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Hearing Thresholds (hearing + threshold)

Distribution by Scientific Domains

Medical Sciences	84%

Selected Abstracts

Field hearing measurements of the Atlantic sharpnose shark Rhizoprionodon terraenovae

JOURNAL OF FISH BIOLOGY, Issue 10 2009
B. M. Casper
Field measurements of hearing thresholds were obtained from the Atlantic sharpnose shark Rhizoprionodon terraenovae using the auditory evoked potential method (AEP). The fish had most sensitive hearing at 20 Hz, the lowest frequency tested, with decreasing sensitivity at higher frequencies. Hearing thresholds were lower than AEP thresholds previously measured for the nurse shark Ginglymostoma cirratum and yellow stingray Urobatis jamaicensis at frequencies <200 Hz, and similar at 200 Hz and above. Rhizoprionodon terraenovae represents the closest comparison in terms of pelagic lifestyle to the sharks which have been observed in acoustic field attraction experiments. The sound pressure levels that would be equivalent to the particle acceleration thresholds of R. terraenovae were much higher than the sound levels which attracted closely related sharks suggesting a discrepancy between the hearing threshold experiments and the field attraction experiments. [source]

Hearing thresholds in patients affected by rheumatoid arthritis

CLINICAL OTOLARYNGOLOGY, Issue 1 2004
F. Salvinelli
Hearing thresholds in patients affected by rheumatoid arthritis The aim of the study was to evaluate hearing thresholds in 38 patients with rheumatoid arthritis, divided according to disease activity into active (group A, n = 20) and non-active (group B, n = 18) patients. Pure tone audiometry, tympanometry and complete rheumatological assessment were performed. All patients presented poorer auditory thresholds compared with controls. Patients of group A had both air and bone conduction thresholds poorer than group B (although not statistically significant), and most patients of both groups presented an air,bone (a,b) gap. No significant difference in middle ear pressure was noticed between patients and controls. No correlation between hearing impairment and duration of the disease or patients' age was found. The high prevalence of hearing loss in autoimmune diseases supports the importance of audiometric evaluation in such patients. The auditory recovery through middle ear surgery before cranial nerve involvement could be considered in selected patients. Further investigations are needed for a better knowledge of the middle and inner ear involvement in patients with rheumatoid arthritis. [source]

Sensory ecology of prey rustling sounds: acoustical features and their classification by wild Grey Mouse Lemurs

FUNCTIONAL ECOLOGY, Issue 1 2007
H. R. GOERLITZ
Summary 1Predatory mammals and birds from several phylogenetic lineages use prey rustling sounds to detect and locate prey. However, it is not known whether these rustling sounds convey information about the prey, such as its size or profitability, and whether predators use them to classify prey accordingly. 2We recorded rustling sounds of insects in Madagascar walking on natural substrate and show a clear correlation between insect mass and several acoustic parameters. 3In subsequent behavioural experiments in the field, we determined whether nocturnal animals, when foraging for insects, evaluate these parameters to classify their prey. We used field-experienced Grey Mouse Lemurs Microcebus murinus in short-term captivity. Mouse Lemurs are generally regarded as a good model for the most ancestral primate condition. They use multimodal sensorial information to find food (mainly fruit, gum, insect secretions and arthropods) in nightly forest. Acoustic cues play a role in detection of insect prey. 4When presented with two simultaneous playbacks of rustling sounds, lemurs spontaneously chose the one higher above their hearing threshold, i.e. they used the rustling sound's amplitude for classification. We were not able, despite attempts in a reinforced paradigm, to persuade lemurs to use cues other than amplitude, e.g. frequency cues, for prey discrimination. 5Our data suggests that Mouse Lemurs, when foraging for insects, use the mass,amplitude correlation of prey-generated rustling sounds to evaluate the average mass of insects and to guide their foraging decisions. [source]

Auditory-evoked potentials in general anesthesia monitoring: baseline study of availability in relation to hearing function in awake status

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 6 2005
L. De Siena
Background:, It has been confirmed that middle latency auditory-evoked potentials are good indicators of the hypnotic level in patients undergoing general anesthesia. The focal point for the evocation of auditory-evoked potentials is the presence of a serviceable hearing function. The aim of the study was to evaluate the limit of hearing loss above which the test could not be applied. Methods:, To determine the limit of applicability of the technique, 100 subjects were studied. Twenty of them were normally hearing and 80 were affected by sensorineural hearing loss of various degrees. Each subject was submitted to pure tone audiometry, to determine hearing threshold, and then, in awake status, to auditory-evoked potentials recording using acoustic stimuli of 85 dB HL. Results:, All the 20 normally hearing subjects showed a reliable auditory-evoked potentials. Among the 80 subjects affected by hearing loss, only five had no potentials. These five subjects presented a pure tone audiometry threshold greater than 85 dB HL. Conclusion:, The study demonstrated that middle latency auditory-evoked potentials recorded using an A-Line® (software version 1.4) AEP monitor (Danmeter, Odense, Denmark) can be carried out even in presence of hearing loss if the pure tone threshold is less than 85 dB HL. [source]

Tympanoplasty , reporting hearing results and ,hearing objective'

CLINICAL OTOLARYNGOLOGY, Issue 6 2004
P.J.D. Dawes
When reporting the results of tympanoplasty, the postoperative air,bone gap (ABG) presented in 10 dB bins, ABG closure and air conduction threshold gain are commonly reported indicators of tympanoplasty outcome. When tympanoplasty is performed, the reconstruction aims either to improve hearing threshold or to maintain satisfactory thresholds, that is, the surgical intention is either for ,hearing gain' or for ,hearing preservation'. This review of the early results of tympanoplasty examines whether classifying surgery as either for hearing gain or for hearing preservation influences the reported results. Closure of the ABG to within 20 dB was achieved in 72,94% of cases, the average postoperative ABG was between 13.1 and 17.1 dB with the postoperative air conduction threshold being between 27.4 and 33.5 dB. These figures were similar for both hearing preservation and hearing gain procedures. However air conduction threshold gain was significantly greater for the ,hearing gain' group (17 dB versus 0 dB) and was reduced to 8 dB by combining the two groups. Overall, indicating whether surgery attempted hearing preservation or hearing gain did not significantly alter the parameters used for reporting tympanoplasty outcome. [source]

Hearing loss among Ohio farm youth: A comparison to a national sample

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 3 2009
Katherine M. Renick MS
Abstract Background Hearing loss is prevalent among adults in the farming community, with some evidence it begins in childhood. Our objective was to compare hearing thresholds of Ohio farm youth to published data on national norms. Methods Baseline data were collected on youth (n,=,212) in 1994,1996 with follow-up (n,=,132) in 2003,2004 including pure-tone air conduction thresholds at 0.5, 1, 2, 3, 4, 6, and 8 kHz. Results When compared to nationally-representative data, study youth had a higher prevalence of hearing loss. The high-frequency range was most affected, particularly at 6 kHz where nearly 50% of the farm youth exhibited some degree of hearing loss at baseline testing. The prevalence of noise-induced threshold shifts, characterized by an audiometric notch, was nearly twice that of the national sample. Conclusions These data suggest that hearing loss, which is common among adult farmers, may be problematic for farm youth as well. Am. J. Ind. Med. 52:233,239, 2009. © 2008 Wiley-Liss, Inc. [source]

Management of patients with acoustic neuromas: A Markov decision analysis,

THE LARYNGOSCOPE, Issue 4 2010
Daniel Morrison MD
Abstract Objectives/Hypothesis: The management of patients with small (<1.5 cm) acoustic neuromas is controversial. Immediate treatment via microsurgical resection or radiosurgery is often advocated. A period of observation is sometimes advised followed by microsurgery or radiosurgery for tumors that demonstrate growth during the observation period. The purpose of this study is to calculate quality-adjusted life expectancy for the most commonly applied management strategies in hypothetical cohorts of patients of various ages. Study Design: Markov decision analysis; societal perspective. Methods: Assumptions used in creating this model and event probabilities were obtained from a thorough literature review. Key parameters were identified and defined by the best available evidence. The main outcome measure is the benefit derived from each management strategy in quality-adjusted life years (QALYs). Sensitivity analysis was used to define benchmark performance information for these parameters. Results: The benefit of a period of observation followed by radiosurgery, if needed, for significant tumor growth is greater then all other strategies for all age groups and both sexes. When compared to observation followed by microsurgery, the additional benefit is small. QALY totals for the two immediate treatment groups were significantly lower than that for the observation groups. Conclusions: For patients of all ages, a period of observation during which tumor growth and hearing thresholds are closely monitored is the superior strategy. For tumors that grow substantially or when hearing deteriorates, definitive management via radiosurgery is recommended. Laryngoscope, 2010 [source]

The Mechanism of Hearing Loss in Paget's Disease of Bone,

THE LARYNGOSCOPE, Issue 4 2004
Edwin M. Monsell MD
Abstract Objectives/Hypothesis The mechanism of hearing loss (HL) in Paget's disease of bone was investigated. The present study was a systematic, prospective, controlled set of clinical investigations to test the hypothesis that there is a general underlying mechanism of HL in Paget's disease of bone and to gain additional insights into the auditory and otologic dynamics of this disease. Specific questions were 1) whether the mechanism is cochlear or retrocochlear and 2) whether the bone mineral density of the cochlear capsule is related to hearing levels. Study Design Several double-blinded, cross-sectional, prospective, correlational studies were conducted in a population of elderly human subjects with skull involvement with Paget's disease versus a control population of elderly subjects free of Paget's disease. Demographic and clinical data were recorded. Longitudinal observations were made in subjects under treatment. Methods Subjects were recruited from a Paget's disease clinic. Pure-tone auditory thresholds, word recognition, and auditory brainstem responses (ABRs) were recorded. The dimensions of the internal auditory canals were measured using computed tomographic (CT) images and digital image analysis. The precision, accuracy, and temporal stability of methods to measure the bone mineral density of the cochlear capsule and an adjacent area of nonotic capsule bone were validated and applied. Correlations were sought between hearing levels and cochlear capsule bone mineral density. Results ABRs were recorded in 64 ears with radiographically confirmed Paget's disease involving the skull. Responses were absent in eight ears, all of which had elevated high pure-tone thresholds. ABRs were interpreted as normal in 56 ears; none were abnormal. The mid-length diameter and minimum diameter of the internal auditory canal of 68 temporal bones from subjects with Paget's disease were found to have no statistically significant relationship to hearing thresholds. The Pearson product-moment correlation coefficients (age- and sex-adjusted) in the group with Paget's disease involving the temporal bone were ,0.63 for left ears and ,0.73 for right ears for high-frequency air conduction pure-tone thresholds (mean of 1, 2, and 4 kHz) versus cochlear capsule density. Correlation coefficients (age- and sex-adjusted) between cochlear capsule density and air-bone gap (mean at 0.5 and 1 kHz) for the affected group were ,0.67 for left ears and ,0.63 for right ears. All correlations between hearing thresholds and cochlear capsule density in pagetic subjects were significant at P < .001. The regressions were consistent throughout the ranges of hearing level. There were no significant correlations between cochlear capsule mean density and hearing level in the volunteer subjects. Conclusions The evidence supports the existence of a general, underlying, cochlear mechanism of pagetic HL that is closely related to loss of bone mineral density in the cochlear capsule. This mechanism accounts well for both the high-frequency sensorineural HL and the air-bone gap. Early identification, radiographic diagnosis of temporal bone involvement, and vigorous treatment with third-generation bisphosponates are important to limit the development and progression of pagetic HL. [source]

Bilateral Bone-Anchored Hearing Aids (BAHAs): An Audiometric Evaluation,

THE LARYNGOSCOPE, Issue 1 2004
Claudia Priwin MD
Abstract Objectives Since the technique to implant bone-anchored hearing aids (BAHAs) with the use of osseointegrated implants was developed in 1977, more than 15,000 patients have been fitted with BAHAs worldwide. Although the majority have bilateral hearing loss, they are primarily fitted unilaterally. The main objective of this study was to reveal benefits and drawbacks of bilateral fitting of BAHAs in patients with symmetric or slight asymmetric bone-conduction thresholds. The possible effects were divided into three categories: hearing thresholds, directional hearing, and binaural hearing. Study Design Prospective study of 12 patients with bilateral BAHAs. Methods Baseline audiometry, directional hearing, speech reception thresholds in quiet and in noise, and binaural masking level difference were tested when BAHAs were fitted unilaterally and bilaterally. Results Eleven of the 12 patients used bilateral BAHAs on a daily basis. Tests performed in the study show a significant improvement in sound localization with bilateral BAHAs; the results with unilateral fitting were close to the chance level. Furthermore, with bilateral application, the improvement of the speech reception threshold in quiet was 5.4 dB. An improvement with bilateral fitting was also found for speech reception in noise. Conclusions Overall, the results with bilateral fitted BAHAs were better than with unilaterally fitted BAHA; the benefit is not only caused simply by bilateral stimulation but also, to some extent, by binaural hearing. Bilateral BAHAs should be considered for patients with bilateral hearing loss otherwise suitable for BAHAs. [source]

Outcomes of the overlay graft technique in tympanoplasty

ANZ JOURNAL OF SURGERY, Issue 9 2010
Jennifer E. Ryan
Abstract Background:, This audit was undertaken to review the outcomes achieved with the overlay graft technique of tympanic membrane repair in tympanoplasty surgery. Methods:, The charts of all patients who underwent tympanoplasty, in whom an overlay graft technique of temporalis fascia tympanic membrane repair was used, between 1994 and 2007 were reviewed. Information with respect to patient demographics, presence of cholesteatoma or active infection and perforation size was documented. Details of the surgical procedure and clinical outcomes and pre- and post-operative hearing thresholds were recorded in a computer database. Results:, A total of 147 overlay graft procedures were performed in 130 patients. Graft failure with reperforation occurred following five procedures, for an overall success rate of 96.6%. Eighty Type 1 tympanoplasty procedures were performed in which one failure occurred for a 98.75% success rate. Overlay grafting was combined with intact canal wall mastoidectomy (ICW) in 38 cases and with modified radical mastoidectomy (MRM) in 17 cases for a success rate of 93.8 and 95%, respectively. Delayed graft healing as a result of infection, problems such as epithelial pearl, blunting and myringitis occurred in 39 cases (26.5%). Thirty-one cases underwent procedures for ossicular chain reconstruction, 21 of which were 2nd stage procedures. Hearing outcomes were significantly better with Type 1 tympanoplasty compared with ICW or MRM procedures. Conclusion:, This review demonstrates the overlay graft technique of tympanoplasty to be highly successful for tympanic membrane repair, particularly for the more difficult cases such as revision surgery, subtotal perforations and mesotympanic cholesteatoma. [source]

Audiometric evaluation of an attempt to optimize the fixation of the transducer of a middle-ear implant to the ossicular chain with bone cement

CLINICAL OTOLARYNGOLOGY, Issue 1 2004
A. Snik
Audiometric evaluation of an attempt to optimize the fixation of the transducer of a middle-ear implant to the ossicular chain with bone cement Typically, an implantable hearing device consists of a transducer that is coupled to the ossicular chain and electronics. The coupling is of major importance. The Vibrant Soundbridge (VSB) is such an implantable device; normally, the VSB transducer is fixed to the ossicular chain by means of a special clip that is crimped around the long process of the incus. In addition to crimping, bone cement was used to optimize the fixation in six patients. Long-term results were compared to those of five controls with crimp fixation alone. To assess the effect of bone cement (SerenoCem®, Corinthian Medical Ltd, Nottingham, UK) on hearing thresholds, long-term post-surgery thresholds were compared to pre-surgery thresholds. Bone cement did not have any negative effect. Next, to test the hypothesis that aided thresholds might be better with the use of bone cement, aided thresholds were studied. After correction for the severity of hearing loss, only a small difference was found between the two groups at one frequency, viz. 2 kHz. It was concluded that there was no negative effect of using bone cement; however, there is also no reason to use bone cement in VSB users on a regular basis. [source]