Impact of stimulus frequency and recording electrode on electrocochleography in Hybrid cochlear implant users

In this study we measured the electrically evoked compound action potential (ECAP) from different recording electrodes in the cochlea. Under the assumption that different response latencies may be the result of differences in the neural population contributing to the response, we assessed the relationship between neural response latency and spread of excitation. First, we evaluated changes in N1 latency when the recording electrode site was varied. Second, we recorded channel interaction functions using a forward masking technique but with recording electrodes at different intracochlear locations. For most individuals, N1 latency was similar across recording electrodes. However, reduced N1 latencies were observed in 21% of cochlear implant users when ECAPs were recorded using a remote recording electrode. We hypothesized that if recordings from different electrodes represented contributions from different populations of neurons, then one might expect that channel interaction functions would be different. However, we did not observe consistent differences in channel interaction functions (neither peak location nor breadth of the functions), and further, any variation in channel interaction functions was not correlated with ECAP latency. These results suggest that ECAPs from different recording electrodes with different latencies originate from similar neural populations.

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Vestibulo-Ocular and Vestibulospinal Function before and after Cochlear Implant Surgery

Annals of Otology Rhinology & Laryngology ◽

10.1177/00034894870960s157 ◽

1987 ◽

Vol 96 (1_suppl) ◽

pp. 106-109 ◽

Cited By ~ 24

Author(s):

F. O. Black ◽

D. J. Lilly ◽

R. J. Peterka ◽

L. P. Fowler ◽

F. B. Simmons

Keyword(s):

Cochlear Implant ◽

Speech Processing ◽

Stimulus Frequency ◽

Vestibular Function ◽

High Amplitude ◽

Stimulus Amplitude ◽

Processing Strategies ◽

Cochlear Implant Surgery ◽

Before And After ◽

Vestibular Reflex

Vestibular function in cochlear implant candidates varies from normal to total absence of function. In patients with intact vestibular function preoperatively, invasion of the otic capsule places residual vestibular function at risk. Speech-processing strategies that result in large amplitude electrical transients or strategies that employ high amplitude broad frequency carrier signals have the potential for disrupting vestibular function. Five patients were tested with and without electrical stimulation via cochlear electrodes. Two patients experienced subjective vestibular effects that were quickly resolved. No long-term vestibular effects were noted for the two types of second generation cochlear implants evaluated. Histopathological findings from another patient, who had electrically generated vestibular reflex responses to intramodiolar electrodes, indicated that responses elicited were a function of several variables including electrode location, stimulus intensity, stimulus amplitude, and stimulus frequency. Differential auditory, vestibulocolic, and vestibulospinal reflexes were demonstrated from the same electrode as a function of stimulus amplitude, frequency, and duration.

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The Acoustic Change Complex in Response to Frequency Changes and Its Correlation to Cochlear Implant Speech Outcomes

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2021.757254 ◽

2021 ◽

Vol 15 ◽

Author(s):

Kelli McGuire ◽

Gabrielle M. Firestone ◽

Nanhua Zhang ◽

Fawen Zhang

Keyword(s):

Word Recognition ◽

Cochlear Implant ◽

Change Detection ◽

Detection Threshold ◽

Stimulus Frequency ◽

Event Related Potential ◽

Frequency Change ◽

Eeg Recordings ◽

Frequency Changes ◽

Acoustic Change Complex

One of the biggest challenges that face cochlear implant (CI) users is the highly variable hearing outcomes of implantation across patients. Since speech perception requires the detection of various dynamic changes in acoustic features (e.g., frequency, intensity, timing) in speech sounds, it is critical to examine the ability to detect the within-stimulus acoustic changes in CI users. The primary objective of this study was to examine the auditory event-related potential (ERP) evoked by the within-stimulus frequency changes (F-changes), one type of the acoustic change complex (ACC), in adult CI users, and its correlation to speech outcomes. Twenty-one adult CI users (29 individual CI ears) were tested with psychoacoustic frequency change detection tasks, speech tests including the Consonant-Nucleus-Consonant (CNC) word recognition, Arizona Biomedical Sentence Recognition in quiet and noise (AzBio-Q and AzBio-N), and the Digit-in-Noise (DIN) tests, and electroencephalographic (EEG) recordings. The stimuli for the psychoacoustic tests and EEG recordings were pure tones at three different base frequencies (0.25, 1, and 4 kHz) that contained a F-change at the midpoint of the tone. Results showed that the frequency change detection threshold (FCDT), ACC N1′ latency, and P2′ latency did not differ across frequencies (p > 0.05). ACC N1′-P2 amplitude was significantly larger for 0.25 kHz than for other base frequencies (p < 0.05). The mean N1′ latency across three base frequencies was negatively correlated with CNC word recognition (r = −0.40, p < 0.05) and CNC phoneme (r = −0.40, p < 0.05), and positively correlated with mean FCDT (r = 0.46, p < 0.05). The P2′ latency was positively correlated with DIN (r = 0.47, p < 0.05) and mean FCDT (r = 0.47, p < 0.05). There was no statistically significant correlation between N1′-P2′ amplitude and speech outcomes (all ps > 0.05). Results of this study indicated that variability in CI speech outcomes assessed with the CNC, AzBio-Q, and DIN tests can be partially explained (approximately 16–21%) by the variability of cortical sensory encoding of F-changes reflected by the ACC.

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Simultaneous Intra- and Extracochlear Electrocochleography During Cochlear Implantation to Enhance Response Interpretation

Trends in Hearing ◽

10.1177/2331216521990594 ◽

2021 ◽

Vol 25 ◽

pp. 233121652199059

Author(s):

Leanne Sijgers ◽

Flurin Pfiffner ◽

Julian Grosse ◽

Norbert Dillier ◽

Kanthaiah Koka ◽

...

Keyword(s):

Cochlear Implant ◽

Cochlear Implantation ◽

Residual Hearing ◽

Recording Electrode ◽

Cochlear Function ◽

Study Results ◽

Signal Changes ◽

The Relationship ◽

Amplitude Decrease ◽

Harmonic Distortions

The use of electrocochleography (ECochG) for providing real-time feedback of cochlear function during cochlear implantation is receiving increased attention for preventing cochlear trauma and preserving residual hearing. Although various studies investigated the relationship between intra-operative ECochG measurements and surgical outcomes in recent years, the limited interpretability of ECochG response changes leads to conflicting study results and prevents the adoption of this method for clinical use. Specifically, the movement of the recording electrode with respect to the different signal generators in intracochlear recordings makes the interpretation of signal changes with respect to cochlear trauma difficult. Here, we demonstrate that comparison of ECochG signals recorded simultaneously from intracochlear locations and from a fixed extracochlear location can potentially allow a differentiation between traumatic and atraumatic signal changes in intracochlear recordings. We measured ECochG responses to 500 Hz tone bursts with alternating starting phases during cochlear implant insertions in six human cochlear implant recipients. Our results show that an amplitude decrease with associated near 180° phase shift and harmonic distortions in the intracochlear difference curve during the first half of insertion was not accompanied by a decrease in the extracochlear difference curve’s amplitude ( n = 1), while late amplitude decreases in intracochlear difference curves (near full insertion, n = 2) did correspond to extracochlear amplitude decreases. These findings suggest a role for phase shifts, harmonic distortions, and recording location in interpreting intracochlear ECochG responses.

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Comparison of the Normal and Noise-Suppression Settings on the Spectra 22 Speech Processor of the Nucleus TM 22-Channel Cochlear Implant System

American Journal of Audiology ◽

10.1044/1059-0889.0403.55 ◽

1995 ◽

Vol 4 (3) ◽

pp. 55-58 ◽

Cited By ~ 3

Author(s):

Laura K. Holden ◽

Margaret W. Skinner ◽

Timothy A. Holden

Keyword(s):

Cochlear Implant ◽

Noise Suppression ◽

Speech Processor ◽

Implant System

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Letter to the Editor Concerning Skuk et al., “Parameter-Specific Morphing Reveals Contributions of Timbre and Fundamental Frequency Cues to the Perception of Voice Gender and Age in Cochlear Implant Users”

Journal of Speech Language and Hearing Research ◽

10.1044/2020_jslhr-20-00563 ◽

2020 ◽

Vol 63 (12) ◽

pp. 4325-4326 ◽

Cited By ~ 1

Author(s):

Hartmut Meister ◽

Katrin Fuersen ◽

Barbara Streicher ◽

Ruth Lang-Roth ◽

Martin Walger

Keyword(s):

Cochlear Implant ◽

Fundamental Frequency ◽

Stimulus Type ◽

Voice Perception ◽

Letter To The Editor ◽

Gender And Age ◽

General Influence

Purpose The purpose of this letter is to compare results by Skuk et al. (2020) with Meister et al. (2016) and to point to a potential general influence of stimulus type. Conclusion Our conclusion is that presenting sentences may give cochlear implant recipients the opportunity to use timbre cues for voice perception. This might not be the case when presenting brief and sparse stimuli such as consonant–vowel–consonant or single words, which were applied in the majority of studies.

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Perceptual Learning of Vocoded Speech With and Without Contralateral Hearing: Implications for Cochlear Implant Rehabilitation

Journal of Speech Language and Hearing Research ◽

10.1044/2020_jslhr-20-00385 ◽

2020 ◽

pp. 1-10

Author(s):

Martin Chavant ◽

Alexis Hervais-Adelman ◽

Olivier Macherey

Keyword(s):

Cochlear Implant ◽

Perceptual Learning ◽

Speech Signal ◽

Training Phase ◽

Monosyllabic Words ◽

Low Pass ◽

Contralateral Ear ◽

Number Of Individuals ◽

Insight Into ◽

Vocoded Speech

Purpose An increasing number of individuals with residual or even normal contralateral hearing are being considered for cochlear implantation. It remains unknown whether the presence of contralateral hearing is beneficial or detrimental to their perceptual learning of cochlear implant (CI)–processed speech. The aim of this experiment was to provide a first insight into this question using acoustic simulations of CI processing. Method Sixty normal-hearing listeners took part in an auditory perceptual learning experiment. Each subject was randomly assigned to one of three groups of 20 referred to as NORMAL, LOWPASS, and NOTHING. The experiment consisted of two test phases separated by a training phase. In the test phases, all subjects were tested on recognition of monosyllabic words passed through a six-channel “PSHC” vocoder presented to a single ear. In the training phase, which consisted of listening to a 25-min audio book, all subjects were also presented with the same vocoded speech in one ear but the signal they received in their other ear differed across groups. The NORMAL group was presented with the unprocessed speech signal, the LOWPASS group with a low-pass filtered version of the speech signal, and the NOTHING group with no sound at all. Results The improvement in speech scores following training was significantly smaller for the NORMAL than for the LOWPASS and NOTHING groups. Conclusions This study suggests that the presentation of normal speech in the contralateral ear reduces or slows down perceptual learning of vocoded speech but that an unintelligible low-pass filtered contralateral signal does not have this effect. Potential implications for the rehabilitation of CI patients with partial or full contralateral hearing are discussed.

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