Effect of Speech Processor Program Modifications on Cochlear Implant Recipients’ Threshold and Maximum Acceptable Loudness Levels

This study’s purpose was to determine whether or not modifications in speech processor electrical stimulation levels were associated with changes in five Nucleus 22 cochlear implant recipients’ thresholds or maximum acceptable loudness levels (MALs). These modifications in minimum and maximum stimulation levels were made to optimize hearing in everyday life. One threshold and one MAL were obtained on each active electrode during six, weekly test sessions, three before and three after program modification. Only one participant had a significant change in threshold after program modification; this participant and four others had significant changes in MAL. Participants’ threshold variability was the same, but MAL variability was higher than that observed in other studies. Because these participants had no experience making MAL judgments prior to this study, this result suggests that implant recipients should be given sufficient practice in making MAL judgments to provide a stable clinical estimate of the upper boundary of the electrical dynamic range.

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Comparison of Electrically Evoked Compound Action Potential Thresholds and Loudness Estimates for the Stimuli Used to Program the Advanced Bionics Cochlear Implant

Journal of the American Academy of Audiology ◽

10.3766/jaaa.21.1.3 ◽

2010 ◽

Vol 21 (01) ◽

pp. 016-027 ◽

Cited By ~ 20

Author(s):

Eun Kyung Jeon ◽

Carolyn J. Brown ◽

Christine P. Etler ◽

Sara O'Brien ◽

Li-Kuei Chiou ◽

...

Keyword(s):

Cochlear Implant ◽

Dynamic Range ◽

Compound Action Potential ◽

Behavioral Measures ◽

Speech Processor ◽

Compound Action Potentials ◽

Evoked Compound Action Potential ◽

The Individual ◽

The Relationship ◽

Compound Action

Background: In the mid-1990s, Cochlear Corporation introduced a cochlear implant (CI) to the market that was equipped with hardware that made it possible to record electrically evoked compound action potentials (ECAPs) from CI users of all ages. Over the course of the next decade, many studies were published that compared ECAP thresholds with levels used to program the speech processor of the Nucleus CI. In 2001 Advanced Bionics Corporation introduced the Clarion CII cochlear implant (the Clarion CII internal device is also known as the CII Bionic Ear). This cochlear implant was also equipped with a system that allowed measurement of the ECAP. While a great deal is known about how ECAP thresholds compare with the levels used to program the speech processor of the Nucleus CI, relatively few studies have reported comparisons between ECAP thresholds and the levels used to program the speech processor of the Advanced Bionics CI. Purpose: To explore the relationship between ECAP thresholds and behavioral measures of perceptual dynamic range for the range of stimuli commonly used to program the speech processor of the Advanced Bionics CI. Research Design: This prospective and experimental study uses correlational and descriptive statistics to define the relationship between ECAP thresholds and perceptual dynamic range measures. Study Sample: Twelve postlingually deafened adults participated in this study. All were experienced users of the Advanced Bionics CI system. Data Collection and Analysis: ECAP thresholds were recorded using the commercially available SoundWave software. Perceptual measures of threshold (T-level), most comfortable level (M-level), and maximum comfortable level (C-level) were obtained using both “tone bursts” and “speech bursts.” The relationship between these perceptual and electrophysiological variables was defined using paired t-tests as well as correlation and linear regression. Results: ECAP thresholds were significantly correlated with the perceptual dynamic range measures studied; however, correlations were not strong. Analysis of the individual data revealed considerable discrepancy between the contour of ECAP threshold versus electrode function and the behavioral loudness estimates used for programming. Conclusion: ECAP thresholds recorded from Advanced Bionics cochlear implant users always indicated levels where the programming stimulus was audible for the listener. However, the correlation between ECAP thresholds and M-levels (the primary metric used to program the speech processor of the Advanced Bionics CI), while statistically significant, was quite modest. If programming levels are to be determined on the basis of ECAP thresholds, care should be taken to ensure that stimulation is not uncomfortably loud, particularly on the basal electrodes in the array.

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Optimizing Cochlear Implant Speech Performance

Annals of Otology Rhinology & Laryngology ◽

10.1177/00034894031120s903 ◽

2003 ◽

Vol 112 (9_suppl) ◽

pp. 4-13 ◽

Cited By ~ 20

Author(s):

Margaret W. Skinner

Keyword(s):

Cochlear Implant ◽

Everyday Life ◽

Speech Coding ◽

Hearing Level ◽

Stimulation Rate ◽

Speech Processor ◽

Speech Performance ◽

Coding Strategy ◽

Learning Language

Results of studies performed in our laboratory suggest that cochlear implant recipients understand speech best if the following speech processor parameters are individually chosen for each person: minimum and maximum stimulation levels on each electrode in the speech processor program (MAP), stimulation rate, and speech coding strategy. If these and related parameters are chosen to make soft sounds (from approximately 100 to 6,000 Hz) audible at as close to 20 dB hearing level as possible and loud sounds not too loud, recipients have the opportunity to hear speech in everyday life situations that are of key importance to children who are learning language and to all recipients in terms of ease of communication.

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A Multiple-Channel Cochlear Implant: An Evaluation using Nonsense Syllables

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348948109000306 ◽

1981 ◽

Vol 90 (3) ◽

pp. 227-230 ◽

Cited By ~ 15

Author(s):

Graeme M. Clark ◽

Yit Chow Tong ◽

Lois F. Martin ◽

Peter A. Busby ◽

Richard C. Dowell ◽

...

Keyword(s):

Electrical Stimulation ◽

Cochlear Implant ◽

Speech Processor ◽

Average Percentage ◽

Multiple Channel ◽

Wearable Unit ◽

Nonsense Syllables

A study using nonsense syllables has shown that a multiple-channel cochlear implant with speech processor is effective in providing information about voicing and manner and to a lesser extent place distinctions. These distinctions supplement lipreading cues. Furthermore, the average percentage improvements in overall identification scores for multiple-channel electrical stimulation and lipreading compared to lipreading alone were 71 % for a laboratory-based speech processor and 122% for a wearable unit.

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Effects of Chronic Electrical Stimulation on Patients using a Cochlear Prosthesis

Otolaryngology ◽

10.1177/019459989110500605 ◽

1991 ◽

Vol 105 (6) ◽

pp. 797-801 ◽

Cited By ~ 8

Author(s):

Susan B. Waltzman ◽

Noel L. Cohen ◽

William H. Shapiro

Keyword(s):

Electrical Stimulation ◽

Speech Recognition ◽

Cochlear Implant ◽

Dynamic Range ◽

Cochlear Prosthesis ◽

Postoperative Performance ◽

Open Set ◽

Chronic Electrical Stimulation

Eighteen patients using the Nucleus multichannel cochlear prosthesis underwent annual evaluations for electrical thresholds, dynamic range, and speech recognition abilities for a period of 1 to 5 years. Results revealed no correlation between length of usage of a cochlear implant and electrical thresholds. The dynamic range was initially wider in the patients with open-set speech recognition, but narrowed in subsequent years. There was a correlation between length of deafness and postoperative performance.

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Optimization of Programming Parameters in Children with the Advanced Bionics Cochlear Implant

Journal of the American Academy of Audiology ◽

10.3766/jaaa.23.5.2 ◽

2012 ◽

Vol 23 (05) ◽

pp. 302-312 ◽

Cited By ~ 26

Author(s):

Jacquelyn Baudhuin ◽

Jamie Cadieux ◽

Jill B. Firszt ◽

Ruth M. Reeder ◽

Jerrica L. Maxson

Keyword(s):

Speech Recognition ◽

Cochlear Implant ◽

Repeated Measures ◽

Mixed Model ◽

Dynamic Range ◽

Profound Hearing Loss ◽

Detection Thresholds ◽

Speech Processor ◽

Low Level ◽

Pediatric Recipients

Background: Cochlear implants provide access to soft intensity sounds and therefore improved audibility for children with severe-to-profound hearing loss. Speech processor programming parameters, such as threshold (or T-level), input dynamic range (IDR), and microphone sensitivity, contribute to the recipient's program and influence audibility. When soundfield thresholds obtained through the speech processor are elevated, programming parameters can be modified to improve soft sound detection. Adult recipients show improved detection for low-level sounds when T-levels are set at raised levels and show better speech understanding in quiet when wider IDRs are used. Little is known about the effects of parameter settings on detection and speech recognition in children using today's cochlear implant technology. Purpose: The overall study aim was to assess optimal T-level, IDR, and sensitivity settings in pediatric recipients of the Advanced Bionics cochlear implant. Research Design: Two experiments were conducted. Experiment 1 examined the effects of two T-level settings on soundfield thresholds and detection of the Ling 6 sounds. One program set T-levels at 10% of most comfortable levels (M-levels) and another at 10 current units (CUs) below the level judged as “soft.” Experiment 2 examined the effects of IDR and sensitivity settings on speech recognition in quiet and noise. Study Sample: Participants were 11 children 7–17 yr of age (mean 11.3) implanted with the Advanced Bionics High Resolution 90K or CII cochlear implant system who had speech recognition scores of 20% or greater on a monosyllabic word test. Data Collection and Analysis: Two T-level programs were compared for detection of the Ling sounds and frequency modulated (FM) tones. Differing IDR/sensitivity programs (50/0, 50/10, 70/0, 70/10) were compared using Ling and FM tone detection thresholds, CNC (consonant-vowel nucleus-consonant) words at 50 dB SPL, and Hearing in Noise Test for Children (HINT-C) sentences at 65 dB SPL in the presence of four-talker babble (+8 signal-to-noise ratio). Outcomes were analyzed using a paired t-test and a mixed-model repeated measures analysis of variance (ANOVA). Results: T-levels set 10 CUs below “soft” resulted in significantly lower detection thresholds for all six Ling sounds and FM tones at 250, 1000, 3000, 4000, and 6000 Hz. When comparing programs differing by IDR and sensitivity, a 50 dB IDR with a 0 sensitivity setting showed significantly poorer thresholds for low frequency FM tones and voiced Ling sounds. Analysis of group mean scores for CNC words in quiet or HINT-C sentences in noise indicated no significant differences across IDR/sensitivity settings. Individual data, however, showed significant differences between IDR/sensitivity programs in noise; the optimal program differed across participants. Conclusions: In pediatric recipients of the Advanced Bionics cochlear implant device, manually setting T-levels with ascending loudness judgments should be considered when possible or when low-level sounds are inaudible. Study findings confirm the need to determine program settings on an individual basis as well as the importance of speech recognition verification measures in both quiet and noise. Clinical guidelines are suggested for selection of programming parameters in both young and older children.

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Auditory Cortical Images of Cochlear-Implant Stimuli: Coding of Stimulus Channel and Current Level

Journal of Neurophysiology ◽

10.1152/jn.00211.2001 ◽

2002 ◽

Vol 87 (1) ◽

pp. 493-507 ◽

Cited By ~ 35

Author(s):

John C. Middlebrooks ◽

Julie Arenberg Bierer

Keyword(s):

Auditory Cortex ◽

Cochlear Implant ◽

Speech Processing ◽

Common Ground ◽

Dynamic Range ◽

Current Level ◽

Physiological Data ◽

Cochlear Prosthesis ◽

Active Electrode ◽

Stimulus Current

This study quantified the accuracy with which populations of neurons in the auditory cortex can represent aspects of electrical cochlear stimuli presented through a cochlear implant. We tested the accuracy of coding of the place of stimulation (i.e., identification of the active stimulation channel) and of the stimulus current level. Physiological data came from the companion study, which recorded spike activity of neurons simultaneously from 16 sites along the tonotopic axis of the guinea pig's auditory cortex. In that study, cochlear electrical stimuli were presented to acutely deafened animals through a 6-electrode animal version of the 22-electrode Nucleus banded electrode array (Cochlear). Cochlear electrode configurations consisted of monopolar (MP), bipolar (BP + N) with N inactive electrodes between the active and return electrodes (0 ≤ N ≤ 3), tripolar (TP) with one active electrode and two flanking return electrodes, and common ground (CG) with one active electrode and as many as five return electrodes. In the present analysis, an artificial neural network was trained to recognize spatiotemporal patterns of cortical activity in response to single presentations of particular stimuli and, thereby, to identify those stimuli. The accuracy of pair-wise discrimination of stimulation channels or of current levels was represented by the discrimination index, d′, where d′ = 1 was taken as threshold. In many cases, the threshold for discrimination of place of cochlear stimulation was <0.75 mm, and the threshold for discrimination of current levels was <1 dB. Cochlear electrode configurations varied in the accuracy with which they signaled to the auditory cortex the place of cochlear stimulation. The BP + N and TP configurations provided considerably greater sensitivity to place of stimulation than did the MP configuration. The TP configuration maintained accurate signaling of place of stimulation up to the highest current levels, whereas sensitivity was degraded at high current levels in BP + N configurations. Electrode configurations also varied in the dynamic range over which they signaled stimulus current level. Dynamic ranges were widest for the BP + 0 configuration and narrowest for the TP configuration. That is, the configuration that showed the most accurate signaling of cochlear place of stimulation (TP) showed the most restricted dynamic range for signaling of current level. These results suggest that the choice of the optimal electrode configuration for use by human cochlear-prosthesis users would depend on the particular demands of the speech-processing strategy that is to be employed.

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Auditory Cortical Images of Cochlear-Implant Stimuli: Dependence on Electrode Configuration

Journal of Neurophysiology ◽

10.1152/jn.00212.2001 ◽

2002 ◽

Vol 87 (1) ◽

pp. 478-492 ◽

Cited By ~ 124

Author(s):

Julie Arenberg Bierer ◽

John C. Middlebrooks

Keyword(s):

Cochlear Implant ◽

Guinea Pigs ◽

Common Ground ◽

Dynamic Range ◽

Primary Auditory Cortex ◽

Stimulus Level ◽

Electrode Configuration ◽

Spatiotemporal Pattern ◽

Active Electrode ◽

Sensitive Site

This study examines patterns of auditory cortical activity elicited by single-pulse cochlear implant stimuli that vary in electrode configuration, cochlear place of stimulation, and stimulus level. Recordings were made from the primary auditory cortex (area A1) of ketamine-anesthetized guinea pigs. The spatiotemporal pattern of neural spike activity was measured simultaneously across 16 cortical locations spanning approximately 2–3 octaves of the tonotopic axis. Such a pattern, averaged over 40 presentations of any particular stimulus, was defined as the “cortical image” of that stimulus. Acutely deafened guinea pigs were implanted with a 6-electrode animal version of the 22-electrode Nucleus banded electrode array (Cochlear). Cochlear electrode configurations consisted of monopolar (MP), bipolar (BP + N) with N inactive electrodes between the active and return electrodes (0 ≤ N ≤ 4), tripolar (TP) with one active electrode and two flanking return electrodes, and common ground (CG) with one active electrode and as many as five return electrodes. Cortical images typically showed a focus of maximum spike probability and minimum latency. Spike probabilities tended to decrease, and latencies tended to increase, with increasing cortical distance from that focus. Cortical images of TP stimuli were the most spatially compact, followed by BP + N images, and then MP images, which were the broadest. Images of CG stimuli were rather variable across animals and stimulus channels. The locations of cortical images shifted systematically from caudal to rostral as the cochlear place of stimulation changed from basal to apical. At the most sensitive cortical site for each condition, the dynamic ranges over which spike rates increased with increased current level were restricted to about 1–2 dB, regardless of configuration. Dynamic ranges tended to increase with increasing cortical distance from the most sensitive site. Electrode configurations that produced compact cortical images (e.g., TP and BP + 0) showed the greatest range of thresholds within each cortical image and the largest dynamic range at cortical sites removed from the most sensitive site.

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Electrically Evoked Whole Nerve Action Potentials in Ineraid Cochlear Implant Users: Responses to Different Stimulating Electrode Configurations and Comparison to Psychophysical Responses

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.3903.453 ◽

1996 ◽

Vol 39 (3) ◽

pp. 453-467 ◽

Cited By ~ 71

Author(s):

Carolyn J. Brown ◽

Paul J. Abbas ◽

James Borland ◽

Michael R. Bertschy

Keyword(s):

Electrical Stimulation ◽

Cochlear Implant ◽

Action Potentials ◽

Detection Threshold ◽

Growth Function ◽

Forward Masking ◽

Poor Correlation ◽

Speech Processor ◽

Growth Functions ◽

Nerve Action

Electrically evoked whole nerve action potentials (EAP) have been recorded from 20 Ineraid cochlear implant users in response to bipolar and/or monopolar electrical stimulation of the cochlea. EAP growth functions and refractory recovery functions were obtained for a variety of different stimulating conditions. Where possible, parallel psychophysical experiments were conducted that measured the just detectable increment in stimulus current level (JND), forward-masking functions, and detection thresholds for a range of different stimuli. Variations in EAP threshold, slope of the EAP growth function, and the rate of recovery of the EAP from the refractory state were observed both across subjects for a given place and by mode of stimulation (bipolar versus monopolar), as well as across electrodes within a subject. A poor correlation between slope of the EAP growth functions and current JNDs was obtained. However, good correlations were observed between EAP threshold and psychophysical detection threshold and between the EAP refractory recovery functions and the psychophysical forward-masking functions. Our interpretation of these findings is that these particular physiological measures are related to the excitability of the auditory nerve to electrical stimulation and further that these measures are related to performance of cochlear implant patients on listening tasks. Consequently, such information may prove to be useful in adjusting the stimulation parameters of the cochlear implant speech processor in order to maximize an individual’s performance with the device.

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