The Effect of Aging on the Electrically Evoked Compound Action Potential

Mussoi, Bruna S; Brown, Carolyn J.

doi:10.1097/mao.0000000000002688

Cited by 8 publications

(12 citation statements)

References 58 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%

“…Reasons for this discrepancy in results between these studies remain unknown but may be related to the ages of participants included in the study and/or the number and locations of electrodes tested. Mussoi & Brown (2020) only recorded eCAP thresholds at one electrode location, while Cafarelli Dees et al (2005) and the present study recorded eCAP thresholds at three or more electrode locations. As observed in Figure 6, the differences in eCAP thresholds between the age groups varies across the electrode array.…”

Section: Discussionmentioning

confidence: 75%

“…Results of the present study did not show a significant effect of age group on the eCAP threshold, which is consistent with the results presented in Cafarelli Dees et al (2005). However, a recent study reported that CI users between the ages of 68 and 82 years had significantly higher eCAP thresholds than CI users between the ages of 18 and 40 years (Mussoi & Brown 2020). Reasons for this discrepancy in results between these studies remain unknown but may be related to the ages of participants included in the study and/or the number and locations of electrodes tested.…”

Section: Discussionmentioning

confidence: 99%

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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%

Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

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

et al. 2021

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“…Results of previously published studies have reported a significant aging effect on the slope of the eCAP input/output function (e.g., Mussoi & Brown 2020; Shader et al 2020) and on the sensitivity of the AN to amplitude modulation cues delivered using trains of biphasic pulses (Riggs et al 2021a). It should be pointed out that the single-pulse evoked eCAP results, as those measured for the eCAP input/output function, do not provide information about the effects of prior neural activity on response properties of the AN (e.g., Wilson et al 1997; Matsuoka et al 2000).…”

Section: Discussionmentioning

confidence: 99%

Characteristics of the Adaptation Recovery Function of the Auditory Nerve and Its Association With Advanced Age in Postlingually Deafened Adult Cochlear Implant Users

Skidmore

Carter

2022

Ear &Amp; Hearing

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Objective: This study aimed to (1) characterize the amount and the speed of recovery from neural adaptation at the auditory nerve (AN) and(2) assess their associations with advanced age in postlingually deafened adult cochlear implant users.Design: Study participants included 25 postlingually deafened adult, Cochlear Nucleus device users, ranging in age between 24.83 and 83.21 years at the time of testing. The stimulus was a 100-ms pulse train presented at four pulse rates: 500, 900, 1800, and 2400 pulses per second (pps). The pulse trains were presented at the maximum comfortable level measured for the 2400-pps pulse train. The electrically evoked compound action potential (eCAP) evoked by the last pulse of the pulse train (i.e., the probe pulse) was recorded. The remaining pulses of the pulse train served as the pulse-train masker. The time interval between the probe pulse and the last pulse of the pulse-train masker [i.e., masker-probe-interval (MPI)] systematically increased from 0.359 ms up to 256 ms. The adaptation recovery function (ARF) was obtained by plotting normalized eCAP amplitudes (re: the eCAP amplitude measured at the MPI of 256 ms) as a function of MPIs. The adaptation recovery ratio (ARR) was defined as the ratio between the eCAP amplitude measured at the MPI of 256 ms and that measured for the single-pulse stimulus presented at the same stimulation level. The time constants of the ARF were estimated using a mathematical model with an exponential function with up to three components. Generalized Linear Mixed effects Models were used to compare ARRs and time constants measured at different electrode locations and pulse rates, as well as to assess the effect of advanced age on these dependent variables.Results: There were three ARF types observed in this study. The ARF type observed in the same study participant could be different at different electrode locations and/or pulse rates. Substantial variations in both the amount and the speed of neural adaptation recovery among study participants were observed. The ARR was significantly affected by pulse rate but was not affected by electrode location. The effect of electrode location on the time constants of the ARF was not statistically significant. Pulse rate had a statistically significant effect on τ 1, but not on τ 2 or τ 3 . There was no statistically significant effect of age on the ARR or the time constants of the ARF. Conclusions:Neural adaptation recovery processes at the AN demonstrate substantial variations among human cochlear implant users. The recovery pattern can be nonmonotonic with up to three phases. While the amount of neural adaptation recovery decreases as pulse rate increases, only the speed of the first phase of neural adaptation recovery is affected by pulse rate. Electrode location or advanced age has no robust effect on neural adaptation recovery processes at the level of the AN for a 100-ms pulse-train masker with pulse rates of 500 to 2400 pps. The lack of sufficient participants in this study who were 40 years of age or ...

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“…As the aging process leads to SGN loss (11), findings from animal studies suggest that older age is associated with shallower eCAP AGF slopes, smaller eCAP amplitudes, and/or higher eCAP thresholds (12)(13)(14). In human CI users, studies also indicate that older recipients have shallower AGF slopes than their younger or middle-aged counterparts (15)(16)(17)(18)(19), with age at implantation being the most significant predictor of AGF slopes, although duration of deafness also has a significant effect on AGF slopes (20). However, findings across CI studies have been ambiguous on the effect of aging on eCAP maximum amplitudes (15,16) and on eCAP thresholds (15)(16)(17).…”

Section: Introductionmentioning

confidence: 99%

The Effect of Aging on Auditory Nerve Function: Insights from Intraoperative eCAP Recordings in Cochlear Implant Users

2023

Self Cite

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BackgroundAdvanced age is associated with poorer speech perception outcomes in cochlear implant (CI) users. In an effort to improve our understanding of the basis for this decline, this study focused on the contributions from peripheral auditory processing, using the electrically evoked compound action potential (eCAP).ObjectivesTo investigate the effect of aging on intraoperative, suprathreshold eCAP responses (amplitude growth function [AGF] slopes, eCAP maximum amplitudes, and N1 latencies) across the electrode array, in a large cohort of recipients of newer generation devices, who met hearing preservation criteria.MethodsParticipants of this retrospective study consisted of 113 middle-aged and older CI recipients. Intraoperative eCAP measures consisted of AGF slopes, maximum amplitudes, and N1 latencies at the maximum amplitude. eCAP recordings were obtained at several intracochlear electrodes, which were grouped by electrode location (basal, middle, and apical).ResultsThere was a moderate to strong association between suprathreshold eCAP measures (eCAP AGF slopes and maximum amplitudes) and age, particularly for basal and middle electrodes. For apical electrodes, correlations between both suprathreshold eCAP measures and age were weak (and for eCAP maximum amplitudes, not statistically significant). N1 latencies at the maximum amplitudes were not associated with age at any electrode location.ConclusionsResults of this study add to a growing body of evidence suggesting that aging may negatively affect suprathreshold eCAP responses, especially in basal and middle cochlear regions. Although it is difficult to separate the effects of aging from those of duration of deafness, both would support recommending early implantation in the clinical setting.

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The Effect of Aging on the Electrically Evoked Compound Action Potential

Cited by 8 publications

References 58 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

Characteristics of the Adaptation Recovery Function of the Auditory Nerve and Its Association With Advanced Age in Postlingually Deafened Adult Cochlear Implant Users

The Effect of Aging on Auditory Nerve Function: Insights from Intraoperative eCAP Recordings in Cochlear Implant Users

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