Mechanical stress-induced reactive gliosis in the auditory nerve and cochlear nucleus

2011 ◽  
Vol 114 (2) ◽  
pp. 414-425 ◽  
Author(s):  
Tetsuji Sekiya ◽  
Masahiro Matsumoto ◽  
Ken Kojima ◽  
Kazuya Ono ◽  
Yayoi S. Kikkawa ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Auditory Brainstem ◽  
Reactive Gliosis ◽  
Auditory Pathways ◽  
Microsurgical Treatment ◽  
Auditory Nerves ◽  
Brainstem Response ◽  
Temporal Bones

Object Hearing levels following microsurgical treatment gradually deteriorate in a number of patients treated for vestibular schwannoma (VS), especially in the subacute postoperative stage. The cause of this late-onset deterioration of hearing is not completely understood. The aim of this study was to investigate the possibility that reactive gliosis is a contributory factor. Methods Mechanical damage to nerve tissue is a feature of complex surgical procedures. To explore this aspect of VS treatment, the authors compressed rat auditory nerves with 2 different degrees of injury while monitoring the compound action potentials of the auditory nerve and the auditory brainstem responses. In this experimental model, the axons of the auditory nerve were quantitatively and highly selectively damaged in the cerebellopontine angle without permanent compromise of the blood supply to the cochlea. The temporal bones were processed for immunohistochemical analysis at 1 week and at 8 weeks after compression. Results Reactive gliosis was induced not only in the auditory nerve but also in the cochlear nucleus following mechanical trauma in which the general shape of the auditory brainstem response was maintained. There was a substantial outgrowth of astrocytic processes from the transitional zone into the peripheral portion of the auditory nerve, leading to an invasion of dense gliotic tissue in the auditory nerve. The elongated astrocytic processes ran in parallel with the residual auditory neurons and entered much further into the cochlea. Confocal images disclosed fragments of neurons scattered in the gliotic tissue. In the cochlear nucleus, hypertrophic astrocytic processes were abundant around the soma of the neurons. The transverse diameter of the auditory nerve at and proximal to the compression site was considerably reduced, indicating atrophy, especially in rats in which the auditory nerve was profoundly compressed. Conclusions The authors found for the first time that mechanical stress to the auditory nerve causes substantial reactive gliosis in both the peripheral and central auditory pathways within 1–8 weeks. Progressive reactive gliosis following surgical stress may cause dysfunction in the auditory pathways and may be a primary cause of progressive hearing loss following microsurgical treatment for VS.

scholarly journals Congenital Unilateral Hypoplasia of Depressor Anguli Oris

2012 ◽  
Vol 2012 ◽  
pp. 1-3 ◽  
Author(s):  
Seckin O. Ulualp ◽  
Ronald Deskin
Keyword(s):  
Tertiary Care ◽  
Auditory Brainstem ◽  
Nasolabial Fold ◽  
Lower Lip ◽  
Normal Limits ◽  
Facial Musculature ◽  
The Face ◽  
Brainstem Response ◽  
Depressor Anguli Oris ◽  
Temporal Bones

Objectives. Asymmetric facial appearance may originate from abnormalities of facial musculature or facial innervation. We describe clinical features of congenital hypoplasia of depressor anguli oris muscle in a child.Material and Methods. Chart of a 10-month-old female referred to a tertiary care pediatric hospital for assessment of facial paralysis was reviewed. Data included relevant history and physical examination, diagnostic work up, and management.Results. The child presented with asymmetric movement of lower lip since birth. Asymmetry of lower lip was more pronounced when she smiled and cried. Rest of the face movement was symmetric. On examination, the face appeared symmetric at rest. The child had inward deviation of right lower lip when she smiled. Facial nerve function, as determined by frowning/forehead, wrinkling, eye closure, nasolabial fold depth, and tearing, was symmetric. Magnetic resonance imaging of the temporal bones and internal auditory canals were within normal limits. Echocardiogram did not show cardiac abnormality. Auditory brainstem response showed no abnormality.Conclusions. Congenital hypoplasia of depressor anguli oris is a rare anomaly that causes asymmetric crying face. Pediatricians and otolaryngologists need to be cognizant of cardiac, head and neck, and central nervous system anomalies associated with congenital unilateral hypoplasia of depressor anguli oris.

Accuracy of Synchrony Judgment and its Relation to the Auditory Brainstem Response: the Difference Between Pianists and Non-Pianists

2011 ◽  
Vol 15 (8) ◽  
pp. 962-971
Author(s):  
Eriko Aiba ◽  
◽  
Koji Kazai ◽  
Takayuki Shimotomai ◽  
Toshie Matsui ◽  
...  
Keyword(s):  
Auditory Nerve ◽  
Physiological Responses ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Judgment Accuracy ◽  
Synchrony Judgment ◽  
Significant Difference ◽  
Brainstem Response ◽  
The Difference ◽  
Onset Asynchrony

Synchrony judgment is one of the most important abilities for musicians. Only a few milliseconds of onset asynchrony result in a significant difference in musical expression. Using behavioural responses and Auditory Brainstem Responses (ABR), this study investigates whether synchrony judgment accuracy improves with training and, if so, whether physiological responses are also changed through training. Psychoacoustic experiments showed that accuracy of synchrony judgment of pianists was higher than that of non-pianists, implying that pianists’ ability to perceive tones increased through training. ABRmeasurements also showed differences between pianists and non-pianists. However, cochlear delay, an asymmetric aspect of temporal processing in the human auditory system, did not change with training. It is possible that training improved ability related to temporal tone perception and that training may increase synchrony in auditory nerve firing.

R446 – Rostral Cochlear Nucleus Changes After Cochlear Ablation

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P194-P194 ◽  
Author(s):  
Kyle Robinson ◽  
Donald A Godfrey ◽  
Matthew A. Godfrey
Keyword(s):  
Auditory Processing ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
High Performance ◽  
Nerve Fibers ◽  
Average Concentration ◽  
Gamma Aminobutyric Acid ◽  
Freeze Dried ◽  
Concentration Changes ◽  
Temporal Bones

Problem Identification of neurotransmitter concentration changes occurring in the rostral anterior ventral cochlear nucleus (AVCN) following transection of the auditory nerve within the cochlea. Methods Chinchillas with cochlear ablations, as well as sham-lesioned chinchillas, were euthanized at times ranging from 3 to 84 days post ablation. Both temporal bones and brains were saved. Temporal bones were fixed, embedded in paraffin and sectioned to document the completeness of the cochlear lesion. Brain portions containing the cochlear nuclei were frozen-sectioned, and sections were freeze dried. Freeze-dried sections were microdissected into samples of AVCN for high performance liquid chromatography (HPLC) assay of 12 amino acid concentrations. Results The average concentration of glutamate, the most likely neurotransmitter of auditory nerve fibers, declined in the lesioned-side rostral AVCN by about 25% at 15 days. This decrease was maintained through 31 days post ablation and became bilateral at 83 days. There was no decrease in the adjacent granular region. Larger lesioned-side decreases, approaching 50%, were found more caudally in the AVCN at 31 days post ablation. The average concentration of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) decreased bilaterally by 15–25% at 3 through 15 days post ablation. Conclusion The degeneration of the central portion of the auditory nerve following mechanical ablation of the cochlea is accompanied by decreases of glutamate concentration on the lesioned side but bilateral decreases of GABA in the rostral part of the AVCN. These decreases were smaller than those reported previously for the posteroventral cochlear nucleus (PVCN). However, changes more caudally in AVCN approach those found in PVCN. Significance Our results are consistent with other evidence that damage to the cochlea leads to neurotransmitter changes in the central auditory system. The smaller changes in AVCN than in PVCN may correlate with different types of auditory processing in these two regions. Support The American Tinnitus Association and the University of Toledo Foundation.

scholarly journals Auditory brainstem response demonstrates that reduced peripheral auditory input is associated with self-report of tinnitus

2019 ◽  
Author(s):  
Naomi Bramhall ◽  
Garnett McMillan ◽  
Frederick Gallun ◽  
Dawn Konrad-Martin
Keyword(s):  
Animal Models ◽  
Auditory Brainstem Response ◽  
Otoacoustic Emissions ◽  
Auditory Brainstem ◽  
Self Report ◽  
Auditory Input ◽  
Distortion Product ◽  
Brainstem Response ◽  
Temporal Bones ◽  
The Relationship

Tinnitus is one of the predicted perceptual consequences of cochlear synaptopathy, a type of age-, noise-, or drug-induced auditory damage that has been demonstrated in animal models to cause homeostatic changes in central auditory gain. Although synaptopathy has been observed in human temporal bones, assessment of this condition in living humans is limited to indirect non-invasive measures such as the auditory brainstem response (ABR). In animal models, synaptopathy is associated with a reduction in ABR wave I amplitude at suprathreshold stimulus levels. Several human studies have explored the relationship between wave I amplitude and tinnitus, with conflicting results. This study investigates the hypothesis that reduced peripheral auditory input due to synaptic/neuronal loss is associated with tinnitus. ABR wave I amplitude data from 193 individuals (43 with tinnitus (22%), 150 without tinnitus (78%)), who participated in up to three out of four different studies, were included in a logistic regression analysis to estimate the relationship between wave I amplitude and tinnitus at a variety of stimulus levels and frequencies. Statistical adjustment for sex and distortion product otoacoustic emissions was included in the analysis. The results suggest that smaller ABR wave I amplitudes are associated with an increased probability of reporting tinnitus.

scholarly journals PromBERA: A preoperative eABR: An update

2018 ◽  
Vol 4 (1) ◽  
pp. 563-565 ◽  
Author(s):  
Daniel Polterauer ◽  
Maike Neuling ◽  
Joachim Müller ◽  
John-Martin Hempel ◽  
Giacomo Mandruzzato ◽  
...  
Keyword(s):  
Cochlear Implantation ◽  
Auditory Nerve ◽  
Round Window ◽  
Electrode Array ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Speech Comprehension ◽  
Testing Procedures ◽  
Brainstem Response ◽  
Round Window Niche

AbstractPrior to cochlear implantation, audiological tests are performed to determine candidacy in subjects with a hearing loss. This is usually done by measuring the acoustic auditory brainstem response (ABR). Unfortunately, for some subjects, a reproducible ABR recording cannot be obtained, even at high acoustic levels. Having a healthy stimulating auditory nerve is required for cochlear implantation in order to benefit from the electrical pulses that are generated by the implant and to improve speech comprehension. In some subjects, this prerequisite cannot be measured using routine audiological tests. In this study, the feasibility of recording electrically evoked auditory brainstem responses (eABR) using a stimulating transtympanic electrode, placed on the round window niche, together with MED-EL clinical system is investigated. The results show that it is possible to record reproducible eABR measurements using PromBERA. The response was also confirmed with intraoperative eABR measurements that were stimulated using the implanted CI electrode array. Similarities between the intraoperative measurements and the preoperative recorded waveforms were observed. In summary, the integrity and excitability of the auditory nerve can be objectively measured using the PromBERA in subjects where standard clinical testing procedures are unable to provide the information required.

Diffusion Tensor Imaging of Auditory Pathway in Patients With Crigler-Najjar Syndrome Type I: Correlation With Auditory Brainstem Response

2021 ◽  
pp. 088307382110258
Author(s):  
Ahmed Abdel Khalek Abdel Razek ◽  
Mohamed Ezz El Regal ◽  
Mortada El-Shabrawi ◽  
Mohamed Moustafa Abdeltawwab ◽  
Ahmed Megahed ◽  
...  
Keyword(s):  
Diffusion Tensor Imaging ◽  
Inferior Colliculus ◽  
Cochlear Nucleus ◽  
Auditory Brainstem Response ◽  
Diffusion Tensor ◽  
Auditory Brainstem ◽  
Type I ◽  
Syndrome Type ◽  
Brainstem Response ◽  
Olivary Nucleus

Aim: To evaluate the role of diffusion tensor imaging of the auditory pathway in patients with Crigler Najjar syndrome type I and its relation to auditory brainstem response. Methods: Prospective study was done including 12 patients with Crigler Najjar syndrome type I and 10 age- and sex-matched controls that underwent diffusion tensor imaging of brain. Mean diffusivity and fractional anisotropy at 4 regions of the brain and brainstem on each side were measured and correlated with the results of auditory brainstem response for patients. Results: There was significantly higher mean diffusivity of cochlear nucleus, superior olivary nucleus, inferior colliculus, and auditory cortex of patients versus controls on both sides for all regions ( P = .001). The fractional anisotropy of cochlear nucleus, superior olivary nucleus, inferior colliculus, and auditory cortex of patients versus controls was significantly lower, with P values of, respectively, .001, .001, .003, and .001 on the right side and .001, .001, .003, and .001 on left side, respectively. Also, a negative correlation was found between the maximum bilirubin level and fractional anisotropy of the left superior olivary nucleus and inferior colliculus of both sides. A positive correlation was found between the mean diffusivity and auditory brainstem response wave latency of the right inferior colliculus and left cochlear nucleus. The fractional anisotropy and auditory brainstem response wave latency of the right superior olivary nucleus, left cochlear nucleus, and inferior colliculus of both sides were negatively correlated. Conclusion: Diffusion tensor imaging can detect microstructural changes in the auditory pathway in Crigler Najjar syndrome type I that can be correlated with auditory brainstem response.

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