 25 normal-hearing adults exposed to degraded auditory input simulating signals provided by a cochlear implant. The identification accuracy of degraded digits in isolation was measured before digit span testing. Forward and backward digit spans were shorter when digits were degraded than when they were normal. Participants’ normal digit spans and their accuracy in identifying isolated digits were used to predict digit spans in the degraded speech condition. The observed digit spans in degraded conditions did not differ significantly from predicted digit spans. This suggests that the decrease in memory span is related primarily to misidentification of digits rather than memory processing errors related to cognitive load. These findings provide complementary information to earlier research on auditory memory span of listeners exposed to degraded speech either experimentally or as a consequence of a hearing-impairment.     

IL-37靶向TSLP减轻变应性鼻炎炎症反应的研究进展

目的变应性气道炎症的研究转向关注上皮损伤与下游炎症反应之间的关系而成为目前研究的前沿和热点。上皮衍生的细胞因子胸腺基质淋巴细胞生成素(thymic stromal lymphopoietin,TSLP)是变应性炎症疾病的主要开关,在变应性鼻炎(callergic rhinitis,AR)发病机制中起重要作用。白细胞介素 37（interleukin 37,IL 37）是IL 1家族新发现的细胞因子,通过降低循环和器官细胞因子水平而成为先天免疫和炎症反应的天然抑制因子。本文主要就IL 37靶向TSLP减轻AR炎症反应进行综述。     

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。     

The cochlear implant and possibilities for narrowing the remaining gaps between prosthetic and normal hearing

BackgroundThe cochlear implant has become the standard of care for severe or worse losses in hearing and indeed has produced the first substantial restoration of a lost or absent human sense using a medical intervention. However, the devices are not perfect and many efforts to narrow the remaining gaps between prosthetic and normal hearing are underway.ObjectiveTo assess the present status of cochlear implants and to describe possibilities for improving them.ResultsThe present-day devices work well in quiet conditions for the great majority of users. However, not all users have high levels of speech reception in quiet and nearly all users struggle with speech reception in typically noisy acoustic environments. In addition, perception of sounds more complex than speech, such as most music, is generally poor unless residual hearing at low frequencies can be stimulated acoustically in conjunction with the electrical stimuli provided by the implant. Possibilities for improving the present devices include increasing the spatial specificity of neural excitation by reducing masking effects or with new stimulus modes; prudent pruning of interfering or otherwise detrimental electrodes from the stimulation map; a further relaxation in the criteria for implant candidacy, based on recent evidence from persons with high levels of residual hearing and to allow many more people to benefit from cochlear implants; and “top down” or “brain centric” approaches to implant designs and applications.ConclusionsProgress in the development of the cochlear implant and related treatments has been remarkable but room remains for improvements. The future looks bright as there are multiple promising possibilities for improvements and many talented teams are pursuing them.     

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.     

Systematic review: Radiological and histological evidence of cochlear implant insertion trauma in adult patients

Introduction: Cochlear implantation (CI) has developed from its origins in the 1980s. Initially, CI was for profound bilateral hearing impairment. However, candidacy for CI have become more widespread in recent years with unilateral implantation and an emphasis on hearing preservation.

Evidence supports full electrode insertion in an atraumatic fashion into the scala tympani (ST) provides optimal hearing outcomes. The main aim of this systematic review was to elucidate the degree of trauma associated with CI insertion.

Methods: A systematic literature search was undertaken using PubMed Medline. A grading system described by Eshraghi was used to classify cochlear trauma. Both radiological and histological studies were included.

Results: Twenty one papers were identified which were relevant to our search. In total, 653 implants were inserted and 115 (17.6%) showed evidence of trauma. The cochleas with trauma had basilar membrane elevation in 5.2%, ruptured in 5.2%, the electrode passed from the ST to the SV in 84.4% and there was grade 4 trauma in 5.2%. The studies used a variety of histological and radiological methods to assess for evidence of trauma in both cadaveric temporal bones and live recipients.

Conclusions: Minimizing cochlear trauma during implant insertion is important to preserve residual hearing and optimize audiological performance. An overall 17.6% trauma rate suggests that CI insertion could be improved with more accurate and consistent electrode insertion such as in the form of robotic guidance. The correlation of cochlea trauma with post-operative hearing has yet to be determined.     

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.     

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.     

An X-ray fluorescence microscopic analysis of the tissue surrounding the multi-channel cochlear implant electrode array

Objectives: The aim of this study was to analyse the tissue surrounding the University of Melbourne's (UOMs) multi-channel cochlear implant electrode array and cochlear limited replacements, after long-term implantations. In particular, it aimed to identify the particulate material in the fibrous tissue capsule of the arrays implanted in 1978, 1983, and 1998, by using the Australian Synchrotron for X-ray fluorescence microscopy (XFM) to reveal the characteristic spectrum of metal, in particular platinum. This also helped to determine its format and chemical state. Tissue was retrieved following the recipient's death in 2007.

Methods: Tissue was fixed and sections taken across the UOM and Cochlear Corporation (CI-22 and CI-24) electrode tracks. These were stained with Masson's trichrome. The Australian Synchrotron enabled XFM to accurately identify platinum from its characteristic fluorescence spectrum.

Results: There was a fibrous tissue capsule (about 100-µm thick) and small regions of calcification around the UOM and CI-22 arrays, but a thinner capsule (40–60-µm thick) around CI-24, and a greater degree of calcification. Dark particulate matter was observed within macrophages and especially in fibrous tissue in proximity to the UOM and CI-22 arrays. This was identified as platinum using X-ray fluorescence. There was also diffusion of platinum into the tissue surrounding the UOM and CI-22 electrodes and fine particles had penetrated the spiral ligament.

Discussion: The larger particulate matter in the tissue around the UOM and CI-22 arrays suggested that it had flaked off in the manufacturing of the UOM electrodes. The more diffuse spread of platinum in the tissue around the UOM and CI-22 electrodes was likely due to electrolysis, probably from charge imbalance with the bipolar pulses from the UOM implant. This did not occur with the Cochlear CI-24 device. Furthermore, the widespread fine particles of platinum could have also been due to corrosion, especially from the UOM electrodes.     

Perception of vowels and prosody by cochlear implant recipients in noise

The aim of the present study was to compare the ability of cochlear implant (CI) recipients to recognise speech prosody in the presence of speech-weighted noise to their ability to recognise vowels in the same test paradigm and listening condition. All test materials were recorded from four different speakers (two male, two female). Two prosody recognition tasks were developed, both using single words as stimuli. The first task involved a question/statement distinction, while the second task required listeners to make a judgement about the speaker's attitude. Vowel recognition tests were conducted using vowel pairs selected on the basis of specific acoustic cues (frequencies of the first two formants and duration). Ten CI users and ten normal-hearing controls were tested in both quiet and an adaptive noise condition, using a two-alternative forced-choice test paradigm for all the tests. Results indicated that vowel recognition was significantly better than prosody recognition in both listener groups in both quiet and noise, and that question/statement discrimination was the most difficult task for CI listeners in noise. Data from acoustic analyses were used to interpret differences in performance on different tasks and with different speakers.Learning outcomes: As a result of this activity, readers will be able to (1) describe suitable methods for comparing vowel and prosody perception in noise, (2) compare performance on vowel and prosody perception tasks in quiet in normal-hearing listeners and cochlear implant recipients, (3) compare performance on vowel and prosody perception tasks in noise in normal-hearing listeners and cochlear implant recipients and (4) relate performance on prosody tasks in quiet to performance on these tasks in noise.     

鼓岬电刺激试验对耳蜗植入者言语康复的预测

目的探讨鼓岬电刺激测试对人工耳蜗植入术后患者言语康复预测的价值。方法选语前及语后聋患者各２例,测试每秒５０、１００及２００次脉冲率方波的电听觉阈值（μＡ）、最大舒适水平及间隔辨别力,４例患者均植入Ｎｕｃｌｅｕｓ２２导人工耳蜗装置,术前及术后言语康复训练后以半定量方法进行言语可懂度主观评价。结果２例成年人鼓岬刺激阈值在１０μＡ以下,术后言语可懂度有不同程度的改善,一例幼儿术后言语可懂度有提高。结论本研究未发现术后言语可懂度与鼓岬刺激阈值的函数关系,探讨了其可能的原因。     

Effects of fine structure and extended low frequencies in pediatric cochlear implant recipients

Objective

In recent years, new speech coding strategies have been developed with the aim of improving the transmission of temporal fine structure to cochlear implant recipients. This study reports on the implementation of one such strategy (fine structure processing, FSP) in children.

Methods

This was a prospective study investigating the upgrade to a new speech processor. The upgrade used a repeated measures design with an alternating order of conditions (A-B-A-B design). Twelve pre- and perilingually deaf children with MED-EL C40+ cochlear implants were enrolled in the study. Patients were upgraded from their Tempo+ speech processor, which used continuous interleaved sampling (CIS) in combination with a frequency spectrum of 200-8500 Hz, to an Opus speech processor, which used FSP with an extended frequency spectrum of 70-8500 Hz. The primary means of testing was an HSM (Hochmair, Schulz and Moser) sentence test at 65 and 80 dB in quiet. In addition, the “Mainzer Kindersprachtest” (Mainz audiometric speech test for children) was applied at 65 and 70 dB.

Results

When the new FSP speech processor was used together with the extended low frequency range, HSM sentence tests at 65 and 80 dB resulted in scores indicating statisticially significant improvements of 7.1 and 9.9 percentage points, respectively. Scores in the “Mainzer Kindersprachtest” at 65 and 70 dB indicated statistically significant improvements of 9.3 and 6.1 percentage points, respectively.

Conclusions

The present study clearly shows that children benefit from the fine structure speech coding strategy in combination with an extended frequency spectrum in the low frequencies, as is offered by the Opus speech processors. This should be taken into consideration when fitting pre- and perilingually deaf children implanted almost a decade previously.