Masking in audiometry; further studies.
TL;DR: Attempts have been made to increase the average figure of 50 db for ordinary, air conduction receivers to higher insulation by using an ear canal insert which greatly reduces the area under the sound, using a hearing-aid type plastic tube in the meatus.
Abstract: Interaural attenuation plays an important part in clinical masking tests Attempts have been made to increase the average figure of 50 db for ordinary, air conduction receivers to higher insulation by using an ear canal insert which greatly reduces the area under the soundTwo types of inserts were used: one, made of plastic and fitted over the earphone, led the tone via a perforated tip into the meatus The other employed a microphone of hearing-aid type, leading the tone to the ear canal by a plastic tube with soft rubber point Interaural attenuation was measured by the masking methodThe hearing-aid type plastic tube in the meatus was the better of the two, providing 70 db insulation It proved to be easy to handle and convenient to useThe rules governing the use of masking in audiometry are discussed briefly For clinical routine use, white noise is preferred to bands of noise
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TL;DR: A number of investigators have shown that pure tones may be heard in the better ear, either across the head by air conduction or through the headBy bone conduction, when the intensity of the tone presented to the poorer ear may be raised to such a level that it is heard inThe better ear.
Abstract: The Problem One of the major problems in audiometry is that of determining thresholds in monaural and asymetrical binaural hearing losses. The clinician confronted with a patient whose two ears differ in acuity may have serious difficulty in obtaining accurate measures of hearing for the poorer ear. Under such circumstances, the clinician may arrive at estimates of hearing for the poorer ear that are better than the actual thresholds in that ear. Such erroneous results may even lead to attempted middle ear surgery on an ear having a profound sensorineural hearing loss. When the two ears differ sufficiently in acuity, the intensity of the tone presented to the poorer ear may be raised to such a level that it is heard in the better ear, either across the head by air conduction or through the head by bone conduction. A number of investigators 10,12-14,22 have shown that pure tones may
18 citations
TL;DR: The authors at present prefer a frontal placement of the bone conduction receiver, the masking noise being led to the ear by an ear canal insert, which increases the interaural attenuation by 15 to 20 db and thus facilitatesBone conduction audiometry.
Abstract: The rules governing the use of masking in air and bone conduction audio-metry are discussed and the situations leading to cross-hearing are presented. The advantages and disadvantages of the bone conduction masking procedure (Rainville) are considered. The authors at present prefer a frontal placement of the bone conduction receiver, the masking noise being led to the ear by an ear canal insert. The latter increases the interaural attenuation by 15 to 20 db and thus facilitates bone conduction audiometry.
16 citations
TL;DR: The author gives a typical example of severe bilateral middle ear deafness where neither the air-conduction curves nor the bone-Conduction curves could be determined correctly by means of ordinary receivers of commercially available audiometers, whereas by using hearing-aid type earphones the audiometrist was able to establish a more strictly accurate audiogram.
Abstract: In a preceding article (Konig, 1962) it was demonstrated that the most important factors which actually limit the range of application of the different procedures normally employed in clinical audiometry are the transcranial and transtemporal leakages The observations reported here are intended to concretize our previous theoretical considerations and to show how the use of hearing-aid type earphones may enhance the accuracy of audiometric measurements In order to evidence the advantages of such earphones in a striking manner, the author gives a typical example of severe bilateral middle ear deafness where neither the air-conduction curves nor the bone-conduction curves could be determined correctly by means of ordinary receivers of commercially available audiometers, whereas by using hearing-aid type earphones the audiometrist was able to establish a more strictly accurate audiogram In contrast to the maximum bone-air gap generally observed in the different audiology centres, transtympanic transmissio
9 citations
8 citations
TL;DR: Abnormal fatigability may appear in all categories of perceptive hearing loss and as such is not pathognomonic to any particular locus localization of the lesion.
Abstract: Results are reported in a series of 125 perceptively impaired ears by determining the course of threshold tracings during a 3-min stimulation, first in quiet and then in the presence of 83 db (over-all) white noise. Larger than 10 db threshold shifts occurred in 21 ears in quiet (17 per cent) and in 44 ears in the presence of noise (35 per cent). Abnormal fatigability may appear in all categories of perceptive hearing loss and as such is not pathognomonic to any particular locus localization of the lesion.
5 citations
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TL;DR: In this article, the authors present the results of a study of the monaural masking of pure tones by white noise at eight sensation levels (SL) from 20 to 90 db, and construct a set of contours to represent the masked threshold for pure tones heard monaurally against background of white noise having an ideal flat spectrum at the ear of the listener.
Abstract: This report presents the results of a study of the monaural masking of pure tones by white noise at eight sensation levels (SL) from 20 to 90 db. The observed values of masking were employed to determine two basic functions: (a) The critical band width of a masking noise, i.e., the ratio, in decibels, between the level of a pure tone and the level per cycle of the noise that is just able to mask the tone. (b) The function relating the amount of masking to the effective level of the masking noise. With the aid of these two functions, a set of contours was constructed to represent the masked threshold for pure tones heard monaurally against background of white noise having an ideal flat spectrum at the ear of the listener. A study was also made of the masking by white noise of speech in the form of continuous discourse. Measurements of the threshold of detectability and of the threshold of intelligibility were made at the same eight noise levels used to mask pure tones.
406 citations
TL;DR: In this paper, a narrow band of noise was used to mask pure tones, and it was shown that the amount by which the test signal at the center of the band exceeds the level/cycle of the noise is less than that obtained with a considerably wider band of noises.
Abstract: The masking audiogram of a pure tone is complicated by phenomena that arise from the interaction of the test tone with the masking stimulus. The production of beats and of difference tones results in a masking audiogram that does not represent the pattern of activity in the cochlea or nerve due to a simple masking stimulus. In the present experiments a narrow band of noise was used to mask pure tones. The “beat” heard in the immediate vicinity of the masking noise is not prominent, and a test tone higher in frequency than the band of noise is detected in terms of the characteristic pitch of that tone rather than by means of a difference tone.With a band of noise slightly wider than a critical band (Fletcher), the amount by which the test signal at the center of the band exceeds the level/cycle of the noise is less than that obtained with a considerably wider band of noise. This smaller signal‐to‐noise ratio obtained with the narrow band of noise is probably due to “beats,” since the test tone is heard as ...
305 citations
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31 Mar 2012
TL;DR: The vital mechanisms of human communication, speech and hearing are examined, through a discussion of the body's role in these functions.
215 citations
TL;DR: Bone conduction was shown to be chiefly responsible for the acoustical leakage between the ears, and conditions were determined under which interaural insulation could be increased considerably.
Abstract: In an investigation of the acoustical insulation between the ears, various earphones and obturating devices were used. Bone conduction was shown to be chiefly responsible for the acoustical leakage between the ears. Conditions were determined under which interaural insulation could be increased considerably. Most of the measurements were performed with a compensation method which appears to give more precise results than methods previously used, and which permits phase measurements.
144 citations