Tests Of Speech Understanding Research Articles

Assessment of cochlear implant hearing outcomes using ecological momentary assessment in both controlled and real-world settings

Laboratory tests of speech understanding demonstrate high effectiveness of cochlear implants (CIs) for individuals with severe-to-profound hearing loss. However, understanding real-world benefits remains challenging. Retrospective questionnaires may be unreliable due to recall bias and limited acoustic information. To address this, we used an Ecological Momentary Assessment (EMA) smartphone app to collect subjective feedback and acoustic data from CI recipients in lab and real-world settings. We characterised challenging acoustic environments for CI users and the influence of internal factors on self-ratings of environmental noisiness, device benefit, and speech understanding. Twenty adults underwent cognitive tests, questionnaires, EMA, and the NAL Dynamic Conversation Test in the lab. Acoustic scenes were reproduced in an anechoic chamber to assess comprehension, familiarise participants with EMA, and establish benchmarks for real-world EMA data. Over four weeks, participants recorded experiences using the EMA app. Analysis of real-world EMA data revealed perceived noisiness was influenced by spectro-temporal properties and sound level. Self-reported communication factors were associated with environmental sound level and predictive of self-reported CI device benefit. Communication factors were also correlated with CI experience and cognitive performance. EMA offers valuable insights into CI recipients' real-world experiences, aiding customization and efficacy evaluation.

Functional Outcomes and Quality of Life after Cochlear Implantation in Patients with Long-Term Deafness.

Background: Hearing-related quality of life (QoL) after cochlear implantation (CI) is as important as audiological performance. We evaluated the functional results and QoL after CI in a heterogeneous patient cohort with emphasis on patients with long-term deafness (>10 years). Methods: Twenty-eight patients (n = 32 implanted ears, within n = 12 long-term deaf ears) implanted with a mid-scala electrode array were included in this retrospective mono-centric cohort study. Speech intelligibility for monosyllables (SIM), speech reception thresholds (SRT50) and QoL with Nijmegen Cochlear Implant Questionnaire (NCIQ) were registered. Correlation of SIM and QoL was analyzed. Results: SIM and SRT50 improved significantly 12 months postoperatively up to 54.8 ± 29.1% and 49.3 ± 9.6 dB SPL, respectively. SIM progressively improved up to 1 year, but some early-deafened, late implanted patients developed speech understanding several years after implantation. The global and all subdomain QoL scores increased significantly up to 12 months postoperatively and we found a correlation of SIM and global QoL score at 12 months postoperatively. Several patients of the “poor performer” (SIM < 40%) group reported high improvement of hearing-related QoL. Conclusions: Cochlear implantation provides a benefit in hearing-related QoL, even in some patients with low postoperative speech intelligibility results. Consequently, hearing-related QoL scores should be routinely used as outcome measure beside standard speech understanding tests, as well. Further studies with a prospective multi-centric design are needed to identify factors influencing post-implantation functional results and QoL in the patient group of long-term deafness.

Predicting speech intelligibility from EEG in a non-linear classification paradigm * *Submitted for review on 7 June 2021. The research conducted in this paper is funded by KU Leuven Special Research Fund C24/18/099 (C2 project to Tom Francart and Hugo Van hamme), by a PhD Grant (1S89620N) of the Research Foundation Flanders (FWO) and from the European Research Council (ERC)

Objective. Currently, only behavioral speech understanding tests are available, which require active participation of the person being tested. As this is infeasible for certain populations, an objective measure of speech intelligibility is required. Recently, brain imaging data has been used to establish a relationship between stimulus and brain response. Linear models have been successfully linked to speech intelligibility but require per-subject training. We present a deep-learning-based model incorporating dilated convolutions that operates in a match/mismatch paradigm. The accuracy of the model’s match/mismatch predictions can be used as a proxy for speech intelligibility without subject-specific (re)training. Approach. We evaluated the performance of the model as a function of input segment length, electroencephalography (EEG) frequency band and receptive field size while comparing it to multiple baseline models. Next, we evaluated performance on held-out data and finetuning. Finally, we established a link between the accuracy of our model and the state-of-the-art behavioral MATRIX test. Main results. The dilated convolutional model significantly outperformed the baseline models for every input segment length, for all EEG frequency bands except the delta and theta band, and receptive field sizes between 250 and 500 ms. Additionally, finetuning significantly increased the accuracy on a held-out dataset. Finally, a significant correlation (r = 0.59, p = 0.0154) was found between the speech reception threshold (SRT) estimated using the behavioral MATRIX test and our objective method. Significance. Our method is the first to predict the SRT from EEG for unseen subjects, contributing to objective measures of speech intelligibility.

The Effects of Task Difficulty Predictability and Noise Reduction on Recall Performance and Pupil Dilation Responses.

Objectives:Communication requires cognitive processes which are not captured by traditional speech understanding tests. Under challenging listening situations, more working memory resources are needed to process speech, leaving fewer resources available for storage. The aim of the current study was to investigate the effect of task difficulty predictability, that is, knowing versus not knowing task difficulty in advance, and the effect of noise reduction on working memory resource allocation to processing and storage of speech heard in background noise. For this purpose, an “offline” behavioral measure, the Sentence-Final Word Identification and Recall (SWIR) test, and an “online” physiological measure, pupillometry, were combined. Moreover, the outcomes of the two measures were compared to investigate whether they reflect the same processes related to resource allocation.Design:Twenty-four experienced hearing aid users with moderate to moderately severe hearing loss participated in this study. The SWIR test and pupillometry were measured simultaneously with noise reduction in the test hearing aids activated and deactivated in a background noise composed of four-talker babble. The task of the SWIR test is to listen to lists of sentences, repeat the last word immediately after each sentence and recall the repeated words when the list is finished. The sentence baseline dilation, which is defined as the mean pupil dilation before each sentence, and task-evoked peak pupil dilation (PPD) were analyzed over the course of the lists. The task difficulty predictability was manipulated by including lists of three, five, and seven sentences. The test was conducted over two sessions, one during which the participants were informed about list length before each list (predictable task difficulty) and one during which they were not (unpredictable task difficulty).Results:The sentence baseline dilation was higher when task difficulty was unpredictable compared to predictable, except at the start of the list, where there was no difference. The PPD tended to be higher at the beginning of the list, this pattern being more prominent when task difficulty was unpredictable. Recall performance was better and sentence baseline dilation was higher when noise reduction was on, especially toward the end of longer lists. There was no effect of noise reduction on PPD.Conclusions:Task difficulty predictability did not have an effect on resource allocation, since recall performance was similar independently of whether task difficulty was predictable or unpredictable. The higher sentence baseline dilation when task difficulty was unpredictable likely reflected a difference in the recall strategy or higher degree of task engagement/alertness or arousal. Hence, pupillometry captured processes which the SWIR test does not capture. Noise reduction frees up resources to be used for storage of speech, which was reflected in the better recall performance and larger sentence baseline dilation toward the end of the list when noise reduction was on. Thus, both measures captured different temporal aspects of the same processes related to resource allocation with noise reduction on and off.

Speech Understanding and Sound Source Localization by Cochlear Implant Listeners Using a Pinna-Effect Imitating Microphone and an Adaptive Beamformer.

Sentence understanding scores for patients with cochlear implants (CIs) when tested in quiet are relatively high. However, sentence understanding scores for patients with CIs plummet with the addition of noise. To assess, for patients with CIs (MED-EL), (1) the value to speech understanding of two new, noise-reducing microphone settings and (2) the effect of the microphone settings on sound source localization. Single-subject, repeated measures design. For tests of speech understanding, repeated measures on (1) number of CIs (one, two), (2) microphone type (omni, natural, adaptive beamformer), and (3) type of noise (restaurant, cocktail party). For sound source localization, repeated measures on type of signal (low-pass [LP], high-pass [HP], broadband noise). Ten listeners, ranging in age from 48 to 83 yr (mean = 57 yr), participated in this prospective study. Speech understanding was assessed in two noise environments using monaural and bilateral CIs fit with three microphone types. Sound source localization was assessed using three microphone types. In Experiment 1, sentence understanding scores (in terms of percent words correct) were obtained in quiet and in noise. For each patient, noise was first added to the signal to drive performance off of the ceiling in the bilateral CI-omni microphone condition. The other conditions were then administered at that signal-to-noise ratio in quasi-random order. In Experiment 2, sound source localization accuracy was assessed for three signal types using a 13-loudspeaker array over a 180° arc. The dependent measure was root-mean-score error. Both the natural and adaptive microphone settings significantly improved speech understanding in the two noise environments. The magnitude of the improvement varied between 16 and 19 percentage points for tests conducted in the restaurant environment and between 19 and 36 percentage points for tests conducted in the cocktail party environment. In the restaurant and cocktail party environments, both the natural and adaptive settings, when implemented on a single CI, allowed scores that were as good as, or better, than scores in the bilateral omni test condition. Sound source localization accuracy was unaltered by either the natural or adaptive settings for LP, HP, or wideband noise stimuli. The data support the use of the natural microphone setting as a default setting. The natural setting (1) provides better speech understanding in noise than the omni setting, (2) does not impair sound source localization, and (3) retains low-frequency sensitivity to signals from the rear. Moreover, bilateral CIs equipped with adaptive beamforming technology can engender speech understanding scores in noise that fall only a little short of scores for a single CI in quiet.

Communication in military environments: Influence of noise, hearing protection and language proficiency

Military training and international operations require different nationalities to communicate in a common language, where there are potential challenges with non-native (L2) speech communication. An experiment of speech communication in military noise was conducted for co-located (face-to-face [F2F]) and distributed (using communication headsets) talker-listener pairs. Half of the twenty-four participants were monolingual English speakers (native group, NA) and the remaining half had obtained English fluency after the age of eight years (non-native group, NN). Two tests of speech understanding were used: the Modified Rhyme Test (MRT) and the Speech Perception in Noise test (SPIN). In the F2F condition, the participants wore a communication headset (earmuff) with the power off for occluded listening. Three levels of armoured vehicle noise were used, 55, 60 and 65dBA, for speech-to-noise ratios ranging from −10 to +5dB. In the radio condition, the pairs were separated by a visual barrier and used the communication headset for the tests in 80dBA armoured vehicle noise. The results showed that the NN group had difficulty with the SPIN test in the radio and F2F conditions. This result was attributed to the open-response set of the SPIN. Headset occlusion likely contributed to the lower scores for the NN listeners in the F2F condition. There was a main effect of talker for the MRT in the F2F and radio conditions, and for the SPIN in the radio condition, suggesting that foreign accent reduced the intelligibility for both the NA and NN groups. The results were surprising considering the high L2 proficiency of the NN group. Training methods for improving L2 communication in operational settings should be further investigated.

Clinical evaluation of the Nucleus® 6 cochlear implant system: Performance improvements with SmartSound iQ

Objective: This paper provides a detailed description of the Nucleus 6 system, and clinically evaluates user performance compared to the previous Nucleus 5 system in cochlear implant recipients. Additionally, it clinically evaluates a range of Nucleus 6 and Nucleus 5 programs to determine the performance benefits provided by new input processing technologies available in SmartSound iQ. Design: Speech understanding tests were used to clinically validate the default Nucleus 6 program, by comparing performance outcomes against up to five custom Nucleus 5 or Nucleus 6 programs in a range of listening environments. Clinical comparisons between programs were conducted across the following listening environments; quiet, speech weighted noise (co-located and spatially separated noise), and 4-talker babble (co-located and spatially separated noise). Study sample: Twenty-one adult cochlear implant recipients participated. Results: Significant speech understanding benefits were found with the default Nucleus 6 program compared to the participants’ preferred program using their Nucleus 5 processor and compared to a range of custom Nucleus 6 programs. All participants successfully accepted and upgraded to the new default Nucleus 6 SmartSound iQ program. Conclusion: This study demonstrates the acceptance and clinical benefits of the Nucleus 6 cochlear implant system and SmartSound iQ.

Bilateral Cochlear Implantation for Children in Nagasaki, Japan

ObjectivesThe number of patients with bilateral cochlear implant (CI) has gradually increased as patients and/or parents recognize its effectiveness. The purpose of this report is to evaluate the efficacy of 29 bilateral CI out of 169 pediatric CI users, who received auditory-verbal/oral habilitation at our hearing center.MethodsWe evaluated the audiological abilities 29 Japanese children with bilateral CIs including wearing threshold, word recognition score, speech discrimination score at 1 m from front speaker (SP), 1 m from second CI side SP, speech discrimination score under the noise (S/N ratio=80 dB sound pressure level [SPL]/70 dB SPL, 10 dB) at 1 m from front SP, word recognition score under the noise (S/N ratio=80 dB SPL/70 dB SPL, 10 dB) at 1 m from front SP.ResultsBinaural hearing using bilateral CI is better than first CI in all speech understanding tests. Especially, there were significant differences between the results of first CI and bilateral CI on SDS at 70 dB SPL (P=0.02), SDS at 1 m from second CI side SP at 60 dB SPL (P=0.02), word recognition score (WRS) at 1 m from second CI side SP at 60 dB SPL (P=0.02), speech discrimination score (SDS) at 1 m from front SP under the noise (S/N=80/70; P=0.01) and WRS at 1 m from front SP under the noise (S/N=80/70; P=0.002). At every age, a second CI is very effective. However, the results of under 9 years old were better than of over 9 years old on the mean SDS under the noise (S/N=80/70) on second CI (P=0.04). About use of a hearing aid (HA) in their opposite side of first CI, on the WRS and SDS under the noise, there were significant differences between the group of over 3 years and the group of under 10 months of HA non user before second CI.ConclusionThese results may show important binaural effectiveness such as binaural summation and head shadow effect. Bilateral CI is very useful medical intervention for many children with severe-to-profound hearing loss in Japan as well as elsewhere.

The Use of Frequency Compression by Cochlear Implant Recipients with Postoperative Acoustic Hearing

The number of cochlear implant (CI) recipients who have usable acoustic hearing in at least one ear is continuing to grow. Many such CI users gain perceptual benefits from the simultaneous use of acoustic and electric hearing. In particular, it has been shown previously that use of an acoustic hearing aid (HA) with a CI can often improve speech understanding in noise. To determine whether the application of frequency compression in an HA would provide perceptual benefits to CI recipients with usable acoustic hearing, either when used in combination with the CI or when the HA was used by itself. A repeated-measures experimental design was used to evaluate the effects on speech perception of using a CI either alone or simultaneously with an HA that had frequency compression either enabled or disabled. Eight adult CI recipients who were successful users of acoustic hearing aids in their nonimplanted ears participated as subjects. The speech perception of each subject was assessed in seven conditions. These required each subject to listen with (1) their own HA alone; (2) the Phonak Naida HA with frequency compression (SoundRecover) enabled; (3) the Naida with SoundRecover disabled; (4) their CI alone; (5) their CI and their own HA; (6) their CI and the Naida with SoundRecover enabled; and (7) their CI and the Naida with SoundRecover disabled. Test sessions were scheduled over a period of about 10 wk. During part of that time, the subjects were asked to use the Phonak Naida HA with their CIs in place of their own HAs. The speech perception tests included measures of consonant identification from a closed set of 12 items presented in quiet, and measures of sentence understanding in babble noise. The speech materials were presented at an average level of 60 dB SPL from a loudspeaker. Speech perception was better, on average, in all conditions that included use of the CI in comparison with any condition in which only an HA was used. For example, consonant recognition improved by approximately 50 percentage points, on average, between the HA-alone listening conditions and the CI-alone condition. There were no statistically significant score differences between conditions with SoundRecover enabled and disabled. There was a small but significant improvement in the average signal-to-noise ratio (SNR) required to understand 50% of the words in the sentences presented in noise when an HA was used simultaneously with the CI. Although each of these CI users readily accepted the Phonak Naida HA with SoundRecover frequency compression, no benefits related specifically to the use of SoundRecover were found in the particular tests of speech understanding applied in this study. The relatively high levels of perceptual performance attained by these subjects with use of a CI by itself are consistent with the finding that the addition of an HA provided little further benefit. However, the use of an HA with the CI did provide better performance than the CI alone for understanding sentences in noise.

Audition and Cognition: Where Lab Meets Clinic

Audition and Cognition: Where Lab Meets Clinic

Cochlear implants: A remarkable past and a brilliant future

The aims of this paper are to (i) provide a brief history of cochlear implants; (ii) present a status report on the current state of implant engineering and the levels of speech understanding enabled by that engineering; (iii) describe limitations of current signal processing strategies; and (iv) suggest new directions for research. With current technology the “average” implant patient, when listening to predictable conversations in quiet, is able to communicate with relative ease. However, in an environment typical of a workplace the average patient has a great deal of difficulty. Patients who are “above average” in terms of speech understanding, can achieve 100% correct scores on the most difficult tests of speech understanding in quiet but also have significant difficulty when signals are presented in noise. The major factors in these outcomes appear to be (i) a loss of low-frequency, fine structure information possibly due to the envelope extraction algorithms common to cochlear implant signal processing; (ii) a limitation in the number of effective channels of stimulation due to overlap in electric fields from electrodes; and (iii) central processing deficits, especially for patients with poor speech understanding. Two recent developments, bilateral implants and combined electric and acoustic stimulation, have promise to remediate some of the difficulties experienced by patients in noise and to reinstate low-frequency fine structure information. If other possibilities are realized, e.g., electrodes that emit drugs to inhibit cell death following trauma and to induce the growth of neurites toward electrodes, then the future is very bright indeed.

Effect of digital frequency compression (DFC) on speech recognition in candidates for combined electric and acoustic stimulation (EAS).

To compare the effects of conventional amplification (CA) and digital frequency compression (DFC) amplification on the speech recognition abilities of candidates for a partial-insertion cochlear implant, that is, candidates for combined electric and acoustic stimulation (EAS). The participants were 6 patients whose audiometric thresholds at 500 Hz and below were <or=60 dB HL and whose thresholds at 2000 Hz and above were >or=80 dB HL. Six tests of speech understanding were administered with CA and DFC. The Abbreviated Profile of Hearing Aid Benefit (APHAB) was also administered following use of CA and DFC. Group mean scores were not statistically different in the CA and DFC conditions. However, 2 patients received substantial benefit in DFC conditions. APHAB scores suggested increased ease of communication, but also increased aversive sound quality. Results suggest that a relatively small proportion of individuals who meet EAS candidacy will receive substantial benefit from a DFC hearing aid and that a larger proportion will receive at least a small benefit when speech is presented against a background of noise. This benefit, however, comes at a cost-aversive sound quality.

Performance of Patients Using Different Cochlear Implant Systems: Effects of Input Dynamic Range

To determine, for patients who had identical levels of performance on a monosyllabic word test presented in quiet, whether device differences would affect performance when tested with other materials and in other test conditions. For Experiment 1, from a test population of 76 patients, three groups (N = 13 in each group) were created. Patients in the first group used the CII Bionic Ear behind-the-ear (BTE) speech processor, patients in the second group used the Esprit3G BTE speech processor, and patients in the third group used the Tempo+ BTE speech processor. The patients in each group were matched on (i) monosyllabic word scores in quiet, (ii) age at testing, (iii) duration of deafness, and (iv) experience with their device. Performance of the three groups was compared on a battery of tests of speech understanding, voice discrimination, and melody recognition. In Experiments 2 (N = 10) and 3 (N = 10) the effects of increasing input dynamic range in the 3G and CII devices, respectively, was assessed with sentence material presented at conversational levels in quiet, conversational levels in noise, and soft levels in quiet. Experiment 1 revealed that patients fit with the CII processor achieved higher scores than Esprit3G and Tempo+ patients on tests of vowel recognition. CII and Tempo+ patients achieved higher scores than Esprit3G patients on difficult sentence material presented in noise at +10 and +5 dB SNR. CII patients achieved higher scores than Esprit3G patients on difficult sentence material presented at a soft level (54 dB SPL). Experiment 2 revealed that increasing input dynamic range in the Esprit3G device had (i) no effect at conversational levels in quiet, (ii) degraded performance in noise, and (iii) improved performance at soft levels. Experiment 3 revealed that increasing input dynamic range in the CII device improved performance in all conditions. Differences in implant design can affect patient performance, especially in difficult listening situations. Input dynamic range and the method by which compression is implemented appear to be the major factors that account for our results.

Normalization and feasibility of speech understanding tests for Dutch speaking toddlers

As a result of newborn hearing screening programs, hearing impairment is often identified early in life and proper intervention (hearing aids, cochlear implant) will enable children to develop expressive and receptive skills as young as possible. The goals of this study are to obtain normative data on speech tests that are suitable for evaluation of young hearing-impaired Dutch speaking children in Flanders and the Netherlands and to determine the youngest age at which these tests are feasible. Normative data are obtained with 143 normal-hearing children with normal cognitive and language development for the Göttinger I (3–4 years) and Göttinger II (5–6 years). It is shown that one performance intensity curve can describe both tests. Moreover, a subsequent study with 35 normal-hearing children showed that the Göttinger I can also be administered to children with normal cognitive and language development younger than three years of age. In addition, the feasibility of two analytical tests was examined. These tests were designed to obtain information on the transmission of spectral and temporal speech cues by the hearing aid or cochlear implant in children as young as 2 1 2 years of age.

Is there a critical period for cochlear implantation in congenitally deaf children? Analyses of hearing and speech perception performance after implantation

A range of basic and applied studies have demonstrated that during the development of the auditory system, early experimental manipulations or clinical interventions are generally more effective than those made later. We present a short review of these studies. We investigated this age-related plasticity in relation to the timing of cochlear implantation in deaf-from-birth children. Cochlear implantation is a standard intervention for providing hearing in children with severe to profound deafness. An important practical question is whether there is a critical period or cutoff age of implantation after which hearing outcomes are significantly reduced. In this article, we present data from prelingually deaf children (mostly congenitally deaf) implanted at ages ranging from 1 to 15 years. Each child was tested with auditory and speech understanding tests before implantation, and at regular intervals up to 8 years postimplantation. We measured the improvement in performance of speech understanding tests in younger implanted children and compared it with the results of those implanted at a later age. We also used a binary partitioning algorithm to divide the data systematically at all ages at implant to determine the optimum split, i.e., to determine the age at implant which best separates performance of early implanted versus later implanted children. We observed distinct age-of-implant cutoffs, and will discuss whether these really represent critical periods during development.

Cognitive performance and perceived effort in speech processing tasks: effects of different noise backgrounds in normal-hearing and hearing-impaired subjectsDesempeño cognitivo y percepción del esfuerzo en tareas de procesamiento del lenguaje: Efectos de las diferentes condiciones de fondo en sujetos normales e hipoacúsicos

Cognitive tests of speech understanding were administered (presented as text, or in auditory or audiovisual modality) and perceived effort was rated. This was done in four background conditions: in silence, and in three types of noise (S/N=+10 dB) varying in temporal structure and meaningfulness. Four groups of 12 subjects each (young/elderly with normal hearing and young/elderly with hearing impairment) participated. The presence of noise had a negative effect on accuracy and speed of performance in the speech processing tasks, and resulted in higher scores of perceived effort, even when the stimuli were presented as text. Differences in performance between noise conditions existed. In the subjective scores, the noise with temporal variations, but without meaningful content, was the most disruptive of the three noise conditions. In the objective scores, the hearing-impaired subjects showed poorer results in noise with temporal variations. The elderly subjects were more distracted by noise with temporal variations, and especially by noise with meaningful content. In noise, all subjects, particularly those with impaired hearing, were more dependent upon visual cues than in the quiet condition.

Improvements in speech perception with an experimental nonlinear frequency compression hearing device

The performance of an experimental frequency compression hearing device was evaluated using tests of speech understanding in quiet. The device compressed frequencies above a programmable cut-off, resulting in those parts of the input signal being shifted to lower frequencies. Below the cut-off, signals were amplified without frequency shifting. Subjects were experienced hearing aid users with moderate-to-severe sensorineural hearing loss and sloping audiograms. Their recognition of monosyllabic words was tested using the experimental device in comparison with conventional hearing aids. Of the 17 subjects, eight showed a significant score improvement (p < 0.05), whereas one subject showed a significant score decrease. Some of the improvements may have resulted from the better audibility provided in the high frequencies by the experimental device in comparison with the conventional aids. However, a subsequent study found that increasing the high-frequency gain in the conventional aids did not produce equivalent perceptual benefits.

Two years of experience using stimulation rates between 800 and 5000 pps with the clarion CII implant

The aim of our investigations with the Clarion CII device was to determine the effect of high stimulation rates on speech perception performance. On average, speech perception performance increased remarkably when changing from low-rate speech coding strategies to high-rate strategies. Performance increase is highly significant in noise ( p<0.01). However, a few patients only show a negligible effect and some patients even achieve worse speech understanding when using very high rates, i.e., 3000 pps/channel or higher. Interestingly, a weak correlation between the M-levels and the hearing performance could be found. Overall, these investigations suggest that the technology of high stimulation rates brings a benefit both when measured subjectively and when using tests of speech understanding, particularly those conducted in competing noise. However, a correlation between rate and performance could not be found in all subjects.

Tests of speech understanding in noise

Tests of speech understanding in noise

Speech recognition and frequency discrimination with the Ineraid and CIS cochlear prostheses

Measures of frequency discrimination and speech understanding were made for cochlear implant patients using the Ineraid, analog signal processor and for patients using the continuous interleaved sampling (CIS) processor. For patients using the Ineraid, measures of frequency discrimination are significantly correlated with performance on tests of speech understanding. The correlation coefficients range from 0.60 to 0.82 depending on the frequency domain of the discrimination test and on the nature of the test of speech understanding. When Ineraid patients were fitted with a CIS processor, speech understanding improved significantly. An improvement in frequency discrimination may be the principal factor in the high word recognition scores achieved by patients using the CIS processor. [Research supported by NIDCD.]