Comparisons between neural response imaging thresholds, electrically evoked auditory reflex thresholds and most comfortable loudness levels in CII bionic ear users with HiResolution sound processing strategies

CONCLUSIONS: The data collected in this study indicated that first Neural Response Imaging (NRI) thresholds had a better correlation with HiResolution most comfortable loudness (M) levels than tNRI thresholds. Electrically evoked auditory reflex thresholds (EARTs) had a higher correlation with HiResolution M levels than tNRI thresholds and a lower correlation than first NRI thresholds. NRI is a very useful method for programming the cochlear implants of young children who cannot demonstrate a reliable judgment of loudness. OBJECTIVE: To investigate how HiResolution sound processing, designed to deliver high-rate stimuli, relates to EARTs and electrically evoked compound action potential measurements produced by low-rate stimuli. MATERIAL AND METHODS: Nine profoundly hearing-impaired children and adults aged 6-29 years participated in the study. NRI responses were elicited using pulse trains consisting of biphasic pulses at a pulse width per phase of 32 micros delivered at a frequency of 30 Hz using SoundWave programming software. Stimuli were delivered to the odd electrodes (1, 3, 5, 7, 9, 11, 13 and 15) along the array. tNRI (NRI threshold) and first NRI thresholds were recorded for each stimulating electrode. "Speech bursts" stimuli used in EARTs recording were delivered to four electrodes at a time and stapedial reflexes were recorded from the impedance bridge. The M levels used were those used by each patient in their everyday HiResolution programs. RESULTS: For 8 patients (53 stimulating electrodes) the correlation between tNRI threshold and M level was r=0.675 (p=0.000) and that between first NRI thresholds and M level was r=0.741 (p=0.000). On average the M-level value was 20 CU (Current Unit) lower than the first NRI threshold value and 12 CU higher than the tNRI threshold value. The M-level patterns across the electrode array overall were similar to the tNRI or first NRI threshold patterns. For 7 patients (112 stimulating electrodes) the correlation between EART and M levels was r=0.710 (p=0.000). On average the EART value was 14 CU higher than the M-level value.     

Relationships among objective measures and speech perception in adult users of the HiResolution Bionic Ear

Abstract

The purpose of this study was to describe speech recognition performance for subjects using electrically evoked stapedial reflex thresholds (eSRT) based on programs with the HiResolution Bionic Ear system. A secondary goal was to evaluate the relationship of the electrically evoked compound action potentials (eCAP) as measured with neural response imaging (NRI) relative to the subjects' most comfortable stimulation levels (M levels). M levels, eSRT and eCAP thresholds were measured in 19 postlinguistically deafened adults using either a CII or HiRes 90K cochlear implant. The results showed that eSRTs could be measured easily in a majority of subjects, whereas eCAPS were measured in all subjects. There were close agreements between eSRTs and M levels in the subjects' behaviorally based programs. In contrast, the correspondence between M levels and eCAP thresholds was not as strong. New programs were created with M levels based on the eSRTs for 11 subjects. Programs created using eSRTs as a guide for setting levels yielded better speech recognition than programs using conventional behavioural measures of M levels. These data indicate that individuals can obtain strong benefits from cochlear implants using programs with stimulation levels based on objective measures. Copyright © 2008 John Wiley & Sons, Ltd.     

Relationships among objective measures and speech perception in adult users of the HiResolution Bionic Ear

The purpose of this study was to describe speech recognition performance for subjects using electrically evoked stapedial reflex thresholds (eSRT) based on programs with the HiResolution Bionic Ear system. A secondary goal was to evaluate the relationship of the electrically evoked compound action potentials (eCAP) as measured with neural response imaging (NRI) relative to the subjects' most comfortable stimulation levels (M levels). M levels, eSRT and eCAP thresholds were measured in 19 postlinguistically deafened adults using either a CII or HiRes 90K cochlear implant. The results showed that eSRTs could be measured easily in a majority of subjects, whereas eCAPS were measured in all subjects. There were close agreements between eSRTs and M levels in the subjects' behaviorally based programs. In contrast, the correspondence between M levels and eCAP thresholds was not as strong. New programs were created with M levels based on the eSRTs for 11 subjects. Programs created using eSRTs as a guide for setting levels yielded better speech recognition than programs using conventional behavioural measures of M levels. These data indicate that individuals can obtain strong benefits from cochlear implants using programs with stimulation levels based on objective measures.     

The influence of lexical-access ability and vocabulary knowledge on measures of speech recognition in noise

Objective: The main objective was to investigate the effect of linguistic abilities (lexical-access ability and vocabulary size) on different measures of speech-in-noise recognition in normal-hearing listeners with various levels of language proficiency. Design: Speech reception thresholds (SRTs) were measured for sentences in steady-state (SRT_stat) and fluctuating noise (SRT_fluc), and for digit-triplets in steady-state noise (DIN). Lexical-access ability was measured with a lexical-decision test and a word-naming test. Vocabulary size was also measured. For the SRT, keyword scoring and sentence scoring were compared. Study sample: To introduce variation in linguistic abilities, three groups of 24 young normal-hearing listeners were included: higher-educated native, lower-educated native, and higher-educated non-native listeners. Results: Lexical-access ability was most accurately measured with combined results of lexical decision and word naming. Lexical-access ability explained 60% of the variance in SRT. The effect of linguistic abilities on SRTs was up to 5.6 dB for SRT_stat and 8 dB for SRT_fluc. Using keyword scoring reduced this effect by approximately 1.5 dB. For DIN the effect of linguistic ability was less than 1 dB. Conclusions: Lexical-access ability is an important predictor of SRTs in normal-hearing listeners. These results are important to consider in the interpretation of speech-in-noise scores of hearing-impaired listeners.     

Normative data on audiovisual speech integration using sentence recognition and capacity measures

Objective: The ability to use visual speech cues and integrate them with auditory information is important, especially in noisy environments and for hearing-impaired (HI) listeners. Providing data on measures of integration skills that encompass accuracy and processing speed will benefit researchers and clinicians. Design: The study consisted of two experiments: First, accuracy scores were obtained using City University of New York (CUNY) sentences, and capacity measures that assessed reaction-time distributions were obtained from a monosyllabic word recognition task. Study sample: We report data on two measures of integration obtained from a sample comprised of 86 young and middle-age adult listeners: Results: To summarize our results, capacity showed a positive correlation with accuracy measures of audiovisual benefit obtained from sentence recognition. More relevant, factor analysis indicated that a single-factor model captured audiovisual speech integration better than models containing more factors. Capacity exhibited strong loadings on the factor, while the accuracy-based measures from sentence recognition exhibited weaker loadings. Conclusions: Results suggest that a listener’s integration skills may be assessed optimally using a measure that incorporates both processing speed and accuracy.     

Development of materials for the clinical assessment of speech recognition: the speech sound pattern discrimination test.

The purpose of this investigation was to evaluate the validity and reliability of materials designed for an assessment procedure capable of making meaningful distinctions in speech recognition ability among individuals having mild-to-moderate hearing losses. Sets of phonetic contrasts were presented within sentence contexts to 53 listeners (22 normal hearing, 31 hearing impaired) in 4 listening conditions (quiet and with background competition at signal-to-noise ratios of +5, 0, and -5 dB). The listeners were asked to discriminate pairs of sentences (e.g., "The man hid the dog" and "The man hit the dog") using same-different judgments. Their performances were analyzed in a manner enabling comparisons among items in terms of the classification of phonetic contrasts. Listener performance was also compared to performance on a set of independent variables, including the W-22 and QuickSIN speech tests, high-frequency hearing loss, speech reception threshold, listener age, and others. Results indicated that the new materials distinguished the normal-hearing from the hearing-impaired group and that listener performance (a) declined about 17% for each 5 dB decrement in SNR and (b) was influenced by the phonetic content of items in a manner similar to that reported by G. A. Miller and P. E. Nicely (1955). The performances of the hearing-impaired listeners were much more strongly related to high-frequency hearing loss, listener age, and other variables than were their performances on either the W-22 or QuickSIN tests. These findings are discussed with specific reference to the use of a mathematical model (i.e., the Rasch model for person measurement) for scaling items along a continuum of difficulty. The mathematical model and associated item difficulty values will serve as the basis for construction of a clinically useful computerized, adaptive test of speech recognition ability known as the Speech Sound Pattern Discrimination Test (Bochner, J., Garrison, W., Palmer, L., MacKenzie, D., & Braveman, A., 1997).     

Vibrant sound bridge application to middle ear windows versus conventional hearing aids: a comparative study based on international outcome inventory for hearing aids

In this study, we aimed to compare the outcomes of satisfaction of the patients who used hearing aids preceding the vibrant sound bridge (VSB) application on middle ear windows (14 oval window and 5 round window). Nineteen adult patients with conductive or mixed hearing loss were included in the study. All patients used behind the ear hearing aids on the site which was selected for VSB application. The patients used hearing aids for at least 3 months before the VSB operation. The floating mass transducer (FMT) was placed on one of the middle ear windows (oval or round) in VSB operation. The patients were evaluated with International Outcome Inventory for Hearing Aids (IOI-HA) preoperatively after at least 3 months trial of conventional hearing aid and postoperatively after 3 months use of VSB. No perioperative problem was encountered. The total score of IOI-HA was significantly higher with VSB compared with conventional hearing aids (p < 0.05). No statistically significant difference was found between the daily use, residual activity limitations, satisfaction, impact on others, quality of life between middle ear implant and hearing aid (p > 0.05). The IOI-HA scores were significantly higher with the middle ear implant than the conventional hearing aid regarding benefit and residual participation restrictions (p < 0.05). Although the scores for quality of life assessment was similar between VSB and hearing aid use, there was a superiority of VSB in terms of benefit and residual participation restrictions as well as overall IOI-HA scores as the FMT was placed on one of the middle ear windows.     

A comparison of two approaches to assessment of speech recognition ability in single cases

Single-case design with the randomization test (RT) has been proposed as an alternative to the binomial distribution (BD) tables of Thornton and Raffin (1978) to assess changes in speech recognition performance in individual subjects. The present study investigated whether data analyzed using both approaches would result in similar outcomes. Sixty-two adults with normal hearing were evaluated using phoneme scoring and a restricted alternating treatments design under two signal-to-noise conditions. Results revealed a significant correlation between the RT and a BD analysis using at least 50-word lists, although the BD analysis was a more sensitive measure. The absence of correlation between the RT with a BD analysis using 25-word lists challenges the common clinical practice of using reduced list size, and supports the use of phoneme scoring and other attempts to find clinically acceptable yet evidence-based solutions to overcome the conflict between time and accuracy.     

Modernising speech audiometry: using a smartphone application to test word recognition

Objective: This study aimed to develop and assess a method to measure word recognition abilities using a smartphone application (App) connected to an audiometer.

Design: Word lists were recorded in South African English and Afrikaans. Analyses were conducted to determine the effect of hardware used for presentation (computer, compact-disc player, or smartphone) on the frequency content of recordings. An Android App was developed to enable presentation of recorded materials via a smartphone connected to the auxiliary input of the audiometer. Experiments were performed to test feasibility and validity of the developed App and recordings.

Study sample: Participants were 100 young adults (18–30 years) with pure tone thresholds ≤15?dB across the frequency spectrum (250–8000?Hz).

Results: Hardware used for presentation had no significant effect on the frequency content of recordings. Listening experiments indicated good inter-list reliability for recordings in both languages, with no significant differences between scores on different lists at each of the tested intensities. Performance-intensity functions had slopes of 4.05%/dB for English and 4.75%/dB for Afrikaans lists at the 50% point.

Conclusions: The developed smartphone App constitutes a feasible and valid method for measuring word recognition scores, and can support standardisation and accessibility of recorded speech audiometry.     

Vibrant semi-implantable hearing device with digital sound processing: effective gain and speech perception.

BACKGROUND: The Vibrant Soundbridge (Symphonix Devices, San Jose, Calif) is a semi-implantable hearing device. The transducer is attached directly to the incus and is linked by telemetry to the externally worn audioprocessor. A major advantage of this semi-implantable setup, especially during its experimental phase, is that the audioprocessor can be updated. Recently, we replaced the previous 2-channel analog audioprocessor in 14 patients with a 3-channel digital device. DESIGN: Prospective clinical study. Basic functions were measured, including gain as a function of input level and speech perception in quiet. PATIENTS: Patients (n = 14) had moderate to severe sensorineural hearing impairment (average hearing threshold at 0.5, 1.0, 2.0, and 4.0 kHz of 40- to 76-dB hearing level [HL]) and chronic external otitis, which contraindicated use of an ear mold. RESULTS: Gain of the 3-channel audioprocessor for comfortable listening levels and for conversational levels varied from approximately 15- to 30-dB HL, suggesting that the device is suitable for patients with hearing loss of up to 60- to 70-dB HL. In 5 patients, identical measurements were performed using their conventional hearing aids. The other 9 patients did not use a conventional hearing device because of severe external otitis. On average, results obtained with the Vibrant Soundbridge were not as good as those obtained with the conventional device. Nevertheless, patients were satisfied with the Vibrant Soundbridge because they could use it all day without pain or itching. CONCLUSIONS: The Vibrant Soundbridge is suitable for patients with hearing loss of up to 70-dB HL. Compared with conventional devices, in audiometric terms, a surplus value of the Vibrant Soundbridge was not found.     

Rate-of-processing ability in children using cochlear implants and its relevance to speech perception

The aim was to assess the ability of young children using cochlear implants to process a change in place of stimulation under conditions of shortened stimulus duration and shortened interstimulus interval. The study investigated whether or not this ability accounted for a significant amount of the variance in the speech performance of the children additional to the variance accounted for by electrode discrimination ability (measured in a previous study). An adaptation of the play audiometry procedure was used to assess 'rate-of-processing' ability in 17 children aged between 4 and 10 years. Initially the child was required to respond with a game-like motor response when a repeating stimulation on a reference electrode 'changed' to a different electrode in relatively 'slow' conditions. The child was then required to respond to the 'change', when the duration of the stimuli and the time interval between the stimuli were decreased. All but one of the children using cochlear implants scored significantly above chance for all conditions of stimulus duration and interstimulus interval assessed. That is, they were able to discriminate place pitch changes when these changes occurred more rapidly in time. A stepwise regression was computed to determine the relative contributions of a number of variables, including rate-of-processing ability, in accounting for variance in the children's speech perception performance (measured in a previous study). Rate-of-processing ability did not account for any variance additional to that accounted for by electrode discrimination ability, which was found to be the most significant predictor of speech perception performance for this group of children in the previous study.     

Rate-of-processing ability in children using cochlear implants and its relevance to speech perception

Abstract

The aim was to assess the ability of young children using cochlear implants to process a change in place of stimulation under conditions of shortened stimulus duration and shortened interstimulus interval. The study investigated whether or not this ability accounted for a significant amount of the variance in the speech performance of the children additional to the variance accounted for by electrode discrimination ability (measured in a previous study). An adaptation of the play audiometry procedure was used to assess ‘rate-of-processing’ ability in 17 children aged between 4 and 10 years. Initially the child was required to respond with a gamelike motor response when a repeating stimulation on a reference electrode ‘changed’ to a different electrode in relatively ‘slow’ conditions. The child was then required to respond to the ‘change’, when the duration of the stimuli and the time interval between the stimuli were decreased. All but one of the children using cochlear implants scored significantly above chance for all conditions of stimulus duration and interstimulus interval assessed. That is, they were able to discriminate place pitch changes when these changes occurred more rapidly in time. A stepwise regression was computed to determine the relative contributions of a number of variables, including rate-of-processing ability, in accounting for variance in the children's speech perception performance (measured in a previous study). Rate-of-processing ability did not account for any variance additional to that accounted for by electrode discrimination ability, which was found to be the most significant predictor of speech perception performance for this group of children in the previous study.     

Implication of central asymmetry in speech processing on selecting the ear for cochlear implantation.

OBJECTIVE: Emerging evidence in auditory neuroscience suggests that central auditory pathways process speech asymmetrically. In concert with left cortical specialization for speech, a "right-ear advantage" in speech perception has been identified. The purpose of this study is to determine if this central asymmetry in speech processing has implications for selecting the ear for cochlear implantation. STUDY DESIGN: Retrospective cohort study. SETTING: Academic university medical center PATIENTS: One hundred one adults with bilateral severe-to-profound sensorineural hearing loss INTERVENTION: Cochlear implantation with the Nucleus 24 Contour device. MAIN OUTCOME MEASUREMENTS: Patients were divided into two groups according to the ear implanted. Results were compared between left-ear- and right-ear-implanted patients. Further subgroup analysis was undertaken, limited to right-handed patients. Postoperative improvement on audiograms and scores on speech perception tests (Hearing in Noise test, City University of New York in quiet and in noise test, Consonant-Vowel Nucleus- Consonant words, and phonemes) at 1 year was compared between groups. Analysis of covariance was used to control for any intergroup differences in preoperative characteristics. RESULTS: The groups were matched in age, duration of hearing loss, duration of hearing aid use, percentage implanted in the better hearing ear, and preoperative audiologic testing. Postoperatively, there were no differences between left-ear- and right-ear-implanted patients in improvement on speech recognition tests. CONCLUSION: Despite central asymmetry in speech processing, our data do not support a right-ear advantage in speech perception outcomes with cochlear implantation. Therefore, among the many factors in choosing the ear for cochlear implantation, central asymmetry in speech processing does not seem to be a contributor to postoperative speech recognition outcomes.     

Sensitivity to structure in the speech signal by children with speech sound disorder and reading disability

PurposeChildren with speech sound disorder (SSD) and reading disability (RD) have poor phonological awareness, a problem believed to arise largely from deficits in processing the sensory information in speech, specifically individual acoustic cues. However, such cues are details of acoustic structure. Recent theories suggest that listeners also need to be able to integrate those details to perceive linguistically relevant form. This study examined abilities of children with SSD, RD, and SSD + RD not only to process acoustic cues but also to recover linguistically relevant form from the speech signal.MethodTen- to 11-year-olds with SSD (n = 17), RD (n = 16), SSD + RD (n = 17), and Controls (n = 16) were tested to examine their sensitivity to (1) voice onset times (VOT); (2) spectral structure in fricative-vowel syllables; and (3) vocoded sentences.ResultsChildren in all groups performed similarly with VOT stimuli, but children with disorders showed delays on other tasks, although the specifics of their performance varied.ConclusionChildren with poor phonemic awareness not only lack sensitivity to acoustic details, but are also less able to recover linguistically relevant forms. This is contrary to one of the main current theories of the relation between spoken and written language development.Learning outcomes: Readers will be able to (1) understand the role speech perception plays in phonological awareness, (2) distinguish between segmental and global structure analysis of speech perception, (3) describe differences and similarities in speech perception among children with speech sound disorder and/or reading disability, and (4) recognize the importance of broadening clinical interventions to focus on recognizing structure at all levels of speech analysis.     

Monaural middle ear destruction in juvenile and adult mice: effects on responses to sound direction in the inferior colliculus ipsilateral to the intact ear

This study examined the effect of monaural middle ear destruction on auditory responses to sound direction in the inferior colliculus (IC) of the laboratory mice, Mus musculus. Monaural middle ear destruction was performed on juvenile and adult mice (the experimental mice). Auditory response properties of neurons to ipsilateral and contralateral sounds (I-40 degrees and C-40 degrees ) were examined in the IC ipsilateral to the intact ear 4 weeks later. IC neurons of control mice had higher minimum thresholds (MTs), larger Q(n) (Q(10), Q(30)) values but smaller dynamic ranges at I-40 degrees than at C-40 degrees. These direction-dependent response properties were not observed for IC neurons of experimental juvenile and adult mice. However, Q(n) values of IC neurons were significantly smaller in experimental juvenile than in control and experimental adult mice. Normal tonotopic organization in terms of positive correlation between recording depth and best frequency (BF) was observed in the IC of control and experimental adult mice at both sound directions but not in the IC of experimental juvenile mice. A positive correlation of increasing MT with BF was only observed for IC neurons in control mice but not in both experimental mice. Possible mechanisms for these different response properties are discussed.     

Cochlear implantation in postlingually hearing-impaired adults: Choosing the most appropriate ear

Choice of the most appropriate ear for CI in postlingually hearing-impaired adults is becoming more relevant as more patients are considered eligible for intervention. The aim of this study is to review factors that influence this choice and to formulate a flowchart. An extensive Medline search was performed. Factors can be divided into surgical, audiological, and patient factors. Surgical factors are anatomic variation and otological medical history. Both are divided in absolute and relative contraindications. Duration of deafness and residual hearing are combined in the audiological factor. Likeliness of improvement of speech perception after CI at different durations of deafness is estimated. This is followed by comparison of between-ear differences in duration of deafness. If there is a large difference, above the presented 5% interval, the ear with the shortest duration is preferred. This review and its flowchart are an aid for decision making in the choice of ear for CI. Being as representative of current knowledge as possible, future refinements may occur as new insights are gained.     

Effects of user training with electronically-modulated sound transmission hearing protectors and the open ear on horizontal localization ability

Abstract

Objective: To determine if training with electronically-modulated hearing protection (EMHP) and the open ear results in auditory learning on a horizontal localization task. Design: Baseline localization testing was conducted in three listening conditions (open-ear, in-the-ear (ITE) EMHP, and over-the-ear (OTE) EMHP). Participants then wore either an ITE or OTE EMHP for 12, almost daily, one-hour training sessions. After training was complete, participants again underwent localization testing in all three listening conditions. A computer with a custom software and hardware interface presented localization sounds and collected participant responses. Study sample: Twelve participants were recruited from the student population at Virginia Tech. Audiometric requirements were 35 dBHL at 500, 1000, and 2000 Hz bilaterally, and 55 dBHL at 4000 Hz in at least one ear. Results: Pre-training localization performance with an ITE or OTE EMHP was worse than open-ear performance. After training with any given listening condition, including open-ear, performance in that listening condition improved, in part from a practice effect. However, post-training localization performance showed near equal performance between the open-ear and training EMHP. Auditory learning occurred for the training EMHP, but not for the non-training EMHP; that is, there was no significant training crossover effect between the ITE and the OTE devices. Conclusion: It is evident from this study that auditory learning (improved horizontal localization performance) occurred with the EMHP for which training was performed. However, performance improvements found with the training EMHP were not realized in the non-training EMHP. Furthermore, localization performance in the open-ear condition also benefitted from training on the task.