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Electroencephalography and Clinical... Jul 1980Evoked potential recordings were studied in the acoustic nerve and cochlear nucleus of adult decerebrate cats as a function of the tone duration (1-1500 msec) and the...
Evoked potential recordings were studied in the acoustic nerve and cochlear nucleus of adult decerebrate cats as a function of the tone duration (1-1500 msec) and the tone repetition rate (0.5/sec-200/sec). Response decrements due to repetitive tonal stimulation were primarily a function of the inter-tone interval. At inter-tone intervals longer than 100 msec, no response decrements were observed in the acoustic nerve or the cochlear nucleus. With shorter inter-tone intervals, reversible response decrements of identical magnitudes ocurred in both the acoustic nerve and the cochlear nucleus evoked potentials. The mechanism of response decrement may be due to depression at the hair cell-acoustic nerve junction.
Topics: Acoustic Stimulation; Animals; Cats; Cochlear Nerve; Decerebrate State; Electroencephalography; Evoked Potentials, Auditory; Vestibulocochlear Nerve
PubMed: 6159156
DOI: 10.1016/0013-4694(80)90347-8 -
Archives of Oto-rhino-laryngology 1974
Topics: Action Potentials; Animals; Cochlea; Cochlear Nerve; Electric Stimulation; Electrophysiology; Evoked Potentials; Guinea Pigs
PubMed: 4479079
DOI: 10.1007/BF00460282 -
HNO Jun 2022The data of 86 patients with retrosigmoid microsurgical resection of vestibular schwannoma in tumor stage Koos II-IV were evaluated. In more than two thirds of the...
The data of 86 patients with retrosigmoid microsurgical resection of vestibular schwannoma in tumor stage Koos II-IV were evaluated. In more than two thirds of the cases it was shown that the cochlear nerve followed the facial nerve, which is easily identified by electroneurography, in recurrent similar patterns in the region of the internal auditory canal. Starting from the fundus, this facilitated early identification and thus preservation of continuity of the cochlear nerve in the course of the internal auditory canal. This was of particular importance when safe functional preservation could not be guaranteed due to tumor size or formation despite intraoperative derivation of somatosenoric potentials, but when the possibility of subsequent hearing rehabilitation with a cochlear implant should be granted. Preoperative MRI sequences gave an indication of the possible nerve courses in some cases, but intraoperative imaging in the internal auditory canal was superior to MRI.
Topics: Cochlear Nerve; Facial Nerve; Humans; Neuroma, Acoustic; Osteotomy; Petrous Bone
PubMed: 34812915
DOI: 10.1007/s00106-021-01116-y -
The Journal of Comparative Neurology Nov 1969
Topics: Animals; Brain Mapping; Brain Stem; Cerebellum; Cochlear Nerve; Nerve Endings; Pons; Rats; Staining and Labeling; Trigeminal Nerve; Vestibular Nerve; Vestibulocochlear Nerve
PubMed: 4187631
DOI: 10.1002/cne.901370303 -
Neurosurgery Feb 2004The functional anatomy (i.e., tonotopy) of the human cochlear nerve is unknown. A better understanding of the tonotopy of the central nervous system segment of the...
OBJECTIVE
The functional anatomy (i.e., tonotopy) of the human cochlear nerve is unknown. A better understanding of the tonotopy of the central nervous system segment of the cochlear nerve and of the pathophysiology of tinnitus might help to ameliorate the disappointing results obtained with microvascular decompressions in patients with tinnitus.
METHODS
We assume that vascular compression of the cochlear nerve can induce a frequency-specific form of hearing loss and that when the nerve is successfully decompressed, this hearing loss can recuperate. Thirty-one patients underwent a microvascular decompression of the vestibulocochlear nerve for vertigo or tinnitus. Preoperative audiograms were subtracted from postoperative audiograms, regardless of the surgical result with regard to the tinnitus and vertigo, because the hearing improvement could be the only sign of the vascular compression. The frequency of maximal improvement was then correlated to the site of vascular compression. A tonotopy of the cochlear nerve was thus obtained.
RESULTS
A total of 18 correlations can be made between the site of compression and postoperative maximal hearing improvement frequency when 5-dB hearing improvement is used as threshold, 13 when 10-dB improvement is used as threshold. A clear distribution can be seen, with clustering of low frequencies at the posterior and inferior side of the cochlear nerve, close to the brainstem, and close to the root exit zone of the facial nerve. High frequencies are distributed closer to the internal acoustic meatus and more superiorly along the posterior aspect of the cochlear nerve.
CONCLUSION
The tonotopic organization of the cisternal segment of the cochlear nerve has an oblique rotatory structure as a result of the rotatory course of the cochlear nerve in the posterior fossa. Knowledge of this tonotopic organization of the auditory nerve in its cisternal course might benefit surgeons who perform microvascular decompression operations for the vestibulocochlear compression syndrome, especially in the treatment of unilateral severe tinnitus.
Topics: Adult; Aged; Cochlear Nerve; Decompression, Surgical; Female; Humans; Male; Microcirculation; Middle Aged; Nerve Compression Syndromes; Retrospective Studies; Tinnitus; Treatment Outcome
PubMed: 14744285
DOI: 10.1227/01.neu.0000103420.53487.79 -
Hearing Research Dec 1989In human temporal bones of patients with normal hearing or sensory neural deafness, the cochlear neurons were quantitatively and qualitatively evaluated at the level of...
In human temporal bones of patients with normal hearing or sensory neural deafness, the cochlear neurons were quantitatively and qualitatively evaluated at the level of the osseous spiral lamina, the spiral ganglion and the cochlear nerve. We found from 32,000 to 31,000 myelinated nerve fibres in the cochlear nerve of normal hearing individuals and any lower number in cases of sensory neural deafness. There was in general a good correspondence between the counted numbers of the myelinated nerve fibres in the osseous spiral lamina, the spiral ganglion cells and the myelinated nerve fibres in the cochlear nerve in the inner acoustic meatus. The diameter of the peripheral axons of the type I neurons are about half the diameter of the central axons. The average diameter of the central axons is 2.5 millimicrons with a narrow distribution in children, but an increasingly larger range of fiber calibers with increasing age (0.5 to 7 microns in the 40 to 50 year age group adults).
Topics: Adult; Child; Cochlea; Cochlear Nerve; Deafness; Humans; Microscopy, Electron; Spiral Ganglion; Vestibulocochlear Nerve
PubMed: 2613564
DOI: 10.1016/0378-5955(89)90056-7 -
Revue de Laryngologie - Otologie -... 1961
Topics: Cochlear Nerve; Cranial Nerve Neoplasms; Humans; Neoplasms; Neurilemmoma; Neuroma, Acoustic
PubMed: 13718648
DOI: No ID Found -
Acta Oto-laryngologica 1959
Topics: Cochlear Nerve; In Vitro Techniques; Neuroglia; Schwann Cells
PubMed: 13676976
DOI: 10.3109/00016485909129196 -
Journal of Neurosurgery Feb 1965
Topics: Adolescent; Cochlear Nerve; Geriatrics; Humans; Neoplasm Recurrence, Local; Neoplasms; Neurilemmoma; Neurologic Manifestations; Neurosurgery; Peripheral Nervous System Neoplasms; Postoperative Complications; Prognosis
PubMed: 14288423
DOI: 10.3171/jns.1965.22.2.0127 -
Cancer Bulletin (Houston, Tex.) 1958
Topics: Acoustics; Cochlear Nerve; Neoplasms; Vestibulocochlear Nerve
PubMed: 13536983
DOI: No ID Found