Communication abilities of children with aided residual hearing: comparison with cochlear implant users

OBJECTIVE: To compare the communication outcomes between children with aided residual hearing and children with cochlear implants. DESIGN: Measures of speech recognition and language were administered to pediatric hearing aid users and cochlear implant users followed up longitudinally as part of an ongoing investigation on cochlear implant outcomes. The speech recognition measures included the Lexical Neighborhood Test, Phonetically Balanced-Kindergarten Word Lists, and the Hearing in Noise Test for Children presented in quiet and noise (+5 dB signal-to-noise ratio). Language measures included the Peabody Picture Vocabulary Test: Third Edition (PPVT-III), the Reynell Developmental Language Scales, and the Clinical Evaluation of Language Fundamentals-Revised.Subjects The experimental group was composed of 39 pediatric hearing aid users with a mean unaided pure-tone average threshold of 78.2 dB HL (hearing level). The comparison group was composed of 117 pediatric cochlear implant users with a mean unaided pure-tone average threshold of 110.2 dB HL. On average, both groups lost their hearing at younger than 1 year and were fitted with their respective sensory aids at 2 to 2.6 years of age. Not every child was administered every test for a variety of reasons. RESULTS: Between-group performance was equivalent on most speech recognition and language measures. The primary difference found between groups was on the PPVT-III, in which the hearing aid group had a significantly higher receptive vocabulary language quotient than the cochlear implant group. Notably, the cochlear implant group was substantially younger than the hearing aid group and had less experience with their sensory devices on this measure. CONCLUSION: Data obtained from children with aided residual hearing can be useful in determining cochlear implant candidacy.     

Monosyllable speech perception of Japanese hearing aid users with prelingual hearing loss: implications for surgical indication of cochlear implant

OBJECTIVE: The monosyllable speech perception ability after years of educational intervention was compared between prelingually deafened pediatric hearing aid users and their cochlear implant counterparts. DESIGN: An open-set monosyllabic speech perception test was conducted on all subjects. The test required subjects to indicate a corresponding Japanese character to that spoken by the examiner. Fifty-two subjects with prelingual hearing impairment (47 hearing aid users and 5 cochlear implant users) were examined. RESULTS: Hearing aid users with average pure-tone thresholds less than 90 dB HL demonstrated generally better monosyllable perception than 70%, which was equivalent or better performance than that of the cochlear implant group. Widely dispersed speech perception was observed within the 90-99 dB HL hearing-aid user group with most subjects demonstrating less than 50% speech perception. In the cluster of >100 dB HL, few cases demonstrated more than 50% in speech perception. The perception ability of the vowel part of each mora within the cochlear implant group was 100% and corresponding to that of hearing aid users with moderate and severe hearing loss. CONCLUSION: Hearing ability among cochlear implant users can be comparable with that of hearing aid users with average unaided pure-tone thresholds of 90 dB HL, after monosyllabic speech perception testing was performed.     

Effects of stimulus level on the speech perception abilities of children using cochlear implants or digital hearing aids

OBJECTIVE: The present investigation was designed to provide information to facilitate the decision of whether a child should continue using digital signal processing (DSP) hearing aids with wide dynamic range compression (WDRC) or be recommended for a cochlear implant, based on the unaided pure-tone average (PTA at 500, 1000, and 2000 Hz). DESIGN: Fifty-two children (ages 5 to 15 yr) with unaided PTAs in the moderately severe to profound range, wearing (DSP) hearing aids with (WDRC) or a Nucleus 24, Clarion 1.2, or CII cochlear implant system, participated: 26 with unaided PTAs from 60 to 98 dB HL using DSP hearing aids and 26 with pre-implant unaided PTAs from 93 to 120 dB HL, using cochlear implants. An open-set speech perception test, the Lexical Neighborhood Test (LNT; ), was administered at intensity levels representative of raised (70 dB SPL) and soft (50 dB SPL) speech at two different times approximately 1 mo apart. Minimum audibility of soft sounds was determined for the children with implants and with DSP hearing aids using warble-tone thresholds at octave intervals between 250 and 4000 Hz. RESULT: Regression analyses and significance testing were used to determine the unaided PTA values at which the performance of the DSP Hearing Aid group (DSP HA group) and Cochlear Implant group on the LNT test were statistically different at the 0.05 significance level. For the 70 dB SPL presentation level, the statistically different PTAs were 113 and 97 dB HL at Time 1 and Time 2, respectively, and 96 and 88 dB HL at 50 dB SPL for Time 1 and Time 2, respectively. CONCLUSIONS: The Unaided PTA at which children in the cochlear implant group would be expected to score significantly better than the children in the DSP HA group was lowest (96 and 88 dB HL) for the lower signal level (50 dB SPL). Assuming that LNT scores at 50 dB SPL are representative of long-term hearing of soft incidental speech that is essential for language learning and fluent communication, the children with PTA values greater than the range from 88 to 96 dB HL would be expected to have significantly better LNT scores with a cochlear implant. These results should be further examined with research efforts focusing on early intervention with optimally fitted DSP hearing aids and cochlear implants.     

Evidence-based guidelines for recommending cochlear implantation for young children: Audiological criteria and optimizing age at implantation

Abstract

Objective: Establish up-to-date evidence-based guidelines for recommending cochlear implantation for young children. Design: Speech perception results for early-implanted children were compared to children using traditional amplification. Equivalent pure-tone average (PTA) hearing loss for cochlear implant (CI) users was established. Language of early-implanted children was assessed over six years and compared to hearing peers. Study sample: Seventy-eight children using CIs and 62 children using traditional amplification with hearing losses ranging 25–120?dB HL PTA (speech perception study). Thirty-two children who received a CI before 2.5 years of age (language study). Results: Speech perception outcomes suggested that children with a PTA greater than 60?dB HL have a 75% chance of benefit over traditional amplification. More conservative criteria applied to the data suggested that children with PTA greater than 82?dB HL have a 95% chance of benefit. Children implanted under 2.5 years with no significant cognitive deficits made normal language progress but retained a delay approximately equal to their age at implantation. Conclusions: Hearing-impaired children under three years of age may benefit from cochlear implantation if their PTA exceeds 60?dB HL bilaterally. Implantation as young as possible should minimize any language delay resulting from an initial period of auditory deprivation.     

Bilateral cochlear implants in children: localization acuity measured with minimum audible angle

OBJECTIVE: To evaluate sound localization acuity in a group of children who received bilateral (BI) cochlear implants in sequential procedures and to determine the extent to which BI auditory experience affects sound localization acuity. In addition, to investigate the extent to which a hearing aid in the nonimplanted ear can also provide benefits on this task. DESIGN: Two groups of children participated, 13 with BI cochlear implants (cochlear implant + cochlear implant), ranging in age from 3 to 16 yrs, and six with a hearing aid in the nonimplanted ear (cochlear implant + hearing aid), ages 4 to 14 yrs. Testing was conducted in large sound-treated booths with loudspeakers positioned on a horizontal arc with a radius of 1.5 m. Stimuli were spondaic words recorded with a male voice. Stimulus levels typically averaged 60 dB SPL and were randomly roved between 56 and 64 dB SPL (+/-4 dB rove); in a few instances, levels were held fixed (60 dB SPL). Testing was conducted by using a "listening game" platform via computerized interactive software, and the ability of each child to discriminate sounds presented to the right or left was measured for loudspeakers subtending various angular separations. Minimum audible angle thresholds were measured in the BI (cochlear implant + cochlear implant or cochlear implant + hearing aid) listening mode and under monaural conditions. RESULTS: Approximately 70% (9/13) of children in the cochlear implant + cochlear implant group discriminated left/right for source separations of 相似文献   

Cochlear implant candidates with psychogenic hearing loss

Conclusions: Specific requests for cochlear implantations by persons with psychogenic hearing loss are a relatively new phenomenon. A number of features seems to be over-represented in this group of patients. The existence of these requests stresses the importance of auditory brainstem response (ABR) measurements before cochlear implantation. Objective: To describe the phenomenon of patients with psychogenic hearing losses specifically requesting cochlear implantation, and to gain first insights into the characteristics of this group. Methods: Analysis of all cases seen between 2004 and 2013 at the University Hospital of Bern, Switzerland. Results: Four cochlear implant candidates with psychogenic hearing loss were identified. All were female, aged 23–51 years. Hearing thresholds ranged from 86 dB to 112 dB HL (pure-tone average 500–4000 Hz). ABRs and otoacoustic emissions (OAEs) showed bilaterally normal hearing in two subjects, and hearing thresholds between 30 and 50 dB in the other two subjects. Three subjects suffered from depression and one from a pathologic fear of cancer. Three had a history of five or more previous surgeries. Three were smokers and three reported other close family members with hearing losses. All four were hearing aid users at the time of presentation.     

Hearing aid and cochlear implant use in children with hearing loss at three years of age: Predictors of use and predictors of changes in use

Objective: To examine usage patterns of hearing aids and cochlear implants in children up to three years of age, how usage changes longitudinally, and factors associated with device usage. Design: Parent report and Parent’s Evaluation of Aural/oral Performance of Children (PEACH) data were obtained at six and twelve months after hearing-aid fitting or cochlear implant switch-on, and again at three years of age. The effect of device use on auditory functional performance was investigated using the PEACH questionnaire. Study sample: Four hundred and thirteen participants from the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study were included for analysis. Results: For users of hearing aids, higher usage at three years was associated with higher maternal education, and more severe hearing loss. For users of cochlear implants, higher usage was associated with higher maternal education and the absence of additional disabilities. Higher PEACH scores were associated with higher usage scores. After allowing for the effects of demographic characteristics, device use was not a significant predictor of functional performance. Conclusions: Sixty-two percent of children achieved consistent use (> 75% of waking hours) within the first year of receiving a hearing aid or a cochlear implant, and 71% by three years of age.     

有低频残余听力感音神经聋的人工耳蜗植入术

目的介绍一种有低频残余听力感音神经聋的人工耳蜗植入技术,探讨人工耳蜗植入手术对有残余听力患者的治疗效果和价值。方法15例有残余听力的患者接受了保护残余听力的人工耳蜗植入手术。术中电极植入深度在19mm～24mm左右。术后分别检测单纯使用助听器、单纯使用人工耳蜗、人工耳蜗结合助听器三种不同状态下的听力。结果15例患者中,有13例术后残余听力保存良好,仅分别丢失5～20dB听力,但另2例术后残余听力全部丧失。术后在安静、信噪比15dB和10dB三种不同状态下的言语测试结果显示,人工耳蜗结合助听器使用者测试得分始终保持在很高水平;单纯使用人工耳蜗者也有较好的成绩,但在信噪比达10dB的条件下,测试成绩下降;而单纯使用助听器者,不仅在安静状态下听力成绩不甚理想,一旦加入竞争性噪声,听力测试成绩急剧下降。结论保护和利用残余听力的人工耳蜗植入技术,使人工耳蜗植入手术对象从重度或极重度聋扩大到高频为重度或极重度聋,低频（≤500Hz）为中、轻度聋的患者。接受这项技术患者的听力和言语识别能力均明显优于其单纯配戴助听器和单纯使用人工耳蜗时的听力和言语识别能力。     

Audiological application criteria for implantable hearing aid devices: a clinical experience at the Nijmegen ORL clinic

Objectives/Hypothesis: To define audiological application criteria for different implantable hearing aid devices. Study Design: Retrospective study. Methods: Comparisons were made between aided speech recognition scores obtained at conversational level (65 dB) in patients with the Vibrant Soundbridge (VSB) (n = 22), the Otologics middle ear transducer (MET) (n = 10), conventional hearing aids (behind-the-ears) (n = 47), and cochlear implants (CIs) (n = 123). Results: In relation to hearing loss, only for mild hearing loss, speech recognition scores with VSB were comparable to that with conventional hearing aids. In the Otologics MET users, speech recognition scores were comparable with those of the conventional hearing aid users until a mean hearing loss of about 75 dB HL. At a sensorineural hearing loss of about 65 dB HL or more, the Otologics MET users have better speech recognition scores than the VSB users. For comparison with CI users, we followed a more conservative approach. In 90% of the users of a CI, speech recognition scores were better than those in: 1) patients with a conventional hearing aid and a mean hearing loss of about 95 dB HL or worse; 2) patients with an Otologics MET and a mean hearing loss of 85 dB HL or worse. Conclusions: Patients fitted with a VSB or an Otologics MET middle ear implant do not demonstrate better speech recognition scores than patients fitted with today's conventional hearing aids. Results might even been worse. However, the VSB and Otologics MET are a good option in patients with moderate (VSB) to severe (Otologics MET) sensorineural hearing loss and external otitis.     

Results of Cochlear Implantation in Patients with Severe to Profound Hearing Loss—Implications for Patient Selection

In patients with some residual hearing and minor benefit from conventional hearing aids, the benefits of cochlear implantation have to be weighed carefully against eventual adverse effects. In this study, pre- and post-operative thresholds as well as functional results after cochlear implantation are reported; 17 of 44 implanted adults had residual hearing pre-operatively (mean threshold(_{250 to 4000 Hz}): 106 dB HL) in the implanted ear. Residual hearing in the implanted ear could not, in general, be preserved post-operatively.

Seventeen of 44 implanted children had some amount of residual hearing in the implanted ear pre-operatively (implanted ear: 114 dB HL; contralateral ear: 109.9 dB HL; mean thresholds(_{250 to 4000 Hz)})).

Contrary to the results in adults, residual hearing in the implanted ear remained statistically unchanged. Hearing in the contralateral ear increased significantly from 109.9 to 101.9 dB HL post-operatively. This increase was mainly attributed to maturation of the central auditory pathway. In adults with residual hearing, the monosyllable word recognition scores increased significantly from 9 per cent pre-operatively to 42 per cent post-operatively. Children with residual hearing tended to perform better on speech-related test material compared to children without prior auditory experience. Cochlear implantation is indicated in adults and children with residual hearing and minor benefit from conventional amplification. The contralateral ear in children should be considered for additional acoustical stimulation.     

Comprehensive hearing aid assessment in adults with bilateral severe-profound sensorineural hearing loss who present for Cochlear implant evaluation

PurposeTo comprehensively assess and describe functional auditory performance in a group of adults with bilateral, moderate sloping to profound sensorineural hearing loss who were dissatisfied users of well-fit bilateral hearing aids and presented for Cochlear implant evaluation. Participants were evaluated with bilateral hearing aids and after six months of bimodal (Cochlear implant and a contralateral hearing aid) hearing experience with a Cochlear implant and contralateral hearing aid.MethodsStudy participants were assessed using pure tone audiometry, aided speech understanding in quiet (CNC words) and in noise (AzBio sentences at +10 and +5 dB SNR) in the sound field with unilateral and bilateral hearing aids fit to target. Participants completed subjective scales of quality of life, (Health Utilities Index Mark 3), hearing disability, (Speech, Spatial and Qualities of Hearing Scale) and a device use satisfaction scale. Participants ≥55 years were administered the Montreal Cognitive Assessment screening tool. One-hundred enrolled individuals completed baseline evaluations.ResultsAided bilateral mean speech understanding scores were 28% for CNC words and 31%, and 17% for AzBio sentences at a +10 dB, and +5 dB SNR, respectively. Mean scale ratings were 0.46 for overall quality of life and 3.19 for functional hearing ability. Ninety percent of participants reported dissatisfaction with overall hearing performance.ConclusionsEvaluation results, including functional performance metrics quantifying the deleterious effects of hearing loss for overall wellbeing, underscore that bilateral hearing aids are not an effective treatment for individuals with bilateral, moderate sloping to profound sensorineural hearing loss. Individuals with this degree of hearing impairment, who demonstrate poor aided speech understanding and dissatisfaction with hearing abilities in everyday life, require timely referral to a Cochlear implant clinic for further evaluation.     

影响语前聋患儿人工耳蜗植入术后前语言交流能力的因素分析

目的 探讨影响语前聋患儿人工耳蜗植入术后前语言交流能力的相关因素.方法 对接受人工耳蜗植入术的语前聋患儿 31例进行随访调查,平均植入年龄为46.71±24.78月,术后1个月开机进行康复训练;采用视频分析法于开机后12个月对患儿的轮流交流、主动交流、视觉交流及听觉注意等进行分析,并根据以下方面分组:按植入年龄分为≤36个月组16例,>36个月组15例;按术前有无正规康复训练(时间超过3个月)分为康复组14例,未康复组17例;按术前残余听力分为≤80 dB HL组6例,>80 dB HL组25例;按术前是否使用助听器(时间超过3个月)分为使用组21例,未使用组10例.应用Wilcoxon秩和检验分析各组前语言交流能力的差别.结果 术前进行康复训练、术前佩戴助听器、术前残余听力好的人工耳蜗植入患儿的前语言交流能力得分高于术前未进行康复训练、术前未佩戴助听器、术前残余听力差的人工耳蜗植入患儿(P<0.05);植入年龄≤36个月组与>36个月组间比较差异无统计学意义(P>0.05).结论 术前残余听力好、佩戴助听器、进行过正规康复训练的语前聋患儿人工耳蜗植入术后其前语言交流能力较好,而植入年龄对其无明显影响.     

言语、空间与听觉质量量表在老年听力损失者助听器验配中的应用

目的探讨言语、空间与听觉质量量表(speech,spatial and qualities of hearing scale,SSQ)用于老年听力损失患者佩戴助听器的效果评估作用。方法以100例老年感音神经性听力损失者(60~90岁)为研究对象,采用横断面研究和前瞻性研究,其中,无助听器使用经验者44例(75.8±8.1岁,气导纯音平均听阈59.8±13.3 dB HL)、有助听器使用经验者34例(77.5±6.3岁,气导纯音平均听阈64.5±17.8 dB HL,助听器佩戴时间大于三个月)进行横断面研究;22例(74.3±8.6岁,气导纯音平均听阈58.1±12.6 dB HL)首次配戴助听器者进行前瞻性研究;二组参与横断面研究者进行一次SSQ评估,前瞻性研究组分别在助听前和佩戴助听器1个月后进行二次SSQ评估,均采用面对面问答方式用SSQ量表评估三组受试者在言语理解能力、空间定位能力和声音聆听质量方面的变化。结果横断面研究结果显示,有助听经验组SSQ问卷言语理解(97.29±23.43分)、空间听觉(131.94±19.27分)、声音质量(143.53±20.31分)和总分(372.76±51.92分)均显著高于无助听经验组(分别为58.66±30.13、99.41±37.09、108.09±43.28、266.16±78.18分)。前瞻性研究结果显示,受试者初次佩戴助听器一个月后的SSQ问卷言语理解(106.27±13.86分)、空间听觉(136.00±14.09分)、声音质量(151.73±13.91分)和总分(394.00±34.70分)均显著高于佩戴助听器前(分别为65.64±21.89、115.09±17.17、111.91±25.41、292.64±45.58分),横断面研究和前瞻性研究结果均显示,老年听力损失患者佩戴助听器后在言语理解能力、空间声源定位能力和声音聆听质量方面均有显著改善(P<0.05)。结论SSQ量表可以有效评估老年听力损失患者助听器使用效果;老年听力损失患者佩戴助听器后在言语理解能力、空间定位能力和声音聆听质量方面均有显著提高。     

Preservation of residual hearing with cochlear implantation: How and why

Conclusions Hearing may be conserved in adults after implantation with the Nucleus Contour Advance perimodiolar electrode array. The degree of hearing preservation and the maximum insertion depth of the electrode array can vary considerably despite a defined surgical protocol. Residual hearing combined with electrical stimulation in the same ear can provide additional benefits even for conventional candidates for cochlear implantation.

Objectives We present preliminary results from a prospective multicentre study investigating the conservation of residual hearing after implantation with a standard-length Nucleus Contour Advance perimodiolar electrode array and the benefits of combined electrical and acoustic stimulation.

Material and methods The subjects were 12 adult candidates for cochlear implantation recruited according to national selection criteria. A “soft” surgery protocol was defined, as follows: 1–1.2-mm cochleostomy hole anterior and inferior to the round window; Nucleus Contour Advance electrode array inserted using the “Advance-off-stylet” technique; and insertion depth controlled by means of three square marker ribs left outside the cochleostomy hole. These procedures had been shown to reduce insertion forces in temporal bone preparations. Variations in surgical techniques were monitored using a questionnaire. Pure-tone thresholds were measured pre- and postoperatively. Patients who still retained thresholds <90 dB HL for frequencies up to 500 Hz were re-fitted with an in-the-ear (ITE) hearing aid. Word recognition was tested in quiet and sentence perception in noise for the cochlear implant alone and in combination with an ipsilateral hearing aid.

Results Hearing threshold level data were available for 12 patients recruited from 6 of the centres. Median increases in hearing threshold levels were 23, 27 and 33 dB for the frequencies 125, 250 and 500 Hz, respectively. These median increases include the data for two patients who had total loss of residual hearing due to difficulties encountered during surgery. “Cochlear view” X-ray images indicated that the depth of insertion varied between 300 and 430°, despite modest variations in the length of the electrode inserted (17–19 mm). The insertion angle had some influence on the preservation of residual hearing at frequencies of 250–500 Hz. Six of the 12 patients retained sufficient hearing for effective use of an ipsilateral ITE hearing aid (≤80 dB HL at 125 and 250 Hz; ≤90 dB HL at 500 Hz). Word recognition scores in quiet were improved from 10% to 30% with the cochlear implant plus ipsilateral hearing aid in 3 patients who had at least 3 months postoperative experience. Signal:noise ratio thresholds for sentence recognition were improved by up to 3 dB. Patients reported that they experienced greatly improved sound quality and preferred to use the two devices together.     

Better defining best-aided condition: The role of hearing aids on cochlear implantation qualification rates

ObjectiveDescribe the effect of hearing aid type used during cochlear implantation evaluation on qualification rates.MethodsConsecutive adult patients at an academic cochlear implant program undergoing cochlear implantation evaluation were identified to determine cochlear implantation qualification rate according to history of hearing aid use and type of hearing aid used during evaluation.Results609 patients met criteria. 90.1% of patients reported prior use of a hearing aid, and 77.4% reported current use of a hearing aid. Patients were most likely to undergo cochlear implantation evaluation utilizing their own personal hearing aids exclusively (61.6%) followed by loaner hearing aids fitted at the time of the evaluation (28.2%). White patients were more likely to be tested using personal hearing aids (OR = 2.60, 95% CI 1.43 to 4.71). Married patients were more likely to be current hearing aid users (OR 1.62, 95% CI 1.04 to 2.51) and were more likely to be tested using personal hearing aids (OR = 1.68, 95% CI 1.10 to 2.56). Patients with a history of any hearing aid use (OR = 2.50, 95% CI 1.42 to 4.40) and current hearing aid use (OR = 1.62, 95% CI 1.06 to 2.49) were more likely to qualify for cochlear implantation. Patients tested using personal hearing aids were 1.5 times more likely to qualify for cochlear implantation (95% CI 0.99 to 2.27).ConclusionHistory of hearing amplification and current amplification predict cochlear implant qualification. Hearing aids fitted at the time of cochlear implantation evaluation may result in lower qualification rates.     

Total implantation of the Implex TICA hearing amplifier implant for high frequency sensorineural hearing loss: the Tübingen University experience

Hearing devices may be classified as sound-producing hearing aids, electrically stimulating devices, and vibratory hearing aids. Because patients may lose physiologic cochlear amplification, hearing devices for the treatment of sensorineural hearing loss are used as signal amplifiers. The totally implantable communication assistance (TICA) device is a European-approved totally implantable vibratory amplifier implant. It picks up the sound signal transcutaneously from the external auditory canal near the eardrum, amplifies the signal, and transduces the signal into microvibrations that are delivered to the ossicular chain.     

Combined electric and acoustic stimulation of the auditory system: results of a clinical study

Combined electric and acoustic stimulation (EAS) of the auditory system is a new therapy for patients with severe to profound high- and mid-frequency hearing loss but remaining low-frequency hearing. In a prospective study, 13 patients with low-frequency hearing of better than 60 dB below 1 kHz were implanted with a MED-EL COMBI 40+ cochlear implant. Pure tone thresholds as well as monosyllabic word scores and Hochmair-Schulz-Moser sentences in quiet and in noise were measured with hearing aids, cochlear implant alone and in the combined stimulation mode (EAS) in the same ear. Hearing could be partially preserved in 11 out of the 13 patients. All patients scored significantly higher with cochlear implant alone than with hearing aids. Seven patients scored higher in the EAS mode than with cochlear implant alone for sentences in noise, 4 remained unchanged, and 2 could not use EAS. Synergistic effects of EAS were most prominent for hearing in noise with increases of up to 72% as compared to cochlear implant alone.     

Comparison of hearing aids and cochlear implants in profoundly and totally deaf persons

Cochlear implants are increasingly used in the rehabilitation of the profoundly and totally deaf. Usually, insufficient gain of speech discrimination with a powerful conventional hearing aid is considered as a prerequisite for a cochlear prosthesis. With recent improvements of electronic systems, the criterion for this decision may change. To keep pace with the technical progress, a battery of speech sound tests suited for minimal auditory capabilities (MAC-battery) was developed and applied to groups of patients fitted with conventional instruments and with two different types of cochlear implants. Based on the comparison of the MAC-battery results of hearing aid groups, with the average performance of an implanted group, most conventionally fitted regular users of hearing aids should not be considered as candidates for cochlear implantation. The MAC-battery, although not a strictly standardized procedure, is a useful instrument for patient counselling and for the selection of implant candidates.     

Preservation of residual hearing with cochlear implantation: how and why

CONCLUSIONS: Hearing may be conserved in adults after implantation with the Nucleus Contour Advance perimodiolar electrode array. The degree of hearing preservation and the maximum insertion depth of the electrode array can vary considerably despite a defined surgical protocol. Residual hearing combined with electrical stimulation in the same ear can provide additional benefits even for conventional candidates for cochlear implantation. OBJECTIVES: We present preliminary results from a prospective multicentre study investigating the conservation of residual hearing after implantation with a standard-length Nucleus Contour Advance perimodiolar electrode array and the benefits of combined electrical and acoustic stimulation. MATERIAL AND METHODS: The subjects were 12 adult candidates for cochlear implantation recruited according to national selection criteria. A "soft" surgery protocol was defined, as follows: 1-1.2-mm cochleostomy hole anterior and inferior to the round window; Nucleus Contour Advance electrode array inserted using the "Advance-off-stylet" technique; and insertion depth controlled by means of three square marker ribs left outside the cochleostomy hole. These procedures had been shown to reduce insertion forces in temporal bone preparations. Variations in surgical techniques were monitored using a questionnaire. Pure-tone thresholds were measured pre- and postoperatively. Patients who still retained thresholds <90 dB HL for frequencies up to 500 Hz were re-fitted with an in-the-ear (ITE) hearing aid. Word recognition was tested in quiet and sentence perception in noise for the cochlear implant alone and in combination with an ipsilateral hearing aid. RESULTS: Hearing threshold level data were available for 12 patients recruited from 6 of the centres. Median increases in hearing threshold levels were 23, 27 and 33 dB for the frequencies 125, 250 and 500 Hz, respectively. These median increases include the data for two patients who had total loss of residual hearing due to difficulties encountered during surgery. "Cochlear view" X-ray images indicated that the depth of insertion varied between 300 and 430 degrees, despite modest variations in the length of the electrode inserted (17-19 mm). The insertion angle had some influence on the preservation of residual hearing at frequencies of 250-500 Hz. Six of the 12 patients retained sufficient hearing for effective use of an ipsilateral ITE hearing aid (< or = 80 dB HL at 125 and 250 Hz; < or = 90 dB HL at 500 Hz). Word recognition scores in quiet were improved from 10% to 30% with the cochlear implant plus ipsilateral hearing aid in 3 patients who had at least 3 months postoperative experience. Signal:noise ratio thresholds for sentence recognition were improved by up to 3 dB. Patients reported that they experienced greatly improved sound quality and preferred to use the two devices together.