Impact of Aging and the Electrode-to-Neural Interface on Temporal Processing Ability in Cochlear-Implant Users: Gap Detection Thresholds

Shader, Maureen J.; Gordon‐Salant, Sandra; Goupell, Matthew J.

doi:10.1177/2331216520956560

Cited by 15 publications

(23 citation statements)

References 49 publications

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“…Specifically, the middle-aged adults had significantly greater slopes than the elderly adults. This result is consistent with the previously reported age-related decline in slope of the eCAP AGF in the literature (Cafarelli Dees et al 2005; Jahn & Arenberg 2020b; Mussoi & Brown 2020; Shader et al 2020). Overall, these studies provide strong evidence that the slope of the eCAP AGF is negatively affected by advanced age.…”

Section: Discussionsupporting

confidence: 93%

The Effect of Advanced Age on the Electrode-Neuron Interface in Cochlear Implant Users

et al. 2021

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Objectives: This study aimed to determine the effect of advanced age on how effectively a cochlear implant (CI) electrode stimulates the targeted cochlear nerve fibers (i.e., the electrode-neuron interface [ENI]) in postlingually deafened adult CI users. The study tested the hypothesis that the quality of the ENI declined with advanced age. It also tested the hypothesis that the effect of advanced age on the quality of the ENI would be greater in basal regions of the cochlea compared to apical regions.Design: Study participants included 40 postlingually deafened adult CI users. The participants were separated into two age groups based on age at testing in accordance with age classification terms used by the World Health Organization and the Medical Literature Analysis and Retrieval System Online bibliographic database. The middle-aged group included 16 participants between the ages of 45 and 64 years and the elderly group included 24 participants older than 65 years. Results were included from one ear for each participant. All participants used Cochlear Nucleus CIs in their test ears. For each participant, electrophysiological measures of the electrically evoked compound action potential (eCAP) were used to measure refractory recovery functions and amplitude growth functions (AGFs) at three to seven electrode sites across the electrode array. The eCAP parameters used in this study included the refractory recovery time estimated based on the eCAP refractory recovery function, the eCAP threshold, the slope of the eCAP AGF, and the negative-peak (i.e., N1) latency. The electrode-specific ENI was evaluated using an optimized combination of the eCAP parameters that represented the responsiveness of cochlear nerve fibers to electrical stimulation delivered by individual electrodes along the electrode array. The quality of the electrode-specific ENI was quantified by the local ENI index, a value between 0 and 100 where 0 and 100 represented the lowest-and the highest-quality ENI across all participants and electrodes in the study dataset, respectively.Results: There were no significant age group differences in refractory times, eCAP thresholds, N1 latencies or local ENI indices. Slopes of the eCAP AGF were significantly larger in the middle-aged group compared to the elderly group. There was a significant effect of electrode location on each eCAP parameter, except for N1 latency. In addition, the local ENI index was significantly larger (i.e., better ENI) in the apical region than in the basal and middle regions of the cochlea for both age groups. Conclusions:The model developed in this study can be used to estimate the quality of the ENI at individual electrode locations in CI users. The quality of the ENI is affected by the location of the electrode along the length of the cochlea. The method for estimating the quality of the ENI developed in this study holds promise for identifying electrodes with poor ENIs that could be deactivated from the clinical programming map. The ENI is not strongly affected by advanced age i...

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Section: Discussionsupporting

confidence: 93%

The Effect of Advanced Age on the Electrode-Neuron Interface in Cochlear Implant Users

et al. 2021

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“…Specifically, psychophysical measures were conducted using long-duration pulsatile stimulation. In contrast, the AN function was quantified based on either the slope of the eCAP input/output function (Shader et al 2020a(Shader et al , 2020bJohnson et al 2021) or the time constant estimated based on the eCAP HE ET AL. / EAR & HEARING, VOL.…”

Section: Introductionmentioning

confidence: 99%

Neural Adaptation of the Electrically Stimulated Auditory Nerve Is Not Affected by Advanced Age in Postlingually Deafened, Middle-aged, and Elderly Adult Cochlear Implant Users

Skidmore

Conroy

et al. 2022

Ear &Amp; Hearing

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Objective: This study aimed to investigate the associations between advanced age and the amount and the speed of neural adaptation of the electrically stimulated auditory nerve (AN) in postlingually deafened adult cochlear implant (CI) users.Design: Study participants included 26 postlingually deafened adult CI users, ranging in age between 28.7 and 84.0 years (mean: 63.8 years, SD: 14.4 years) at the time of testing. All study participants used a Cochlear Nucleus device with a full electrode array insertion in the test ear. The stimulus was a 100-ms pulse train with a pulse rate of 500, 900, 1800, or 2400 pulses per second (pps) per channel. The stimulus was presented at the maximum comfortable level measured at 2400 pps with a presentation rate of 2 Hz. Neural adaptation of the AN was evaluated using electrophysiological measures of the electrically evoked compound action potential (eCAP). The amount of neural adaptation was quantified by the adaptation index (AI) within three time windows: around 0 to 8 ms (window 1), 44 to 50 ms (window 2), and 94 to 100 ms (window 3). The speed of neural adaptation was quantified using a two-parameter power law estimation. In 23 participants, four electrodes across the electrode array were tested. In three participants, three electrodes were tested. Results measured at different electrode locations were averaged for each participant at each pulse rate to get an overall representation of neural adaptation properties of the AN across the cochlea. Linear-mixed models (LMMs) were used (1) to evaluate the effects of age at testing and pulse rate on the speed of neural adaptation and (2) to assess the effects of age at testing, pulse rate, and duration of stimulation (i.e., time window) on the amount of neural adaptation in these participants.Results: There was substantial variability in both the amount and the speed of neural adaptation of the AN among study participants. The amount and the speed of neural adaptation increased at higher pulse rates. In addition, larger amounts of adaptation were observed for longer durations of stimulation. There was no significant effect of age on the speed or the amount of neural adaptation. Conclusions:The amount and the speed of neural adaptation of the AN are affected by both the pulse rate and the duration of stimulation, with higher pulse rates and longer durations of stimulation leading to faster and greater neural adaptation. Advanced age does not affect neural adaptation of the AN in postlingually deafened, middle-aged and elderly adult CI users.

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“…It should be noted that the predictive validity of ECAP AGFs to temporal processing appears to be inconsistent with some of the extant literature ( Hay-McCutcheon et al., 2005 ; Hughes et al., 2014 ; Shader et al., 2020a ). However, consistent with our results, Shader et al. (2020a) found that steep ECAP AGF slopes were not predictive of better temporal processing as measured by an amplitude modulation detection task.…”

Section: Discussionmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 71%

“…Natural aging processes negatively affect peripheral neural health (e.g., the loss of spiral ganglion cells and auditory nerve fibers; Sergeyenko et al., 2013 ) and central auditory processing abilities ( Clinard et al., 2010 ; Gaskins et al., 2019 ), which may contribute to declines in temporal processing in CI users ( Committee on Hearing, Bioacoustics, and Biomechanics, 1988 ; Gordon-Salant et al., 2011 ; Jin et al., 2014 ). Indeed, age-related deficits in auditory temporal processing have been documented in older CI listeners on measures of word identification based on silence duration cues ( Xie et al., 2019 ), amplitude modulation detection ( Shader et al., 2020a ), gap detection ( Shader et al., 2020b ), and voice emotion recognition ( Chatterjee et al., 2015 ; Christensen et al., 2019 ). However, it remains unclear whether aging impacts the ability to discriminate pulse rate changes in CI users.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Chronological Age on Pulse Rate Discrimination in Adult Cochlear-Implant Users

et al. 2021

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Cochlear-implant (CI) users rely heavily on temporal envelope cues to understand speech. Temporal processing abilities may decline with advancing age in adult CI users. This study investigated the effect of age on the ability to discriminate changes in pulse rate. Twenty CI users aged 23 to 80 years participated in a rate discrimination task. They attempted to discriminate a 35% rate increase from baseline rates of 100, 200, 300, 400, or 500 pulses per second. The stimuli were electrical pulse trains delivered to a single electrode via direct stimulation to an apical (Electrode 20), a middle (Electrode 12), or a basal location (Electrode 4). Electrically evoked compound action potential amplitude growth functions were recorded at each of those electrodes as an estimate of peripheral neural survival. Results showed that temporal pulse rate discrimination performance declined with advancing age at higher stimulation rates (e.g., 500 pulses per second) when compared with lower rates. The age-related changes in temporal pulse rate discrimination at higher stimulation rates persisted after statistical analysis to account for the estimated peripheral contributions from electrically evoked compound action potential amplitude growth functions. These results indicate the potential contributions of central factors to the limitations in temporal pulse rate discrimination ability associated with aging in CI users.

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Impact of Aging and the Electrode-to-Neural Interface on Temporal Processing Ability in Cochlear-Implant Users: Gap Detection Thresholds

Cited by 15 publications

References 49 publications

The Effect of Advanced Age on the Electrode-Neuron Interface in Cochlear Implant Users

The Effect of Advanced Age on the Electrode-Neuron Interface in Cochlear Implant Users

Neural Adaptation of the Electrically Stimulated Auditory Nerve Is Not Affected by Advanced Age in Postlingually Deafened, Middle-aged, and Elderly Adult Cochlear Implant Users

Effect of Chronological Age on Pulse Rate Discrimination in Adult Cochlear-Implant Users

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