Correlation of Electrically Evoked Compound Action Potential Amplitude Growth Function Slope and Anamnestic Parameters in Cochlear Implant Patients—Identification of Predictors for the Neuronal Health Status

Gärtner, Lutz; Klötzer, Katharina; Lenarz, Thomas; Scheper, Verena

doi:10.3390/life11030203

Cited by 6 publications

(7 citation statements)

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“…Thresholds determined by the evaluators and the algorithm were closest to each other at electrode contacts located at the apical end of the electrode array and differed the most from each other at contacts located on the basal side ( Fig 4B and 4C ). This is in agreement with ECAP amplitudes and slopes being largest at apical and lowest at basal electrode contacts in MED-EL CI users [ 3 , 19 , 21 ] and indicates that estimating the threshold is more challenging in the basal region for the evaluators, for the FG-SNR algorithm, and for both. This might be due to more recording noise in the base of the cochlea, possibly due to contacts being located further away from neural structures or a lower density/survival of neurons compared to the apex.…”

Section: Discussionsupporting

confidence: 77%

Optimized SNR-based ECAP threshold determination is comparable to the judgement of human evaluators

et al. 2021

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In cochlear implant (CI) users, measurements of electrically evoked compound action potentials (ECAPs) prove the functionality of the neuron-electrode interface. Objective measures, e.g., the ECAP threshold, may serve as a basis for the clinical adjustment of the device for the optimal benefit of the CI user. As for many neural responses, the threshold determination often is based on the subjective assessment of the clinical specialist, whose decision-making process could be aided by autonomous computational algorithms. To that end, we extended the signal-to-noise ratio (SNR) approach for ECAP threshold determination to be applicable for FineGrain (FG) ECAP responses. The new approach takes advantage of two features: the FG stimulation paradigm with its enhanced resolution of recordings, and SNR-based ECAP threshold determination, which allows defining thresholds independently of morphology and with comparably low computational power. Pearson’s correlation coefficient r between the ECAP threshold determined by five experienced evaluators and the threshold determined with the FG-SNR algorithm was in the range of r = 0.78–0.93. Between evaluators, r was in a comparable range of 0.84–0.93. A subset of the parameters of the algorithm was varied to identify the parameters with the highest potential to improve the FG-SNR formalism in the future. The two steps with the strongest influence on the agreement between the threshold estimate of the evaluators and the algorithm were the removal of undesired frequency components (denoising of the response traces) and the exact determination of the two time windows (signal and noise and noise only).”The parameters were linked to the properties of an ECAP response, indicating how to adjust the algorithm for the automatic detection of other neurophysiological responses.

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Section: Discussionsupporting

confidence: 77%

Optimized SNR-based ECAP threshold determination is comparable to the judgement of human evaluators

et al. 2021

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“…Although it may not be possible to separate the effects of age at implantation from those of duration of hearing loss in human CI users, animal studies may be better positioned to do that. Yet, in many cases, the clinical implication of a negative effect of either age at implantation or duration of hearing loss would likely be the same—to recommend early implantation, as soon as potential recipients meet eligibility criteria (as discussed by Gärtner et al [20]).…”

Section: Discussionmentioning

confidence: 99%

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

2023

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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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“…extent they allow fitting of the CI to the individual properties of the auditory nerve (NRT based fitting in children) and the assessment (of changes) of the electrical stimulating properties of the auditory nerve. In a similar way the spread of excitation for assessing channel interaction inside the cochlea and the electric field distribution can be measured [6]. To some extent, the functional status of the auditory nerve can be checked [7] using this technique.…”

Section: Referatmentioning

confidence: 99%

“…Sie erlauben in begrenztem Rahmen eine Anpassung des CI an die individuellen Eigenschaften des Hörnerven (NRT based fitting bei Kindern), die Erfassung (von Veränderungen) der elektrischen Stimulierbarkeit des Hörnerven sowie die Messung der elektrischen Feldausbreitung (Electrical Field Imaging EFI) bei Stimulation einzelner Elektrodenkontakte zur Bestimmung der Kanal-Interaktion in der Cochlea 6 . Zusätzlich sind Aussagen zum Funktionsstatus des Hörnerven möglich 7…”

Section: Ci-technologieunclassified

“…In a similar way the spread of excitation for assessing channel interaction inside the cochlea and the electric field distribution can be measured 6 . To some extent, the functional status of the auditory nerve can be checked 7 using this technique. Summating potentials (SP) generated by the (inner) hair cells can be also recorded to assess residual hearing during hearing preservation cochlear implantation and to determine the electrode position in the cochlea (rarely applied) 8 .…”

Section: CI Technologymentioning

confidence: 99%

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Cochlea-Implantation: Konzept, Therapieergebnisse und Lebensqualität

Lenarz

Büchner

Illg

2022

Laryngorhinootologie

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ZusammenfassungCochlea-Implantate stellen heute eine unverzichtbare Methode zur auditiven Rehabilitation hochgradig hörgeschädigter Patienten dar. Durch die rasante Entwicklung der Implantat-technologie haben sich die Hörergebnisse erheblich verbessert, ca 80% der Patienten können telefonieren und Kinder erreichen eine nahezu normale Hör- und Sprachentwicklung. Das hat zu einer Indikationsausweitung hin zu Patienten mit Hochtontaubheit und einseitiger Taubheit geführt. Zur Zeit sind aber nur etwa 60 000 der ca 1 Million CI-Kandidaten implantiert. Zukünftig werden multimodale universelle Hörimplantate für die kombinierte elektro-mechanische Stimulation zur Verfügung stehen, die fortlaufend eine Anpassung der Stimulationsstrategie an den jeweiligen Funktionszustand von Haarzellen und Hörnerven auch bei progredienter Schwerhörigkeit ermöglichen. Brain-Computer-Interfaces erlauben die automatisierte Anpassung an die Hörsituation und eine Optimierung der Signalverarbeitung zur Erzielung eines bestmöglichen Hörvermögens. Binaurale Hörsysteme erlauben eine Verbesserung von Richtungshören und Hören im Störgeräusch. Advanced Implants besitzen additiv gefertigte individualisierte Elektroden, die sich nach atraumatischer robotisch assistierter Insertion aktiv der Anatomie der Cochlea anpassen. Sie sind in Abhängigkeit von der Pathophysiologie mit integrierten biologischen Komponenten ausgestattet, unterstützen die Erhaltung des Restgehörs und ermöglichen die Regeneration neuraler Elemente zur Verbesserung der Elektroden-Nerven-Schnittstelle. Dadurch lassen sich die heutigen grundsätzlichen Grenzen der CI-Technologie überwinden und in Richtung des physiologischen Gehörs verschieben. Das Bionische Ohr ist somit in Reichweite. Durch konsequente Weiterentwicklung mit Vereinfachung der Versorgung, hörerhaltender Implantation unter Lokal-Anästhesie und Anwendung robotischer Systeme werden zukünftig mehr Patienten von dem neuen physiologischen Hören profitieren.

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Correlation of Electrically Evoked Compound Action Potential Amplitude Growth Function Slope and Anamnestic Parameters in Cochlear Implant Patients—Identification of Predictors for the Neuronal Health Status

Cited by 6 publications

References 46 publications

Optimized SNR-based ECAP threshold determination is comparable to the judgement of human evaluators

Optimized SNR-based ECAP threshold determination is comparable to the judgement of human evaluators

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

Cochlea-Implantation: Konzept, Therapieergebnisse und Lebensqualität

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