大学の教室で音声を聴取する際の残響の影響が, 指向性マイクを使用するとどの程度改善されるかを明らかにする目的で以下の実験を行った。防音室と教室 (残響時間1.6秒) でHINT日本語版文リストを再生し, これを, 防音室と, 教室の音源から2mと8mの位置で無指向性および指向性マイクを用いて録音した。これらの検査素材 (防音室リスト, 教室2, 8mリスト) を用いて, 健聴成人12名を対象に語音了解閾値 (SRT) を測定し比較検討した。無指向性マイクの録音では, 防音室リストと比較して, 教室2m, 8mリストのSRTは有意に上昇した。指向性マイクでは残響下のSRTに有意な改善がみられ, 教室2mリストでは無残響下と同等の成績であった。難聴者が残響の大きい教室で講演等を聴く場合, FM補聴器が使用できない状況では, 最前列で指向性補聴器を用いて聴取することが次善の策として有効である可能性が示唆され, 今後難聴者による検討が必要と考えられた。
The purpose of this study aimed to develop an auditory behavior checklist in order to investigate the auditory development of children with cochlear implants and compare that of peers with normal hearing.The auditory behavior checklist developed for this study was a parent questionnaire which included a total of 80 questions consisting of 5 questions for each 3-month developmental stages between the chronological age of 0-48 months.The items of the auditory behavior checklist were selected from the literature related to children's auditory behavior development of early childhood education, special education, and language development.The validity and reliability for items were conducted by attempting a content validity analysis, a factor analysis, and an internal consistency reliability analysis.Receptive-listening scores were obtained from 350 normal hearing infants and toddlers in ages 0 to 48 months.The results of this study were summarized as follows; First, reliabilities of the items of auditory behavior checklist showed 0.821 in receptive listening and 0.834 in expressive listening significantly.Also, the correlation coefficient about receptive-listening was significantly high ranging from 0.805 to 0.940.Second, the means and standard deviations for receptive-listening scores obtained from 350 normal hearing infants and toddlers revealed 17. 43±1.91 (16.72-18.06)respectively.The difference in scores was less than 1, indicating a negligible difference.Significant gender differences were not found among normal hearing groups.In conclusion, cochlear implantation in children at the youngest age possible allows the best opportunity for them to develop listening behaviors that approximate those of their peers with normal hearing.
The use of sensitized verbal tests in the diagnosis of central deafness is critically reviewed. The concept of intrinsic (neural) redundancy is the main point in the operational model; different modalities of coupling between intrinsic and extrinsic redundancy bring forth different patterns of intelligibility. The age of the subject thus becomes critical; on the contrary, the influence of the IQ can be minimized by carefully selecting the tests. These can be divided into monaural and dichotic; among the latter, only the tests involving competing information are of value, whilst the so-called summation tests should now be disregarded. The clinical results are only briefly quoted, since they are well-known. The contribution to the advances in neurophysiology seems to be more interesting. The influence of reticular formation on auditory stimulation, the crossing of the auditory pathways, the existence of a secondary auditory area have been psychoacoustically confirmed by the use of the monaural tests. In their turn, the dichotic competing message tests have enabled a beautiful model of language perception to be drawn, and have definitely demonstrated the so-called hemispheric specialization (or dominance) for verbal and nonverbal messages.
Background and Aim: The short-term memory (STM) has been studied to a great extent so far. Using some strategies and techniques to help the subject to access to his/her memory is important for Speech pathologist. Priming is a process that increases the chance of accessing to some information of memory by means of some simulations. So, primings are some words which facilitate the retrieval of the target words. The purpose of this study is comparing phonological and semantic priming on the short verbal memory span.Materials and Methods: The research was conducted on sixty-four 18-25 year-old male students in Tehran University of Medical sciences. Due to some distortion factors, including bilingualism, stutter-ing, and articulation problem, that can effect the reaction time, were determined as exclusion critenia. In additiion, subjects with difficulty in Wepman auditory discrimination were ruled out. The test was performed via the second version of programmed DMDX software and reaction time was recorded.Results: Semantic tasks and rhyming tasks were retrieved faster than the other tasks in lexical access respectively. There was a significant difference between the semantic and rime tasks but there is no significant difference between alliteration and unrelated tasks.Conclusion: The result of this research indicates that the semantic level is activated faster than the other levels and the phonological level is activated right after that. The alliteration level is the last level that activated. It has some similarities with some other investigations on the reaction time in phono-logical tasks.
聴覚障害児が学ぶ教室の音響環境を改善するために, 補聴システムが必要である。FM補聴システムのようにSN比, 残響時間を改善するものをはじめとし, 指向性マイクロホンシステム等が検討されている。これらの補聴システムを選択する際, 各システムの特徴を考えると, SN比のみならず, 残響時間の改善をパラメータに加える必要がある。本研究ではSN比, 残響時間が音声聴取に及ぼす影響について, RASTIを指針として文章了解度, 主観的評価という2つの観点から考察した。結果, 両群共にRASTIの向上に伴って文章了解度が向上すること, 残響時間の改善によって主観的評価が向上することが明らかになった。この点からは, 補聴システムを選択する際, SN比のみでなく, 残響時間を含め, 複合的な評価が必要であることが示唆できた。
Guinea pigs were exposed to a pure tone at 6 kHz and 80 dB SPL for 30 minutes in order to induce mild reversible auditory fatigue over the 4 hours following exposure. Cochlear monitoring aimed to compare the shifts in round-window compound action potentials (CAP) thresholds to those of 2f1-f2 distortion-product otoacoustic emissions (DPOAE, frequency of stimuli f1 and f2). Both responses were evaluated every 1/10th octave between 6 and 12 kHz for CAP thresholds, and from 4 to about 14 kHz for DPOAEs in response to 50- and 70-dB SPL stimuli. The auditory fatigue turned out to be sufficiently mild that DPOAEs remained present, so that their microstructure could be followed up while the stimulus frequency ratio f2/f1 was swept from 1.06 to 1.30 (fixed f2) so as to derive DPOAE level profiles against f2/f1 and group latencies. CAP thresholds decreased by about 10 dB above 7.2 kHz, whereas DPOAE amplitudes decreased at most f2 frequencies from 6.6 kHz to 15.2 kH.z, with the range of decrease being slightly narrower at higher stimulus intensities. While the mean DPOAE shift after 1 hour was around 5 dB irrespective of stimulus intensity, it tended to increase slightly after 2 hours despite stable CAP thresholds. DPOAE profiles against f2/f1 were slightly modified by the auditory fatigue, so that the maximum tended to be reached at lower ratio. No significant variation of DPOAE latencies was found after acoustic overstimulation. These experiments show that complex DPOAE changes were induced by auditory fatigue and their relationship to CAP threshold changes does not seem to be straight-forward. Nonetheless, fine DPOAE recordings might be useful to detect early changes in cochlear mechanics.
The stria vascularis (SV) of 3-, 8- and 18-month-old C57 mice was examined with a fluorescence microscope in order to evaluate the capillary density and vessel diameter. The capillary density was significantly reduced in 18-month-old mice compared to 3-month-old (P<0.001) and to 8-month-old (.P<0.001) mice. The difference between 3- and 18-month-old mice was significant for the basal, middle and apical cochlear turns, while the difference between 8- and 18-month-old mice was significant only for the middle and basal turns. Vessel diameter within the whole SV was significantly reduced in all turns in 18-month-old mice (P<0.01) versus 3-month-old animals, while vessel diameter was reduced only in the basal turn in 8-month-old versus 3-month-old mice. The results suggest that previously described histopathological changes in the organ of Corti of C57 mice may be related to modifications of strial capillaries.
The present study has evaluated the use of distortion product otoacoustic emission (DPOAE) responses in the detection of cisplatin-induced ototoxicity in a Sprague Dawley rat animal model. The cisplatin was administered as a 16 mg/kg, dose introduced by a slow 30-min intraperitoneal infusion. Data from three DP-gram protocols, DPOAE input-output responses at 8 kHz, and auditory brainstem responses (ABRs) at 8, 12 and 16 kHz were collected before and 72 h after treatment. The post-treatment ABRs at 16 kHz showed the greatest mean threshold shift of 33.6 dB. The post-treatment DP-gram data showed significant reduction of the signal to noise ratios in the majority of the frequencies tested, across all tested protocols. The data suggest that the most sensitive DPOAE procedure for the early detection of the cisplatin-induced ototoxic damage is the DPOAE I/O protocol. Morphological analyses indicated that the inner hair cells remained intact, while several types of alterations were observed in the arrangement of the stereocilia in the outer hair cells.
Because of their short lifespan and genetic homogeneity, mice can provide valuable insights into the biological basis of age-related hearing loss. In C57BL/6 mice, hair cell loss begins around 1-2 months of age and progresses rapidly along a base-to-apex gradient, whereas CBA mice show relatively little hair cell loss until late in life. This anatomical difference is reflected in dehydrogenase histochemistry, an indirect measure of aerobic energy metabolism. A small, but significant, decrease in hair cell dehydrogenase staining occurred in CBA mice between 1.5 and 18 months of age. Significantly, dehydrogenase levels in 1.5-month C57 mice were substantially lower than in CBA mice of any age. Thus, deficits in aerobic energy metabolism presage degeneration of the hair cells. The superoxide radical, O2*-, a normal byproduct of cellular metabolism, is potentially toxic and can cause cellular damage if it is not inactivated by superoxide dismutases. Cytosolic copper/zinc superoxide dismutase (SOD1) is highly expressed in the cochlea. Knockout mutant mice with a single (HET) or double deletion (KO) of the Sod1 gene coding for SOD1 showed greater age-related losses than wild-type (WT) mice. KO mice had the worst hearing, WT the best, and HETs were intermediate. KOs exhibited considerably greater hair cell loss than WT mice; however, losses in KOs were only slightly greater than in HETs. KO mice showed significantly greater loss of spiral ganglion cells and nerve fibers than WT mice. These results indicate that SOD1 and O2*- play important roles in age-related hearing loss. Intervention strategies targeting O2*- may reduce age-related hearing loss.
The present study aims to evaluate tone decay (auditory adaptation) in Digisonic cochlear implant patients, and to compare tone decay results with speech recognition performance. The following criteria are evaluated: tone decay occurrence, place effect, pulse rate effect, and correlation with speech recognition. A great variability in tone decay was found among the subjects. The amount of tone decay, measured as a percentage of the electrical dynamic range, depends to some extent on electrode location, which may be linked with the frequency dependence of acoustical tone decay. However, it is likely that acoustically and electrically evoked adaptation does not involve the same process. Also, an effect of pulse rate was found. However, no relationship between the amount of tone decay and speech recognition abilities was observed. Evaluation of tone decay in cochlear implant patients might not only allow further evaluation of the condition of their auditory system, but also provide a means to determine preoperatively the specific characteristics of a subject's residual auditory capacities.
The objective was to determine normative values for tympanometric variables for 7- and 24-month-old children and to assess the effect of various factors on these variables. Tympanometry was performed at scheduled health visits at 7 and 24 months of age on children recruited to a prospective vaccine efficacy trial (n=2497 children at enrolment). Tympanograms obtained successfully from healthy ears with no recent otitis media were analysed. Normative values for static acoustic admittance (SAA), tympanometric peak pressure (TPP) and tympanometric width (TW) were calculated. The mean SAA was 0.25 cm3 at the 7-month visit compared to 0.34 cm3 at the 24-month visit. The TW decreased and TPP remained unchanged with age. Higher SAA values were found in boys. A history of recurrent acute otitis media and history of tympanostomy tubes were found to increase SAA and decrease TW at 24 months. In conclusion, age-specific normative values for interpretation of SAA and TW are necessary.
To achieve detailed information on the outcome. of hearing rehabilitation in a clinical setting, measurements of hearing disability and hearing handicap have been introduced, and the present study describes the preliminary experiences with measures in a series of hearing-impaired these subjects referred for audiological evaluation. TO outline hearing disability/hearing handicap (HD/HH), before continuation or initiation of treatment, the Gothenburg profile and a generic health-related quality of life-the SF-36 questionnaire-were used to evaluate any adverse effects resulting from hearing disorders. The Gothenburg profile and the SF-36 questionnaire were mailed to 634 subjects appointed for audiological examination with a request to complete the questionnaires at home. Three questions were enclosed concerning the capacity to complete the questionnaires, showing that 1.9 per cent were incapable of completing them, 17.5 per cent needed assistance. 43.5 per cent completed the questionnaires. and 37.1 per cent did not respond to them. Thus the response rate was only 55.5 per cent and, in addition, these responses were characterised by missing data. An arbitrary criterion of an average score per question of >3 for the averaged HD and HH items respectively was applied, resulting in 72.7 per cent indicating HD, whereas 30.3 per cent indicated HH according to the items in the profile. Significant differences in hearing levels were found between those experiencing HD and HH having a score >3 and those with a score <3. When analysing the general health status. general perception of health and social functioning, significantly lower scores were found for those experiencing HD/HH, whereas no significant differences were found between he total sample of hearing-impaired subjects and the age-matched population for these parameters. It is concluded that the present procedure cannot be implemented as a routine outcome measure in a clinical setting and alternative outcome measures should be considered.
The mean pure-tone air conduction (AC) and bone conduction (BC) hearing thresholds (HT) of 534 randomly selected, caucasian, white, urban children with normal otoscopy, otomicroscopy and impedance audiometry, i.e. normal middle ear function, are presented here. Children with pathological middle ear findings or abnormal impedance audiometry were excluded. The average age was 13.8 years, SD 0.5, at the date of examination. The mean air conduction thresholds varied between 0.6 dB at 1 kHz and 9.9 dB at 6 kHz, and the bone conduction thresholds varied between -1.1 dB at 0.5 kHz and 1.1 dB at 4 kHz. The pure-tone average (PTA) (the average of AC hearing thresholds of 0.5, 1 and 2 kHz) of all ears was 1.5 dB. Ninety to ninety-eight per cent of pure-tone AC hearing thresholds at frequencies of 0.5-4 kHz were between -5 dB and 10 dB. The distributions are presented and compared.
Current standards involving technical specification of hearing aids provide limited possibilities for assessing the influence of the spectral and temporal characteristics of the input signal, and these characteristics have a significant effect on the output signal of many recent types of hearing aids. This is particularly true of digital hearing instruments, which typically include non-linear amplification in multiple channels. Furthermore, these instruments often incorporate additional non-linear functions such as "noise reduction" and "feedback cancellation". The output signal produced by a non-linear hearing instrument relates to the characteristics of the input signal in a complex manner. Therefore, the choice of input signal significantly influences the outcome of any acoustic or psychophysical assessment of a non-linear hearing instrument. For this reason, the International Collegium for Rehabilitative Audiology (ICRA) has introduced a collection of noise signals that can be used for hearing aid testing (including real-ear measurements) and psychophysical evaluation. This paper describes the design criteria, the realisation process, and the final selection of nine test signals on a CD. Also, the spectral and temporal characteristics of these signals are documented. The ICRA noises provide a well-specified set of speech-like noises with spectra shaped according to gender and vocal effort, and with different amounts of speech modulation simulating one or more speakers. These noises can be applied as well-specified background noise in psychophysical experiments. They can also serve as test signals for the evaluation of digital hearing aids with noise reduction. It is demonstrated that the ICRA noises show the effectiveness of the noise reduction schemes. Based on these initial measurements, some initial steps are proposed to develop a standard method of technical specification of noise reduction based on the modulation characteristics. For this purpose, the sensitivity of different noise reduction schemes is compared by measurements with ICRA noises with a varying ratio between unmodulated and modulated test signals: a modulated-unmodulated ratio. It can be anticipated that this information is important to understand the differences between the different implementations of noise reduction schemes in different hearing aid models and makes.
In this paper, we present a new computerised technique for the automatic construction of the latency-intensity curve (LI curve). We take a pattern recognition approach determined by a priori information. We use knowledge gained fi om the audiogram and from physiological considerations. Therefore, we consider all recordings at different intensities as well as results from the extraction of a single auditory brainstem response (ABR) at a given stimulus intensity. We tested our method successfully: it allows us to prevent misrecognition errors in response detection or in latency measurements. Automatic recognition of the waves and recognition by the ear, nose and throat (ENT) specialist coincided in at least 90 per cent of cases. For wave V. the average deviation between the response thresholds given by our automatic recognition algorithm and those given by the ENT specialist was 5 dB, and the average deviation of the latencies was 0.05 ms.
