PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ACOUSTIC TRAUMA”

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 55 records · Page 3Linked to original sources
PubMed1987

Local vs systemic effects of acoustic trauma on cochlear structure and transport.

Whether certain effects of acoustic trauma on cochlear structure and function were due to local or systemic agents was investigated in the chinchilla. After unilateral ossicular disarticulation, the animals were given a noise exposure known to cause cochlear damage and vessel transport changes in the stria vascularis. The cochleas with disarticulated ossicular chains received an effective exposure well below one that causes pathologic damage. Only the cochleas with intact ossicular chains showed an increase in the permeability of the strial vessels to horseradish peroxidase tracer and manifested strial edema and organ of Corti damage. These results indicate that the effects of acoustic trauma on cochlear structure and strial vessel transport are induced locally, not systemically. In addition, the minimum time of exposure to 120-dB, 700- to 2800-Hz noise that causes massive cochlear damage in the chinchilla was shown to be between five and ten minutes.

Animals↗
PubMed1990

Influence of acoustic deprivation on recovery of hair cells after acoustic trauma.

The purpose of this study was to investigate how the recovery of the cochlea, after acoustic trauma, might be influenced by acoustic stimulation or deprivation. In anaesthetized adult chinchillas, both ears were simultaneously exposed to a traumatizing acoustic stimulus (2 kHz tone, at 117 dB SPL for 15 min). Probe microphones positioned in both bullae were used to ensure identical exposure to the two ears; this was important because the experiment relies on within-animal controls. Cochlear action potential thresholds across frequency (CAP audiograms) were used to verify the similarity of threshold shifts to the two ears. Immediately following, a unilateral ossiculectomy was performed which resulted in one cochlea being acoustically deprived during the recovery period, whilst the other was not. In groups of animals with recovery periods of 1, 3, 6, and 12 weeks, both the acoustically deprived and the normally stimulated cochleas were examined with scanning electron microscopy. To quantify hair cell damage, we used a damage scale based on stereociliar integrity; for each cochlea, a standard region 5.5-8.5 mm from the apex was studied in detail. We found that after acoustic trauma, hair cell damage to the cochlea which is deprived of sound during the recovery period, is significantly greater compared with that in the normally stimulated, contra-lateral cochlea. Our results suggest that mechanical activation of the inner ear acts to inhibit long-term degenerative processes, or influence repair of partially damaged hair cells.

Action Potentials↗
PubMedDate not supplied

Rapid recovery from acoustic trauma: chicken soup, potato knish, or drug interaction?

OBJECTIVES: To describe the phenomenology and consider possible mechanisms mediating rapid and unexpected recovery from acoustic trauma after ingestion of a food substance (potato knish). STUDY DESIGN: Single subject with repeated test measures. SETTING: Regional Veteran's Administration Medical Center, tertiary care medical center. METHODS: Pure-tone audiometry and distortion product otoacoustic emissions (DPOAEs) performed at 6 days, 21 days, and 1 year postexposure. RESULTS: Medical treatment with corticosteriods and a diuretic alone failed to improve auditory function and related symptoms (tinnitus and aural fullness) over a 2-week period. Rapid recovery of auditory function (dramatic improvement in pure tone thresholds; reappearance of DPOAEs) and abatement of related symptoms directly followed physiologic reactions from ingesting a food substance. CONCLUSIONS: Rapid recovery from acoustic trauma was temporally correlated with urodynamic and cardiovascular reactions from ingesting food containing sulfite preservative, a substance to which the individual was allergic. Factors that may have contributed to recovery of function include massive diuresis, increased heart rate, release of biochemical mediators, mediator-induced vasodilatation, and changes in vascular or cell membrane permeability. Establishing relationships that lead to recovery of function from acoustic trauma may facilitate research and aid in the development of new treatment options for this condition.

Anaphylaxis↗
PubMed1996

[Acoustic trauma and development of endolymphatic hydrops among the personnel in the self defense forces].

An investigation was carried out among the military personnel in the Self Defense Forces to assess acoustic trauma in association with the onset of endolymphatic hydrops (ELH). Four hundred seventy servicemen were offered general physical examinations in an inpatient setting prior to their discharge from the SDF for mandatory age retirement. A questionnaire on the history of intense acoustic exposure and of dizzy spells was given to the same individuals. A routine ENT examination and audiography were performed for each of them. The following results were noteworthy: five men had a history of Ménière's disease, and 32.5 percent of those questioned had experienced dizzy spells. Hearing thresholds in those who reported that they had had dizzy spells were considerably higher than those who had not had such spells. Although a quantitative analysis as well as a well-established control study seems necessary to implicate acoustic trauma as one of the etiological factors of ELH, this study strongly suggests a relationship between acoustic trauma and development of ELH among the SDF personnel examined.

Endolymphatic Hydrops↗
PubMed1979

Binaural hearing spectacles with "no mould" by acoustic trauma.

Patients with selective hearing loss in the trebles, as commonly seen in acoustic trauma, often have a considerable hearing handicap. They seldom benefit from the usual hearing aids with closed ear moulds. When Ewertsen (1970) and Cortois (1972) reported their experiences with binaural fitting of hearing spectacles, using a free plastic tube in the ear canal ("no mould"), we at the Hearing Centre in Namsos began to fit such hearing aids to 33 patients with acoustic traumas. All of them were followed-up in February--March 1978. The results have been evaluated on the basis of answers from the patients entered on questionnaires, and speech audiometry in open field, monosyllable, with 60 dB wide-band background noise. 27 patients (80%) stated that they were greatly satisfied, and 7 (20%) well satisfied. The average daily use was 4 1/2 hrs. All of the patients emphasized the great benefit obtained with the hearing aid at conferences, meetings, social occasions, etc. The average hearing gain was 13 dB. Among those who had discrimination loss there was an average gain of 30% .

Adult↗
PubMed1998

Effect of hyperbaric oxygen therapy in comparison to conventional or placebo therapy or no treatment in idiopathic sudden hearing loss, acoustic trauma, noise-induced hearing loss and tinnitus. A literature survey.

With the published clinical data to hand on the therapeutic results of patients with idiopathic sudden hearing loss, acoustic trauma or noise-induced hearing loss, it may be confirmed that 65% of those polypragmatically treated patients demonstrated a hearing improvement of 19 +/- 4 dB. In 35% of the cases, no hearing improvement was detected independent of the drugs administered. This corresponds to the results obtained from placebo-treated patients who demonstrated a hearing improvement of 20 +/- 2 dB in 61% of cases and no hearing gain in 39% of cases (fig. 1). A different set of results was obtained from patients with a hearing loss who were treated either with prednisolone or placebo. The percentage of patients who achieved normal hearing again in the placebo-treated group amounted to 31% and 38% and in the verum-treated group 50% and 78%. It may be concluded that a placebo therapy is equally effective to that of all nonsteroidal drugs. Problems arise when comparing non-treated patients since information on spontaneous remission rates differs greatly in the references, i.e. between 25-68% for spontaneous full remissions and 47-89% for spontaneous partial remissions. From a statistical view, 35% and 39% of patients experienced no success with nonsteroidal drugs or placebo, respectively. These patients can still be helped with HBO therapy. 18 patients only underwent primary HBO therapy. In all other 50 studies evaluated here with a total of 4, 109 patients suffering from idiopathic sudden hearing loss, acoustic trauma or noise-induced hearing loss and/or tinnitus, HBO therapy was administered as a secondary therapy, i.e. following unsuccessful conventional therapy. If the onset of affliction was more than 2 weeks but no longer than 6 weeks, one half of the cases showed a marked hearing gain (in at least 3 frequencies of more than 20 dB), one-third showed a moderate improvement (10-20 dB) and 13% showed no hearing improvement at all (fig. 2). 4% no longer experienced tinnitus, 81.3% observed an intensity decrease and 1.2% an intensity increase of their tinnitus condition. 13.5% remained unchanged (fig. 2). If HBO therapy was administered at a later stage, but still within 3 months following onset of affliction, 13% showed a definite improvement in hearing, 25% a moderate improvement and 62% no improvement at all. 7% no longer suffered from tinnitus, 44% reported an intensity decrease, a similar percentage noticed no change and 5% a temporary deterioration of their tinnitus condition. If the onset of affliction was longer than 3 months up to several years, no hearing improvement can be expected in the majority of patients (fig. 3); however, one third of the cases reported an intensity decrease of tinnitus, 60-62% reported no change and 4-7% noticed a temporary intensity increase (fig. 4). In conclusion, it may be deduced that HBO therapy is recommended and warranted in those patients with idiopathic sudden deafness, acoustic trauma or noise-induced hearing loss within 3 months after onset of disorder.

Clinical Trials as Topic↗
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↗
PubMed2004

Protective effect of carnosine on excitable structures of the auditory apparatus in albino rats with acute acoustic trauma.

We studied the effect of natural antioxidant carnosine on Wistar rats with experimental acoustic trauma of the auditory apparatus. Repeated intraperitoneal injection of carnosine in a dose of 200 mg/kg 12 and 0.5 h before modeling of acute acoustic trauma decreased the severity of degenerative and atrophic changes in the nuclei of hair cells in the cochleae. Carnosine compensated the deficiency of tissue antioxidant systems and suppressed generation of lipid peroxidation products in tissues of the membranous cochlea and auditory cortex of the temporal lobes. Carnosine holds much promise as a nonspecific otoprotector.

Animals↗
PubMed1999

[Instructor in the army and fortifications guard--risk occupations for acute acoustic trauma and for wearing a hearing aid].

In the Swiss army instructors and fortifications guards are exposed to firearms' noise which harms the ear. It was investigated whether the decline in the cases of acute acoustic traumas in non-professional soldiers serving in the army from 1987 to 1996 also was detectable in army instructors and fortifications guards (professional soldiers) and whether these persons were wearing hearing aids (as an indicator of hearing loss) more often than the average of the male Swiss population. First, we analyzed a historical time series of the incidence density of acute acoustic traumas in non-professional soldiers as well as in army instructors and fortifications guards. Second, we compared the prevalence rate of wearing a hearing aid in army instructors and fortifications guards with the male Swiss population. The incidence density for acute acoustic traumas in army instructors and fortifications guards observed over ten years showed no significant change whereas among non-professional soldiers a strong decline (-12% per year) was observed. The prevalence rate of wearing a hearing aid in army instructors and fortifications guards was significantly higher (RR 3.91 [95% CI 3.09-4.96]) than in the male Swiss population. These results suggest increased hearing impairment among army instructors and fortifications guards which is probably due to the high exposure to impulse noise events (occupational disease). It is recommended that these persons be subjected to a compulsory prevention program.

Accidents, Occupational↗
PubMed1993

Reorganization of the chick basilar papilla after acoustic trauma.

The auditory epithelium in birds and mammals consists of a postmitotic population of hair cells and supporting cells. Unlike mammals, birds can regenerate their auditory epithelia after trauma. Recent evidence indicates that supporting cells undergo mitosis after acoustic trauma, suggesting that supporting cells may transdifferentiate into hair cells. The goals of this study were to 1) characterize the responses of hair cells and supporting cells to acoustic trauma, and 2) determine whether hair cell loss is a prerequisite for generation of new hair cells. Chicks were exposed to an octave-band noise and their inner ears assayed with fluorescence or scanning electron microscopy. In one area of the basilar papilla, defined as the center of the lesion, extensive hair cell degeneration occurred. Expanded supporting cells obliterated degenerating hair cells and invaded spaces normally occupied by hair cells. Aggregates of DNA were found within the basilar papilla, suggesting that hair cell death and disintegration may occur within the epithelium. The epithelial sheet appeared structurally confluent at all times examined. Supporting cells exhibited altered apical contour in distal regions of the basilar papilla, where hair cell damage was mild or inconspicuous. Four days after noise exposure, newly generated hair cells were found in the center of the lesion and in the distal areas, where no hair cell loss could be detected. The results suggest that supporting cells may play an important role in maintenance and repair of the traumatized basilar papilla and raise the possibility that production of new hair cells is not dependent on hair cell loss in the immediate vicinity.

Animals↗
PubMedDate not supplied

Regeneration of adult budgerigar's hair cells following acoustic trauma.

The functional and structural changes of hair cells of the adult budgerigar following acoustic trauma were examined using auditory brainstem response (ABR), and both scanning and transmission electron microscopy. Just after exposure to a 1,500-Hz pure tone at 120 dBSPL for 98 h, severe damages and disappearance of short hair cells were observed in the middle region of the basilar papilla. Fourteen days after the exposure, the threshold of ABR recovered to the level before the exposure, and normal short hair cells, which have synapses with nerve endings, were rearranged all over the damaged region of the basilar papilla. These results indicate that the hair cells of the adult budgerigar have capability to regenerate, and to restore the auditory perceptive function following acoustic trauma.

Animals↗
PubMed1993

The effect of endocochlear potential suppression upon susceptibility to acoustic trauma.

In the present study we investigated the influence of decreased endocochlear potential (EP) on acoustic trauma. Guinea pigs with decreased EP following i.v. administration of furosemide (FUR) and normal EP given physiological saline solution (PSS) i.v. instead of FUR were exposed to 2 kHz pure tone ranging from 110 to 130 dB SPL for 5 min. The input-output curves of the compound action potential (CAP) before acoustic overstimulation were compared with those at 2 h after the exposure. In 125 and 130 dB SPL exposure there was no difference in threshold shift between the FUR and PSS groups. In 115 and 120 dB SPL exposure, however, the threshold shift of the FUR group was significantly smaller than that of the PSS group. There was no significant difference between the two groups in 110 dB SPL exposure. These results indicate that the threshold shift of the CAP is mainly due to excessive vibration of the basilar membrane in the greater stimulus groups (125-130 dB SPL) but that the energy exhaustion of the hair cells to a certain extent participates in the threshold shift when the stimulus is milder (115-120 dB SPL). It is concluded that susceptibility to acoustic trauma of a milder intensity (115-120 dB SPL) is reduced when the energy consumption rate of the organ of Corti is decreased by EP suppression.

Acoustic Stimulation↗
PubMed1997

[Treatment results of acoustic trauma].

20 patients aged from 18 to 42 treated in the past few years because of acoustic trauma. Together the investigations concerned 24 years. Therapeutic schema comprised intravenous infusion--Sermion (Nicergoline--amp. a 4 mg) or Cavinton (Vinpocetine--amp. a 10 mg) 1 amp.--twice a day for 10 days. The treatment of 60% of the patients started in the first week after the trauma occurred, of 20% in the second week and the remaining 20% later on after 15 days when the trauma took place. The obtained results of treatment both of improvement of hearing (79.2%) and tinnitus (66.6%), support the necessity of treatment of acoustic trauma independently from the time that passed after trauma had occurred. Better results of audiometric improvement of hearing (54.2%) and tinnitus disappearance (50%) were obtained in the patients whose treatment started in the first week after trauma. The improvement of hearing and tinnitus disappearance was more observed in patients after treatment by using Sermion than Cavinton.

Adolescent↗
PubMed1995

Appearance of free radicals in the guinea pig inner ear after noise-induced acoustic trauma.

The emergence of superoxide anion radicals (O2-) in the guinea pig inner ear following acoustic trauma was investigated by histochemical methods. Five minutes after exposure to sound at 120-125 dB SPL for 3 h, an O2- reaction product was detected in the cochlea along the luminal membrane of the marginal cells of the stria vascularis. This reaction product could not be found at 30 min, but reappeared at 2 h. The first appearance of O2- is not explainable by our studies, but the second appearance may be related to recirculation of strial blood flow after blood flow stasis. The present observations raise the possibility that free radicals are produced in the inner ear after acoustic trauma and lead to inner ear damage.

Animals↗
PubMed2003

Involvement of poly(ADP-ribose) synthetase in acoustic trauma of the cochlea.

We investigated effects of poly(ADP-ribose) synthetase (PARS) inhibitors on acoustic trauma. Albino guinea pigs were intravenously given 3-aminobenzamide, nicotinamide or 3-aminobenzoic acid (an inactive analog of 3-aminobenzamide) just prior to exposure to a 2 kHz pure tone of 120 dB sound pressure level (SPL) for 10 minutes. The threshold of the compound action potential (CAP) and the amplitude of distortion-product otoacoustic emissions (DPOAEs) were measured before and 4 hours after the acoustic overexposure. Statistically significant decreases in the CAP threshold shifts and significant increases in the DPOAE amplitudes were observed 4 hours after the acoustic overexposure in the animals treated with 3-aminobenzamide or nicotinamide, whereas 3-aminobenzoic acid did not exert any protective effect. These results strongly suggest that excessive activation of PARS is involved in generation of the acoustic trauma.

Acoustic Stimulation↗
PubMed1996

The effect of methylprednisolone on acoustic trauma.

The effect of methylprednisolone (mPSL) upon acoustic trauma was studied using albino guinea pigs which were exposed to 2 kHz pure tone of 110, 115 or 120 dB SPL for 10 min. After the exposure to intense sound, mPSL of 6, 12 or 40 mg/kg was intraperitoneally given daily for 7 days and the threshold of the compound action potential (CAP) was examined on the 8th day. Compared with CAP of the control animals given physiological saline solution, no significant difference was observed in the CAP threshold shift between the mPSL group and the controls following exposures to the sound of 115 and 120 dB SPL, respectively. However, when the animals were exposed to the sound of 110 dB SPL, the CAP threshold shift was significantly smaller in the mPSL animals than in the controls. The present results indicate that mPSL possesses a therapeutic effect in cases of mild acoustic overstimulation.

Acoustic Stimulation↗
PubMed2005

Extended high-frequency audiometry in patients with acoustic trauma.

OBJECTIVES: The aim of this study was to examine extended high-frequency (EHF) hearing in patients with acoustic trauma. DESIGN: A prospective, case-control study in a group of soldiers with acoustic trauma caused by shooting practice during basic training. SETTING: Tertiary referral centre. PARTICIPANTS: A total of 39 young soldiers hospitalized for hearing loss and tinnitus following exposure to weapon impulse noise were studied. Conventional audiometry in the frequency range 0.25-8 kHz and EHF audiometry in the frequency range 9-20 kHz were performed, both on admittance and before discharge. Thirty healthy recruits of similar age and sex were used as controls. MAIN OUTCOME MEASURES: Pure-tone threshold changes documented by conventional and EHF audiometry. RESULTS: The most significant differences in pure-tone thresholds on initial testing were found in the frequency range 0.25-11.2 kHz, and especially in the 4-8 kHz region. Reduction in thresholds across most frequencies was observed after treatment, although recovery was partial in most cases. CONCLUSIONS: The EHF audiometry adds no significant additional information to conventional pure-tone audiometry in assessing and monitoring noise-induced hearing loss.

Acoustic Impedance Tests↗