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Auditory Thresholds (auditory + threshold)
Selected AbstractsPericranial muscular, respiratory, and heart rate components of the orienting responsePSYCHOPHYSIOLOGY, Issue 6 2002J.J. Stekelenburg We have earlier found that voluntary attention to weak auditory stimuli induces inhibition of respiration, heart rate, and electromyographic (EMG) activity of masticatory and lower facial muscles and that these responses lower the auditory threshold for low-frequency sounds. In the current study, we examined whether this inhibitory response pattern also occurs during involuntary orienting to novel, nonsignal sounds. Environmental sounds of low intensity were presented unexpectedly during the performance of a reading task. Orienting responses (ORs) were elicited as indicated by heart rate deceleration and skin conductance responses. Inhibitory respiratory and pericranial EMG responses appeared to be intrinsic components of the OR. Together with the autonomic responses, they habituated when a nonsignal auditory stimulus was repeatedly presented. Our results also suggest that eye and pinna movements occurred toward the sound source. The results of the current study are consistent with the hypothesis of Sokolov (1963) that the primary function of the OR is enhancement of sensory sensitivity. [source] On the development of low-level auditory discrimination and deficits in dyslexiaDYSLEXIA, Issue 2 2004Burkhart Fischer Abstract Absolute auditory thresholds, frequency resolution and temporal resolution develop with age. It is still discussed whether low-level auditory performance is of clinical significance,specifically, for delayed maturation of central auditory processing. Recently, five new auditory tasks were used to study the development of low-level auditory discrimination. It was found that the development lasts up to the age of 16,18 years (on an average). Very similar tasks were now used with 432 controls and 250 dyslexic subjects in the age range of 7,22 years. For both groups the performance in one of the tasks was not related to the performance in another task indicating that the five tasks challenge independent subfunctions of auditory processing. Surprisingly high numbers of subjects were classified as low performers (LP), because they could not perform one or the other task at its easiest level and no threshold value could be assigned. For the dyslexics the incidence of LP was considerably increased in all tasks and age groups as compared with the age matched controls. The development of dynamic visual and optomotor functions and the corresponding deficits in dyslexia are discussed in relation to the auditory data presented here. Copyright © 2004 John Wiley & Sons, Ltd. [source] Spatio-temporal distribution of cellular retinoid binding protein gene transcripts in the developing and the adult cochlea.EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2000CRBPI-null mutant mice, Morphological, functional consequences in CRABP- Abstract The expression patterns of the mouse cellular retinoid binding protein genes were investigated by in situ hybridization analysis in the inner ear from 10.5 days post coïtum (dpc) up to the adult stage. The cellular retinoic acid binding protein II (CRABPII) and cellular retinol binding protein I (CRBPI) were present in a widespread and abundant pattern in cochlear structures during embryogenesis. Expression of the cellular retinoic acid binding protein I (CRABPI) is restricted during development in Kölliker's organ whilst cellular retinol binding protein II (CRBPII) is only visible after birth with a ubiquitous distribution in most regions of the cochlea including nervous components. No CRABP or CRBP transcripts were observed in the auditory receptors. Morphological observations of CRBPI- and CRABPI/CRABPII-null mutant fetus at 18.5 dpc do not show any structural modification at the level of the organ of Corti. Furthermore, electrophysiological tests performed by measuring distorsion-product otoacoustic emissions and auditory brainstem evoked responses did not present significant alteration of the auditory function for the different types of mutants. The expression of retinoid binding proteins in cochlear structures during embryogenesis could suggest important roles for these proteins during ontogenesis and morphogenesis of the inner ear. Despite these observations, morphological and functional data from mutant mice did not present obvious modifications of the cochlear structures and auditory thresholds. It is therefore unlikely that CRABPs and CRBPI are directly involved in development of the cochlea and hair cell differentiation. [source] Improved treatment of sudden hearing loss by specific fibrinogen aphaeresisJOURNAL OF CLINICAL APHERESIS, Issue 2 2004Heidrun Ullrich Abstract The etiology of sudden sensorineural hearing loss is still unclear and is thought to result from disturbances of microcirculation, infectious causes, or autoimmune disorders. So far standard therapy did not show clear improvement over spontaneous remission rate, which is assumed to be about 50% [Nakashima et al., Acta. Otolaryngol. Stockh. 514:14,16, 1994; Schuknecht and Donovan, Arch. Otorhinolaryngol. 243:1,15, 1986; Harris and Sharp, Laryngoscope 100:516,524, 1990; Mayot et al., Clin. Immunol. Immunopath. 68:41,45, 1993; Gussen, Ann. Otol. Rhinol. Laryngol. 85:94,100, 1976]. Elevated blood viscosity due to high fibrinogen levels is supposed to cause decreased cochlear blood flow and thus initiate sudden hearing loss. The specific lowering of fibrinogen immediately decreases plasma viscosity exactly to the desired extent and should lead to improved cochlear blood flow [Suckfüll et al., Acta. Otolaryngol 119:763,766, 1999; Suckfüll, Lancet 360:1811,1817, 2002; Walch et al., Laryngol. Rhino. Otol. 75:641,645, 1996; Suckfüll et al., Otol. Neurotol. 23:309,311, 2002]. In a prospective uncontrolled pilot study on 36 patients with unilateral sudden onset sensorineural hearing loss (SHL) we tried to establish that 1,3 specific fibrinogen aphaereses alone improve recovery of hearing and that it is possible to lower fibrinogen to the target of 80,100 mg/dl without important side effects. Pure tone audiometry was carried out immediately before and after each aphaeresis as well as at 2 and 4 weeks and 6 months after treatment. Sixteen patients recovered spontaneously before undergoing fibrinogen adsorption. All 20 aphaeresis patients improved during immunoadsorption; in 60% of patients auditory thresholds returned to normal after the first immunoadsorption and treatment could be discontinued, in another 20% of patients complete recovery was reached after 4 weeks. The mean plasma fibrinogen concentration of the 20 patients before the first aphaeresis session was 308.1 ± 51.5 mg/dl. Immediately after the first treatment session, the fibrinogen concentration was lowered to 100.7 ± 25.3 mg/dl (P < 0.001). The second and third sessions also showed highly significant reductions in plasma fibrinogen. No important side effects were seen. In conclusion, specific fibrinogen adsorption is a promising new treatment modality that should be tested in a prospective, randomized controlled trial in patients with sudden hearing loss. J. Clin. Apheresis 19:71,78, 2004. © 2004 Wiley-Liss, Inc. [source] The auditory system of last instars in Gryllus bimaculatus DeGeerPHYSIOLOGICAL ENTOMOLOGY, Issue 1 2009ERICH M. STAUDACHER Abstract Aspects of the auditory development of Gryllus bimaculatus are compared with those of other Orthopterans and Mantodea. Auditory receptor cell branching patterns and first-order auditory interneurones of last-instar crickets are morphologically very similar to adult cells; auditory thresholds are 30,45 dB higher in last instars than in adults; the ears of most ultimate nymphs lack directionality; and the tympana of last instars are not set apart clearly from the surrounding cuticle, are still thick, backed by a thick layer of epithelium, and lack microtrichia. Thus, the development of the auditory system from last-instar to adult shows close similarities between G. bimaculatus and Teleogryllus commodus but not to other Orthopteran or Mantid species. This supports the hypothesis that the pattern of post-embryonic development of the auditory system in crickets differs significantly from that in other Orthopterans and in Mantodea. [source] A comparison of auditory brainstem responses and behavioral estimates of hearing sensitivity in Lemur catta and Nycticebus coucangAMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2010Marissa A. Ramsier Abstract Primates depend on acoustic signals and cues to avoid predators, locate food, and share information. Accordingly, the structure and function of acoustic stimuli have long been emphasized in studies of primate behavioral and cognitive ecology. Yet, few studies have addressed how well primates hear such stimuli; indeed, the auditory thresholds of most primate species are unknown. This empirical void is due in part to the logistic and economic challenges attendant on traditional behavioral testing methods. Technological advances have produced a safe and cost-effective alternative,the auditory brainstem response (ABR) method, which can be utilized in field conditions, on virtually any animal species, and without subject training. Here we used the ABR and four methods of threshold determination to construct audiograms for two strepsirrhine primates: the ring-tailed lemur (Lemur catta) and slow loris (Nycticebus coucang). Next, to verify the general efficacy of the ABR method, we compared our results to published behaviorally-derived audiograms. We found that the four ABR threshold detection methods produced similar results, including relatively elevated thresholds but similarly shaped audiograms compared to those derived behaviorally. The ABR and behavioral absolute thresholds were significantly correlated, and the frequencies of best sensitivity and high-frequency limits were comparable. However, at frequencies ,2,kHz, ABR thresholds were especially elevated, resulting in decreased agreement with behavioral thresholds and, in Lemur, the ABR 10-dB range starting points were more than 2 octaves higher than the behavioral points. Finally, a comparison of ABR- and behaviorally-derived audiograms from various animal taxa demonstrates the widespread efficacy of the ABR for estimating frequency of best sensitivity, but otherwise suggests caution; factors such as stimulus properties and threshold definition affect results. We conclude that the ABR method is a promising technique for estimating primate hearing sensitivity, but that additional data are required to explore its efficacy for estimating low-frequency thresholds. Am. J. Primatol. 72:217,233, 2010. © 2009 Wiley-Liss, Inc. [source] The Mechanism of Hearing Loss in Paget's Disease of Bone,THE LARYNGOSCOPE, Issue 4 2004Edwin 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] Ototoxicity in Rats Exposed to Ortho-, Meta- and Para-Xylene Vapours for 13 WeeksBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 1 2001François Gagnaire Brainstem auditory-evoked responses were used to determine auditory thresholds at different frequencies. Among the three isomers studied, only para-xylene produced moderate to severe ototoxicity in rats exposed at 900 and 1800 p.p.m. Increased auditory thresholds were observed at 2, 4, 8 and 16 kHz in rats exposed to 1800 p.p.m. para-xylene. The auditory threshold shifts (35 to 38 dB) did not reverse after 8 weeks of recovery. Moderate and severe losses of outer hair cells of the organ of Corti occurred in animals exposed to 900 and 1800 p.p.m. para-xylene respectively. Thus, the no observed effect level of para-xylene was 450 p.p.m. based on the loss of outer hair cells observed by light and electron microscopy. [source] Hearing thresholds in patients affected by rheumatoid arthritisCLINICAL OTOLARYNGOLOGY, Issue 1 2004F. 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] | ||||||||||||||||