Influence of signal processing strategy in auditory abilities

The signal processing strategy is a parameter that may influence the auditory performance of cochlear implant and is important to optimize this parameter to provide better speech perception, especially in difficult listening situations.ObjectiveTo evaluate the individual's auditory performance using two different signal processing strategy.Methods: Prospective study with 11 prelingually deafened children with open-set speech recognition. A within-subjects design was used to compare performance with standard HiRes and HiRes 120 in three different moments. During test sessions, subject's performance was evaluated by warble-tone sound-field thresholds, speech perception evaluation, in quiet and in noise.ResultsIn the silence, children S1, S4, S5, S7 showed better performance with the HiRes 120 strategy and children S2, S9, S11 showed better performance with the HiRes strategy. In the noise was also observed that some children performed better using the HiRes 120 strategy and other with HiRes.ConclusionNot all children presented the same pattern of response to the different strategies used in this study, which reinforces the need to look at optimizing cochlear implant clinical programming.     

Development of auditory and language skills in children using cochlear implants with two signal processing strategies

IntroductionThe increase in the spectral information offered by the sound processing strategy HiRes 120 has led to great expectations for the pediatric population. Due to a shorter duration of auditory deprivation and higher neural plasticity, children could benefit more substantially from the spectral information of this sound processing strategy.ObjectiveTo compare auditory and language skills in Brazilian children with cochlear implants using the HiRes and HiRes 120 sound processing strategies.MethodsThirty children, aged 1–3 years, with congenital hearing loss, were divided into two groups, according to the signal processing strategy adjusted at the time of the cochlear implant activation. The assessed children were matched according to chronological age and the time of the cochlear implant use. The auditory and language skills were evaluated longitudinally through the Infant-Toddler Meaningful Auditory Integration Scale and Production Infant Scale Evaluation, carried out before surgery, and 3, 6 and 12 months after device implantation. The Mann–Whitney test was applied for the comparison between the two groups with a 5% significance level.ResultsThe findings indicated development of hearing and language skills in the first year of cochlear implant use; however, there was no statistically significant difference in the evolution of such skills due to the adjusted processing strategy in the activation of the cochlear implant electrodes.ConclusionThe development of auditory and language skills in the assessed children was similar during the entire study period, regardless of which signal processing strategy was used.     

Short-term study of the effect of speech coding strategy on the auditory performance of pre- and post-lingually deafened adults implanted with the Clarion CII®

Objective The auditory performance of cochlear implantees is linked to numerous variables, such as audiological characteristics, age and type of speech coding strategy. In recent years, many different ways of processing sounds have been developed, with possible implications for auditory performance. The purpose of this study was to evaluate the intra-individual differences of patients for speech perception tasks in quiet and in noise as a result of switching from a standard strategy [Continuous Interleaved Sampling (CIS)/Simultaneous Analog Strategy (SAS)] to Hi-Resolution (HiRes).

Material and Methods A total of 14 post-lingual adults implanted with the Clarion CII® were selected for trials. At switch-on, six patients chose a CIS strategy and eight an SAS strategy. After an average period of 9.3 months, all patients were switched over to HiRes. All patients were tested (open-set mode) with bisyllabic words and sentences, in both quiet and noise [speech/noise ratio (SNR)=+10]. Testing was carried out after an initial period with the CIS/SAS strategy and 3 months after switching over to HiRes.

Results After switch-over a significant improvement was seen for both speech in quiet (words +25.2%, sentences +10.8%) and speech in noise (words 44.8%, sentences 45.4%).

Conclusion Despite individual differences, all patients improved their performance with HiRes use, the greatest improvements being seen under unfavourable listening conditions (SNR=+10). Subjective improvements in speech discrimination and overall sound quality perception were reported even after the first week of HiRes use.     

HiResolution and conventional sound processing in the HiResolution bionic ear: using appropriate outcome measures to assess speech recognition ability

OBJECTIVE: This study compared speech perception benefits in adults implanted with the HiResolution (HiRes) Bionic Ear who used both conventional and HiRes sound processing. A battery of speech tests was used to determine which formats were most appropriate for documenting the wide range of benefit experienced by cochlear-implant users. STUDY DESIGN: A repeated-measures design was used to assess postimplantation speech perception in adults who received the HiResolution Bionic Ear in a recent clinical trial. Patients were fit first with conventional strategies and assessed after 3 months of use. Patients were then switched to HiRes sound processing and assessed again after 3 months of use. To assess the immediate effect of HiRes sound processing on speech perception performance, consonant recognition testing was performed in a subset of patients after 3 days of HiRes use and compared with their 3-month performance with conventional processing. SETTING: Subjects were implanted and evaluated at 19 cochlear implant programs in the USA and Canada affiliated primarily with tertiary medical centers. PATIENTS: Patients were 51 postlinguistically deafened adults. MAIN OUTCOME MEASURES: Speech perception was assessed using CNC monosyllabic words, CID sentences and HINT sentences in quiet and noise. Consonant recognition testing was also administered to a subset of patients (n = 30) using the Iowa Consonant Test presented in quiet and noise. All patients completed a strategy preference questionnaire after 6 months of device use. RESULTS: Consonant identification in quiet and noise improved significantly after only 3 days of HiRes use. The mean improvement from conventional to HiRes processing was significant on all speech perception tests. The largest differences occurred for the HINT sentences in noise. Ninety-six percent of the patients preferred HiRes to conventional sound processing. Ceiling effects occurred for both sentence tests in quiet. CONCLUSIONS: Although most patients improved after switching to HiRes sound processing, the greatest differences were seen in the 'poor' performers because 'good' performers often reached ceiling performance, especially on tests in quiet. Future evaluations of cochlear-implant benefit should make use of more difficult measures, especially for 'good' users. Nonetheless, a range of difficulty must remain in test materials to document benefit in the entire population of implant recipients.     

Effect of signal processing strategy and stimulation type on speech and auditory perception in adult cochlear implant users

Objective: The objective of this study was to investigate the effects of signal processing strategy on speech understanding and auditory function for adult cochlear implant (CI) users with a focus on the effects of sequential versus paired stimulation.

Design: Within-subjects, repeated measures design was utilised to compare performance between processing strategies and stimulation type on various measures of auditory function and subjective sound quality. Testing with subsequent strategies was completed after a total familiarisation time of two weeks.

Study Sample: Ten post-lingually deafened adult CI users were recruited from a clinical population. Participants had a minimum of 13?months CI experience. Ages ranged from 25–78?years. All participants had long-term experience with the optima strategy; eight with sequential stimulation and two with paired stimulation.

Results: We found no statistically significant effect of processing strategy. We observed an effect of stimulation type with sequential stimulation yielding significantly higher performance than paired stimulation for speech understanding in quiet and in noise, and subjective estimates of sound quality. No significant differences were noted across strategy or stimulation for music perception, spectral resolution or temporal resolution.

Conclusions: Many patients utilise paired stimulation – the default stimulation type in the clinical software; however, sequential stimulation yielded significantly higher outcomes on multiple measures.     

Sequential bilateral cochlear implant: results in children and adolescents

IntroductionThe use of the bilateral cochlear implants can promote the symmetrical development of the central auditory pathways, thus benefiting the development of auditory abilities and improving sound localization and the ability of auditory speech perception in situations of competitive noise.ObjectiveTo evaluate the ability of speech perception in children and adolescents using sequential bilateral cochlear implants, considering the association of these variables: age at surgery, time of device use and interval between surgeries.MethodsA total of 14 individuals between 10 and 16 years of age, who demonstrated surgical indication for the use of sequential bilateral cochlear implants as intervention in the auditory habilitation process, were assessed. The speech perception ability was assessed through sentence lists constructed in the Portuguese language, presented in two situations: in silence, with fixed intensity of 60 dB SPL, and in competitive noise, with a signal-to-noise ratio of +15 dB. The evaluation was performed under the following conditions: unilateral with the first activated cochlear implant, unilateral with the second activated cochlear implant and bilateral with both devices activated.ResultsThe results of the speech perception tests showed better performance in both silence and in noise for the bilateral cochlear implant condition when compared to the 1st cochlear implant and the 2nd cochlear implant alone. A worse result of speech perception was found using the 2nd cochlear implant alone. No statistically significant correlation was found between age at the surgical procedure, interval between surgeries and the time of use of the 2nd cochlear implant, and the auditory speech perception performance for all assessed conditions. The use of a hearing aid prior to the 2nd cochlear implant resulted in benefits for auditory speech perception with the 2nd cochlear implant, both in silence and in noise.ConclusionThe bilateral cochlear implant provided better speech perception in silence and in noise situations when compared to the unilateral cochlear implant, regardless of the interval between surgeries, age at the surgical procedure and the time of use of the 2nd cochlear implant. Speech perception with the 1st cochlear implant was significantly better than with the 2nd cochlear implant, both in silence and in noise. The use of the hearing aid prior to the 2nd cochlear implant influenced speech perception performance with the 2nd cochlear implant, both in silence and in noise.     

Multicentre evaluation of music perception in adult users of Advanced Bionics cochlear implants

Abstract

Objectives

To document musical listening and enjoyment in recipients of Advanced Bionics cochlear implants (CIs) and to compare musical perception in those using early coding strategies with subjects using the newer HiRes and HiRes 120 strategies.

Methods

A questionnaire was completed by 136 adult subjects, including questions on the ability to identify specific musical features. The subjects were in three groups: those using early coding strategies (n = 29), HiRes (n = 59), and HiRes 120 (n = 48), and results were compared with a group of 84 normally hearing (NH) subjects.

Results

Of the CI users, 79% reported listening to music. The NH group rated listening frequency and enjoyment higher than the CI users. Thirty-five users reported that they sang and this group had significantly higher overall performance. There were no significant differences in overall perception of specific musical features among the strategy groups, though some individual questions showed significantly higher performance in the HiRes 120 users.

Discussion

Users of current CI technology show a high level of musical appreciation, though still significantly less than NH subjects. Frequency of listening and enjoyment were significantly correlated and active participation in musical activities, specifically singing, resulted in significantly higher overall performance scores.     

Evaluation of a non-linear spectral subtraction noise suppression scheme in cochlear implant users

Abstract

The aim of the study was to determine benefit to speech recognition in noise by adult cochlear implant users with the non-linear spectral subtraction (NSS) noise suppression strategy. Users of the Nucleus 22 or Nucleus 24 cochlear implant systems were tested with sentence materials combined with stationary noise at +5 and +10 dB signal to noise ratio (SNR), with and without NSS processing applied offline. Sentence scores were significantly higher with NSS processing, for both SNRs. The effect was greater at +5 dB SNR (12% improvement with NSS) than at +10 dB SNR (5% improvement with NSS). These results are promising and suggest that online implementation of NSS as part of cochlear implant processors has the potential to yield benefits for speech recognition in noise. Copyright © 2006 John Wiley & Sons, Ltd.     

Speech perception results in children implanted with Clarion® devices: Hi-resolution™ and standard resolution modes

Conclusions Formal testing showed that HiRes users seem to make significant use of acoustic information. Furthermore, from observations reported by experienced care-givers, for example, family, teachers and speech therapists, these children learn a lot from their surrounding environment. Incidental learning, which takes place when acquiring skills or knowledge through naturally occurring events, is a key become available to these deaf paediatric cochlear implant recipients.

Objective To compare speech perception skills in children with a Clarion® cochlear implant using different speech coding strategies, such as continuous interleaved sampling (CIS), simultaneous analogue stimulation (SAS) and Hi-Resolution (HiRes)?.

Material and methods The study population comprised 40 children, 17 implanted with a Clarion Hi-Focus 1.2 and 23 with a Clarion CII. All children were pre-lingually deaf and differed in terms of age and cause of deafness. All children had undergone a trial (minimum 6 months) with hearing aids before implantation. Children implanted with a Clarion 1.2 were either CIS or SAS users [Standard Resolution mode (SRM) group]; children implanted with a Clarion CII were Hi-Resolution users [Hi-Resolution mode (HRM) group]. Findings were assessed according to Erber's hierarchical model (detection, discrimination, identification, recognition and comprehension), making use of a battery of speech perception tests calibrated to the age of the child. Further information concerning use of the implant in everyday situations was obtained by means of the Meaningful Auditory Integration Scale (MAIS) questionnaire, which was administered to the parents. Tests were carried out prior to each fitting session, at switch-on and then at 3, 6, 9 and 12 months. Findings at pre-implantation and at 12 months follow-up were collected for both the SRM and HRM groups. Speech perception results were analysed for the SRM and HRM groups, independent of age at implantation, for five subgroups of children according to the paediatric test battery in use and for two subgroups of children, one<?and one?>5 years of age.

Results Clarion-implanted children using the Hi-Resolution strategy can develop better speech perception skills at 12 months post-implantation compared to children fitted with the SAS or CIS strategy. SAS or CIS users implanted before the age of 5 years tend to achieve better results at 1 year follow-up than children implanted later. In contrast, in Hi-Resolution users, a trend towards better results for recognition and comprehension tasks was observed in children implanted after 5 years of age.     

The effect of intensity on pitch in electric hearing and its relationship to the speech perception performance of cochlear implantees

This study investigated the effect of intensity on pitch in electric hearing and its relationship to the speech perception ability of cochlear implantees. Subjects were 13 adult users of the Nucleus 22 cochlear implant system, using either the Spectra22 or ESPrit22 speech processor and the SPEAK speech processing strategy. A multidimensional scaling technique was employed. Speech perception was measured using sentences and vowels. All measurements were performed in a soundfield condition, and subjects wore their own speech processors with their normally used settings. Results showed a significant correlation between the degree of deviation of the subjects' stimulus spaces from the "ideal" space and subjects' performance with the sentences, but not with the vowels. A significant correlation was found between subjects' response variability in performing the multidimensional scaling task and their speech perception measures, suggesting that spectral smearing or underlying cognitive abilities might affect implantees' speech perception performance.     

Spectral-Ripple Resolution Correlates with Speech Reception in Noise in Cochlear Implant Users

Speech perception ability in noise is one of the most practical measures of success with a cochlear implant; however, with experience, this ability can change dramatically over time, making it a less than ideal tool for comparing performance among different processing strategies. This study examined performance on a spectral discrimination task and compared it to speech perception in noise. An adaptive procedure was used to determine the spectral-ripple density that subjects could discriminate. A closed-set, forced-choice adaptive procedure was used to determine speech reception thresholds for words in two-talker babble and in speech-shaped, steady-state noise. Spectral-ripple thresholds (ripples/octave) were significantly correlated with speech reception thresholds (dB SNR) in noise for 29 cochlear implant users (r = −0.55, p = 0.002 in two-talker babble; r = −0.62, p = 0.0004 in steady-state noise), demonstrating that better spectral resolution was associated with better speech perception in noise. A significant correlation was also found between the spectral-ripple discrimination ability and word recognition in quiet (r = 0.50, p = 0.009). In addition, test–retest reliability for spectral-ripple discrimination was good, and no learning was observed. The present study demonstrates that the spectral-ripple discrimination test, which is time efficient and nonlinguistic, would be a useful tool to evaluate cochlear implant performance with different signal processing strategies.     

Speech perception and auditory performance in Finnish adult cochlear implant users

Abstract

Objective This study aimed at investigating the association between speech perception and categories of auditory performance (mCAP) in everyday life for adult cochlear implant users.

Design A prospective repeated measures design over a two-year follow-up period was used.

Methods The speech perception and auditory performance of 19 Finnish-speaking adults were assessed before implantation and 1, 3, 6, 12 and 24 months after switching on the implant. Spearman's rank order correlation coefficients (r_s) were calculated between mCAP and sentence, word, syllable, vowel and consonant recognition. Pearson's product moment correlation coefficients (r) were calculated among the speech perception results.

Results The correlation between mCAP and the speech perception results was high and statistically significant (r_s = 0.81?0.85, p 0.0001), as well as the correlation among the speech perception tests (r = 0.79?0.92, p 0.0001).

Conclusions The speech perception tests used may be considered as good describers of everyday performance of the subjects of this investigation.     

Short-term study of the effect of speech coding strategy on the auditory performance of pre- and post-lingually deafened adults implanted with the Clarion CII

OBJECTIVE: The auditory performance of cochlear implantees is linked to numerous variables, such as audiological characteristics, age and type of speech coding strategy. In recent years, many different ways of processing sounds have been developed, with possible implications for auditory performance. The purpose of this study was to evaluate the intra-individual differences of patients for speech perception tasks in quiet and in noise as a result of switching from a standard strategy [Continuous Interleaved Sampling (CIS)/Simultaneous Analog Strategy (SAS)] to Hi-Resolution (HiRes). MATERIAL AND METHODS:A total of 14 post-lingual adults implanted with the Clarion CII were selected for trials. At switch-on, six patients chose a CIS strategy and eight an SAS strategy. After an average period of 9.3 months, all patients were switched over to HiRes. All patients were tested (open-set mode) with bisyllabic words and sentences, in both quiet and noise [speech/noise ratio (SNR) = +10]. Testing was carried out after an initial period with the CIS/SAS strategy and 3 months after switching over to HiRes. RESULTS: After switch-over a significant improvement was seen for both speech in quiet (words +25.2%, sentences +10.8%) and speech in noise (words 44.8%, sentences 45.4%). CONCLUSION: Despite individual differences, all patients improved their performance with HiRes use, the greatest improvements being seen under unfavourable listening conditions (SNR = +10). Subjective improvements in speech discrimination and overall sound quality perception were reported even after the first week of HiRes use.     

Use of the Phantom Electrode strategy to improve bass frequency perception for music listening in cochlear implant users

Abstract

Objectives

The Phantom Electrode strategy makes use of partial bipolar stimulation on the two most apical electrodes in an effort to extend the frequency range available to cochlear implant (CI) users. This study aimed to quantify the effect of the Phantom Electrode strategy on bass frequency perception in music listening in CI users.

Methods

Eleven adult Advanced Bionics users with the Fidelity 120 processing strategy and 16 adult normal hearing (NH) individuals participated in the study. All subjects completed the CI-multiple stimulus with hidden reference and anchor (MUSHRA), a test of an individual's ability to make discriminations in sound quality following the removal of bass frequency information. NH participants completed the CI-MUSHRA once, whereas CI users completed the task twice – once with their baseline clinical program and once with the Phantom Electrode strategy, in random order. CI users’ performance was assessed in comparison with NH performance.

Results

The Phantom Electrode strategy improved CI users performance on the CI-MUSHRA compared with Fidelity 120.

Discussion

Creation of a Phantom Electrode percept through partial bipolar stimulation of the two most apical electrodes appears to improve CI users’ perception of bass frequency information in music, contributing to greater accuracy in the ability to detect alterations in musical sound quality.

Conclusion

The Phantom Electrode processing strategy may enhance the experience of listening to music and thus acoustic stimuli more broadly by improving perception of bass frequencies, through direction of current towards the apical portion of the cochlea beyond the termination of the electrode.     

Brain voice processing with bilateral cochlear implants: a positron emission tomography study

Most cochlear implantations are unilateral. To explore the benefits of a binaural cochlear implant, we used water-labelled oxygen-15 positron emission tomography. Relative cerebral blood flow was measured in a binaural implant group (n = 11), while the subjects were passively listening to human voice sounds, environmental sounds non-voice or silence. Binaural auditory stimulation in the cochlear implant group bilaterally activated the temporal voice areas, whereas monaural cochlear implant stimulation only activated the left temporal voice area. Direct comparison of the binaural and the monaural cochlear implant stimulation condition revealed an additional right temporal activation during voice processing in the binaural condition and the activation of a right fronto-parietal cortical network during sound processing that has been implicated in attention. These findings provide evidence that a bilateral cochlear implant stimulation enhanced the spectral cues associated with sound perception and improved brain processing of voice stimuli in the right temporal region when compared to a monaural cochlear implant stimulation. Moreover, the recruitment of sensory attention resources in a right fronto-parietal network allowed patients with bilateral cochlear implant stimulation to enhance their sound discrimination, whereas the same patients with only one cochlear implant stimulation had more auditory perception difficulties.     

Comparison of outcomes in a case of bilateral cochlear implantation using devices manufactured by two different implant companies (Cochlear Corporation and Med-El)

Abstract

Objective

This paper reports a case of a patient who has had bilateral cochlear implants that have been manufactured by different cochlear implant companies (Cochlear Corporation and Med-El).

Method

Comparison of speech perception tests following single implant insertion and bilateral insertion (3 and 12 months). The patient was also interviewed to obtain a subjective opinion on their quality of hearing.

Results

The patient reported that their Med-El implant had better sound quality than their Cochlear Corporation implant. The speech perception tests however failed to show any difference.

Conclusion

Despite no difference found with the objective tests hearing is very subjective and therefore the patient's opinion on the quality of sound is important. It is only a matter of time before other patients are fitted with bilateral cochlear implants from different companies and this information should be collated to allow comparison between manufacturers.     

Benefit and predictive factors for speech perception outcomes in pediatric bilateral cochlear implant recipients

IntroductionDespite recent advancement in the prediction of cochlear implant outcome, the benefit of bilateral procedures compared to bimodal stimulation and how we predict speech perception outcomes of sequential bilateral cochlear implant based on bimodal auditory performance in children remain unclear.ObjectivesThis investigation was performed: (1) to determine the benefit of sequential bilateral cochlear implant and (2) to identify the associated factors for the outcome of sequential bilateral cochlear implant.MethodsObservational and retrospective study. We retrospectively analyzed 29 patients with sequential cochlear implant following bimodal-fitting condition. Audiological evaluations were performed; the categories of auditory performance scores, speech perception with monosyllable and disyllables words, and the Korean version of Ling. Audiological evaluations were performed before sequential cochlear implant with the bimodal fitting condition (CI1 + HA) and one year after the sequential cochlear implant with bilateral cochlear implant condition (CI1 + CI2). The good performance group (GP) was defined as follows; 90% or higher in monosyllable and bisyllable tests with auditory-only condition or 20% or higher improvement of the scores with CI1 + CI2. Age at first implantation, inter-implant interval, categories of auditory performance score, and various comorbidities were analyzed by logistic regression analysis.ResultsCompared to the CI1 + HA, CI1 + CI2 provided significant benefit in categories of auditory performance, speech perception, and Korean version of Ling results. Preoperative categories of auditory performance scores were the only associated factor for being GP (odds ratio = 4.38, 95% confidence interval – 95% = 1.07–17.93, p = 0.04).ConclusionsThe children with limited language development in bimodal condition should be considered as the sequential bilateral cochlear implant and preoperative categories of auditory performance score could be used as the predictor in speech perception after sequential cochlear implant.     

Performance of subjects fit with the Advanced Bionics CII and Nucleus 3G cochlear implant devices

OBJECTIVE: To determine if subjects who used different cochlear implant devices and who were matched on consonant-vowel-consonant (CNC) identification in quiet would show differences in performance on speech-based tests of spectral and temporal resolution, speech understanding in noise, or speech understanding at low sound levels. DESIGN: The performance of 15 subjects fit with the CII Bionic Ear System (CII Bionic Ear behind-the-ear speech processor with the Hi-Resolution sound processing strategy; Advanced Bionics Corporation) was compared with the performance of 15 subjects fit with the Nucleus 24 electrode array and ESPrit 3G behind-the-ear speech processor with the advanced combination encoder speech coding strategy (cochlear corporation). SUBJECTS: Thirty adults with late-onset deafness and above-average speech perception abilities who used cochlear implants. MAIN OUTCOME MEASURES: Vowel recognition, consonant recognition, sentences in quiet (74, 64, and 54 dB SPL [sound pressure level]) and in noise (+10 and +5 dB SNR [signal-to-noise ratio]), voice discrimination, and melody recognition. RESULTS: Group differences in performance were significant in 4 conditions: vowel identification, difficult sentence material at +5 dB and +10 dB SNR, and a measure that quantified performance in noise and low input levels relative to performance in quiet. CONCLUSIONS: We have identified tasks on which there are between-group differences in performance for subjects matched on CNC word scores in quiet. We suspect that the differences in performance are due to differences in signal processing. Our next goal is to uncover the signal processing attributes of the speech processors that are responsible for the differences in performance.     

Simultaneous Bilateral Cochlear Implantation: Prospective Study in Adults

Normal-hearing listeners gain important everyday benefits from having two ears, particularly for determining where sounds come from and for understanding speech in noisy environments. Users of two cochlear implants may have the opportunity to experience some of these bilateral advantages. The primary aim of this study was to document bilateral versus unilateral listening benefit in 15 postlinguistically deafened adults implanted simultaneously with two Harmony^® (HiRes 90K^®) cochlear implants. Speech perception (in quiet and in noise) and localization accuracy were assessed for each ear alone and both ears together. Subjects showed improved sound localization and better speech perception in quiet and in noise when using two implants compared with using one implant alone.     

Performance and benefit as outcome measures following cochlear implantation in non-traditional adult candidates: a pilot study

Abstract

Objectives To measure the reported benefit in quality of life (QoL) and audiological performance in a group of 'non-traditional' patients undergoing cochlear implantation, and compare the results with those of patients satisfying established criteria for implantation.

Design Longitudinal retrospective observational study.

Patients Ten consecutive early-deafened, late-implanted patients, here termed 'nontraditional' patients, with a mean age of 31.3 years (range 15-52 years) and implant experience from 8 to 76 months (mean 40.9 months).

Methods The Glasgow Benefit Inventory (GBI) was used to evaluate benefit in QoL. Auditory performance tests consisted of: (a) recognition of environmental sounds using the UCL/RNID lists; (b) speech pattern perception using the Three Alternative Forced Choice Test; (c) speech discrimination using modified CUNY sentences in two conditions: lip-reading alone and lip-reading with the implant. Lip-reading enhancement scores were extrapolated.

Results GBI scores varied widely from 3 to 67, with a mean of 38.9, which is comparable to the mean score of 40 reported for 'traditional' candidates. Half the subjects were totally satisfied with their implant (scoring 100), and the mean satisfaction rating was 82.7. The mean scores obtained in environmental sound discrimination (40.5%) were a little below those of conventional, 'traditional' candidates, while those for speech pattern perception (73%) were within a comparable range. In contrast all ten subjects scored zero on open-set speech perception tests after implantation. The mean lip-reading enhancement score (7.6%) was significantly below that achieved by 'traditional' cochlear implant candidates.

Conclusion This group of 'non-traditional' adults demonstrates measured benefit in QoL, which is comparable to that achieved by 'traditional' candidates, but is not accompanied by a parallel improvement in performance on speech perception tasks. These results suggest that factors other than auditory performance may be equally important from the patient's perspective, and that some patients who might be considered poor candidates may still derive considerable benefit. It is suggested that benefit and performance be viewed as separate outcomes in this 'non-traditional' population.