Prosthetic Stimulation of the Auditory System with Intraneural Electrodes

2003 ◽  
Vol 112 (9_suppl) ◽  
pp. 20-25 ◽  
Author(s):  
H. Alexander Arts ◽  
Derek A. Jones ◽  
David J. Anderson
Keyword(s):  
Auditory System ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Current Status ◽  
Practical Reasons ◽  
Scala Tympani ◽  
Electrode Arrays ◽  
Nucleus Surface ◽  
Recent Developments ◽  
Stimulation Of

Prosthetic electrical stimulation of the auditory system is presently accomplished either via scala tympani electrode arrays or via cochlear nucleus surface electrode arrays. Many of the early cochlear implant studies, however, used electrode arrays placed within the auditory nerve itself — either within the modiolus or within the trunk of the nerve. For many reasons, such intraneural electrode arrays were abandoned in favor of intrascalar arrays. There remain, however, several theoretical and practical reasons why intraneural arrays might be advantageous, and recent developments in electrode technology solve many of the problems posed by early attempts at intraneural stimulation. In this article, we review the history and current status of intraneural auditory stimulation, and present some preliminary results of this mode of stimulation in an animal model.

Electrical Cochlear Stimulation in the Deaf Cat: Comparisons Between Psychophysical and Central Auditory Neuronal Thresholds

2000 ◽  
Vol 83 (4) ◽  
pp. 2145-2162 ◽  
Author(s):  
Ralph E. Beitel ◽  
Russell L. Snyder ◽  
Christoph E. Schreiner ◽  
Marcia W. Raggio ◽  
Patricia A. Leake
Keyword(s):  
Electrical Stimulation ◽  
Auditory System ◽  
Pulse Rate ◽  
Auditory Nerve ◽  
Round Window ◽  
Electrode Array ◽  
Scala Tympani ◽  
Behavioral Thresholds ◽  
Current Pulses ◽  
Stimulation Of

Cochlear prostheses for electrical stimulation of the auditory nerve (“electrical hearing”) can provide auditory capacity for profoundly deaf adults and children, including in many cases a restored ability to perceive speech without visual cues. A fundamental challenge in auditory neuroscience is to understand the neural and perceptual mechanisms that make rehabilitation of hearing possible in these deaf humans. We have developed a feline behavioral model that allows us to study behavioral and physiological variables in the same deaf animals. Cats deafened by injection of ototoxic antibiotics were implanted with either a monopolar round window electrode or a multichannel scala tympani electrode array. To evaluate the effects of perceptually significant electrical stimulation of the auditory nerve on the central auditory system, an animal was trained to avoid a mild electrocutaneous shock when biphasic current pulses (0.2 ms/phase) were delivered to its implanted cochlea. Psychophysical detection thresholds and electrical auditory brain stem response (EABR) thresholds were estimated in each cat. At the conclusion of behavioral testing, acute physiological experiments were conducted, and threshold responses were recorded for single neurons and multineuronal clusters in the central nucleus of the inferior colliculus (ICC) and the primary auditory cortex (A1). Behavioral and neurophysiological thresholds were evaluated with reference to cochlear histopathology in the same deaf cats. The results of the present study include: 1) in the cats implanted with a scala tympani electrode array, the lowest ICC and A1 neural thresholds were virtually identical to the behavioral thresholds for intracochlear bipolar stimulation; 2) behavioral thresholds were lower than ICC and A1 neural thresholds in each of the cats implanted with a monopolar round window electrode; 3) EABR thresholds were higher than behavioral thresholds in all of the cats (mean difference = 6.5 dB); and 4) the cumulative number of action potentials for a sample of ICC neurons increased monotonically as a function of the amplitude and the number of stimulating biphasic pulses. This physiological result suggests that the output from the ICC may be integrated spatially across neurons and temporally integrated across pulses when the auditory nerve array is stimulated with a train of biphasic current pulses. Because behavioral thresholds were lower and reaction times were faster at a pulse rate of 30 pps compared with a pulse rate of 2 pps, spatial-temporal integration in the central auditory system was presumably reflected in psychophysical performance.

Far-field responses to stimulation of the cochlear nucleus by microsurgically placed penetrating and surface electrodes in the cat

2001 ◽  
Vol 95 (5) ◽  
pp. 845-852 ◽  
Author(s):  
Steffen K. Rosahl ◽  
Gerhard Mark ◽  
Martin Herzog ◽  
Christos Pantazis ◽  
Farnaz Gharabaghi ◽  
...  
Keyword(s):  
Cochlear Nucleus ◽  
Auditory Brainstem ◽  
Mastoid Process ◽  
Electrode Arrays ◽  
Content Type ◽  
Surface Electrodes ◽  
Brainstem Response ◽  
The Mean ◽  
Fine Print ◽  
Stimulation Of

Object. A new generation of penetrating electrodes for auditory brainstem implants is on the verge of being introduced into clinical practice. This study was designed to compare electrically evoked auditory brainstem responses (EABRs) to stimulation of the cochlear nucleus (CN) by microsurgically implanted surface electrodes and insertion electrodes (INSELs) with stimulation areas of identical size. Methods. Via a lateral suboccipital approach, arrays of surface and penetrating microelectrodes with geometric stimulation areas measuring 4417 µm2 (diameter 75 µm) were placed over and inserted into the CN in 10 adult cats. After recording the auditory brainstem response (ABR) at the mastoid process, the CN, and the level of the inferior colliculus, EABRs to stimulation of the CN were recorded using biphasic, charge-balanced stimuli with phase durations of 80 µsec, 160 µsec, and 240 µsec at a repetition rate of 22.3 Hz. Waveform, threshold, maximum amplitude, and the dynamic range of the responses were compared for surface and penetrating electrodes. The EABR waveforms that appeared for both types of stimulation resembled each other closely. The mean impedance was slightly lower (30 ± 3.4 kΩ compared with 31.7 ± 4.5 kΩ, at 10 kHz), but the mean EABR threshold was significantly higher (51.8 µA compared with 40.5 µA, t = 3.5, p = 0.002) for surface electrode arrays as opposed to penetrating electrode arrays. Due to lower saturation levels of the INSEL array, dynamic ranges were almost identical between the two types of stimulation. Sectioning of the eighth cranial nerve did not abolish EABRs. Conclusions. Microsurgical insertion of electrodes into the CN complex may be guided and monitored using techniques similar to those applied for implantation of surface electrodes. Lower thresholds and almost equivalent dynamic ranges indicate that a more direct access to secondary auditory neurons is achieved using penetrating electrodes.

Direct Electrical Stimulation of the Cochlear Nucleus: Surface vs. Penetrating Stimulation

1991 ◽  
Vol 105 (4) ◽  
pp. 533-543 ◽  
Author(s):  
Hussam K. El-Kashlan ◽  
John K. Niparko ◽  
Richard A. Altschuler ◽  
Josef M. Miller
Keyword(s):  
Electrical Stimulation ◽  
Cochlear Nucleus ◽  
Direct Electrical Stimulation ◽  
Nucleus Surface ◽  
Stimulation Of

Electrical stimulation of the auditory nerve in deaf kittens: Effects on cochlear nucleus morphology

1991 ◽  
Vol 56 (1-2) ◽  
pp. 133-142 ◽  
Author(s):  
Jun-ichi Matsushima ◽  
Robert K. Shepherd ◽  
H.Lee Seldon ◽  
Shi-ang Xu ◽  
Graeme M. Clark
Keyword(s):  
Electrical Stimulation ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Stimulation Of

Auditory evoked potentials recorded from the cochlear nucleus and its vicinity in man

1983 ◽  
Vol 59 (6) ◽  
pp. 1013-1018 ◽  
Author(s):  
Aage R. Møller ◽  
Peter J. Jannetta
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Auditory Evoked Potentials ◽  
Auditory Pathway ◽  
Content Type ◽  
Negative Peak ◽  
Auditory Brain Stem ◽  
Stimulation Of

✓ Intracranial responses from the auditory nerve and the cochlear nucleus were recorded from patients undergoing neurosurgical operations during which these structures were exposed. Responses to stimulation of the ipsilateral ear with short tonebursts from the vicinity of the cochlear nucleus show a large surface-negative peak, the latency of which is close to that of peak III in the auditory brain-stem evoked potentials recorded from scalp electrodes. There was also a response to contralateral stimulation, smaller in amplitude and with a longer latency. It is concluded that the cochlear nucleus is the main generator of peak III responses, and that structures of the ascending auditory pathway that are more central than the cochlear nucleus are unlikely to contribute to wave III of the auditory brain-stem evoked potentials.

Some Considerations of Multichannel Electrical Stimulation of the Auditory Nerve in the Profoundly Deaf; Interfacing Electrode Arrays with the Auditory Nerve Array

1979 ◽  
Vol 87 (3-6) ◽  
pp. 196-203 ◽  
Author(s):  
Michael M. Merzenich ◽  
Mark White ◽  
Michael C. Vivion ◽  
Patricia A. Leake-jones ◽  
Shiela Walsh
Keyword(s):  
Electrical Stimulation ◽  
Auditory Nerve ◽  
Electrode Arrays ◽  
Stimulation Of
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