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At least 1,171 records · Page 65Linked to original sources
PubMed1992

[Development of sound lateralization].

Perceptual sound lateralization is determined from differences in time and loudness of signals arriving separately at bilateral ears, with the time difference being the more important one. The author examined the development of sound lateralization using a self-recording device developed by Sato T, which measures the sensitivity of sound lateralization on the basis of time and loudness differences separately. Subjects were 59 children aged 2 to 18 years and 12 adults who were audiologically and neurologically normal. Sound stimulus was 500 Hz continuous band noise. (1) The testable rate was increased in children older than the age of 4, and all children over 7 years of age could be tested. (2) Children over 4 years of age could lateralize sound on the basis of time difference. Sensitivity to time differences improved rapidly, showing a steep curve, in children from the ages of 4 to 6, and then increased slowly until adulthood. (3) Sensitivity to loudness differences increased and the normal range distribution decreased with age. There is a possibility that children aged 4 can discriminate loudness difference almost as well as adults.

Acoustic Stimulation↗
PubMed1992

Towards a quantitative description of asthmatic cough sounds.

This study describes a method of quantitatively characterizing cough sounds using digital signal processing techniques. Differences between asthmatic and non-asthmatic cough sounds are presented. Coughs from 12 asthmatic and 5 non-asthmatic subjects were analysed. Cough sounds and flows were digitized, at a sampling rate of 5 kHz, before and after a free-running exercise test. Individual coughs were divided into two or three phases, corresponding to the initial glottal opening burst, the quieter middle phase, and (sometimes) the final closing burst. Standard signal processing techniques were then invoked to characterize the spectral and temporal shapes of the first two phases. Factor analysis indicated that the spectral shapes of the two phases are independent, with each being largely described by the degree of "peakedness" in the spectrum, and by the balance of energy between low and high frequencies. Both the duration of the initial burst and zero-crossing rates of the cough waveform (which indicates the "spectral balance") during each of the first two phases were smaller for asthmatic than for non-asthmatic coughs. Fewer asthmatic coughs contained a final burst. Discriminant analysis between the two groups gave classification error rates of 20-30%. The peak flow recorded during the cough was significantly smaller for asthmatics, and correlated very well with the peak flow recorded during forced expiration. Thus, significant differences exist between asthmatic and non-asthmatic cough sounds. An effective representation of the temporal structure of the cough sound is required to successfully characterize the cough.

Asthma, Exercise-Induced↗
PubMed1992

Sound levels in the human uterus.

OBJECTIVE: We sought to determine the degree to which noises and voices are attenuated or enhanced as they pass into the uterus. METHODS: In eight parturients, a hydrophone in the uterus was used to measure sound pressure levels for externally generated one-third-octave band noises, male and female voices, and the subject's voice. RESULTS: Low-frequency sounds (0.125 kHz) generated outside the mother were enhanced by an average of 3.7 dB. There was a gradual increase in attenuation for increasing frequencies, with a maximum attenuation of 10.0 dB at 4.0 kHz. Sound attenuation was slightly less if the insonation was from in front of the woman rather than behind. Intrauterine sound levels of the mother's voice were enhanced by an average of 5.2 dB, whereas external male and female voices were attenuated by 2.1 and 3.2 dB, respectively. The effect of frequency on attenuation, the differences between front and back insonation, and the differences between speakers in attenuation were all statistically significant. CONCLUSIONS: The intrauterine environment is rich with externally generated sounds. This may imply fetal risk from maternal noise exposure and may aid in understanding fetal imprinting from prenatal exposure to voices.

Acoustics↗
PubMed2005

The optimal method for recording prosthetic heart valve sounds in clinical situations.

BACKGROUND: Valve sounds are thought to be useful in evaluating the functioning of prosthetic heart valves. In previous reports, two recording instruments have mainly been used, a condenser microphone (instrument A) and an accelerometer (instrument B), respectively. This study aimed to investigate the applicability of these conventional devices in recording mechanical heart valve sounds in daily clinical situations. In addition, two other instruments, namely, a stethoscope including a small microphone in its tube (instrument C) and an electrostethoscope (instrument D), were proposed and examined. METHODS: Mechanical valve sounds were recorded from postoperative patients using each-device and the signal to noise ratio (SNR) of each was calculated. Frequency characteristics of the two newly proposed instruments were also investigated by recording a sweep signal in an anechoic chamber. RESULTS: The SNR values of the new instruments were significantly superior to those of conventional ones (A, sound signals were not defined from noises; B, 0.97 +/- 0.59 dB; C, 11.5 +/- 4.7 dB; and D, 9.4 +/- 3.5 dB, respectively p<0.05). The frequency characteristics of the two newly proposed instruments were also shown to be acceptable (under 10 kHz), though resonance frequency peaks were observed. CONCLUSIONS: Two newly proposed instruments can record mechanical heart valve sounds more noiselessly and with more ease than previous ones, and their frequency characteristics are acceptable.

Acoustics↗
PubMed1991

Closing click of St Jude Medical and Duromedics Edwards bileaflet valves: complaints created by valve noise and their relation to sound pressure and hearing level.

The metallic clicking sound created by mechanical heart valve prostheses frequently bothers patients. To test whether sounds generated by different bileaflet valves correlate to complaints related to the prosthetic clicking 73 patients were investigated after valve replacement with Duromedics Edwards (DE) (n = 38) and St Jude Medical (SJM) (n = 35) valves. The patients were asked about their complaints, sound pressure levels were recorded and audiometry was performed. Sixty-five percent of patients could hear their valve, 18% had sleeping disturbances, 5% felt bothered during daytime and 12% would prefer a less noisy valve. In symptomatic patients, sound pressure levels were higher than in asymptomatic patients (valve audible 45 +/- 8 db(A) vs not audible 39.9 +/- 10 db(A) at 10 cm; P = 0.016). These differences were most apparent in the high frequency bands, corresponding to the metallic click. Symptomatic patients had better hearing and were younger than patients without complaints. Fifty-one percent could hear their valve by conduction through the body, after eliminating air conduction by the use of headsets. The DE prostheses were louder than the SJM valves in general (47.4 +/- 7 vs 39.8 +/- 5 db (A) at 10 cm; P = 0.001) and in each valve position. Patients with DE prostheses had significantly more complaints. The intensity of the closing click of mechanical valves correlates to the complaints caused by prosthetic clicking and thus sound emission should be considered when a mechanical heart valve prosthesis is selected.

Adult↗
PubMedDate not supplied

[The effect of the rate of movement of a sound image on human long-latency auditory evoked potentials].

In 10 healthy subjects, studies have been made on changes in amplitude-temporal characteristics of N1-P2 components at different rates of movement of a sound image (3.14, 1.57 and 0.78 rad/s). It was shown that only movement of the sound image from the right ear to the median line of the head with sufficiently high rate (3.14 rad/s) results in the increase in total peak amplitude of N1-P2 components relatively similar parameters obtained during the effect of a resting sound image lateralized at the same ear. Latent periods of N1 component in both hemispheres are longer during the effect of the moving sound image than during the effect of the resting lateralized one, although with the decrease in the rate the difference becomes less significant. It is suggested that the right hemisphere is more sensitive to changes in the rate of movement of the sound image.

Acoustic Stimulation↗
PubMed1990

Infants' localization of sounds within hemifields: estimates of minimum audible angle.

Infants' acuity in localizing sounds within hemifields was examined by determining the smallest sound shift off 60 degrees and along the horizontal axis that infants could discriminate reliably, that is, minimum audible angle (MAA). Infants 6, 12, and 18 months of age were tested using a Go/No-Go conditioned head-turn procedure in which infants received an equal number of no-change (control) trials and sound-shift (experimental) trials. A correct response (i.e., a head turn toward the loud-speakers) on an experimental trial resulted in visual reinforcement. Localization acuity for sounds within hemifields was fairly poor and improved systematically with increasing age. MAA estimates at each age were significantly higher, indicating poorer localization acuity, in comparison to those obtained previously in research examining infants' resolution of auditory space near midline. These findings are consistent with adult data and demonstrate a finer partitioning of auditory space near midline than within hemifields. The implications of these findings for our understanding of the development of auditory processing mechanisms in sound localization are discussed.

Age Factors↗
PubMed1989

[Relationship of TMJ sounds and mandibular movements].

TMJ sounds are very important for diagnosing the state of TMJ and for evaluation of the effect of treatment. We made a report on a recording system of TMJ sounds and mandibular movement which objectively can evaluate the relationship between TMJ sounds and mandibular movement. This time we recorded and analyzed the TMJ sounds and mandibular movement under following condition. 1. Opening and closing the mandibular on some regulated velocity. 2. Opening and closing the mandibular after clenching. Conclusion 1. In case of changing habitual opening velocity, there were significantly different position of clicking in the most of TMJ disorders patients. Especially with the increasing of the velocity, the position of closing clicking tended to come near the closed condyle position. 2. The amplitude of clicking sound increased very much at the time of opening stage after clenching on the non clicking side.

Bite Force↗
PubMedDate not supplied

Temporal discrepancies between low and high frequency vibrations of the second heart sound.

The morphologic analysis of the second heart sound may provide some useful informations, not enough debated in the literature, concerning the functional status of cardiac patients. We noticed significant temporal discrepancies on the phonocardiographic tracings between the onset of the second heart sound in the lowest and in the highest frequency ranges. The correlations between the highest and the lowest frequency vibrations of the second heart sound were analysed in 119 controls, without overt cardiovascular disease, aged from 20 to 40 years and 50 to 70 years and in 148 patients with old myocardial infarction aged 42 to 80 years. The lowest frequency vibrations of the second heart sound appeared earlier in healthy young subjects than in middle-aged people. These differences may be explained by the reduced aortic compliance with advanced age. The incidence of early beginning of the low frequency vibrations of the second heart sound is greater in patients with old myocardial infarction and a poor myocardial contractile condition than in controls of about the same age. This difference may be due to impaired ventricular relaxation.

Adult↗
PubMedDate not supplied

Investigation regarding the VIth cardiac sound under pathological and normal physiological condition.

Starting from the fact that specialty data regarding a VIth cardiac sound, are scarce the paper studies the phonocardiogram recorded on four frequency bands in parallel with a EKG derivation and a carotid pulse in a lot of 532 persons (healthy and sick) using a 6-NEK-4-apparatus. The presence of this sound has not been remarked in healthy persons. In 5% out of the tested sick that presented aortic insufficiency we remarked the presence of a VIth cardiac sound of a low frequency and amplitude, possibly of a vascular nature. In all the patients that exhibited this VIth sound a 50% increase of the left ventricle ejection period as well as a 26% increase of the preejection period was noticed. The presence of this sound in the aged patients with stenosis and aortic insufficiency, exhibiting reductions of the vascular wall elasticity was not remarked.

Aging↗
PubMed1987

Stopping a walking locust with sound: an analysis of variation in behavioural threshold.

Pulses of 3 kHz sound, varying in intensity from 46 dB SPL to 113 dB SPL (reference value = 20 microPa), were presented to fifth instar larvae of the locust Locusta migratoria migratorioides (R. and F.) walking on a recording treadmill. Walking locusts either responded to the sound by stopping within 2.1 s of its presentation or they continued walking apparently unaffected by it. The latency of the stopping response was correlated with stimulus intensity: the higher the stimulus intensity, the sooner the locust stopped walking. Pauses induced by sounds were longer than those that occurred 'spontaneously' and increased in duration with increasing stimulus intensity. This relationship, however, was modulated by walking speed: the faster the locust was walking, the shorter the following pause for a given stimulus intensity. The intensity of sound needed to elicit a response depended on the length of time the locust had spent in uninterrupted walking before the stimulus was presented. The stopping threshold for sound stimuli presented 3 s into the walking bout was 84 dB SPL (SE +/- 1.56), and at 20 s it was significantly less, at 76 dB SPL (SE +/- 1.56). This effect of time was significant even when other factors, such as differences between individual locusts, were allowed for in the regression analysis. This shift in the behavioural threshold could not be explained simply by on-going changes in walking behaviour, for although the speed of walking was correlated with stopping threshold its effect was not statistically significant when differences between individuals and time of stimulus presentation were allowed for in the regression analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMedDate not supplied

[Directionality of sound perception in the external ear of the dog].

Sound pressure level of tone was measured using a probe tube microphone at entrance to the dog's external meatus as a function of the azimuth of the sound source. It was demonstrated that directionality of the dog's external ear and corresponding values of interaural intensity differences (delta I) were gradually increased as the tone frequency raised from 0.5 to 40 kHz. Transfer in pinnae locations from lateral to frontal positions (one of the components of orientation reaction to an unexpected sound) resulted in some narrowing of directionality diagrams and in a displacement of their maxima towards the head midline. It was calculated that owing to this effects the extent of monotonic part of the function relating delta I and azimuth of a source were enlarged. The lateral pinnae position was suggested to be optimal for sound detection and the frontal one for localization of the moving sound source.

Acoustic Stimulation↗
PubMed1979

The first heart sound abnormalities accompanied with alteration of systolic time intervals in incipient heart failure.

A phonocardiological analysis of the first heart sound was made and systolic time intervals were measured in 40 patients (ischaemic heart disease, hypertensive heart disease, cardiomyopathies) with incipient cardiac failure (functional groups I--II according to the NYHA) with auscultatory changes of the first heart sound and in controls of randomly selected healthy persons or patients in whom cardiopulmonary disease was excluded. The patients in all diagnostic groups differed significantly (P less than 0.05--0.001) in practically all the phonocardiographic indicators from the controls. The most constant abnormal finding was a pathological split of the first heart sound which may be divided into three phonocardiographic forms. Simultaneously, systolic time intervals alterations (P less than 0.02--0.001) were also found in these patients and indicated a lowered performance of the left ventricle. The results suggest that 1) a certain relation exists between systolic time intervals and the phonocardiographic pattern of the first heart sound in patients with cardiovascular diseases and those without it; 2) the modified (pathologically splitted and prolonged) first heart sound could be a sign of incipient cardiac failure.

Cardiovascular Diseases↗
PubMed1982

Voluntary ocular tracking movements in response to a sinusoidally moving intermittently active sound source.

Voluntary eye movements in response to a sinusoidally moving, intermittently active sound source were investigated in 40 young healthy human subjects. Visual afferent input was prevented during the experiments. With increasing burst repetition rates of the sound source, different forms of eye movements were observed: a) so-called single and repetitive adversive movements consisting of saccades which occur with certain latencies in response to single bursts; b) so-called saccadic eye tracking movements which are characterized by numerous small saccades occurring in accordance with the target (sound source) movement but lacking a time correlation between the saccades and single bursts. It was found that saccadic eye tracking movements were performed instead of adversive movements when at least 4 to 10 bursts per movement period of the sound source was transmitted (with movement frequencies of the sound source from 0.1 to 0.5 Hz). Slight intersaccadic drifts, which could be regularly observed in all types of eye movements were interpreted as instability of fixation in darkness.

Auditory Perception↗
PubMed1981

[On the genesis of the first heart sound: phono-echocardiographic study in patients with A-V block (author's transl)].

A phono-echocardiographic study of acustic and morphologic events was performed in three patients with atrioventricular block in order to assess the role of the mitral valve in the changes of the amplitude of the first heart and, more generally, in the genesis of the first heart sound. Simultaneous recording of the electrocardiogram, the apical phonocardiogram and the mitral echocardiogram showed: 1) the coincidence between the C point of the echocardiogram and the onset of the earlier high frequency vibrations of the first heart sound (M1); 2) a close correlation between the intensity of the first heart sound and the position of the mitral valve at the onset of ventricular systole (P less than 0.001); 3) longer duration of the first heart sound in those beats when there was superimposition of P wave in QRS. The authors illustrate the recent reports about the genesis of the first heart sound and emphasize the main role of the mitral valve suggesting that the position of the mitral leaflets at the onset of ventricular systole influences the mechanism of acceleration and deceleration of blood and vibrations of the "cardiohemic system".

Adult↗
PubMed1980

[Genesis of 5th sound. A comparative phonomechanographic and echographic study (author's transl)].

846 children between the ages of 6 and 12 were examined by phonocardiogram. The 5th sound was noted in 30.8% of the subjects examined. It appeared as a single or double vibration of approximately 65 msec from the third sound and corresponds to a small wave "H" of apexcardiogram at approximately 50 msec from the end of "E" wave. From the comparative poligraphic and echocardiographic study, the 5th sound corresponds to one or more added waves (G and G1) between point F and point A of the echogram of the anterior mitral leaflet; they are in exact chronological correspondence with the "H" wave of the APG. The 5th sound is evident and also the added waves of the anterior mitral leaflet (G, g1) when the frequency of the heart is slow. When the frequency increase, the 5th sound blends with the 3rd that appears prolonged and G, G1 waves become a single wave until its disappearents.

Adult↗
PubMed1993

[Diagnosis of inhalation injury by larynx-tracheal respiratory sound].

The experiment in rabbits demonstrated that the more narrow the tracheas were, the higher the frequency of respiratory sound was. The frequency of tracheal respiratory sound was about 50-100 Hz in normal rabbits. In mildly narrow frequency of respiratory sound was 50-200 Hz, in mediately narrow trachea 200-300Hz, in severely narrow trachea 400-700 Hz. 74 patients were studied. The patients with more severe inhalation injury had higher tone of respiratory sound and simultaneously showed dyspnea because their larynx-tracheas became more narrow due to edema. When high tone appeared obviously tracheostomy must be immediately performed to release obstruction of the respiratory tract. 26 of these patients underwent tracheostomy. This reliable, simple diagnosis can be used to monitor larynx-tracheal condition, and high tone of respiratory sound can be used as an indication for tracheostomy.

Adolescent↗
PubMed1994

An in vitro study of mechanical heart valve sound loudness.

The purpose of the study was to measure the valve sound loudness of eight 25 mm aortic mechanical heart valve prostheses under controlled laboratory conditions in an isolated acoustic environment. A specially designed single-chamber pulse duplicator was constructed within an anechoic box that isolated the sounds of the valve from external noise. The valves were closed with a stimulated aortic pressure waveform of three different amplitudes. Valve sound loudness was measured with ISO-532/B (Zwicker method), which is based on a model of loudness perception that is better than dB(A), the traditional A-weighted sound pressure level. The average loudness for each valve was St. Jude Medical, 0.97 sones; CarboMedics, 0.98 sones; Sorin Biomedica Bicarbon, 1.08 sones; Edwards Tekna, 1.92 sones; Edwards Duromedics, 2.36 sones; Monostrut, 2.48 sones; Sorin Biomedica Carbocast, 3.17 sones; and Medtronic Hall, 3.57 sones. There was a positive trend between valve sound loudness and aortic drive pressure for most valves in the study.

Aortic Valve↗