[The electrophonic effect in persons with normal and impaired hearing].
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to R Chocholle.
Explore the source record for details and available documents.
TTS2 of 20dB was produced in a group of subjects using a 1000 Hz pure tone. All TTS and related measurements were made at 1500 Hz. The recovery of TTS, and of TLS or 'temporary loudness shift' (measured against a reference tone at 20db, 40dB and 60dB SL in the opposite ear), as well as N1-P2 amplitude of the Vertex potential, were plotted. There was an orderly recovery of both TLS and TTS although the rate of recovery of the latter was noticeably more rapid. Recovery of N1-P2 amplitude was much less orderly, although it did recover in much the same way. When the amplitudes were measured at 40dB SL the recovery was more orderly and followed the course of TTS more closely. It was concluded that any relation between N1-P2 amplitude and growth of loudness was indirect.
The loudness of brief tones have been studied in relation to rise and decay times, by reference a long tone of same frequency. Some differences appear, but they are different with the subjects and the sound pressure levels.
A preliminary study was performed on 5 normal subjects to investigate and compare the reduction and recovery of the auditory evoked response (AER), and to compare this with the temporary threshold shift (TTS) that occurs with fatiguing sounds. The findings are discussed in relation to the basic nature of the AER.
Loudness egalizations between short tone (1 to 400 ms) and a long reference tone (800 ms) were made. Two frequencies, 500 and 1000 Hz, were employed. Loudness comparisons were made at 20, 40 and 80 dB SL. Results show a frequency effect on the loudness of short tones. Some partial recuperation of loudness appears, it is greater for the high level.
Loudness equalizations between two short 2500 Hz tones (15 to 120 ms, about 50 dB SPL) were made. One tone, either the first or the second one, was twice as long as the other. The intensity level differences between tones of the same loudness were calculated. Results show that the relations between duration and loudness of the tones differ for different subjects. Nevertheless the calculated differences diminished with subject experience. Subject evaluations in accordance with the intensity levels of tones, i.e. independently of the duration, were quite often obtained even for the pairs 15 ms-30 ms.
The relation between loudness and duration judgments of short tones was investigated. Sounds (15 to 120 ms, 2500 Hz, about dB SPL), were exposed in pairs; one tone of the pair, the first or the second one, was twice as long as the other. Subjects had to compare the loudness of the tones, or the duration, or the loudness and the duration at the same time. Results show that the loudness judgments are independent of experiences with duration judgments and of immediate duration judgments, but duration judgments were less precise when loudness judged at the same time.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Studies on this type of discrimination are very interesting, as they can be made at suprathreshold levels. The nature of auditory intensity discriminations and the most useful methods for measuring the auditory intensity difference limens are briefly described. The most important results obtained with normal subjects are then presented; the monaural intensity difference limens, the intensity difference limens measured on one ear while stimulating the other ear by an unvarying tone or a noise, are treated successively. The most important clinical applications of the intensity auditory difference limens are presented (especially, the monaural intensity difference limens, and the difference lemens on one ear in presence of an unvarying tone on the other ear). New explanations of the results obtained in the monaural intensity difference limen tests used are proposed, based on the localization areas in the cochlea, along the auditory nervous system and in the higher auditory centers. New suggestions for the use of the difference limens in audiometry are made.
A case is reported in which a patient was become unable to identify all kinds of auditory material, including speech, despite only subnormal audiometric thresholds (i.e. "auditory agnosia"). The following audiological disorders were shown: some fragility in the perception of brief sound stimuli, difficulties to apprehending prolonged series of stimuli (rhythms), defective sound localization, an increase in the homolateral and in the contralateral effects of masking sounds. On the other hand, differential thresholds for frequency and for intensity, as well as fusion thresholds, were little affected, or unaffected. A complete dissociation appeared between the auditory evoked potentials and the audiometric thresholds; a year after the first examination, and the following years, the auditory potentials were largely reduced, or even have elapsed for one ear, while the audiometric thresholds seem to remain nearly the same.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.