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Results for “Auditory Threshold”

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PubMedDate not supplied

Characterization of the effects of N-hydroxy-IDPN on the auditory, vestibular, and olfactory systems in rats.

The mechanism of neurotoxicity of 3,3'-iminodipropionitrile (IDPN) has been widely debated, with either the parent compound or putative metabolites implicated in various studies. The N-hydroxylated form of IDPN (HO-IDPN) has been reported to cause the excitation with choreiform and circling (ECC) syndrome in rats at doses approximately one-eighth of that required to cause comparable signs in rats treated with IDPN. Because of the similarity of symptoms induced by HO-IDPN and IDPN, we investigated the effect of HO-IDPN on other aspects of the nervous system affected by IDPN, specifically the auditory, vestibular, and olfactory systems. In addition, ECC symptoms were quantified to replicate the previous findings. HO-IDPN was administered ip in saline for 3 consecutive days to two different cohorts of young adult male Sprague-Dawley rats. The first cohort (60, 80, 100, and 120 mg/kg; n = 2/group, except for the 120 mg/kg group, where n = 1) was used in a dose range-finding study. After making the neurobehavioral assessments, animals were sacrificed for olfactory mucosal histopathology. Based on the outcome of the first study, the second cohort (n = 10/group) received saline or HO-IDPN at 100 mg/kg/day for 3 consecutive days. Two animals from each of these groups were sacrificed for olfactory mucosal histopathology; the remaining animals were tested for neurobehavioral effects 3 weeks after the last dose. Animals in the second cohort lost approximately 8% of their pretreatment body weight. All rats receiving the 100 mg/kg/day dose of HO-IDPN (and the rat receiving 120 mg/kg/day) developed the ECC syndrome and signs of vestibular dysfunction within 4 days after the last dose. HO-IDPN caused a large decrease in the acoustic startle response and markedly elevated auditory thresholds at all frequencies tested. The threshold for the ECC syndrome and olfactory mucosal damage was 100 mg/kg. These studies extend previous findings on the neurotoxicity of HO-IDPN and point to the need for determining whether HO-IDPN is an in vivo metabolite of IDPN.

Animals↗

PubMed1994

Role of congenital hypothyroidism in hearing loss in children.

No significant difference was found for the auditory thresholds at conversational and high frequencies between 42 children with congenital hypothyroidism treated with L-thyroxine and an age-matched control group, regardless of the cause of the thyroid failure or hormone level and the age at the start of treatment.

Adolescent↗

PubMed2006

Mitigation of hearing loss from semi-circular canal transection in pseudomonas otitis media with ciprofloxacin-dexamethasone irrigation.

HYPOTHESIS: Irrigation of the mastoid with a quinolone antibiotic-steroid solution may mitigate hearing loss caused by iatrogenic semicircular canal injury in the presence of Pseudomonas aeruginosa (PA) otitis media (OM). BACKGROUND: Studies have shown the cochlea to be more vulnerable to semicircular canal transection (SCT)-related hearing loss in the presence of PA OM. Prophylactic systemic antibiotics and steroids may decrease this hearing loss, but SCT is usually not planned. The aim of this study was to determine if irrigation with ciprofloxacin-dexamethasone (cipro-dex) could improve hearing outcomes following SCT in PA OM. METHODS: PA OM was induced in 28 animals. After three to five days, unilateral SCT was performed in each animal, with sham SCT on the contralateral ear. At surgery, half of the animals (n = 14) underwent irrigation of the both mastoid bullae with cipro-dex; the second group of animals (n = 14) underwent irrigation of the bullae with sterile saline. Auditory thresholds were obtained immediately prior to SCT and 7-10 days after SCT. RESULTS: SCT ears treated with cipro-dex showed a mean click threshold improvement of 4.6 dB from pre-transection to 7-10 days post-transection, whereas thresholds in the SCT ears treated with saline worsened by 7.5 dB (p = 0.15). CONCLUSION: Irrigation of the guinea pig bulla with cipro-dex following SCT in the setting of PA OM appears safe and may yield beneficial effects on hearing.

Animals↗

PubMed2001

[Parameters of high-frequency audiometry in patients with vocal defects, vascular diseases or exposed to noise, radiation].

High-frequency audiometry was performed in 100 patients with vascular diseases, vocal defects, exposed to noise or radiation. In normal hearing these patients had in normal frequency range elevated auditory thresholds for higher-frequency tones. The strongest abnormalities were registered in patients with vocal problems and Chernobyl wreckers. Examination of hearing in wide range of frequencies in patients with vocal problems can detect subclinical hearing defects and help in assessment of vocal defects severity and in issues of occupational expertise.

Adolescent↗

PubMed2005

Long-term habituation of the startle response in mice evoked by acoustic and tactile stimuli.

The present study shows that repetitive presentation of tactile and acoustic stimuli evoke long-term habituation (LTH) of the startle response in C57BL/6J mice. This was indicated by a decrease in response strength over several days. For the LTH of the acoustic startle response two controls were included: first, developing hearing loss during the time of testing did not account for the startle decrease--only 7 days of acoustic stimulation but not 7 days of adaptation led to a decrease in the startle. Second, repetitive presentation of loud acoustic startle stimuli did not raise the auditory threshold, which might otherwise have accounted for the startle decrease: prepulse inhibition (used here as a hearing test) was identical after both 7 days of acoustic startle stimulation and 7 days without stimulation. This proves that LTH to tactile and acoustic stimuli is present and fully functional in mice.

Animals↗

PubMed1997

[Suppression of tinnitus by band noise masker--a study of 600 cases].

We performed Band Noise Masker (BNM) therapy for the suppression of tinnitus in 600 patients and measured the pitch, loudness and masking level of tinnitus and residual inhibition (RI). We examined the efficiency of BNM therapy. The purpose of this study was to investigate the mechanism of suppression of tinnitus by BNM. Tinnitus was suppressed in 394 patients (66%) after BNM therapy. In the group of patients in whom we suppressed tinnitus, the loudness of tinnitus was reduced from 7.7 +/- 5.7dBSL to 7.5 +/- 5.5dBSL (p < 0.05) and the pitch of tinnitus did not exhibit a marked change. In the group of patients in whom we did not suppress tinnitus, the loudness and pitch of tinnitus did not exhibit a marked change. The efficiency of BNM therapy was high in the cases of presbyacusis and low in the cases of sudden deafness. There was no significant relationship between RI and the efficiency of BNM therapy. We examined these data and discussed the mechanism of suppression of tinnitus by BNM therapy. In all cases, after BNM therapy, the auditory threshold did not become worse. In 4 cases tinnitus became worse temporarily. In conclusion, BNM therapy is an effective mode for tinnitus control, is easily performed in our outpatient clinic or at home, and has no serious complications.

Adolescent↗

PubMed1990

Auditory sensitivity and tone-sequence reproduction in oral contraceptive users and nonusers.

In two stages spanning a single academic year, 10 women using oral contraceptives and 11 not using oral contraceptives were tested on their auditory threshold sensitivity to six frequencies (250, 750, 1500, 3000, 6000, and 8000 Hz) as a function of phases of the menstrual cycle. 11 women (5 users and 6 nonusers) were also tested on their ability to reproduce successively longer tone sequences. Results showed that there was little variation due to phase of the menstrual cycle, with the exception that oral contraceptive users showed lower relative thresholds at low frequencies during the postmenstrual phase. Over-all, oral contraceptive users had higher absolute and relative thresholds than nonusers, except at 3000 Hz. Although not statistically significant, results on the tone-reproduction test showed an enhanced ability to reproduce tones during the premenstrual phase for women using oral contraceptives. Results are discussed in relation to previous findings.

Adult↗

PubMed1978

Methadone maintenance: an assessment of potential fluctuations in behavior between doses.

Thirty methadone maintenance outpatients were measured 1 and 25 hours after ingestion of methadone on auditory threshold, distance perception, simple and differential reaction time, time perception, attention span, and short-term memory. The results revealed a small but statistically significant difference between the two tests for distance perception. In addition, treatment interacted with preparatory interval on differential reaction time and with sex on attention span.

Adolescent↗

PubMed2000

Heparin-induced extracorporal low-density-lipoprotein precipitation (H.E.L.P.) to improve the recovery of hearing in patients with sudden idiopathic hearing loss.

The pathogenesis of sudden hearing loss (SHL) is still not well understood. Possible causes include increased blood viscosity, microthrombosis or altered blood flow. Hypercholesterolemia, hyperfibrinogenemia and increased platelet aggregation are frequently observed in patients with SHL. The aim of this study was to investigate whether drastic lowering of plasma cholesterol and fibrinogen by selective extracorporal apheresis could have a beneficial effect on hearing recovery in these patients. Seven patients with SHL were treated with an extracorporal procedure removing fibrinogen and cholesterol from plasma. Six of the seven patients showed an immediate improvement in auditory thresholds following a single treatment of heparin-induced low-density lipoprotein precipitation. These findings indicate for the first time that acute and drastic removal of plasma fibrinogen and low-density lipoproteins may be an effective clinical method for the treatment of patients with SHL.

Adult↗

PubMedDate not supplied

[Comparative bioacoustical study of diurnal and nocturanl rodents from closed ranges].

Studies have been made on the evoked potentials at the level of the colliculus inferior in the nocturnal rodent Glis glis and diuranl one--Eutamias sibiricus. In G. glis, the evoked potentials were recorded in a wide range of sonic and ultrasonic frequencies up to 90 kc, while in E. sibiricus these potentials were recorded in a range of frequencies up to 60 kc. The auditory threshold curves for G. glis exhibited two areas of minimum thresholds-- a low frequency area and an area at a boundary between sonic and ultrasonic frequencies. Threshold curves for E. sibiricus have no clear sensitivity maximum. In G. glis, correlation between the spectrum of their communication signals and acoustic noise in the habitat was observed. The species investigated differ in the rate of the recovery of the evoked potentials to paired stimuli and in the values of critical summation time.

Acoustic Stimulation↗

PubMed1997

[Hypercholesteremia and hyperfibrinogenemia in sudden deafness].

BACKGROUND: The pathogenesis of sudden hearing loss has not been elucidated as yet. Insufficient perfusion of the cochlea due to an increased blood viscosity, microthrombosis, or altered vasomotion are assumed. Hypercholesterolemia and hyperfibrinogenemia are frequently observed in patients with sudden sensorineural hearing loss. The aim of this study was to investigate the incidence of hypercholesterolemia and hyperfibrinogenemia in patients suffering from sudden hearing loss compared to normal controls. In an intervention study the impact of drastic lowering of plasma cholesterol and fibrinogen by a selective extracorporal apheresis was studied. METHODS: In a case-control study of 23 patients suffering from sudden hearing loss, plasma cholesterol and fibrinogen levels as well as erythrocyte aggregation and plasma viscosity were determined. Seven sudden hearing loss patients from this group were treated with H.E.L.P. apheresis, an extracorporal procedure removing fibrinogen and idl-cholesterol from plasma. RESULTS: Plasma fibrinogen and cholesterol levels were higher in sudden hearing loss patients, leading to significantly elevated values of erythrocyte aggregation and plasmaviscosity. Six out of the seven patients treated with a single H.E.L.P. apheresis immediately showed an improvement of auditory thresholds. CONCLUSIONS: We conclude that hyperfibrinogenemia and hypercholesterolemia may contribute to the clinical event of sudden hearing loss. Our study shows for the first time that acute and drastic removal of plasma fibrinogen and low density lipoproteins can be an effective clinical tool in the treatment of patients with sudden hearing loss.

Adult↗

PubMed1980

Hearing in the elephant (Elephas maximus).

Auditory thresholds were determined for a 7-year-old Indian elephant. The hearing range extended from 17 hertz to 10.5 kilohertz. The results indicate that the inverse relationship between functional interaural distance (that is, the distance between the two ears divided by the speed of sound) and high-frequency hearing limit is valid even for very large mammals.

Animals↗

PubMed1987

Recovery of psychophysical tuning curves following noise exposure.

Psychophysical tuning curves (PTCs) at 2 kHz and auditory thresholds (2 kHz and 4 kHz) were obtained from 18 normal-hearing listeners before and after exposure to a 5-min 110 dB SPL white noise. PTCs were quantified on five dimensions (Q10 tip, Q10 probe, d1oct, tip level and tip frequency). PTCs revealed continued cochlear effects beyond the time when TTS at 2 kHz demonstrated complete recovery.

Adult↗

PubMed1980

A rabbit preparation for neuro-behavioral auditory research.

Auditory thresholds were determined in rabbits by a classically conditioned nicitating membrane response established with a tone-conditioned stimulus and a shock-unconditioned stimulus. The audiograms obtained were comparable in shape and sensitivity to threshold curves measured for a variety of small mammals by other conditioning techniques. This procedure provides a quick and efficient method for measuring hearing sensitivity in a restrained preparation that permits precise stimulus control as well as providing an ideal situation for a variety of physiological studies of hearing in an awake, behaving animal.

Animals↗

PubMed2006

Alpha1-antitrypsin single dose adjuvant therapy for acute otitis media.

OBJECTIVES: Proteases have been shown to play a role in the pathogenesis of otitis media. Inhibition of these proteases can improve treatment outcomes in certain conditions. The goal of this study was to determine if intratympanic administration of a single dose of the protease inhibitor, recombinant alpha 1-antitrypsin (rAAT), can facilitate resolution of acute otitis media (AOM) in the chinchilla. METHODS AND MEASURES: Pneumococcus was injected into both middle ears of 12 chinchillas. After 3 to 4 days, middle ears were cultured, systemic antibiotics were initiated, and rAAT or its vehicle was administered into the middle ears of all animals. Serial tympanic membrane (TM) scoring, tympanometry, and auditory-evoked brain stem response testing were performed. Animals were sacrificed at varying timepoints and temporal bones studied for objective measures of OM. RESULTS: Although not reaching statistical significance, there was a trend to more rapid resolution of AOM in rAAT-treated ears. Tympanometry, auditory thresholds, and quantitative histologic parameters did not differ between rAAT and vehicle treated ears. CONCLUSIONS: A single dose of intratympanic rAAT likely does not facilitate the resolution of antibiotic-treated pneumococcal AOM in the chinchilla model. Serial administration of this protease inhibitor may be necessary to see a significant treatment effect.

Acute Disease↗

PubMed1994

[Diurnal rhythm of physiologic functions in workers exposed to noise].

To reveal the mechanisms of adaptation to occupational factors, the authors screened the workers exposed to noise for changes of pulse rate, blood pressure, catecholamines content, auditory threshold within a day. The study showed that adaptation to unfavorable work conditions deteriorates within a day (from morning to night shifts). Reliability of catecholamines level was conditioned by the night fall of catecholamines level and its changes within a day. Compromised adaptation to chronic unfavorable occupational factors result in unstable catecholamines level. Functional state of hearing is mediated by vegetative state including catecholamines content.

Adaptation, Physiological↗

PubMed1991

cis-platinum ototoxicity in children.

Despite the recognized ototoxicity of cis-platinum, a clinical outline for the audiologic evaluation of patients receiving this drug has not been clearly defined. In a practical approach to this problem, the audiograms of 48 pediatric patients referred for monitoring during planned cis-platinum therapy were reviewed. Eleven patients tested with auditory brain-stem response (ABR) audiometry demonstrated several limitations of this modality. Fourteen children underwent initial ABR testing followed by at least two pure-tone audiograms. The remaining 23 patients had their hearing evaluated by pure-tone audiometry only. Various factors such as patient age, cis-platinum dosage, and cranial radiation exposure were analyzed for apparent effect. Younger patients tended to be more susceptible to audiologic changes with the administration of cis-platinum. The proportion of patients who demonstrated a hearing loss increased with successive dosing as did the severity of the hearing loss. Prior exposure to cranial radiation was strongly linked to the development of hearing loss following cis-platinum therapy. Guidelines are presented regarding the use of clinical audiometry in the screening of these pediatric oncology patients.

Adolescent↗

PubMed1991

Hereditary deafness occurring in cd/1 mice.

Different strains of mice provide a valuable research tool for studying both hereditary and acquired forms of deafness. The cd/1 strain has been found to demonstrate hereditary cochlear pathology. The characteristics of hearing loss in cd/1 mice have not previously been reported. In this investigation auditory thresholds were obtained by measuring evoked brain stem responses in subjects of three different ages: 3 weeks, 10 weeks and 6 months. The results were compared with thresholds obtained from CBA/Ca mice (which have normal hearing) and C57BL/6 mice (which are known to have a genetically determined pre-senile progressive cochlear hearing loss). A significant hearing loss was observed which progressed from high to low frequencies, and with age. Extensive degeneration was observed throughout the organ of Corti. cd/1 mice may provide a useful model for studying genetically determined deafness.

Age Factors↗