PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “NERVES, ACOUSTIC”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources
PubMed2005

Intraoperative monitoring of the recurrent laryngeal nerve using acoustic, free-run, and evoked electromyography.

The purpose of this study was to explore advantages and disadvantages of electrodes used for monitoring of the recurrent laryngeal nerve (RLN) and to determine the postoperative outcome in 135 patients. A pilot study examined 11 patients to compare the clinical performance of two commercially available recording electrodes and three stimulation electrodes for RLN neuromonitoring. After determining the most reliable and consistent stimulating/recording electrode combination, 124 patients were then monitored. In a total of 135 patients there was no permanent iatrogenic nerve damage to the RLN, although 2 patients developed transient vocal hoarseness that resolved shortly postoperatively. An initial "searching" current for evoked electromyography (EMG) was delivered at 0.7 mA and then decreased to a value of 0.35 mA, which reliably elicited RLN stimulation with a minimal incidence of false-positive results. The combination of auditory feedback from the mechanically elicited EMG and a control channel involving EMG monitoring of an additional peripheral muscle improved the detection of artifact and improved the clinical efficacy of intraoperative electromyography. A video camera showed the surgical manipulation on the EMG screen, allowing the neurophysiologist to correlate dissection with RLN status and location. Auditory responses from the nerve helped to determine the type of distress the RLN was encountering.

Acoustic Stimulation↗
PubMed1995

[The study of factors affecting ABR in high risk newborn infants].

A.B.R. was employed to examine auditory pathways in a group of 78 newborn infants at risk and one of 20 normal infants. The impaired newborn group suffered of various risk factors or pathologies: 20 premature infants, 12 undersize (small for date), 12 with breathing distress, 11 hiv positive, 5 with neonatal jaundice, 4 suffered of convulsion, 4 at risk for hereditary deafness, 4 born by mothers with mellitus diabetes, 2 with dolichocefalia, 1 with the Albers-Schomberg syndrome, 1 with congenital heart disease and 1 with congenital glycogenosis. The results of A.B.R. of the risk group were compared statistically employing the "t Student's test" with those of the group of normal infants. The influence of risk factors in the first group on alterated A.B.R. parameters was then examined using a step-by-step logistic regression analysis method. The result showed a significant increase in a latency of waves V and III and inter-waves I-V and III-V in risk infants, while wave I and I-III internals were normal. These findings appear to demonstrate that in infants at risk, brainstem acoustic pathways are more sensitive to damage than the cochlea and acoustic nerve. This could be explained by the different degree of maturation that exists between the central acoustic pathways and the coclea and acoustic nerve. Analysis of the influence of pathologies and risk factors on A.B.R. indicate that birth weight followed by chronological age and length of the gestation period are significant in the development of A.B.R. alterations. The Albers-Schomberg syndrome, dolicocephalia, microcephalia, congenital glicogenosys, hiv infection, breathing difficulty and neonatal jaundice proved to be the main pathologies responsible for bringing about A.B.R. alterations.

Auditory Pathways↗
PubMed1990

Factors influencing the preservation of the facial nerve during acoustic surgery.

We reviewed the last 30 acoustic neuromas excised in our department and attempted to find out the factors associated with preservation of the facial and cochlear nerves. While the size of the tumour was the most important factor, vascularity and consistency were both important. Facial and cochlear nerves were preserved in 63% and 10% of the patients respectively. The importance of early diagnosis cannot be overemphasized.

Adult↗
PubMed1981

Ultrastructure of capillaries in acoustic neurilemmoma.

The microvasculature of normal acoustic nerve tissue and small intracanalicular and large extracanalicular neurilemmomas was analyzed by electron microscopy. The capillaries of normal acoustic nerve were nonfenestrated, but the microvasculature in nerve-sheath neoplasms was fenestrated. Hypertrophy and hyperplasia of endothelial cells were observed only in the small lesions. The proliferated and enlarge endothelial cells often partially occluded the vascular lumen and formed multichannel vascular lumina. Many fenestrae of capillaries were found in small neoplasms, but these were rarely identified in the large extracanalicular lesions. The gap junctions of endothelium in small nerve-sheath neoplasms were long, wavy, and convoluted, had no openings, and differed from those of large lesions in which the tight junctions were short, straight, and occasionally patent. Additionally, heavy vascularization and erythrocytes within basement membranes were observed only in large neurilemmomas. These ultrastructural features may constitute a basis for differences between large and small acoustic neurilemmomas noted in cerebrospinal fluid findings.

Capillaries↗
PubMed2001

[Evaluation of sensorineural hearing loss in childhood].

OBJECTIVE: To explore the clinical and audiological characteristics of sensorineural hearing loss (SHL) with pathological changes both in cochlea and retrocochlear in children and evaluate the relationship between SHL and the lesions in the central nervous system (CNS). METHODS: Three hundred and ten cases (500 ears) of SHL accepted between 1998 and 2000 were studied. The age of patients was ranged from 1 month to 6 years old. According to the evaluation of function of CNS by pediatric neurologist, all cases were divided into two groups: SHL with CNS disease and SHL without CNS disease. Some same age children without hearing loss were subjected as control group. All children were tested using both auditory brainstem responses (ABR) and distortion product otoacoustic emissions (DPOAE). RESULTS: 1. The rate of SHL accompanied with CNS diseases was very high in these children. 2. Patients with kernicterus-cerebral palsy usually had serious hearing loss caused by acoustic nerve lesion at retrocochlear, but their cochlea function was injured slightly. Patients with external hydrocephalus had only slight acoustic nerve lesion at retrocochlear, and patients with other CNS diseases usually had no change for their cochlea function. 3. In the group of SHL caused by cochlea lesion, amplitudes of DPOAE decreased obviously when the threshold of wave V of ABR was up to 60 dB nHL, and amplitudes of DPOAE seriously decreased or disappeared when the threshold of wave V was up to above 70 dB nHL. CONCLUSION: The patients with SHL are usually accompanied with CNS diseases in childhood, and their hearing loss appears very difference from audiological characteristics. We suggest that it is necessary to test both ABR and DPOAE in these patients, and it is important that pediatric neurologist join in audiologist team for our clinical study.

Brain Edema↗
PubMed1979

[Audiovestibular exploration of the brain stem (author's transl)].

In the context of a postgraduate lecture for specialist physicians, the author describes techniques of objective audiology used on a daily basis in the exploration of the brain stem in the ENT department of Lariboisiere Hospital. The following are reviewed for each of them: --the corresponding anatomical pathways, --the principles and techniques used. The results are illustrated by examples. Increase in the threshold of stapes acoustic reflex above 95 dB on a frequency of 1,000 Hz is highly suggestive of acoustic nerve involvement or the lower part of the brain stem (bar sign). By contrast, the threshold is normal in endocochlear and supratentorial disorders. Comparison of abnormalities in stapes acoustic reflex in ipsi and contralateral stimulation, and in particular analysis of changes in their dynamics, often makes it possible to localise the problem to the acoustic nerve, the facial nerve or the brain stem itself. Recording of brain stem evoked auditory potentials (BERA), combined if necessary with that of the electro-cochleogram, is a delicate technique. This is the most useful and most precise audiological tool available to make a precise diagnosis of acoustic neuroma and to localise brain stem disease.

Acoustic Impedance Tests↗
PubMed1987

[Magnetic resonance tomography in acoustic neurinomas].

The possibilities of MR and CT were compared in respect of neurinomas of the acoustic nerve (n. acusticus). The comparison showed that MR detection of tumours in the posterior of the cranial cavity is the more sensitive method, especially in respect of neurinomas of the acoustic nerve, although CT enables the use of the small-level technique with or without the addition of a contrast substance, as well as the application of pneumocisternography. The sensitivity of MR can be increased further by adding a contrast medium. Whereas in diagnosis of extrameatal neurinomas of the n. acusticus, CT and MR are of equal value, MR shows substantial advantages over CT in the diagnosis of intrameatal tumours (without enlargement of the inner ear canal). The same holds true for very small tumours of up to 1 mm diameter, the visualisation of which is greatly facilitated by the multidimensional possibilities of MR and by the administration of a contrast medium.

Cerebellopontine Angle↗
PubMed1989

Neurofibromatosis type 1 with bilateral acoustic neuromas.

A patient diagnosed as having neurofibromatosis type 1 (NF-1) on the basis of 6 café-au-lait macules, multiple subcutaneous neurofibromas and 1 Lisch nodule is described. He later was found to have bilateral acoustic nerve tumors plus multiple intracranial meningiomas. This patient is one of a few adequately described cases who clinically meets diagnostic criteria for NF-1 and has bilateral acoustic nerve tumors.

Adult↗
PubMed1997

Neurotoxicity testing of a new bioactive bone cement.

Bioactive bone cement (BABC) is a novel artificial bone cement. It has some noteworthy characteristics that are applicable to neurological surgery. The toxicity of BABC to the nervous system was tested by implanting BABC and polymethylmethacrylate (PMMA) cement as a control at the parietal and the suboccipital regions of the skull in beagles. The auditory brainstem response (ABR) was tested before and after implantation. Sections of the cerebral cortex and the acoustic nerve were examined at 3 and 6 months after implantation. No abnormal ABR was found in any animals. Histological examination of the cerebral cortex and acoustic nerve demonstrated slight gliosis in both the BABC and PMMA cement groups, but no other abnormalities.

Animals↗
PubMed1985

[Radiologic diagnosis of acoustic neurinoma. Apropos of 130 patients].

Diagnostic value of radiologic examinations was assessed in a homogeneous series of 130 cases of neurinoma of acoustic nerve seen over the last 10 years. Radiologic exploration is conceived and used at the present time for two purposes. Firstly, it enables selection of patients with suspected acoustic nerve neurinoma. Radiotomography appears to be currently an accessory examination because of the discriminative performance of early auditory evoked potentials tests on the brain stem. Secondly, radiology is necessary for confirmation of diagnosis. Visualization of the tumoral syndrome can be obtained only by a scan or possibly opaque or gas meatocisternography.

Brain Stem↗
PubMed2001

[Removal of large acoustic neuroma via suboccipito-retrosigmoid approach with microsurgical technique].

OBJECTIVE: To probe the treatment effects of large acoustic neuroma (LAN) via a suboccipito-retrosigmoid microsurgical operation. METHODS: 216 patients with LAN in the cerebellar pons angle were confirmed by CT or MRI in our department. Each tumor (diameter > or = 31 mm) was removed via a suboccipito-retrosigmoid microsurgical approach. Treatment results were evaluated and the preoperative and postoperative function of the acoustic nerve or the facial nerve was compared separately. RESULTS: The tumors were totally removed in 172 patients(79.6%), subtotally removed in 33 (15.3%), and partially removed in 11 (5.1%). Anatomic preservation of the acoustic nerve was achieved in 27 patients (12.5%), and functional preservation in 9 patients (Grade A, 4.2%) at discharge. Anatomic preservation of the facial nerve was achieved in 178 patients (82.4%) and functional preservation in 94 (House Grade, Grade I - II, 52.8%) at discharge. Follow-up observation (Median: 3.9 years) of 187 patients revealed good recovery in 128 patients (68.4%), fair recovery in 44 (23.5%), and poor recovery in 15 (8.0%). Late recurrence was noted in those with poor recovery (10 patients, 5.4%) (cured by second treatment). CONCLUSIONS: It is a safe and effective way to remove LAN via suboccipito-retrosigmoid approach with microsurgical technique.

Adult↗
PubMed1994

Cell division in the gerbil cochlea after acoustic trauma.

The recent discovery of hair cell regeneration in the avian inner ear raises the possibility that hair cell regeneration might occur in the mammalian cochlea as well. The authors used 3H-thymidine labeling to detect mitotic activity in the cochleas of normal 3-week old gerbils exposed to acoustic trauma. Following an acoustic insult that caused progressively more severe damage in an apical to basal progression, 3H-thymidine was injected for 5 days. Control animals were not exposed to the acoustic insult. The gerbils' cochleas were sectioned and processed for autoradiography. In the control cochleas, there were extremely rare labeled cells in the stria, the spiral ligament, and the glial cells around the acoustic nerve fibers. In the damaged cochleas, no evidence of hair cell regeneration or of any cell division within the normal sensory epithelial structures was seen. Three labeled cells were seen in intercellular spaces within the sensory epithelium; they appeared to be macrophages. Frequent cell division was seen in numerous other regions of the damaged cochleas and among glial cells adjacent to the acoustic nerve fibers. It is concluded that there is no evidence for hair cell regeneration following acoustic trauma in the gerbil, but acoustic trauma does induce cell division in numerous other areas of the cochlea.

Animals↗