Chronic electrical stimulation of the auditory nerve at high stimulus rates: a physiological and histopathological study

Xu, Jin; Shepherd, Robert K.; Millard, Rodney; Clark, Graeme M.

doi:10.1016/s0378-5955(96)00193-1

Cited by 226 publications

(188 citation statements)

References 56 publications

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“…Ni et al (1992) found that placement of a short electrode in animals did not induce additional tissue damage distal to the region of the electrode. Xu et al (1997) reported similar results. Maintenance of near-normal click evoked ABR thresholds in the majority of cochleae in these studies suggested that hair cells, at least apical to the implanted electrode array, not only survive, but also can function at a near normal sensitivity.…”

Section: Preservation Of Hearing Following Cochlear Implant Surgerysupporting

confidence: 63%

Combined acoustic and electric hearing: Preserving residual acoustic hearing

2008

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The topic of this review is the strategy of preserving residual acoustic hearing in the implanted ear to provide combined electrical stimulation and acoustic hearing as a rehabilitative strategy for sensorineural hearing loss. This chapter will concentrate on research done with the Iowa/Nucleus 10mm Hybrid device, but we will also attempt to summarize strategies and results from other groups around the world who use slightly different approaches. A number of studies have shown that preserving residual acoustic hearing in the implanted ear is a realistic goal for many patients with severe high-frequency hearing loss. The addition of the electric stimulation to their existing acoustic hearing can provide increased speech recognition for these patients. In addition, the preserved acoustic hearing can offer considerable advantages, as compared to a traditional cochlear implant, for tasks such as speech recognition in backgrounds or appreciation of music and other situations where the poor frequency resolution of electric stimulation has been a disadvantage.

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Section: Preservation Of Hearing Following Cochlear Implant Surgerysupporting

confidence: 63%

Combined acoustic and electric hearing: Preserving residual acoustic hearing

2008

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“…However, since the stimulation was not continuous, the total duration of electrical stimulation was limited to a small fraction of the time that was spent in the testing booth. As a result, the subjects in this study received much less electrical stimulation as compared to other studies that employed chronic electrical stimulation to test safe limits or protective effects of electrical stimulation (Walsh et al 1981;Duckert and Miller 1982;Duckert 1983;Ni et al 1992;Xu et al 1997;Coco et al 2007). …”

Section: Methodsmentioning

confidence: 99%

“…However, it is possible that electrical stimulation itself may cause hair cell and SGN loss. Some studies have shown that electrical stimulation is capable of causing degenerative changes in the cochlea (Walsh et al 1981;Duckert and Miller 1982;Duckert 1983), while other studies indicate that hair cells are not adversely affected by electrical stimulation (Ni et al 1992;Xu et al 1997). Electrically induced pathology appears to be dependent on the charge density of the electrical stimulus.…”

Section: Histopathologymentioning

confidence: 99%

“…One animal study suggests that cochlear implantation surgery causes hearing loss due to the direct acute trauma of electrode insertion combined with subsequent apoptotic cell death of hair cells (Eshraghi et al 2005). The effects of electrical stimulation on hair cells have also been studied in the past in several animal species, with mixed results that depend partly on charge density (Walsh et al 1981;Duckert and Miller 1982;Duckert 1983;Ni et al 1992;Xu et al 1997;Coco et al 2007). Thus, cochlear pathology may be a result of the implantation surgery or the electrical stimulation itself.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Hearing Preservation on Psychophysical Responses to Cochlear Implant Stimulation

Kang

Colesa

Swiderski

et al. 2009

JARO

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Previous studies have shown that residual acoustic hearing supplements cochlear implant function to improve speech recognition in noise as well as perception of music. The current study had two primary objectives. First, we sought to determine how cochlear implantation and electrical stimulation over a time period of 14 to 21 months influence cochlear structures such as hair cells and spiral ganglion neurons. Second, we sought to investigate whether the structures that provide acoustic hearing also affect the perception of electrical stimulation. We compared psychophysical responses to cochlear implant stimulation in two groups of adult guinea pigs. Group I (11 animals) received a cochlear implant in a previously untreated ear, while group II (ten animals) received a cochlear implant in an ear that had been previously infused with neomycin to destroy hearing. Psychophysical thresholds were measured in response to pulse-train and sinusoidal stimuli. Histological analysis of all group I animals and a subset of group II animals was performed. Nine of the 11 group I animals showed survival of the organ of Corti and spiral ganglion neurons adjacent to the electrode array. All group I animals showed survival of these elements in regions apical to the electrode array. Group II animals that were examined histologically showed complete loss of the organ of Corti in regions adjacent and apical to the electrode array and severe spiral ganglion neuron loss, consistent with previous reports for neomycin-treated ears. Behaviorally, group II animals had significantly lower thresholds than group I animals in response to 100 Hz sinusoidal stimuli. However, group I animals had significantly lower thresholds than group II animals in response to pulse-train stimuli (0.02 ms/phase; 156 to 5,000 pps). Additionally, the two groups showed distinct threshold versus pulse rate functions. We hypothesize that the differences in detection thresholds between groups are caused by the electrical activation of the hair cells in group I animals and/or differences between groups in the condition of the spiral ganglion neurons.

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“…Animal models show that hair cells apical to implanted electrode arrays can survive over chronic periods (Ni et al 1992;Xu et al 1997) and human studies indicate that acoustic sensitivity can be preserved after implantation (Kiefer et al 1998). The standard animal model for cochlear implant research has long used a deaf cochlea to isolate the direct, electrical, depolarization of auditory nerve fibers (i.e., the Ba^response of Moxon 1971).…”

Section: Introductionmentioning

confidence: 99%

Electrical Excitation of the Acoustically Sensitive Auditory Nerve: Single-Fiber Responses to Electric Pulse Trains

Miller

Abbas

Robinson

et al. 2006

JARO

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Nearly all studies on auditory-nerve responses to electric stimuli have been conducted using chemically deafened animals so as to more realistically model the implanted human ear that has typically been profoundly deaf. However, clinical criteria for implantation have recently been relaxed. Ears with Bresidualâ coustic sensitivity are now being implanted, calling for the systematic evaluation of auditory-nerve responses to electric stimuli as well as combined electric and acoustic stimuli in acoustically sensitive ears. This article presents a systematic investigation of single-fiber responses to electric stimuli in acoustically sensitive ears. Responses to 250 pulse/s electric pulse trains were collected from 18 cats. Properties such as threshold, dynamic range, and jitter were found to differ from those of deaf ears. Other types of fiber activity observed in acoustically sensitive ears (i.e., spontaneous activity and electrophonic responses) were found to alter the temporal coding of electric stimuli. The electrophonic response, which was shown to greatly change the information encoded by spike intervals, also exhibited fast adaptation relative to that observed in the Bdirect^response to electric stimuli. More complex responses, such as Bbuildup^(increased responsiveness to successive pulses) and Bbursting^(alternating periods of responsiveness and unresponsiveness) were observed. Our findings suggest that bursting is a response unique to sustained electric stimulation in ears with functional hair cells.

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Chronic electrical stimulation of the auditory nerve at high stimulus rates: a physiological and histopathological study

Cited by 226 publications

References 56 publications

Combined acoustic and electric hearing: Preserving residual acoustic hearing

Combined acoustic and electric hearing: Preserving residual acoustic hearing

Effects of Hearing Preservation on Psychophysical Responses to Cochlear Implant Stimulation

Electrical Excitation of the Acoustically Sensitive Auditory Nerve: Single-Fiber Responses to Electric Pulse Trains

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