Observations on the pathological mechanism of conductive deafness in certain cases of neuroma of the VIII nerve.
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Cochlear Nerve↗
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[Combined intramuscular and intrameningeal streptomycin therapy of tuberculous meningitis, with special reference to its toxic effect upon the eighth cranial nerve].
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Cochlear Nerve↗
[Inner ear physiological function and pathological morphology in the offsprings of sensorineural hearing loss female guinea pigs induced by homogeneous inner ear antigens immunizing].
OBJECTIVE: To explore if the autoimmune of anti-labyrinth tissues acts as one of pathogenic cause by observing the inner ear physiological functions and pathological morphology changes of offspring of autoimmune sensorineural hearing loss (ASHL) female guinea pig. METHODS: The pregnant guinea pigs were immunized with homogeneous inner ear antigens (HIEAg), then, the hearing function were measured with EcochG [inspecting items including acoustic nerve compound action potential (cAP), summation potential (-SP) and cochlear microphone potential (CM)], while the vestibular function were measured with electronystagmography (inspecting items including spontaneous nystagmus and caloric test), inner ear Celloidin section with haematoxylin-eosin dyeing and being inspected under light microscope. The special antibodies in serum and special lymphocyte immune reaction were measured with ELISA and 3H-TdR intermingling lymphocyte transform test in all female guinea pigs and their offspring guinea pigs. RESULTS: In 7 offspring guinea pigs, 3 animals appeared sensorineural hearing loss. Immuno-inflammation pathologic changes happened in the labyrinth (including the number of bipolar cells reduced and some kind of inflammatory cells infiltrated in spiral ganglion and endolymphatic hydrops et al.), and rise of special antibodies against HIEAg in serum. There were no any obvious abnormity found in non-ASHL pregnant and normal contrastive pregnant guinea pigs and their offspring. CONCLUSIONS: In this study, some of ASHL female guinea pig's offspring demonstrated different grades of sensorineural hearing loss and inner ear inflammation, and the special humoral and cellular immune reaction against HIEAg, which could be induced by autoimmune inflammation against inner ear tissues antigens with special antibodies (maybe including special cellular immune reaction) from matrix through placental barrier. This result suggests that the factor of autoimmune against inner ear tissue antigens may be one of pathogenic causes inducing non-heritage congenital sensorineural hearing loss.
Animals↗
On the vestibular labyrinth of Brachiosaurus brancai.
The extensive remains of large sauropods, excavated in the Upper Jurassic layers of the Tendaguru region of Tanzania, East Africa by Janensch [15], include an intact fossil cast of a vestibular labyrinth and an endocast of the large Brachiosaurus brancai. The approximately 150 million year old labyrinth cast demonstrates clearly a form and organisation congruent in detail to those of extant vertebrate species. Besides the near-orthogonal arrangement of semicircular canals (SCCs), the superior and inferior branches of the vestibulo-acoustic nerve, the endolymphatic duct, the oval and round windows, and the cochlea can be identified. The orientation of the labyrinth in the temporal bone is also equivalent to that of many extant vertebrates. Furthermore, the existence of the twelve cranial nerves can be identified from the endocast. The present study was initiated after the photogrammetric measurement of the skeleton volume of B. brancai [13] yielded a realistic estimate of body mass (74.42 metric tons). Dimensional analysis shows that body mass and average SCC dimensions of B. brancai generally fit with the allometric relationship found in previous studies of extant species. However, the anterior SCC is significantly larger than the allometric relationship would predict. This would indicate greater sensitivity, supporting the idea that the behavioural repertoire must have included much slower pitch movements of the head. These slower movements would most likely have involved flexion of the neck, rather than head pitching about the atlas joint. Pursuing the relationship between body mass and SCC dimensions further, the SCC frequency response is estimated by scaling up from the SCC dimensions of the rhesus monkey; this yields a range between 0.008-26 Hz, approximately one octave lower than for humans.
Animals↗
[Predictive value of intraoperative monitoring of brainstem acoustic evoked potentials during removal of parabrainstem tumors].
The data of intraoperative monitoring of brainstem acoustic evoked potentialities (BAEP) during parabrainstem tumors are analyzed. Of the 24 cases, 16 patients were found to have neurinoma of the acoustic nerve, 4 had petroclival meningioma, 2, tentorial meningioma, 1, cholesteatoma of the cerebellopontine angle, and 1, brainstem angioma. The authors proposed to identify the favorable and unfavorable patterns of BAEP as predictors of an early postoperative period, by comparing the patterns of BAEP, the data on the monitoring vital functions and outcomes of disease. The conformity of actual and predictable results was analyzed. By taking into account the high coincidence of actual and predictable outcomes (79.16%), it can be suggested that the data of intraoperative monitoring of BAEP are not only of value for obtaining information at the moment of surgery, but also informative as a predictor of an early postoperative period and outcomes of disease.
Adult↗
[The electromagnetic fields of cellular phones and the health of children and of teenagers (the situation requiring to take an urgent measure)].
The problem of the influence of electromagnetic fields (EMF) of cellular phones (CP) on the health of children and teenagers is considered in this article. The results of the researchs indicate the increased sensitivity of the children and of the teenagers to this kind of radiation. Direct indicators of electromagnetic influence can be infringement of sleep, decrease of the memory, fatigue, breach of a blood-brain barrier permeability, changes in nervous cells of a brain. As the remote consequences the development of tumors of a brain and acoustic nerve are predicted. However all these results require the realization of independent repeated researches. WHO (World Health Organization) recommends to use "Precautionary principle" with the purposes of decreasing of the risk. Russian National Committee of Non-Ionizing Radiation Protection recommended to limit the use of CP by children and teenagers under 16 years old (2002, February 2004). The corresponding recommendations were included into SunPin H2.1.8/2.2.4.1190-03/(2003).
Adolescent↗
Neoplastic trigeminal neuropathy: presentation of 7 cases.
Trigeminal neuropathy of neoplastic origin accounts for a small percentage of trigeminal neuropathies, though the prognosis may be very poor. It is important to discard neoplastic processes in patients with numbness of the trigeminal territory. We present 7 cases of trigeminal neuropathy secondary to tumors: in four cases there were antecedents of systemic neoplastic disease, while in the remaining three cases neuropathy was the first manifestation of the tumor. The lesion was located in the mandible in three cases, in the region of the skull base in one patient, and in the brainstem and brain in one case each. In one case the lesion level could not be identified. The course was very poor in 5 cases. Recovery was only recorded in one patient in whom the symptoms were seen to disappear after acoustic nerve neurinoma resection. The lesions underlying neoplastic trigeminal neuropathy can be located at any point along the trajectory of the trigeminal nerve, and their prognosis is very poor.
Adult↗
[Effects of lumbar epidural anesthesia on brainstem auditory response].
Auditory brainstem responses (ABR) are used increasingly to monitor the integrity of neural pathways in anesthetized patients. To evaluate the effect of epidural anesthesia on the central nervous system, we studied the effects of lumbar epidural anesthesia with lidocaine on the ABR in 10 patients. The seven peak latencies (waves I-VII) and amplitudes (waves I-VII) of the ABR were recorded before and 15 min after epidural anesthesia. Peak latencies of waves III, IV, V, VI, VII increased after epidural anesthesia compared with control values. Amplitude of waves II only decreased significantly following epidural anesthesia compared with control values. We further compared the interpeak latencies to investigate the brainstem transmission. Interpeak latencies (I-II, II-III, III-IV, IV-V, V-VI, VI-VII) were unchanged from the control values except waves VI-VII interval. Interpeak latencies of every second peak (II-IV, IV-VI, V-VII), of every third peak (II-V, III-VI, IV-VII), of every forth peak (I-VI, II-VII), of every fifth peak (I-VII) increased after epidural anesthesia compared with control values. The data obtained in the study demonstrated that lumbar epidural anesthesia with lidocaine prolonged the interpeak latencies of ABR. Considering that the waves of ABR are related to anatomically distinct sites in the auditory pathway (I; Acoustic nerve, II; Cochlear nucleus, III; Superior olivary complex, IV; Lateral lemniscus, V; Inferior colliculus, VI: Medial geniculate body, VII; Auditory radiation), the delay in the latencies of ABR seems to be present in the time intervals which involve more than two or three synaptic transmissions.
Anesthesia, Epidural↗
[The role of cytomegaloviruses in childhood deafness].
The relationship between cytomegalovirus (CMV) and the auditory apparatus is still unclear. The authors examined 120 children from nursery as well as elementary schools for children with hearing defects and, using the complement-fixation method, they determined the CMV antibodies. The result showed a higher quantity of CMV than that found in a group of healthy children. A detailed examination of the auditory functions (of what remained of them) in this group did not eliminate the possibility of CMV effect on the cochlea, acoustic nerve or even on the higher levels of the hearing passage.
Antibodies, Viral↗
[Short latency somatosensory evoked potentials and brainstem auditory evoked potentials in patients with head trauma].
The SSEPs in 115 patients with head trauma were analysed by NT+ W value, da, db and b/a methods. The results revealed that the abnormal rates of the SSEPs were 94.8%. The pathological bases resulting in it were the direct and/or indirect lesion on the somatosensory pathway. The SSEPs recorded six months after the trauma indicated that the electric activities of neurons in some of the patients were still abnormal although they recovered well. The patients complicated with traumatic lesion of acoustic nerve, blood clots in external ear canal and pre-existing hearing loss had abnormal BAEPs that could not be used in diagnosing brainstem lesion. The patients without these complications in whom BAEPs were abnormal had an unfavourable outcome. The SSEPs and BAEPs simultaneously recorded could aid localization of the injury in the brain and enable discovery of the fact that the rigidity after decortication or decerebration is a result of severe injury of the cerebral hemisphere.
Adolescent↗
[Cochlear implants in 1990].
The various techniques of cochlear implantation are described. Implants may be divided into mono- and multi-electrode and into intra- and extra-cochlear. Cochlear implants are indicated only in patients with total or deep bilateral deafness with residual fibres still functioning in the acoustic nerves. Intra-cochlear multi-electrode implants are the most sophisticated ones and usually provide better performances than those observed with mono-electrode implants.
Adult↗
[Otological manifestations of leukemia. Apropos of a clinical case].
The authors describe a clinical case of acute lymphoblastic leukemia, showing major leukemic infiltration of the cochlea and the acoustic nerve. The patient however didn't present any otological symptom. A brief literature review is added (clinical aspects, histopathological aspects ...). The authors stress on performing routine audiometric examinations in leukemia, especially in the acute forms of the disease.
Adult↗
[Epidemiological examinations of the workers at a thermoelectric power station].
Medical and clinico-laboratory examinations were performed of thermoelectric power station (TES) workers who were exposed to the hazardous factors related to the technological process and contamination substances transferred from other industrial sites. Following prepathologic and pathologic states were registered: respiratory functional disorders, ischemic heart disease, arterial hypertension, audiometric state deviations and acoustic nerve neuritis, irritative dermatitis. Basing on the data obtained, risk groups identification was performed.
Absenteeism↗
Meningioma of the internal auditory canal.
The great majority of tumors that arise in the internal auditory canal are schwannomas of the eighth cranial nerve (acoustic neuromas). Meningiomas constitute the second largest group of posterior fossa tumors. Meningiomas arise from arachnoid villae, the apparatus responsible for cerebrospinal fluid absorption, in proximity to a major vein or dural sinus in most cases. Arachnoid villae are also present along neural foramena at the base of the skull. They have been observed histologically in the internal auditory canal (IAC), and are the probable site of origin of meningiomas in this location. Larger cerebellopontine angle meningiomas occasionally possess a significant intracanalicular component; however, these lesions usually originate from the meningeal lining of the posterior petrous face adjacent to the sigmoid, superior petrosal, or inferior petrosal sinuses and prolapse into the IAC. Two meningiomas have recently been observed that extensively involved the IAC, one of which arose from the lining of the IAC. The clinical manifestations of these meningiomas mimicked those of acoustic neuromas. Preoperative radiographic studies, including magnetic resonance imaging, were unable to differentiate these from acoustic neuromas. Meningiomas have a higher rate of recurrence than acoustic neuromas and should be excised with surrounding dura and several millimeters of subjacent bone. Meningiomas that extensively involve the IAC have a tendency to invade the inner ear and the deeper portions of the temporal bone. In meningiomas that involve the lateral portion of the IAC, consideration should be given to exenteration of the cochlea and semicircular canals.
Diagnosis, Differential↗
[Evoked potentials in neurologically asymptomatic persons during the early stages of HIV infection].
There are few reports on the relevance of evoked potentials in neurologically asymptomatic HIV seropositives. We studied 31 HIV infected males without AIDS or associated clinical neurological abnormalities. Visual evoked potentials by foveal checkerboard stimulation revealed a prolonged VEP latency in 37% of them. HIV seropositives with a pathologic VEP latency showed a significant reduction of their absolute numbers of peripheral blood T-helper cells. This increase of the mean VEP-latency was already significant in HIV seropositives with a T-helper cell count greater than 400/microliters. In 47% of the HIV seropositives the AEP peak I latency was prolonged in combination with a significant decrease of the AEP interpeak latency I-V suggesting endocochlear lesions at peripheral endings of the acoustic nerve or at the basal hair cells. HIV seropositives with a T-helper cell count less than 400/microliters revealed a significant prolongation of the mean AEP interpeak latency III-V indicating a central conduction defect in HIV-seropositives with an immune deficit. Somatosensory evoked potentials after median and tibial nerve stimulation were within the normal range. Since the VEP P100 latencies were significantly longer in HIV seropositives with a normal AEP peak I compared to those with prolonged AEP peak I latencies we postulate that there are different pathophysiological mechanisms underlying.
Adult↗
[Spectrum analysis of vestibular nystagmus].
A procedure for the spectral analysis of nystagmograms obtained by rotary stimulation with the rate of 180 degrees/s for 20 s has been developed with the aim to reveal the most typical changes in the vestibular nystagmus with one or another form of the cochleovestibular pathology. A signal recorded in the analogous form was processed by computer EC-1022. Periodograms were calculated by the method of the fast Fourier transform and periodogram smoothing by averaging of realization sites. In case of Ménière's disease the third harmonic was not recorded on periodograms when right and left labyrinths were stimulated and in the case of neurites of acoustic nerves, the third or fifth harmonic was not observed. A supposition is advanced that the third harmonic reflects the state of the peripheral area of the vestibular analyzer, while the fifth harmonic--the central one.
Adolescent↗
Electrophysiological properties of the isolated vestibulocerebellar complex of the frog in vitro.
Parameters of the electrical activity of the isolated vestibulocerebellar complex of the frog were studied under in vitro conditions. In the region of the vestibular nucleus (nc. VIII), in the presence of stimulation of the stato-acoustic nerve (n. VIII), responses from efferent vestibular neurones and from unidentified (probably vestibulospinal) neurones were recorded. The latent periods of their excitatory postsynaptic potentials (EPSPs, 1.4-2.2 ms) were indicative of mono- and disynaptic connection. Inhibitory postsynaptic potentials (IPSPs) were also observed. Stimulation of the auricular lobe of the cerebellum evoked monosynaptic IPSPs, an EPSP-IPSP complex or pure EPSPs in nc. VIII, the latter probably by way of collaterals to the cerebellum. The inhibitory character of the effect of efferents from the cerebellum to the neurones of nc. VIII was demonstrated in the focal synaptic potential and in spontaneous and evoked unit activity. If n. VIII was stimulated, both focal and unit extra- and intracellular responses characteristic of activation of the Purkinje cells by mossy (MF) or climbing (CF) afferent fibres were recorded in the cerebellar cortex. The electrophysiological picture indicates that both synaptic transmission and the functional manifestations of the individual neurones are preserved in the tested preparation.
Animals↗
Central vestibulocochlear pathology: role of MRI and CT.
Hearing loss, tinnitus, dizziness and disequilibrium are frequent complaints of patients with labyrinthine and retrolabyrinthine lesions. The objective of a neurotological examination is to establish the presence and location of a lesion, whether it is labyrinthine (cochlear or vestibular) or intracranial. On the basis of neurotological and vestibular results, provided by neurotologist or otolaryngologist, if a retrocochlear or retrovestibular lesion is suspected, a magnetic resonance imaging (MRI) or computed tomography (CT) study of the head is obtained with particular attention to the acoustic nerve and posterior fossa. MR and CT are exceedingly helpful to identify the extraaxial and intra-axial lesions involving the vestibulocochlear nerves and their central pathways. The appearances on MR and CT scans of varied pathological entities involving the central vestibulocochlear pathways are reviewed and illustrated.
Cochlear Nerve↗