Showing papers in "Scandinavian Audiology in 1981"
TL;DR: This is a summary of a report which was the result of an epidemiological investigation, carried out under the sponsorship of the Commission for the European Communities and its Committee on Medical and Public Health Research in the nine countries of the European Community, in order to determine the prevalence of childhood deafness.
Abstract: This is a summary of a report which was the result of an epidemiological investigation, carried out under the sponsorship of the Commission for the European Communities (CEC) and its Committee on Medical and Public Health Research (CRM) in the nine countries of the European Community, in order to determine the prevalence of childhood deafness. The design of the study specified that all children born during the year 1969 would be included if their hearing loss averaged 50 dB or worse in the better ear. Most of the children were enumerated in 1977 when they were eight years old.The prevalence of the degree of deafness in the CEC was 0.9/1000 live births in 1969. There were more deaf children born in the winter than in the summer months. Perceptive hearing loss accounts for 92% of all the cases of deafness and Rubella was the largest single cause of the deafness where the aetiology was known. If perceptive deafness is considered as a whole, in 42% of the children no cause was reported. 29% of the children we...
122 citations
TL;DR: The late averaged magnetic field evoked by contra- and ipsilateral auditory stimulation is recorded by means of a SQUID magnetometer from both hemispheres in four normally hearing, right-handed male adults.
Abstract: The late averaged magnetic field evoked by contra- and ipsilateral auditory stimulation is recorded by means of a SQUID magnetometer from both hemispheres in four normally hearing, right-handed male adults. The stimuli consist of 1 kHz, 500 ms tone pulses with intensities from 5 to 85 dB HL and averaging is based on 60 sweeps. Stimulating the right ear the averaged magnetic field from the left hemisphere is approx. twice as great as that from the right hemisphere, whereas stimulating the left ear no difference in magnitude is found. The amplitude input-output functions are steeply rising near threshold and more shallow at high intensities. The responses from contralateral stimulation are approx. 9 ms earlier than those from ipsilateral stimulation with no interhemispheric difference.
106 citations
TL;DR: A hearing examination of 538 teenage boys in vocational school classes--implying future on-the-job noise exposure--showed a hearing loss in 15% of the cases, suggesting a noise etiology--a suggestion emphasized by the noisy hobbies of these teenagers.
Abstract: A hearing examination of 538 teenage boys in vocational school classes—implying future on-the-job noise exposure—showed a hearing loss (greater than 20 dB HL at any frequency) in 15% of the cases. Few correlations could be demonstrated between hearing loss and specific leisure time activities. There was, however, a correlation between high frequency hearing loss in the left ear and hereditary hearing loss. The most affected frequency was 6 kHz, suggesting a noise etiology—a suggestion emphasized by the noisy hobbies of these teenagers. It cannot be excluded that a hereditary deficiency could either manifest itself as a localized dip at 6 kHz or reveal itself as an increased vulnerability to noise, identified at young age as a high frequency dip at 6 kHz.
84 citations
TL;DR: The results justify taking not only measures of speech identification improvement but also questionnaire measures and measures of time of use in field trials when evaluating overall effectiveness of aid provision.
Abstract: A sample of postaural hearing aid users was followed through adaptation to use of an aid over an 18-month period subsequent to issue. Minor assistance and advice was given but no intensive hearing therapy or other instruction. A miniature timing device was installed in an aid substituted for a few days to provide a check on self-reported extent of use. On both objective and self-report measures, postaural aids receive substantially greater use than the body-worn aids in comparable previous investigations, about half the aids being used over 4 hours per day. Word-identification of free-field listening in aided and unaided conditions showed advantages of 10% or more in only 45% of those tested, yet questionnaire responses suggested reliable subjective benefits in specific listening situations. The results justify taking not only measures of speech identification improvement but also questionnaire measures and measures of time of use in field trials when evaluating overall effectiveness of aid provision.
52 citations
TL;DR: Recording BSER in 110 consecutive cochlear ears with click thresholds not in excess of 60 dB HL found that the BSERs were observed for replicability and latencies of waves I, III and V, as well as for I-V and III-V interpeak intervals.
Abstract: The basis for the use of click-evoked BSER in neurotologic differential diagnosis would seem to be its sensitivity to retrocochlear but relative resistivity to cochlear lesions. The present study was performed in order to investigate the presumed robustness of BSER in cochlear hearing loss by recording BSER in 110 consecutive cochlear ears with click thresholds not in excess of 60 dB HL. There were eleven ears with rising, twenty-two ears with flat, and 77 ears with sloping audiograms. Click intensities were 80 dB HL and 60 dB SL, and the BSERs were observed for replicability and latencies of waves I, III and V, as well as for I-V and III-V interpeak intervals. Wave V latency increments (relative to normal values) were related to hearing thresholds at 4 kHz. Wave V was identifiable in all of the ears at 80 dB HL and/or 60 dB SL, whereas waves I and III often failed to appear at 80 dB HL and occasionally at 60 dB SL. At 80 dB HL click level, the wave V latency increment was related to the 4 kHz hearing los...
41 citations
TL;DR: Auditory brainstem responses to monaural 70 dB nHL clicks in normal adults were recorded with wide bandwidth and stored digitally, and filter phase distortion dominated the mean square error in ABR estimation.
Abstract: Auditory brainstem responses (ABRs) to monaural 70 dB nHL clicks in normal adults were recorded with wide bandwidth and stored digitally. Using digital to analogue conversion with expanded time, the ABRs were input to a variable band-pass filter. The order of averaging and filtering was unimportant. Low-pass effects were unremarkable. High-pass filtering in the commonly used range 20 Hz to 500 Hz produced severe waveform distortion, causing emergence of artifactual peaks, amplitude increase and decrease, absolute latency decrease and interpeak interval changes. Digital high-pass filtering gave identical results. The distortion increased with the filter order. Using a zero phase characteristic drastically reduced ABR distortion and abolished latency changes except for poorly resolved peaks. Butterworth and boxcar filter moduli gave identical results. At common high-pass frequencies, filter phase distortion dominated the mean square error in ABR estimation. Off-line digital filtering of ABR is both practicable and desirable, especially for facilitating inter-laboratory pooling of data.
40 citations
TL;DR: The results suggest that certain masker bandwidths can be more efficient than others for the masking of tinnitus, and that masker characteristics deserve close attention in the design and fitting ofTinnitus-masker instruments.
Abstract: The level of noise required to mask tinnitus was measured in 12 subjects with sensorineural tinnitus; the noise was centred on the estimated pitch of the tinnitus, and the overall level required to just mask the tinnitus was measured for masker bandwidths of 2.5, 10, 20, 30 and 50% of the noise centre-frequency. For four of the tinnitus subjects, masking functions were similar to those observed in normal-hearing subjects with a "simulated" tinnitus (15-dB Sensation Level, 4-kHz pure tone). The other eight tinnitus subjects, however, required masking levels that were either independent of masker bandwidth or showed anomalous changes in masker level as bandwidth was increased. These results suggest that certain masker bandwidths can be more efficient than others for the masking of tinnitus, and that masker characteristics deserve close attention in the design and fitting of tinnitus-masker instruments.
39 citations
TL;DR: Threshold measurements with a Präcitronic KH 70 bone vibrator were carried out on 25 young, otologically normal subjects (50 ears) and the equivalent threshold force levels for forehead application were found to be higher by about 11 dB in the whole frequency range.
Abstract: Threshold measurements with a Pracitronic KH 70 bone vibrator were carried out on 25 young, otologically normal subjects (50 ears) in the frequency range between 125 Hz and 8 000 Hz. The vibrator was applied to the human mastoid as well as to the forehead. The non-test ear was masked. Equivalent threshold force levels were determined on an artificial mastoid type B & K 4930. Between 125 Hz and 2 000 Hz, the equivalent threshold force levels for mastoid placement decrease steadily by about 13.5 dB/octave, they then increase again by about 10 dB and remain constant between 4 000 Hz and 8 000 Hz. The equivalent threshold force levels for forehead application were found to be higher by about 11 dB in the whole frequency range.
29 citations
TL;DR: Tone screening was performed in 14391 schoolchildren at three different age-levels, 7, 10, 13 years in grades 1, 4 and 7, and was carried out in 1977, 1978 and 1979.
Abstract: Tone screening was performed in 14391 schoolchildren at three different age-levels, 7, 10, 13 years in grades 1, 4 and 7, and was carried out in 1977, 1978 and 1979. A 4 kHz dip greater than 20 dB was found in 331 (2.3%) of the children; 241 (1.7%) were boys and 98 (0.6%) were girls. The 4 kHz dip was unilateral in 230 (1.6%) and bilateral in 109 children (0.7%). The number of children with the 4 kHz dip increased with age. At the 13-year level it was found in 125 (4.7%) boys and 37 (1.5%) girls. The magnitude of the dip increased with age both in frequency range and intensity. At the 13-year level two and more frequencies were affected in 27 (0.5%) and hearing thresholds of 40 dB and worse were found in 47 (0.9%) of the children. Causes of noise could be established in 210 (63%) of 331 children. Most important noise causes were in the following order: motor vehicles, including tractors, fire-arms and crackers. In a small number, loud music could have been the cause of the 4 kHz dip. A hearing conservation program against noise has been instituted for children, parents, teachers and school nurses. Further studies will show if this program is effective.
29 citations
TL;DR: The effects of impulsive noise exposure upon hearing sensitivity from 8000 to 20000 Hz were determined for a sample of 23 young military veterans whose histories consisted primarily of major incidents of weapons fire.
Abstract: The effects of impulsive noise exposure upon hearing sensitivity from 8 000 to 20 000 Hz were determined for a sample of 23 young military veterans. The subjects' histories consisted primarily of major incidents of weapons fire. Based on audiometric configuration, the subject sample was divided in two groups characterized by predominantly unilateral or bilateral shifts in threshold sensitivity. This division was consistent with history information. The main finding was extensive threshold shifts from 8 000 to 20 000 Hz which was highly individual-specific and unpredictable. High frequency audiometry frequently revealed extensive changes not evident in the 250 through 8 000 Hz range.
29 citations
TL;DR: Parameters of the brainstem auditory evoked potentials to high-intensity clicks of initial rarefaction (R) and condensation (C) phases differed and the preserved BAEP components did not change noticeably with click phase inversion.
Abstract: Parameters of the brainstem auditory evoked potentials (BAEPs) to high-intensity clicks of initial rarefaction (R) and condensation (C) phases differed. The amplitudes of Waves I, II and IV were greater with R clicks, while that of Wave V was greater with C clicks. The peak-latencies of Waves I and VI were shorter with R clicks and those of the remaining components tend to shorten with C clicks. At low stimulus intensities the preserved BAEP components (Waves III, V and VI) did not change noticeably with click phase inversion.
TL;DR: The results suggest that an algebraic addition of the responses from the two stimulated sides is the main mechanism of the binaural BER generation and that the phenomenon recorded at the surface is due to central adaptation or to specific mechanism of bINAural interaction.
Abstract: The brainstem responses (BER) evoked by binaural clicks (0.1 ms) with interaural time differences (Δt) from 0 to 3.5 ms were studied in 6 normal subjects. The responses analysis was carried out via computer in two different ways: (a) Comparison between binaural BER and templates obtained with the addition of two monaural BERs. (b) Extraction from the binaural BER of the second delayed pattern. The results suggest that an algebraic addition of the responses from the two stimulated sides is the main mechanism of the binaural BER generation. In comparison with the templates, the binaural response shows some differences which are evident at Δt = 0–1.5 ms and are limited in the region of VI and VII waves. Such differences are caused essentially to an amplitude decrease of the second pattern—that is response to the delayed stimulus—mainly at Δt = 1.5 ms. However these results do not allow us to say if the phenomenon recorded at the surface is due to central adaptation or to specific mechanism of binaural intera...
TL;DR: While JI latency values of various groups do not differ significantly, groups 2--and especially group 1--JV latency values are statistically different from those of the 3rd and 4th group, this observation was confirmed by JV--JI interval values.
Abstract: ABR (Auditory Brainstem Response) delivering the acoustic stimulus both through a headphone (PHN) and in free field (FF), have been recorded in 59 "normal" children divided into four age-related groups: (1) 22 children born at a gestational age ranging between the 36th and the 41st week; (2) 12 with ages ranging from 1 to 6 months; (3) 15 with ages ranging from 6 to 12 months; (4) 10 with ages ranging from 12 to 36 months. Peak latency values obtained with FF technique have been corrected by calculating the delay due to the distance between the loudspeaker and the tested ears (2.04 ms). When using this correction, no statistically significant differences were found between latency values of peaks JI and JV recorded using the two technique. While JI latency values of various groups do not differ significantly, groups 2--and especially group 1--JV latency values are statistically different from those of the 3rd and 4th group. This observation was confirmed by JV--JI interval values. JV wave in neonates (group 1), using PHN technique, is detectable at 60 dB p.e. SPL (82%) while in all other groups at 60 dB this wave is clearly detectable in all children (100%). Using FF technique, JV wave is still visible at 60 dB in 78% of the neonates (group 1) and in almost all children of the other groups. Considering ABR waveform, using PHN technique, in the first two groups only three waves are visible and the first one disappears at about 80 dB, while the typical 4--5 waves of normal adult tracings are detectable since 8--12 months of age. FF tracings instead show three peaks in all groups, the first (JI) being less evident when compared with the one obtained using PHN technique. JV amplitude values observed in FF are higher than those obtained delivering the stimulus through the headphone.
TL;DR: Assuming ILD to be a valid discriminator between cochlear and retrocochlear lesions, the corrected ILD at equal click hearing levels (90 dB HL), with the critical value set at 0.2 ms, thus gave a 9% false-positive rate whereas the ILS at equal sensation levels, with theCriticalvalue set at zero, gave no false-positives.
Abstract: Interaural latency differences (ILDs) of wave V of the brainstem electric response (BSER) were studied (1) in 20 normal-hearing subjects at 90, 80, 60 and 40 dB HL click level, (2) in 22 patients with symmetrical cochlear hearing loss at 90 dB HL, corresponding to 45–80 dB SL, and (3) in 45 patients with asymetrical cochlear hearing loss with interaural recruitment, at 90 dB HL on one hand and at a click sensation level corresponding to 90 dB HL in the poorer ear (range 10–75 dB SL) on the other hand. In the normal hearing group the ILDs did not exceed 0.2 ms except in one case at 40 dB HL (0.3 ms). In the symmetrical cochlear loss group the ILD did not exceed 0.2 ms in any patient. In the asymmetrical cochlear loss group the ILD at 90 dB HL exceeded 0.2 ms in 12 cases, but only in four cases after correction for pure tone hearing loss at 4 kHz by 0.1 ms for each 10 dB above 50 dB HL; at equal sensation levels the ILDs were all zero or negative meaning that the wave V latency was shorter on stimulation of...
TL;DR: With high-ass noise masking at decreasing cut-off frequencies from 1 800 Hz down to 600 Hz and increasing noise levels, wave V disappears with a slight latency shift, but subsequently to wave V an additional wave occurs which remains stable even in the case of high noise intensities.
Abstract: Investigations, using click stimuli masked by wide-band and high-pass filtered noise with cut-off frequencies of 2 600, 1250 and 850 Hz were carried out. The latency shift of a response evoked by a click of 60 dB HL and wideband masking at 80 dB HL is 0.2–0.3 ms for wave I and about 0.6 ms for wave V. The results obtained with high-pass masking at various cut-off frequencies differ distinctly from those found by other authors. For instance, when using high-pass masking noise at a lower limiting frequency of 850 Hz and levels of 85 and 90 dB no clear brain-stem responses were discernible. Therefore, the appearance of the brain-stem responses with masking noise at various frequency limits and at various levels was examined. With high-pass noise masking at decreasing cut-off frequencies from 1 800 Hz down to 600 Hz and increasing noise levels, wave V disappears with a slight latency shift, but subsequently to wave V an additional wave occurs which remains stable even in the case of high noise intensities. Fu...
TL;DR: It is concluded that this test may reflect Eustachian tube patency during swallowing--and not tubal function.
Abstract: Sound transport through the Eustachian tube in normal ears has been recorded using sonotubometry (Virtanen, 1978). It was found that only 66% of the ears had sound transport through the tube when swallowing. Despite the fact that all ears had adequate aeration of the middle ear at the time of testing, 34% of the ears had no sound passage when swallowing. The explanation for this phenomenon is discussed. Also, it is concluded that this test may reflect Eustachian tube patency during swallowing—and not tubal function.
TL;DR: A study set up to assess the corrosive behaviour of mercury and zinc air batteries in the gastric juice environment of the stomach shows a relatively rapid rate of corrosion for charged mercury batteries.
Abstract: This paper reports on a study set up to assess the corrosive behaviour of mercury and zinc air batteries in the gastric juice environment of the stomach. The results show a relatively rapid rate of corrosion for charged mercury batteries. In contrast, the zinc air battery showed no visible corrosion under the same conditions. In view of the toxic dangers from leakage of mercury batteries, it is recommended that steps be taken to ensure that such batteries do not remain in the acidic environment of the stomach, should ingestion occur.
TL;DR: Evidence is becoming available of the importance of the range of aids in determining level of use achieved by patients and it is concluded that a first essential is an acceptable range of hearing aids.
Abstract: The evidence of the effects of various aspects of the organisation of hearing aid services are reviewed. It is concluded that evidence is becoming available of the importance of the range of aids in determining level of use achieved by patients. However little is known about the effects of aftercare. Two different forms of aftercare service are compared, one of which provided a routine visit at two weeks to a sample of first-time hearing aid users and the other of which provided help only to those who sought it by returning to the hospital. The patients who had the former service showed significantly higher levels of use of their hearing aids compared with the latter group. This data also confirmed that the new National Health Service (NHS) BE10 series aids are used substantially more than was the body worn OL56 and irrespective of aftercare. Implications for the organisation of services are that a first essential is an acceptable range of hearing aids. Secondly, it is essential that the fitting, care and use of the aids are effectively taught. Finally the organisation of aftercare should be such that the patients' performance is monitored against specific criteria in an on-going fashion using senior staff economically to deal with the most difficult patients.
TL;DR: The contention that the LDL represents a sound pressure level above which no improvement in speech recognition occurs, and thus, might reasonably be used as the appropriate level for the saturation sound pressurelevel of a hearing aid, is supported.
Abstract: The purpose of this experiment was to determine the relationship between the loudness discomfort level (LDL) and maximum speech recognition performance for listeners with sensorineural hearing loss. Performance-intensity functions were obtained for 30 listeners with mild to moderate sensorineural hearing impairment at five speech levels from -18 to +4 dB re: the LDL. Recognition scores were obtained for three speech materials. For all speech materials, recognition scores at levels below the LDL were equivalent to or higher than scores obtained at and above the LDL. These results support the contention that the LDL represents a sound pressure level above which no improvement in speech recognition occurs, and thus, might reasonably be used as the appropriate level for the saturation sound pressure level of a hearing aid.
TL;DR: The investigation shows that in practice it is difficult to optimize the etymotic frequency characteristic by modifying the hearing aid and the ear mould, and rather large differences can be found between a hearing aid's frequency characteristic as measured according to IEC 118 (using a 2 cc coupler) and the eTYmotic frequencies as measured by probe microphone at the ear drum.
Abstract: A computerized system is described for measuring a hearing aid's etymotic frequency characteristic on patients. A small-scale clinical investigation using this equipment showed that rather large differences can be found between a hearing aid's frequency characteristic as measured according to IEC 118 (using a 2 cc coupler) and the etymotic frequency characteristic as measured by probe microphone at the ear drum. The investigation shows that in practice it is difficult to optimize the etymotic frequency characteristic by modifying the hearing aid and the ear mould. Measurements of the etymotic frequency characteristic using several different hearing aids, but with the same ear mould on the same test subject showed only limited variation in the upper limiting frequency.
TL;DR: It is proved that considerations are misleading: with more adequate derivation paradigm, with extracephalic placement of the reference electrode, the bilateral asymmetry of BAEP parameters has mainly the opposite sign.
Abstract: Possible sources of individual components of the human brainstem auditory evoked potential (BAEP) were previously considered proceeding from the bilateral asymmetry of their parameters, the latter being determined with the centro-periaural electrode position. It is proved that such considerations are misleading: with more adequate derivation paradigm, i.e. with extracephalic placement of the reference electrode, the bilateral asymmetry of BAEP parameters has mainly the opposite sign.
TL;DR: Noise, Hearing and Hypertension, Volume 10, No. 2, pp 125-126.
Abstract: (1981). Noise, Hearing and Hypertension. Scandinavian Audiology: Vol. 10, No. 2, pp. 125-126.
TL;DR: Results are discussed within the context of: 1) stimulus materials; 2) calibration tolerances; 3) equipment variables; 4) reinforcement; and 5) definitions of 0 dB signal-to-noise ratio.
Abstract: The purpose of the present investigation was to establish developmental norms for word identification in quiet and in white noise in a normally hearing pediatric population. A second purpose of the study was to investigate the influence of minor variations in noise level for word identification performance. Twelve children from each of four age groups (X age = 7.8, 9.0, 11.2, and 13.1 years) and 12 college students participated in Experiment 1. NU-6 half-lists were presented in quiet and in noise (S/N=0). Eleven college students, 7 ten-year-olds (X=10.0 years) for 5 twelve-year-olds (X=12.0 years) served as subjects for Experiment 2. These subjects listened to NU-6 words in quiet and in two noise conditions (S/N = 0 and S/N = +2). A factorial analysis of variance and Duncan's multiple range test revealed significant differences between subjects' performance in quiet and in each noise condition. No age effect was observed. Results are discussed within the context of: 1) stimulus materials; 2) calibration t...
TL;DR: This work has investigated digital phase-correction of distorted average ABRs recorded with conventional filters and found the method is successful and feasible, and it is also possible to digitally recover the ABRs that would have been obtained with wider recording bandwidths, or with different filter orders.
Abstract: Analogue filtering of source data can cause severe distortion of ABR waveform, primarily due to filter phase nonlinearity. This distortion contributes to incompatibility between laboratories. Digital zero-phase filtering of the average ABR obtained with wide bandwidth gives much less distortion, but can cause difficulties with data acquisition protocols. We have investigated digital phase-correction of distorted average ABRs recorded with conventional filters. The method is successful and feasible. It is also possible to digitally recover the ABRs that would have been obtained with wider recording bandwidths, or with different filter orders. This approach can be used for conversion of ABR waveforms to a standard low-distortion filter condition, or to convert between conventional filter conditions used in different laboratories.
TL;DR: Although not all individuals suffering head trauma will yield notch audiograms, when an audiometric notch is observed the possibility of head trauma as well as other factors should be explored in the patient's history.
Abstract: Single-notch and double-notch sensorineural hearing losses were observed in 27 adult patients. All patients denied having a history of noise exposure, but did report at least one episode of head trauma. Generally, the laterality and degree of hearing loss did not appear to correlate well with severity and site of head trauma, or post-traumatic symptoms. Although not all individuals suffering head trauma will yield notch audiograms, when an audiometric notch is observed the possibility of head trauma as well as other factors should be explored in the patient's history.
TL;DR: The experiment found no basis for the attitude that hearing protectors impair the effectiveness of warning sounds, which may not however apply to warning sounds which are not distinct from the ambient noise, those which have to be recognized amongst other discrete sounds, or to users of hearing protection with an existing noise-induced hearing loss.
Abstract: A reason often given by noise-exposed workers for not wearing their hearing protection is that it impairs their ability to hear important sounds such as acoustic warning signals. An experiment was therefore conducted to assess the possible effect of wearing hearing protection on the attention demand of a typical industrial warning sound. Inattention was created by providing uncertainty as to the time of occurrence of the signal, and a separate loading task.The results indicate that neither inattention, nor the combination of inattention and the wearing of hearing protection, need necessarily impair the perception of a warning sound. The experiment therefore found no basis for the attitude that hearing protectors impair the effectiveness of warning sounds. This conclusion may not however apply to warning sounds which are not distinct from the ambient noise, those which have to be recognized amongst other discrete sounds, or to users of hearing protection with an existing noise-induced hearing loss.
TL;DR: An automatic, computerized system for analysis of the ocular movements in nystagmus, slow pursuit and saccades enables an extended application of opto-motor tests in the clinical examination of patients with suspected retrocochlear and brainstem involvement.
Abstract: An automatic, computerized system for analysis of the ocular movements in nystagmus, slow pursuit and saccades is presented. The performance of the system has been tested in healthy subjects, as well as in patients with peripheral or brainstem audio-vestibular disorders. The automatized procedure enables an extended application of opto-motor tests in the clinical examination of patients with suspected retrocochlear and brainstem involvement.
TL;DR: The early auditory evoked electrical activity has been recorded in man at the promontory (transtympanic approach) and on the scalp vertex-mastoid derivation), in response to clicks delivered at different rates.
Abstract: The early auditory evoked electrical activity has been recorded in man at the promontory (transtympanic approach) and on the scalp vertex-mastoid derivation), in response to clicks delivered at different rates. Latency and amplitude of the first two peaks (N1 and N2), as a function of the repetition rate, have been measured and compared. The differences between the latencies of transtympanic and surface N1 are very small, at any rate, with a maximum value of 0.08 msec. In the transtympanic recording, the latency difference between N2 and N1 is constant throughout the whole range of rate values, from 3 to 100 clicks per second. In the surface responses, on the contrary, the latency difference between N2 and N1 tends to increase as the rate is increased. The amplitude of the transtympanic N2 is consistently reduced at click rates above 20–50 per second (more markedly than the amplitude of N1), while the amplitude of the surface N2 is much more insensitive to the rate increase. Some implications of these res...
TL;DR: Surgical results of stapes surgery have been evaluated postoperatively after 3 years, in 834 subjects with otosclerosis, using audiological tests to determine the air-bone gap and the BC loss at 4000 Hz.
Abstract: Surgical results of stapes surgery have been evaluated postoperatively after 3 years, in 834 subjects with otosclerosis. The following audiological tests were used: (1) the air-bone gap; (2) pre- and postoperative speech reception thresholds (SRT); (3) postoperative SRT related to the air-bone gap; (4) the BC loss at 4000 Hz.