{"title":"Tripolar configuration and pulse shape in cochlear implants reduce channel interactions in the temporal domain","authors":"Gunnar L Quass , Andrej Kral","doi":"10.1016/j.heares.2024.108953","DOIUrl":null,"url":null,"abstract":"<div><p>The present study investigates effects of current focusing and pulse shape on threshold, dynamic range, spread of excitation and channel interaction in the time domain using cochlear implant stimulation. The study was performed on 20 adult guinea pigs using a 6-channel animal cochlear implant, recording was performed in the auditory midbrain using a multielectrode array. After determining the best frequencies for individual recording contacts with acoustic stimulation, the ear was deafened and a cochlear implant was inserted into the cochlea. The position of the implant was controlled by x-ray. Stimulation with biphasic, pseudomonophasic and monophasic stimuli was performed with monopolar, monopolar with common ground, bipolar and tripolar configuration in two sets of experiments, allowing comparison of the effects of the different stimulation strategies on threshold, dynamic range, spread of excitation and channel interaction. Channel interaction was studied in the temporal domain, where two electrodes were activated with pulse trains and phase locking to these pulse trains in the midbrain was quantified. The results documented multifactorial influences on the response properties, with significant interaction between factors. Thresholds increased with increasing current focusing, but decreased with pseudomonophasic and monophasic pulse shapes. The results documented that current focusing, particularly tripolar configuration, effectively reduces channel interaction, but that also pseudomonophasic and monophasic stimulation and phase duration intensity coding reduce channel interactions.</p></div>","PeriodicalId":12881,"journal":{"name":"Hearing Research","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2024-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0378595524000066/pdfft?md5=46b1d9b1a9989dd38e73ff073dfb306f&pid=1-s2.0-S0378595524000066-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Hearing Research","FirstCategoryId":"3","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0378595524000066","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"AUDIOLOGY & SPEECH-LANGUAGE PATHOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The present study investigates effects of current focusing and pulse shape on threshold, dynamic range, spread of excitation and channel interaction in the time domain using cochlear implant stimulation. The study was performed on 20 adult guinea pigs using a 6-channel animal cochlear implant, recording was performed in the auditory midbrain using a multielectrode array. After determining the best frequencies for individual recording contacts with acoustic stimulation, the ear was deafened and a cochlear implant was inserted into the cochlea. The position of the implant was controlled by x-ray. Stimulation with biphasic, pseudomonophasic and monophasic stimuli was performed with monopolar, monopolar with common ground, bipolar and tripolar configuration in two sets of experiments, allowing comparison of the effects of the different stimulation strategies on threshold, dynamic range, spread of excitation and channel interaction. Channel interaction was studied in the temporal domain, where two electrodes were activated with pulse trains and phase locking to these pulse trains in the midbrain was quantified. The results documented multifactorial influences on the response properties, with significant interaction between factors. Thresholds increased with increasing current focusing, but decreased with pseudomonophasic and monophasic pulse shapes. The results documented that current focusing, particularly tripolar configuration, effectively reduces channel interaction, but that also pseudomonophasic and monophasic stimulation and phase duration intensity coding reduce channel interactions.
期刊介绍:
The aim of the journal is to provide a forum for papers concerned with basic peripheral and central auditory mechanisms. Emphasis is on experimental and clinical studies, but theoretical and methodological papers will also be considered. The journal publishes original research papers, review and mini- review articles, rapid communications, method/protocol and perspective articles.
Papers submitted should deal with auditory anatomy, physiology, psychophysics, imaging, modeling and behavioural studies in animals and humans, as well as hearing aids and cochlear implants. Papers dealing with the vestibular system are also considered for publication. Papers on comparative aspects of hearing and on effects of drugs and environmental contaminants on hearing function will also be considered. Clinical papers will be accepted when they contribute to the understanding of normal and pathological hearing functions.