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At least 109 records · Page 6Linked to original sources
PubMed1993

Human auditory cortical mechanisms of sound lateralization: I. Interaural time differences within sound.

Neuromagnetic responses to 600-ms binaural click trains, presented once every 1.1 s, were recorded with a 24-channel gradiometer from 6 healthy humans. During the first 300 ms, the left-ear stimulus led the right by 0.7 ms and the sound was lateralized to the left ear. At 300 ms, the interaural time difference (ITD) changed and the lateralization moved to one of 5 different locations between the ears. An N100m response peaked about 110 ms after the sound onset and an N130mc response (c to stress a response to the change) about 135 ms after the ITD change. The source locations of N100m and N130mc agreed with activity in the supratemporal auditory cortex; this was confirmed in one subject by superimposing MEG results on MR images. The sources of N100m and N130mc did not differ statistically significantly from each other, nor were there differences in N130mc sources to various lateralization changes. N130mc grew larger when the ITD change increased, in parallel with the increase in the change of the perceived location. We suggest that N130mc is analogous to N100m, but is delayed due to postmasking induced by the early part of the sound.

Acoustic Stimulation↗
PubMed2005

A dynamic fuzzy neural filter for separation of discontinuous adventitious sounds from vesicular sounds.

This paper presents a recurrent filter that performs real-time separation of discontinuous adventitious sounds from vesicular sounds. The filter uses two Dynamic Fuzzy Neural Networks, operating in parallel, to perform the task of separation of the lung sounds, obtained from patients with pulmonary pathology. Extensive experimental results, including fine/coarse crackles and squawks, are given, and a performance comparison with a series of other models is conducted, underlining the separation capabilities of the proposed filter and its improved performance with respect to its competing rivals.

Algorithms↗
PubMed2005

Characteristics of sound discrimination enhancement after sound exposure in adult rats.

The auditory perceptual capacity of adult rats was assessed with regard to performance during 2-sound-discriminative operant conditioning. If the animals were passively exposed to a sound stimulus before the conditioning, performance was improved (sound-exposure-enhanced discrimination [SED]). SED had a stimulus specificity that could not be predicted in terms of the cochleotopy. SED was obstructed by D-2-amino-5-phosphonovaleric acid, an antagonist of N-methyl-D-aspartate receptors, infused into the auditory cortex (AC). No evidence supported the hypothesis that SED was due to a change of attention or motivation or to interference in the association process (e.g., latent inhibition). These findings suggest that passive auditory experience can enhance the perceptual capacity of an adult rat's AC.

2-Amino-5-phosphonovalerate↗
PubMed2001

Enhancing maximum measurable sound reduction index using sound intensity method and strong receiving room absorption.

The sound intensity method is usually recommended instead of the pressure method in the presence of strong flanking transmission. Especially when small and/or heavy specimens are tested, the flanking often causes problems in laboratories practicing only the pressure method. The purpose of this study was to determine experimentally the difference between the maximum sound reduction indices obtained by the intensity method, RI,max, and by the pressure method, Rmax. In addition, the influence of adding room absorption to the receiving room was studied. The experiments were carried out in an ordinary two-room test laboratory. The exact value of RI,max was estimated by applying a fitting equation to the measured data points. The fitting equation involved the dependence of the pressure-intensity indicator on measured acoustical parameters. In an empty receiving room, the difference between RI,max and Rmax was 4-15 dB, depending on frequency. When the average reverberation time was reduced from 3.5 to 0.6 s, the values of RI,max increased by 2-10 dB compared to the results in the empty room. Thus, it is possible to measure wall structures having 9-22 dB better sound reduction index using the intensity method than with the pressure method. This facilitates the measurements of small and/or heavy specimens in the presence of flanking. Moreover, when new laboratories are designed, the intensity method is an alternative to the pressure method which presupposes expensive isolation structures between the rooms.

Building Codes↗
PubMed1990

Perceived sound quality of reproductions with different frequency responses and sound levels.

Three programs (female voice, jazz music, and pink noise) were reproduced using four different frequency responses and two different sound levels. Fourteen normal hearing subjects listened to the reproduction via earphones and judged the sound quality on seven perceptual scales (loudness, clarity, fullness, spaciousness, brightness, softness/gentleness, and nearness) and a fidelity scale. Significant differences among the reproductions appeared in all scales and could be attributed to the differences in frequency response or sound level or both. Interactions between the reproductions and the programs could be explained by the relations between the spectrum of the programs and the frequency responses used. The results for the noise program were similar to those for the jazz music program.

Adult↗
PubMed1976

Persistence of the third heart sound after resection of the native mitral and tricuspid valves. Evidence against the valvular theory of third sound origin.

A patient is described with severe rheumatic mitral and tricuspid insufficiency in whom both atrioventricular valves with their chordae tendineae and papillary muscles were resected and replaced with Hancock porcine grafts. This would appear to be the second such patient reported and the first described in detail in whom the third heart sound persisted postoperation. This occurrence documents the fact that a third heart sound can occur in the absence of native atrioventricular valve leaflets and the major portions of the subvalvular supporting apparatus, and argues against the theory that the third heart sound is generated by either the valvular leaflets of the subvalvular apparatus.

Adult↗
PubMed1988

Poor breath sounds with good voice sounds. A sign of bronchial stenosis.

The auscultatory finding of disparity in breath and voice sounds, the former being absent or faint whereas the latter are easily heard when compared to the corresponding site over the opposite lung, predicts stenosis of a main, intermediate, or lobar bronchus. Stenosis limits airflow and consequently reduces turbulence, causing diminution or absence of breath sounds over the poorly ventilated region; however, flow-independent voice sounds are not significantly impaired. This sign was present in ten patients, in each of whom bronchial stenosis was confirmed by bronchoscopy.

Bronchial Diseases↗
PubMedDate not supplied

Sound localization for a virtual sound source in cases of chronic otitis media.

Sound localization in subjects with chronic otitis media (COM) was examined before and soon after ear surgery by means of virtual sound presented by headphones, sound being synthesized based on the head-related transfer functions (HRTFs) in a normal subject. The localization ability in COM patients was usually worse than that in normal subjects, but was better than expected when compared with cases of acute loss. On the other hand, the effects of hearing improvement on localization ability observed in COM patients were smaller than those of simulated acute hearing loss achieved by earplugs in normal subjects. This seems to suggest that the localization cues in patients with chronic hearing loss are different from those under normal conditions.

Adult↗
PubMedDate not supplied

[Discrimination of the characteristics of sound signals simulating sound source movement].

The dog's ability to perceive the movement of a sound image was studied on six animals by means of avoidance technique. Rhythmical click trains were used as sound stimuli with interaural time and intensity differences changed gradually in time. Various acoustic parameters of the signal were controlled in order to estimate their significance for perception of the sound movement. The lower click repetition rate was shown to exceed 5 click/s. The threshold change of the interaural time and intensity differences was equal to 130 mcs and 4.5 dB correspondingly.

Animals↗
PubMed1979

Perceived sound quality of sound-reproducing systems.

Perceived sound quality of loudspeakers, headphones, and hearing aids was investigated by multivariate techniques from experimental psychology with the purpose (a) to find out and interpret the meaning of relevant dimensions in perceived sound quality, (b) find out the positions of the investigated systems in these dimensions, (c) explore the relations between the perceptual dimensions and the physical characteristics of the systems, and (d) explore the relations between the perceptual dimensions and overall evaluations of the systems. The resulting dimensions were interpreted as "clearness/distinctness," "sharpness/hardness softness," "brightness-darkness," "fullness-thinness," "feeling of space," "nearness," "disturbing sounds," and "loudness." Their relations to physical variables were explored by studying the positions of the investigated systems in the respective dimensions. Their relations to overall evaluations were studied, and the implications of the investigations for continued research are discussed.

Adult↗
PubMed2004

[Clinical neurophysiological study of verbal and non-verbal sound perception: normal development of P300 event-related potential to different sound stimuli].

Developmental changes of P300 event related potential were evaluated in healthy children and adults aged from 7 to 29 years old, adopting 2 pairs of oddball stimuli: a non-verbal sound (tone burst: TB) pair and a verbal sound (VS) pair. P300 was evident for the target stimuli. In adult subjects, P300 was dominant at Pz for both stimuli. Peak latency of P300 was significantly longer for VS than for TB in both groups. P300 amplitude of the child group was higher than that of the adult group, however, there was no difference in P300 amplitude between stimuli conditions. Developmental changes of P300 from each stimuli condition were simulated by a quadratic equation. The age showing the shortest P300 peak latency was younger for TB (20.3 years) than for VS (23.6 years). The P300 peak latency reduced around 10 years old more rapidly for VS than for TB. In conclusion, there was no difference of the dominancy of P300 between the stimuli. The developmental changes of P300 were regulated by several components of the sound stimuli, such as their frequency.

Acoustic Stimulation↗
PubMed1999

Change of intensity fails to produce an irrelevant sound effect: implications for the representation of unattended sound.

Sequences of changing sounds that are irrelevant to the task at hand disrupt serial recall appreciably even though participants are instructed to ignore the sounds. Three experiments, which compared the effect of changing token identity with that of changing intensity in the 55- to 85-dB (A) range, were conducted. Although serial recall was impaired by changes in token identity, no disruptive effects of a change in intensity were found. This was replicated using speech and nonspeech. Overall, the absence of a changing intensity effect was based on an analysis of the performance of 115 participants in a design whose power was .98. This outcome suggests that the representation of intensity in preattentive processing of auditory stimuli is somewhat different from that of other acoustic features.

Humans↗
PubMedDate not supplied

Peripheral vasoconstriction in the rat in response to sound. II. Dependence on rate of change of sound level.

Vasoconstrictions elicited by sound were studied in the non-anaesthetized rat. Arterial pulsations in the tail were recorded by a non-invasive technique. On slightly heating the animal, the tail vessels became dilated. An 80 dB SPL noise burst caused a decrease in pulse amplitude, usually to less than 10% of the pre-stimulus value. It was found that 4 s bursts of 80 dB SPL noise with rise times 1, 10, or 100 ms were equally efficient in producing vasoconstriction. If the rise time was longer, 1 s, the vasconstriction was significantly smaller. It was pointed out that the feedback control of the stimulus noise provided by the acoustic middle ear reflex would contribute to enhancing rapid variations in sound level, and thereby form part of a physiological explanation for the present findings.

Acoustic Stimulation↗
PubMed2003

Scattering of sound by sound in the vicinity of the liquid-vapor critical point.

We report an experimental study of the scattering of sound by sound in the vicinity of the liquid-vapor critical point of carbon dioxide. We measure the amplitude of the scattered difference frequency wave generated by acoustic bulk nonlinearities. We observe that it is strongly increased in the vicinity of the critical point.

Journal Article↗
PubMedDate not supplied

A sound mind in a sound body: to what extent do they go together before and after psychotherapy?

As in the old adage, we found that a sound mind and a sound body were associated--the frequency of psychological symptoms was highly correlated with the frequency of physical symptoms for seventy-three patients on the Hopkins Symptom Checklist both before and after psychotherapy. The physical and psychological sets of items were each internally consistent and moderately separable from each other. Each set showed some stability over time. The physical symptoms were not associated with current stress, but with worries about physical health. The worries about physical health did not appear to reflect just needless worry since the physical health items correlated with the physicians' physical examinations items (in another sample). Both sets of items were significantly reduced during psychotherapy although the psychological set more so than the physical set. The extent of the reduction in the physical and psychological sets was correlated; the most frequently reduced physical symptoms were those that were initially most common. Reductions in psychological symptoms was moderately correlated with improvement in psychotherapy; for the physical symptoms, the correlation was also significant, but reduced.

Humans↗
PubMed1995

Frequency modulated sound pattern analysis in the lesser bulldog bat: the role of interactions between adjacent frequency elements of complex sounds.

A stereotyped approach phase vocalization response of Noctilio albiventris to artificial echoes simulating a virtual approaching object was used to assess the ability of the bat to analyze and extract distance information from the artificial echoes. The performance of the bats depended on the temporal pattern of frequency change of the continuously sweeping frequency modulated (FM) component of the signals. When the bats were presented with a CF/FM signal containing a time-reversed upward FM sweep, they responded with approach phase behavior at a performance level that was significantly below that seen with a CF/FM signal containing a naturally structured downward FM sweep. When the FM sweep was divided into a series of brief pure tone steps, the extent to which the bats showed a difference in their capability to process upward versus downward FM sweeps depended on the difference in frequency between the pure tone steps. The bats effectively processed downward but not upward FM sweeps when the difference in frequency between pure tone frequency elements of the FM sweeps was from about 100-200 Hz, but they effectually processed both downward and upward FM sweeps when the tonal elements composing the FM sweeps were separated by more than about 200 Hz. This suggests that the ability of the bats to effectively process downward but not upward FM sweeps is based on local interactions between adjacent frequency elements of the complex sounds.

Animals↗