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PubMed1999

Chromosomal localization of a gene responsible for vestibulocochlear defects of BUS/Idr mice: identification as an allele of waltzer.

Mice of the bustling mutant strain BUS/Idr have vestibulocochlear defects. bus/bus homozygotes, but not heterozygotes, are hyperactive and display an abnormal behavior such as circling, head bobbing and head tilting. To characterize BUS mice further, the auditory brain-stem response of the mutant was examined. In +/bus heterozygotes as well as control animals, the auditory brain-stem response was developmentally first recorded as early as 11 days of age and heterozygous and normal adults showed typical auditory brain-stem responses with five peaks in a threshold of 40-45 dB SPL. In contrast, bus/bus homozygotes showed no auditory brain-stem response at any age in response to stimuli up to 130 dB SPL, indicating that they are deaf throughout life. Linkage analysis revealed that the responsible gene, originally designated as bus, maps on chromosome 10, 1.09+/-0.9 cM distal to D10Mit127 and D10Mit59, and 0.72+/-0.51 cM proximal to three markers, D10Mit48, D10Mit112 and D10Mit258, at a site indistinguishable from that of the Albany waltzer, v(A/b). The results of allelism tests between BUS and Albany waltzer indicated that bus is allelic with v(Alb). From these data, we propose here that the bus mutation could represent another allele of waltzer, now designated v(bus).

Alleles↗
PubMed1999

D-Methionine protects against cisplatin damage to the stria vascularis.

D-Methionine (D-met) protects against cisplatin (CDDP)-induced hearing loss and outer hair cell loss (Campbell et al., 1996). However, D-met's protective effects on the stria vascularis has not been previously investigated. The purpose of this study was to examine, using semi-quantitative analysis, whether D-met also protects the stria vascularis. We removed a basal turn section of the stria vascularis from five groups of five male Wistar rats each: (1) a CDDP-treated control group receiving a 30 min i.p. infusion of 16 mg/kg CDDP, (2) a saline-injected control group receiving an equivalent volume of saline, and (3) three groups injected with either 75, 150, or 300 mg/kg D-methionine (D-met) i.p. 30 min prior to receiving the 16 mg/kg CDDP dosing. Using transmission electron microscopy and light microscopy, we analyzed strial volume (i.e. edema), marginal cell damage classification (bulging and/or compression), and relative optical density (ROD) ratios (i.e. depletion of marginal cell cytoplasmic organelles). All three levels of D-met provided complete protection against marginal cell bulging and/or compression but only partial protection against strial edema. At 300 mg/kg, D-met significantly reduced ROD ratio degradation in the spiral prominence and middle stria vascularis regions. In Reissner's membrane region, values from the D-met pretreated group were not significantly different from either the treated or untreated control groups suggesting only partial protection for that area. Protection of marginal cell cytoplasmic organelles was also noted. In summary, D-met partially or fully protects the stria vascularis from several types of CDDP-induced damage.

Animals↗
PubMed1992

Endolymphatic hydrops induced by noise exposure.

In animal with cochlear deafness induced by firecracker explosion, fibrous degeneration of the endolymphatic sac was observed 4 months after the disappearance of Preyer's reflex. Endolymphatic hydrops induced by noise exposure may develop as the results of degeneration of the endolymphatic sac due to cochlear deafness by acoustic trauma after the lapse of a long period of time.

Animals↗
PubMed1998

Cochlear otosclerosis 30 years after stapedectomy confirmed by CT, MRI.

A 64-year-old Japanese male patient, status post-stapedectomy, presented with progressive, bilateral SNHL of 30 years' duration. CT showed extensive demineralization of the otic capsule, suggestive of otospongiotic change in both ears. There were no hyperostotic lesions found, which would have been suggestive of otosclerotic change. MRI showed a morphologically intact membranous labyrinth in both ears, with no obstruction of the cochlear lumen. It was concluded that the patient has progressive otospongiotic change of the otic capsule, but no otosclerotic change.

Calcification, Physiologic↗
PubMed1998

X-linked deafness with stapes gusher in females.

A 22-year-old woman presented with severe mixed hearing loss and a flow of cerebrospinal fluid in the middle ear during stapes surgery (stapes gusher). HRCT of the temporal bones showed characteristic abnormalities of the inner ear (bulbous dilatation of the lateral portion of the internal acoustic meatus with incomplete separation from the cochlea, and widening of the first part of the facial nerve canal) described in X-linked progressive mixed deafness with stapes gusher. The evaluation of the patient's family revealed a sister with the same clinical history and identical HRCT findings, and 11 normal male relatives. This is the first report with typical findings of this entity that affects only female members of a family, suggesting another type of inheritance.

Adult↗
PubMed2002

Application of simulated annealing for estimating BAEPs in endocochlear pathologies.

In this paper, we propose a new approach aimed at handling the temporal Brainstem Auditory Evoked Potentials (BAEPs) non-stationarity. It is pointed out that for some endocochlear pathologies, BAEPs could be randomly delayed from one response to another. This non-stationarity leads to smoothed BAEPs when applying ensemble averaging or any other technique based on BAEPs stationarity. In that case, waves identification is very difficult, sometimes impossible. The problem consists in estimating time delays. Knowing the distribution of delays allows subsequent study of the dynamic of the cochlea and, perhaps, identification of the nature of its pathology. The approach suggested in this paper is based on Simulated Annealing, used to minimize a non-linear criterion involving delays. This technique is advantageously compared to the non-corrected ensemble averaging method, using a set of simulated data based on a realistic model. As an illustration, results based on real signals recorded from two patients are presented and discussed at the end of the paper.

Aged↗
PubMed2005

[Distribution of neurotological findings in patients with cochleovestibular dysfunction].

UNLABELLED: The relationship between spatial body positioning and environment comes from perfect corporal balance. The three most important systems responsible for this relationship are: the optic system (sight), the proprioceptive system, and the labyrinthine system. STUDY DESIGN: Retrospective clinical. A retrospective study conducted on 3,701 patients of a private otolaryngologic clinic, in Jundiaí - São Paulo - Brazil, who underwent vestibular and cochlear labyrinthine function testing, from 1979 to 2004. AIM: To determinate the syndromic distribution occurred at that population and to correlate its relationship with sex, age, symptomatology, as well as otological, clinical and electronystagmographic findings and which were the most frequent medical specialties who asked for this investigation. RESULTS: There was found in the studied population a major prevalence on females (1.75:1). Seventy-nine percent of the patients were from 20 to 59 years old, therefore including people in labor age, with a major prevalence of peripheral syndromes, but there was no a preferential age or sex group among the different syndromes. This study also demonstrated that some otoneurological symptoms were common to all kind of otoneurological syndromes, in opposition to the data found in the world literature. Tinnitus, hearing loss, nausea and vomit as well as harmonic alterations on clinical examination were found with more frequency on peripheral syndrome and no harmonic on central syndromes, according to the reviewed literature. CONCLUSIONS: The study conclusions were able to show that the majority of the patients started their investigation with either otolaryngologists or neurologists and 36% of the patients had peripheral syndrome with almost 25% that had normal evaluation.

Adolescent↗
PubMed1990

Cochlear otosclerosis: statistical analysis of relationship of spiral ligament hyalinization to hearing loss.

This paper presents an analysis of the relationship of the amount of hyalinization of the spiral ligament, secondary to cochlear otosclerosis (spongiosis), to the amount of hearing loss. This relationship was previously studied by Parahy and Linthicum. It was found that the larger the amount of hyalinization, the greater the hearing loss. This hyalinization is a measure of the amount of toxic enzymes being excreted into the inner ear fluid. These enzymes are suspected to affect the metabolic function of the hair cells.

Aged↗
PubMed1991

Perilymph fistula--a diagnostic dilemma.

A retrospective series is presented of 51 cases operated on for suspected perilymph fistula. In 26 ears a fistula was identified at surgery. A positive fistula test was found to strongly indicate a perilymph fistula but was more often negative than positive in surgically demonstrated fistula ears. Other vestibular tests were found to be of little value in the pre-operative diagnosis. Ears with a surgically demonstrated fistula and sensorineural hearing loss had either flat or downward-sloping audiograms. Difficulties in diagnosing a perilymph fistula at tympanotomy are discussed. At follow-up, vestibular symptoms were found to be eliminated or improved in 96 per cent of cases with surgically demonstrated fistulae and in 68 per cent of cases in which no fistula was detected at tympanotomy but hearing improved significantly in only one ear (4 per cent) of the former group and in five ears (20 per cent) of the latter group.

Adolescent↗
PubMed1991

Cochlear fistula found in a naturally healed tympanic cavity.

A cochlear fistula found in a naturally healed mastoid cavity is reported. The patient is a 53-year-old Japanese woman who was complaining of unsteadiness. She had a long history of otorrhoea in childhood. Her tympanic and mastoid cavities were widely open and were covered by thin epithelium. The posterior wall of the ear canal was missing. She had no hearing in the ear but responded to electrical promontory testing. Exploratory surgery was indicated at which fistulae of the basal turn of the cochlea and the horizontal semicircular canal were found. These fistulae were sealed by pieces of bone and muscle.

Cochlea↗
PubMed1992

Speech in noise: a practical test procedure.

A simple and effective speech in noise test is described with clinical findings for patients with normal hearing, cochlear and retrocochlear pathologies and auditory dysacusis. The test utilizes material readily available in Audiology and ENT Departments. It was possible to obtain useful diagnostic information in patients who complain of hearing loss, but who demonstrate normal audiometric thresholds and normal speech in quiet discrimination.

Adolescent↗
PubMed1999

On the relationships of high-frequency hearing loss and cochlear pathology to the acoustic startle response (ASR) and prepulse inhibition of the ASR in the BXD recombinant inbred series.

The measurement of the acoustic startle response (ASR) and prepulse inhibition (PPI) of the ASR in many inbred strains of mice, including C57BL/6 and DBA/2, may be complicated by age-related high-frequency hearing loss (HFHL) and the associated cochlear pathology. Willott and Erway (1998) have recently reported on the age-related changes of the acoustic brain response in the BXD recombinant inbred (RI) series. Based on these data, the RI series was divided into three groups: juvenile-, intermediate-, and adult-onset HFHL. Each of these groups was tested using paradigms which varied the frequency or intensity of the auditory startle and prepulse stimuli. The results obtained in adolescent mice (6-8 weeks) demonstrate that ASR performance is independent of HFHL; there was no group-dependent decline in the ASR amplitudes for high-frequency stimuli. The expected effect of HFHL on PPI is to increase the salience of the still-audible tones. In response to a white-noise prepulse stimulus, the PPI in the juvenile-onset group (which shows marked HFHL at 6 weeks) was similar to that in the adult-onset group. However, when the prepulse stimulus was a pure tone, the juvenile group showed a decrease in salience across all frequencies tested (5-20 kHz). The data point out the need for carefully constructing auditory tasks in the BXD RI series, to avoid the confounding effects of HFHL.

Acoustic Stimulation↗
PubMed1990

Acoustic reflex thresholds in normal and cochlear-impaired ears: effects of no-response rates on 90th percentiles in a large sample.

Ninetieth percentile cutoffs for acoustic reflex thresholds (ARTs) were determined for a sample of 2,748 ears of 1,374 subjects with normal hearing and sensorineural loss of cochlear origin. All subjects had measurable hearing (less than or equal to 110 dB HL, ANSI-1969) at all three activator frequencies (500, 1000, and 2000 Hz). Cutoff values including "no responses" ("absent" reflexes at 125 dB HL) were higher than those excluding no responses when hearing losses were greater than about 55 dB. The 90th percentiles including the effects of no responses identified ears with retrocochlear involvement for hearing losses as great as about 756 dB. For greater hearing losses at the activator frequency, the no-response rate for both cochlear and retrocochlear cases is too high to enable them to be differentiated by acoustic reflex thresholds. The 90th percentiles are derived at each activator frequency collapsed across ears. It is therefore necessary to determine the probabilities that normal or cochlear-impaired ears will have one, two, or three frequencies at which the ARTs exceed their respective 90th percentiles. It was found that among normal and cochlear-impaired ears, 12.2% have one ART elevated above the 90th percentile, but only 5.6% have two or three elevated ARTs. Clinical implications are discussed.

Adult↗
PubMed1998

Transient otoacoustic emissions in children with chronic renal failure.

This study was conducted on 34 children with chronic renal failure: 27 on regular haemodialysis and seven on conservative treatment. Twenty normal healthy children served as controls. They were subjected to clinical examination including otoscopic examination, basic audiological assessment and transient otoacoustic emission testing (TOAE). Four patients had a conductive hearing loss and five had a bilateral moderately severe high frequency sensory neural hearing loss. TOAE testing was carried out for the rest whose ears displayed normal hearing. No response (fail) was obtained in 8% of them but in none of the controls and a partial pass response in 38% versus 10% of controls (P < 0.001). Cochlear dysfunction was significant only at low frequency levels. The mean overall echo-level and reproducibility were significantly lower in patients than in controls. The same holds true for the subgroup of patients on haemodialysis but not for those on conservative treatment. The overall echo-levels did not correlate with serum urea, creatinine, sodium or potassium.

Acoustic Impedance Tests↗
PubMed2003

Inner ear morphology in a bilaterally deaf Dogo Argentino pup.

Two bilaterally deaf and three unilaterally deaf pups were identified from a litter of 10 Dogo Argentino pups presented for hearing evaluation by electrophysiological investigation. One pup, a bilaterally deaf female aged 43 days, was available for histopathology. Examination of both inner ears revealed bilateral cochlear degeneration with atrophy of the stria vascularis, collapse of the cochlear duct, degeneration of the organ of Corti, and abnormal tectorial membrane. The left vestibule, including the sacculus, was normal. The spiral and vestibular ganglia were essentially normal. This is the first histopathological description of lesions associated with deafness in a Dogo Argentino, but abnormalities were similar to those previously described in deaf Dalmatian pups and in other white hair-coated breeds. The defect was classified as a cochleosaccular degeneration. It was probably congenital and genetic causes were suspected.

Animals↗
PubMed2002

[Cochlear and vestibular risk at high altitude].

Exposure to lowered oxygen pressure at high altitude results in various physiological reactions. The most important response besides hyperventilation is the elevation of the oxygen transport capacity, which simply is achieved by plasma diuresis. Hemoconcentration however not only increases oxygen uptake but also raises blood viscosity, serum osmolality and impairs blood flow. Various observations have suggested that hearing and postural properties deteriorate under these conditions at high altitude. Studies in hypobaric chambers and our own data indicate that the elevated hematocrit levels and hypoxemia may impair the central nervous system functions, resulting in altered speech discrimination, directional hearing, and postural control. However, there is no evidence that cochlear and vestibular sensory cells are affected, whether by acute hypoxia, nor by elevated hematocrit levels up to 58 %. Even an greater increase in serum osmolality or an impaired osmoregulation may not interfere with the outer hair cell function resulting in threshold shift and hearing loss.

Altitude Sickness↗