Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cochlear Diseases”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 487 records · Page 27Linked to original sources
PubMed2005

Auditory neuropathy or endocochlear hearing loss?

AIMS: The purpose of the study was to define boundaries between endocochlear hearing loss and auditory neuropathy in children with congenital profound hearing loss and positive otoacoustic emissions. PATIENT: A child presented with bilateral profound hearing loss, which was confirmed by the absence of evoked auditory potentials at 110 dB and with conserved otoacoustic emissions. The lack of any relevant medical history, a normal neurologic pediatric examination, and the improvement obtained with powerful hearing aids suggested an endocochlear cause. Genetic testing identified mutations in OTOF, responsible for the DFNB9 recessive form of hearing loss. RESULTS: In recent years, cases of children with hearing loss associated with positive otoacoustic emissions have been labeled as "auditory neuropathy." Classically, this form of hearing loss is refractory to the use of hearing aids and cochlear implants. Mutations in OTOF lead to inner hair cells dysfunction, whereas the outer hair cells are initially functionally preserved. As this form of endocochlear hearing loss can be detected at a molecular level, genetic testing can be proposed for cases of nonsyndromic auditory neuropathy, as those children could benefit from cochlear implantation. CONCLUSION: It is advisable to reserve the term "auditory neuropathy" for patients who present hearing loss and conserved otoacoustic emissions in the context of a neurologic syndrome or for children with suggestive perinatal history. In other cases, genetic testing for mutations in OTOF should be carried out.

Child, Preschool↗
PubMed2005

Vestibular deterioration precedes hearing deterioration in the P51S COCH mutation (DFNA9): an analysis in 74 mutation carriers.

OBJECTIVES: To analyze cochleovestibular impairment features in P51S COCH mutation carriers (n = 22) in a new, large Dutch family and to compare the results to those obtained in previously identified similar mutation carriers (n = 52). To evaluate age-related features between progressive hearing and vestibular impairment of all mutation carriers (n = 74). STUDY DESIGN: Family study. METHODS: Regression analysis was performed in relation to age to outline the development of hearing thresholds, speech recognition scores, and vestibulo-ocular reflex time constant as the key vestibular response parameter. RESULTS: Pure tone thresholds, phoneme recognition scores, and vestibular responses of the mutation carriers in the new family were essentially similar to those previously established in all other mutation carriers. Hearing started to deteriorate in all mutation carriers from 43 years of age onwards, whereas deterioration of vestibular function started from age 34. CONCLUSION: Vestibular impairment starts earlier, progresses more rapidly, and, eventually, is more complete than hearing impairment in P51S COCH mutation carriers.

Adult↗
PubMed2005

Audiometric, vestibular, and genetic aspects of a DFNA9 family with a G88E COCH mutation.

OBJECTIVES: To perform genetic analysis and to analyze cochleovestibular impairment features in a newly identified Dutch family with nonsyndromic autosomal dominant hearing impairment (DFNA9). STUDY DESIGN: Genetic analysis was performed using microsatellite markers and single nucleotide polymorphisms. Audiometric data were collected and analyzed longitudinally. Results were compared with those obtained in previously identified P51S COCH mutation carriers (n = 74). Special attention was also given to a comparison of age-related features such as progressive hearing loss and vestibular impairment. SETTING: Tertiary referral center. PATIENTS: G88E COCH mutation carriers from a Dutch family. MAIN OUTCOME MEASURES: The study of clinical features of a DFNA9 family carrying a G88E COCH mutation and to compare this to the symptoms of those carrying a P51S/COCH mutation. RESULTS: Pure-tone thresholds, phoneme recognition scores, and vestibular responses of the G88E mutation carriers were essentially similar to those previously established in the P51S mutation carriers. Hearing started to deteriorate in G88E mutation carriers from age 46 to 49 years and onward, whereas deterioration of vestibular function started from approximately age 46 years. In the P51S mutation carriers, vestibular impairment started earlier, at approximately age 34 years. However, the difference in age of onset with the G88E mutation carriers was not significant. Remarkably, the proportion of patients who developed complete vestibular areflexia within the age range of 40 to 56 years was significantly lower for the G88E mutation carriers than for the P51S mutation carriers. CONCLUSION: Apart from a significantly lower frequency of vestibular areflexia between the ages of 40 and 56 years, there are no phenotypic differences between carriers of the G88E and P51S mutations in the COCH gene.

Adult↗
PubMed2007

Intracochlear hemorrhage after gamma knife radiosurgery.

PURPOSE: To describe an acute complication after gamma knife stereotactic radiosurgery (GKRS) for vestibular schwannoma (VS) in a neurofibromatosis type 2 (NF2) patient. STUDY DESIGN: Case report. SETTING: Tertiary care center. PATIENT: A 20-year-old man, who had bilateral VS and was having right-sided profound deafness, underwent GKRS for a 2-cm left-sided VS in an attempt to preserve his only hearing ear. He received a margin dose of 13 Gy to the 50% isodose line. Twenty-four hours after treatment, he presented with spinning vertigo, left-sided dead ear, and ipsilateral mild facial paralysis (House-Brackmann grade 3). RESULTS: Magnetic resonance imaging demonstrated an intracochlear hemorrhage at the level of the basal turn of the left cochlea. Hearing did not recover, and the patient had to resort to lip reading. The facial paralysis regressed completely after 3 months. CONCLUSION: Many cases of hemorrhage caused by GKRS have previously been reported, but all were related to meningiomas or brain metastases. Because the patient had no coagulation defect, sign of trauma, or any history of infection, the hemorrhage might have been caused by a direct thermal effect on the endothelial cells or to an immediate tumoral swelling, inducing an increase in intravascular outflow resistance and leading to venous obliteration. To our knowledge, this is the first report of acute intracochlear hemorrhage after GKRS for VS.

Adult↗
PubMed2005

Prospective clinical study on cochlear function after erbium:yttrium-aluminum-garnet laser stapedotomy.

OBJECTIVE: To assess whether the application of the emitting erbium:yttrium-aluminum-garnet (Er:YAG) laser in stapedotomy has negative effects on vestibular and cochlear functions. DESIGN: Prospective, with 12 to 14 months follow-up. SETTING: Academic tertiary referral center. PATIENTS: Twenty-four patients undergoing stapedotomy (primary surgery) in otosclerosis. INTERVENTION: All patients underwent Er:YAG laser-assisted stapedotomy for otosclerosis between January 2000 and June 2002. MAIN OUTCOME MEASURES: Early (1-3 days after surgery) and late (12-14 months after surgery) postoperative bone-conduction thresholds and the presence of post-operative tinnitus and vertigo were analyzed. In addition, the relation between applied laser energy and postoperative bone-conduction thresholds was calculated. RESULTS: In 22 patients, unchanged preoperative minus early postoperative pure-tone bone-conduction averages at 1, 2, and 4 kHz were observed. In one patient, a slight early deterioration between 10 and 20 dB was seen. In 18 patients, unchanged preoperative minus late postoperative pure-tone bone-conduction averages at 1, 2, and 4 kHz were observed. In two patients, a slight late deterioration between 10 and 20 dB was seen. In two patients, a new postoperative tinnitus was observed. No patient suffered from vertigo at the time of second evaluation. No correlation between applied laser energy and both postoperative bone-conduction thresholds was found. CONCLUSIONS: The Er:YAG laser stapedotomy in otosclerosis is a safe technique. Vestibular and cochlear function is not significantly disturbed after Er:YAG laser stapedotomy.

Adult↗
PubMed2006

Cochlear preservation after meningitis: an animal model confirmation of adjunctive steroid therapy.

OBJECTIVE/HYPOTHESIS: The objective of the present study was to determine whether treating pneumococcal meningitis with a combined antibiotic and steroid regime will prevent cochlear damage, a common pneumococcal meningitis side effect. STUDY DESIGN: This was a prospective animal study. METHODS: Gerbils were randomly assigned to three experimental groups. Animals in group 1, the control animals, received intrathecal saline injections. Animals in groups 2 and 3 received intrathecal injections of Streptococcus pneumoniae to induce meningitis. Although group 2 solely was treated for 7 days with intraperitoneal penicillin injections (48,0000 units), group 3 received, in addition to the antibiotic for 4 days, 0.5 mg/kg intraperitoneal dexamethasone injections. Three months after the meningitis was induced, the animals' cochlear function was determined using auditory brainstem responses (ABRs). Fifteen frequencies were tested, five octaves at three steps per octave between 2 and 50 kHz. RESULTS: ABR thresholds were significantly elevated only in group 2. When compared with group 1, ABR thresholds were 19 dB higher (P<.05). Frequencies at the low-frequency end of the hearing range were affected more than the midfrequencies. Animals that received dexamethasone had 2-dB higher thresholds than the control group (P>.05). CONCLUSIONS: Dexamethasone therapy in conjunction with antibiotic therapy preserves cochlear function in cases of S. pneumoniae meningitis in the Mongolian gerbil model.

Adrenal Cortex Hormones↗
PubMed2006

Cochlear protection by local insulin-like growth factor-1 application using biodegradable hydrogel.

OBJECTIVE: The aim of this experimental study was to examine the potential of local recombinant human insulin-like growth factor-1 (rhIGF-1) application through a biodegradable hydrogel for the treatment of cochleae. METHODS: A hydrogel immersed with rhIGF-1 was placed on the round window membrane of Sprague-Dawley rats while a hydrogel immersed with physiological saline was applied to control animals. On day 3 after drug application, the animals were exposed to white noise at 120 dB sound pressure level (SPL) for 2 hours. Cochlear function was monitored using measurements of auditory brain stem responses (ABRs) at frequencies of 8, 16, and 32 kHz. The temporal bones were collected 7 or 30 days after noise exposure and the loss of hair cells was quantitatively analyzed. RESULTS: Local rhIGF-1 treatment significantly reduced the elevation of ABR thresholds on days 7 and 30 after noise exposure. Histologic analysis revealed that local rhIGF-1 treatment significantly prohibited the loss of outer hair cells. CONCLUSIONS: These findings demonstrate that local IGF-1 application through the biodegradable hydrogel has the potential for protection of cochleae from noise trauma.

Administration, Topical↗
PubMed2006

Human cochleae with three turns: an unreported malformation.

OBJECTIVE: The objective of this histologic study of archival temporal bone sections was to describe the morphology of human cochleae found with three turns, a previously unreported anomaly, found in three pairs of temporal bones. METHODS: The authors conducted histopathologic processing and measurement of basilar membrane length. Basilar membrane length was compared with that found in six normal control bones. RESULTS: Cochleae with three complete turns, rather than the usual two and a half turns, are described for the first time. All had longer than normal basilar membranes, with a mean length of 40.6 mm compared with a mean of 33.8 mm in the normal bones. CONCLUSIONS: Human cochleae with three turns exist as an unreported anomaly. This is a new category of anomaly, not likely based on interruption of development.

Aged↗
PubMed2006

Auditory brainstem implant in a child with severely ossified cochlea.

OBJECTIVE: The hearing outcome after implanting a severely ossified cochlea has always been less satisfactory than implanting a patent one. The aim of our study is to present a case where brainstem implantation was successfully performed as an alternative to cochlear implantation in a child with bilateral severe ossification of the cochlea. STUDY DESIGN: Case presentation. This study was conducted at Gruppo Otologico, Rome, Italy, a private referral center for neurotology and skull base surgery. METHODS: The subject of our study was a 12-year-old female child with postmeningitic deafness and bilaterally ossified cochleae. This case is the first brainstem implantation performed at our center with the indication of severe ossification of the cochlea. RESULTS: Successful brainstem implantation of a device was carried out, and the hearing of the patient was restored to the degree that she can freely use the telephone after 8 months of implantation. CONCLUSION: Although more cases are needed before establishing the exact outcome of brainstem implantation in cases of deafness in the presence of severe bilateral cochlear ossification, preliminary results show the superiority of brainstem implants to conventional or even customized cochlear implants.

Auditory Brain Stem Implants↗
PubMed2004

A novel animal model of acute cochlear mitochondrial dysfunction.

Acute mitochondrial dysfunction in the cochlea is likely to result in hearing loss as a consequence of local energy shortage, similar to ischemia- or noise-induced hearing loss. To establish an animal model of acute cochlear mitochondrial dysfunction, we applied a mitochondrial toxin, 3-nitropropionic acid (3-NP) in the rat cochlea. Rats treated with 500mM 3-NP exhibited permanent threshold shifts in acoustic brainstem response while the same volume of 300mM 3-NP caused temporary threshold shifts. Histological examination in the permanent threshold shift model revealed severe degeneration of fibrocytes within spiral ligament and spiral limbus, indicating these cells are vulnerable to acute mitochondrial dysfunction. This model represents a novel tool for investigating the pathophysiology of acute cochlear mitochondrial dysfunction.

Animals↗
PubMed2006

Enhanced cochlear acoustic sensitivity and susceptibility to endotoxin are induced by adrenalectomy and reversed by corticosterone supplementation in rat.

Glucocorticoid receptors are widely distributed in the cochlea but their role remains poorly known. Previous studies provided contradictory reports on a possible cochlear acoustic hypersensitivity induced by adrenal insufficiency, while several experiments agree on a significant action of glucocorticoid receptors in adverse conditions such as acoustic trauma and restraint stress. The present experiments confirmed a cochlear acoustic hypersensitivity induced by adrenalectomy and reversed by corticosterone supplementation. These observations point to a significant role of corticosteroids in basal cochlear functioning. The glucocorticoids are known to be essential for limiting and resolving inflammatory processes. The endotoxin Escherichia coli lipopolysaccharide is widely used to induce inflammatory reactions. However, in various organs several toxic processes of this endotoxin are not influenced by glucocorticoids. From previous experiments on the cochlea there is no evidence that glucocorticoids are an essential factor against endotoxin cochlear toxicity. In the present experiments it was found that adrenalectomy greatly increased the cochlear susceptibility to endotoxin; the effect was reversed by providing corticosterone supplementation. This shows the essential role of corticosterone in this cochlear inflammation model. In previous studies local administration (at the cochlear base) of endotoxin was used and losses of cochlear acoustic sensitivity were found predominantly at high frequencies; in contrast, the systemic injection used in this study produced a cochlear loss of acoustic sensitivity at all frequencies, indicating a uniform cochlear sensitivity to the toxic effects of endotoxin.

Acoustic Stimulation↗
PubMed1997

Two-tone rate suppression boundaries of cochlear ganglion neurons in chickens following acoustic trauma.

The purpose of the present study was to examine the effects of acoustic trauma and hair cell loss and regeneration on the two-tone rate suppression (TTRS) boundaries of cochlear ganglion neurons in chickens. Chickens were exposed for 48 hours to a 525-Hz, 120-dB SPL tone which destroyed the hair cells and tectorial membrane in a crescent-shaped patch along the abneural side of the basilar papilla. Afterwards, TTRS boundaries were recorded from cochlear ganglion neurons at 0-1, 5, 14, and 28 days postexposure. Acoustic trauma reduced the percentage of neurons with TTRS boundaries below CF (TTRSb) (52.6% to 8.2%) and above CF (TTRSa) (88.4% to 46.6%). In addition, the exposure reduced TTRS boundary slopes, elevated best suppression threshold (BST), and increased the frequency separation between the tips of the TTRS boundaries and CF. All the TTRS measures started to recover by 5 days postexposure and by 14 days and 28 days postexposure, most measures had recovered to normal levels. However, the BST, TTRS slopes, and the frequency separation of TTRSb boundaries from CF were still slightly abnormal near the exposure frequency. In addition, the percentage of neurons with TTRS below CF was reduced significantly. The partial recovery of TTRS boundaries is presumably due to the regeneration of hair cells and the lower honeycomb layer of the tectorial membrane. The residual TTRS deficits observed 28 days postexposure were most closely associated with the missing upper fibrous layer of the tectorial membrane.

Animals↗
PubMed1997

Characterizing cochlear mechano-electric transduction in ears damaged with pure tones.

Cochlear microphonics were recorded in response to Gaussian noise from the round window of Mongolian gerbils. A nonlinear systems identification procedure provided the frequency-domain parameters of a third-order polynomial equation describing cochlear mechano-electric transduction (MET). Exposure to an 8 kHz pure tone at 100 dB SPL for 20 min reduced the magnitude of the linear, quadratic, and cubic terms significantly. Animals exposed to a 1- or 4-kHz pure tone showed changes in the quadratic term. Differentiation of the polynomial equation and algebraic manipulations of the coefficients provided physiologic indices of MET. The sensitivity, saturation voltages, and sound pressures required to saturate MET were altered in animals exposed to an 8-kHz pure tone. Limited changes occurred in animals exposed to a 1- or 4-kHz pure tone.

Animals↗
PubMed2006

Ageing and the auditory system.

There are a number of pathophysiological processes underlying age related changes in the auditory system. The effects of hearing loss can have consequences beyond the immediate loss of hearing, and may have profound effects on the functioning of the person. While a deficit in hearing can be corrected to some degree by a hearing aid, auditory rehabilitation requires much more than simply amplifying external sound. It is important that those dealing with elderly people are aware of all the issues involved in age related hearing loss.

Aged↗
PubMed1996

Sensorineural hearing deficit: a systematic approach based on imaging findings.

Sensorineural hearing loss (SNHL) can be classified audiometrically into two varieties: sensory (cochlear) and neural (retrocochlear). Individuals with sensory SNHL have damage to the "end organ" (the cochlea) at a macroscopic or microscopic level. When present, imaging manifestations may involve the bony labyrinth or membranous labyrinth. Abnormalities of the bony labyrinth are demonstrable primarily with computed tomography and include demineralization, congenital deformities, traumatic lesions, and erosive or destructive lesions. Abnormalities of the membranous labyrinth include enhancement and hemorrhage, which are demonstrable with magnetic resonance (MR) imaging, and obliteration, which may be diagnosed with either modality. Individuals with neural (retrocochlear) SNHL have involvement of the remainder of the auditory pathway exclusive of the cochlea. This type of SNHL requires study of the internal auditory canal, cerebellopontine angle, brain stem, thalamus, and temporal lobe. The entirety of this type of examination is best performed with high-resolution MR imaging in virtually all cases.

Cochlear Diseases↗