PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Auditory Perception”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74Linked to original sources
PubMed1977

Intermodulation product pair 2f1 +/- fh: masking and growth.

To examine the question of whether the distortion product 2f1 - fh is unique--whether a special nonlinear mechanism is responsible for its production--estimates of 2f1 - fh and of 2f1 + fh amplitudes were obtained in three listeners. Threshold shifts measured with a tone-on-tone masking paradigm for each distortion product suggest that each have similar properties and are masked by other tones as if they had a physical realization in the cochlea. Their masking is not a function of stimulus fine-time structure. The 1 dB/dB growth of 2f1 - fh was not changed by rendering it inaudible as previously suggested. Possible explanations of the 1 dB/dB growth of 2f1 - fh compared with the accelerated growth of 2f1 + fh are examined.

Auditory Perception↗
PubMed1977

Behavioral system and apparatus for tone-detection and choice reaction times in the cat.

An efficacious operant-conditioning procedure for psychophysical experiments with cats is described. The system features (a) restraint of the cat and the use of the liquid reinforcement delivery cup to control orientation with respect to the stimuli, (b) a minimum of apparatus between the cat and a free-field sound source, (c) two response pedals so that separate "Yes" and "No" responses are defined, (d) a discrete trial procedure with reaction time (RT) defined as the time from the onset of a trial until the occurrence of a response, and (e) an effective liquid reinforcer and simple delivery system. Operation of the system was demonstrated with the method of constant stimuli. Detectability was directly related, and median RT for correct "Yes" responses inversely related, to tone sound pressure.

Animals↗
PubMed1978

Temporal integration of tone glides.

Temporal integration of rising and falling tone glides against a 50-2800-Hz background of noise at a sound pressure level of 60 dB re 20 micronPa was studied in two experiments. Glides were in the frequency ranges 200-700 Hz and 1200-1700 Hz for durations of 5-120 ms. Results indicate an asymmetry in the detectability of rising and falling glides of short duration, with rising glides detected at lower signal intensities in both frequency ranges. These effects are discussed in terms of differences in pattern of frequency analysis of identical, but temporally reversed, waveforms.

Acoustic Stimulation↗
PubMed1978

Detectability of varying interaural temporal differences.

Detectability and salience of time-varying interaural temporal differences (IATD's) were measured in three experiments by determining observers' ability to follow the temporal fluctuations of a "moving stimulus"--a 3000-Hz low-pass computer-generated noise presented binaurally with a sinusoidally varying IATD. In the first two experiments the peak IATD (deltat the "extent of movement") was manipulated to determine, for different rates of interaural variation (fm), threshold discriminability of the "moving" stimulus from a reference (two-interval forced-choice paradigm). The nonmoving reference was either a dichotic noise stimulus (experiment 1) or a dichotic noise stimulus whose "image width" matched that of the excursions traced by the "moving stimulus" (experiment 2). Threshold deltat's in the two experiments were similar, increasing from 30 microns at fm = 0 Hz to 90 microns at fm = 20 Hz, indicating a "low-pass characteristic" for the binaural system. Thresholds decreased again for fm = 50 Hz, apparently because at these high rates of "movement" observers used other cues than the varying IATD's to perform the task. The third experiment measured the threshold of a binaural click in the presence of a "moving noise" masker as a function of fm and of the instantaneous IATD of the masker when the click was presented. As fm increased, click threshold gradually became independent of the masker's instantaneous IATD, again suggesting a "low-pass" characteristic for the binaural system; additionally, there was some evidence for a lag in the system's response for fm greater than 5 Hz. The data from the three experiments are discussed in terms of results from other studies which have investigated temporal aspects of the binaural system. The possible existence of movement detectors in the auditory system is discussed.

Acoustic Stimulation↗
PubMed1978

Auditory handicap of hearing impairment and the limited benefit of hearing aids.

The aim of this article is to promote a better understanding of hearing impairment as a communicative handicap, primarily in noisy environments, and to explain by means of a quantitative model the essentially limited applicability of hearing aids. After data on the prevalence of hearing impairment and of auditory handicap have been reviewed, it is explained that every hearing loss for speech can be interpreted as the sum of a loss class A (attenuation), characterized by a reduction of the levels of both speech signal and noise, and a loss D (distortion), comparable with a decrease in speech-to-noise ratio. On the average, the hearing loss of class D (hearing loss in noise) appears to be about one-third (in decibels) of the total hearing loss (A + D, hearing loss in quiet). A hearing aid can compensate for class-A-hearing losses, giving difficulties primarily in quiet, but not for class-D hearing losses, giving difficulties primarily in noise. The latter class represents the first stage of auditory handicap, beginning at an average hearing loss of about 24 dB.

Adolescent↗
PubMed1978

Temporal switching between binaural information sources.

An estimate of the rate of perceptual switching between two binaural information sources was sought by a procedure which employed an emergent perceptual property--the shape of the binaural sound image. Random polarity-modulated pulse trains were delivered to the two ears with controlled periods of interaural phase agreement and of phase disagreement. As the rate of alternation between the two interaural states is increased, discrimination suffers. With equal periods of phase agreement and disagreement, threshold periods of 2.2-3.4 ms, or about 300-450 alternations per second, are obtained. Such rates far exceed estimates of the rate of interaural switching obtained by other experimental paradigms. With unequal periods of agreements and disagreements, a minimum threshold period of 1.5 ms is the limiting factor. Large individual differences were noted. Other procedures for coding binary information yielded similar results. Rapid switching rate thresholds are obtained for narrow-band signals over a wide frequency range. A "central integration time" is identified with the threshold interaural switching period, and appears to be identical with the minimum integration time for monaural tasks.

Acoustic Stimulation↗
PubMed1978

Theory of binaural interaction based on auditory-nerve data. III. Joint dependence on interaural time and amplitude differences in discrimination and detection.

This paper is primarily concerned with issues of symmetry-asymmetry in the joint dependence of binaural performance on interaural time delay and interaural amplitude ratio. The predictions of our model based on auditory-nerve data are shown to be inadequate for available data showing asymmetries in interaural time discrimination. Measured detection thresholds for a 500-Hz tone burst masked by wide-band noise are reported for nonunity amplitude ratios and both polarities of delays in order to test for asymmetries analogous to those observed in the time discrimination case. The detection results show only small asymmetries and are not inconsistent with the model. A general discussion of our model and the implications of available empirical results leads to a suggested modification of the model. We show by an example that modifications of the type we are suggesting are capable of describing the detection data and at least the gross trends of the discrimination data.

Auditory Perception↗
PubMed1978

Temporal integration of two-component tone glides.

Temporal integration of complex signals composed of two linearly combined tone glides was studied in a 60-dB SPL noise background. When both glide tones increased or decreased in frequency, integration functions differed for durations shorter than 50 ms in a manner similar to results obtained for single-component tone glides. That is, rising two-component glides were detected at lower thresholds than were falling two-component glides. However, when one component increased in frequency and the other decreased, thresholds were the same, regardless of which component increased and which decreased.

Acoustic Stimulation↗
PubMed1979

Selective adaptation to frequency-modulated tones: evidence for an information-processing channel selectively sensitive to frequency changes.

Exposure to an FM tone elevates FM threshold but not AM threshold. This holds for a wide range of frequency deviations (delta F = +/- 0.4 Hz- +/- 30 Hz at least) provided that modulation frequency is low (fm = 2 Hz), but if fm is somewhat higher (e.g., 8 Hz) the finding only holds for small frequency deviations. FM threshold can rise with time up to an adapting duration of at least 1200 s, through this buildup depends on frequency deviation. Exposure to an AM tone elevates AM threshold, but not FM threshold, over a wide range of modulation depths (at least m = 5%--50%). Quasi-FM (QFM) adapting tones resemble FM adapting tones in their effects upon FM and AM sensitivities, even though QFM and AM adapting tones have identical power spectra. Exposure to a pure tone produces no difference between FM and AM threshold elevations. These data can be explained if the human auditory pathway contains separate information-processing channels for AM and FM signals whose sensitivities do not overlap even with suprathreshold stimuli. We suppose that the FM channel (but not the AM channel) is sensitive to changing differences (or ratios) between signals from different sites along the basilar membrane.

Adaptation, Psychological↗
PubMed1979

Auditory lateralization in monkeys: an examination of two cues serving directional hearing.

In assigning binaural ongoing time differences (phase) as the cue for localization of low frequencies, and binaural intensity differences as the cue for localization of high frequencies, the duplex theory has successfully accounted for human directional hearing of tones. Sensitivity of monkeys to these cues was examined in two experiments. The dependencies on frequency of interaural intensity difference thresholds (lateralization experiment I) and time difference thresholds (lateralization experiment II) were determined behaviorally on three monkeys (M. nemestrina). The range of frequencies was from 125 Hz to 8 kHz in experiment I and from 250 Hz to 2 kHz in experiment II. The results indicate that the duplex theory is applicable to monkeys. However, monkeys are less sensitive than man to both binaural cues. The shortest time disparity monkeys discriminate is 42 microseconds at 1.5 kHz and the smallest intensity difference is 3.5 dB at 500 Hz. Good agreement between the present findings and localization measurements [C. H. Brown et al., J. Acoust. Soc. Am. 63, 1484-1492 (1978)] suggests: (a) that monkeys utilize time disparity cues through higher frequencies than man; and (b) that inaccurate localization by monkeys at high frequencies reflects decreasing sensitivity to interaural intensity cues.

Acoustic Stimulation↗
PubMed1980

Localization of noise bands by Old World monkeys.

The acuity of auditory localization in Old World monkeys (Macaca) was determined psychophysically for 44 noise bands graded in bandwidth and center frequency. The acuity of localization was assessed through the method of constant stimuli under free-field conditions in an anechoic chamber. Monkeys were trained through positive-reinforcement operant-conditioning procedures to report a change in azimuth of the signal by releasing a response disk. The results show that localization thresholds are dependent upon the bandwidth of the signal over much of the macaque's range of audibility. Thresholds for the detection of a change in location varied from 18 degrees (for a signal 250 Hz in bandwidth centered at 11 200 Hz) to 4 degrees (for a signal 8000 Hz in bandwidth centered at 8000 Hz). The results suggest that the localization of spectrally complex signals is determined by a mechanism sensitive to periodicity (time-domain) information across the monkey's range of audibility.

Animals↗
PubMed1980

Gap detection by the chinchilla.

Five monaural chinchillas were trained with a method of shock-avoidance conditioning to respond to silent intervals, or gaps, in an otherwise noise. The noise was low-pass filtered at either 10 or 6 kHz and presented at six intensities ranging between 23- and 77- dB sound-pressure level (SPL). Gap detection thresholds were determined according to the method of constant stimuli. For both noise bands, gap thresholds were approximately 3 ms at the highest intensity levels and increased to approximately 6 ms at the lowest level. The results obtained from the chinchilla are in general agreement with those obtained from man.

Animals↗
PubMed1981

Lateralization of jittered tones.

Lateralization thresholds based on differences in interaural arrival time have been measured for jittered 4-kHz tones. The results are in good agreement with those of other authors obtained with bandpass noise as well as with AM and FM signals. However, thresholds are about two orders of magnitude higher than those of Nordmark [J. Acoust. Soc. Am. 60, 870-880 (1976)] obtained with jittered tones. These results suggest an explanation of the lateralization of jittered tones and other FM signals on the basis of an hypothesized FM-to-AM conversion which may take place peripherally.

Acoustic Stimulation↗