Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SOUNDS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 19 recordsLinked to original sources
PubMed1976

[Sound spectrographic investigations of heart sounds and murmurs and of the sounds produced by artificial valves (author's transl)].

The normal heart sounds, murmurs, opening and closing sounds of aortic and mitral valve prostheses were recorded on a tape in order to obtain the highest frequencies which were recordable on the chest wall. Sections of these tapes were analyzed in terms of contour sonagrams. For this purpose six groups were formed and investigated: group I comprised persons without cardiovascular diseases, group II patients with mitral valve failure, group III patients with aortic valve failure, group IV patients with congenital heart disease, group V patients with Starr-Edwards aortic valve prostheses (model 1260) and group VI patients with various mitral valve prostheses. In each of these groups the highest recordable frequencies were measured. The peak frequencies varied widely in regard to frequency range in a comparison of the six groups. The maximum was reached at about 8000 c.p.s. in the case of the sounds of prosthetic valves. Furthermore, sound level examinations of the normal first and second heart sounds, as well as of the opening and closing sounds of the aortic valve prostheses were performed. The highest sound level of all of these sounds was found to lie within the low frequency range of 40 to 100 c.p.s. The results of both the measurements of the peak frequencies and of the maximal sound level were discussed on the basis of the presently accepted theories on the mechanism of heart sounds and murmurs.

Aortic Valve↗
PubMed1997

[Use of recording methods and sound analysis of cough in the study of sound phenomena associated with respiration].

The objective registration of the human body functions is one of the main tasks of the modern and prospective medicine. The registration of the heart, brain, muscles etc. activity have a long tradition. The registration of sound processes, for instance coughing was not solved completely despite their diagnostic importance. The authors worked out a new non invasive and precise method for cough sound registration and analysis which allows evaluation of the sound pattern, intensity and time duration. Application of this method for registration and analysis of the cry of new-borns gave rise to doubts about its suitability for an assessment of other sounds related to respiratory organs, except that of a cough. We registered and analysed the sound samples from Hirschberg's and Szende's (1982) sound archive for the purpose of the evaluation of the acceptability of the described method. The sound phenomena (109 samples of coughing, crying, barking and breathing) we transcribed from a record on a tape. The recorded signal was converted by A/D converter and analysed by computer by means of our own application programme. The sound and its pattern was transformed into a graphical record. This examination was completed by a sound frequency analysis based on the fast Fourier transformation with help of a computer likewise with our own application programme. It was found out that the used method reflected well the quantitative an qualitative differences of the evaluated sound samples. The graphical records reliably expressed the acoustic sound timbre as it shows the records of dog's and seelion's barking, cough, cry and cackling stridor of new-borns. The histographic curves which expressed the sound pattern showed a principally similar course. The intensity of sound examples was different. The sound samples duration were very often longer as the measurable time extent of software (0-819.2 ms) and therefore its evaluation was omitted. The repeated evaluation of the same sound phenomenon gave equal values. The spectrographic analysis confirmed the differences in sound samples. The values of the evaluated cough and cry sounds do not differ principally from the values registered in the previous author's observations. The results proved that the described method of cough sound registration and analysis was suitable for evaluation of different sound phenomena related to respiratory organs. (Fig. 3, Ref. 14.)

Animals↗
PubMed2001

Pattern of localisation error in patients with stroke to sound processed by a binaural sound space processor.

OBJECTIVE: The ability of 46 patients with supratentorial stroke and 15 healthy subjects to localise sounds was tested using an apparatus with headphone and sound space processor. METHODS: With a binaural sound space processor, sounds were randomly presented from seven directions in the 180 degree frontal area of the subject at intervals of 30 degrees. The subject was asked to imagine a clock face through the horizontal plane passing through the subject's ears with 12 o'clock denoting a sound from directly in front of the subject. After each sound, the subject indicated the direction from which he or she thought the sound came by mentioning the corresponding hour hand on the clock face; therefore, the answer directions were also separated by 30 degrees. A total of 21 sounds with three sounds from each direction, were presented in random order. The error between the presented direction and the answered direction of each sound was calculated. RESULTS: The mean absolute error which does not distinguish whether an error was in the counterclockwise or clockwise direction, was larger in the patients with stroke than in the healthy subjects. Overall, the patients with stroke who had right brain damage (n=29) had a larger mean absolute error than those who had left brain damage (n=17). The patients with right brain damage did not show any systematic deviation such as a rightward error or leftward error. CONCLUSION: A right brain lesion or left brain lesion can cause a patient to have error in sound localisation, and patients with right brain damage generally have a larger mean absolute error of sound localisation. The difference in the mean absolute error of sound localisation between patients with stroke with right brain damage and those with stroke with left brain damage may be explained by the inattention theory of hemispatial neglect.

Acoustic Stimulation↗
PubMed1994

[A study on digitally processed sounds designed to improve speech sound perception].

This study was performed to improve the speech sound perception of patients with sensorineural deafness by using digitally processed sounds. The fourteen CV sounds (/pa, ta, ka, ba, da, ga, ha, sa, za, ma, na, ra, ja, wa/) were selected in this study, and the consonant burst and/or voice onset time (VOT) of these sounds were doubled and/or amplified by digital processing and stored in DAT. These processed sounds and the original unprocessed sound were presented to patients and with moderate sensorineural deafness. The following results were obtained from patients who had made a mistake in discriminating the original sounds. 1. The correct answer rate for /ta/ and /sa/ was improved by amplification of the consonant burst or VOT, and for /ka/, amplification and/or repetition improved the corredt answer rate. Amplification of the consonant burst, or of the consonant burst with VOT, was especially effective for unvoiced explosive sounds (/pa, ta, ka/). 2. In voiced sounds, for /za/ and /ra/ the correct answer rate was improved by repetition or elongation of the consonant burst or transition part, and for /ga/, /ma/, and /na/ the rate was improved by amplification. 3. Semivowels (/wa, ja/) and glottal sounds (/ha/) were seldom misunderstood, and required no processing. Digital filtering processing was performed on monosyllables with the "s" sound (/sa, su, se, so/), and these filtered sounds were presented to the patients and a comparison was made with the original sounds. As a result, it was revealed that the correct answer rate could be improved by filtering, although the pass band was changed slightly by the succeeding vowel. This improvement was more apparent in the presence of environmental noise than under quiet conditions.

Adult↗
PubMed1992

[Wave form of intrabronchial spark sound on the chest wall and sound transmission in the lung-thoracic system].

A spark sound was generated in the canine bronchus and sound waves were observed on the surface (skin) and on each layer (pectoralis major muscle, intercostal muscle and parietal pleura) of the chest wall. The sound wave observed on the surface of the chest wall was 5-10 ms in duration, 400-500 Hz in dominant frequency and 0.6-1.2 ms in the duration of the initial deflection. Reverse dispersion of the waves, i.e., the later components of the wave having longer periods, was also recognized. These characteristics of the wave were similar to those of time-expanded wave-form of crackle, i.e., discontinuous adventitious lung sounds, in clinical cases. Both the spark sound and the sound wave observed on the visceral pleura were of short duration, being 0.7 ms and 1 ms, respectively. therefore, the main component of the sound wave observed on the chest surface was considered to reflect the physical properties of the chest wall itself. The analysis of place relationship within the chest wall suggested that transmission of the sound across the chest occurred not as a surface wave but as a longitudinal wave, therewith traversing the chest wall directly from the sound source. The arrival time of the sound was well correlated with the distance between the sound source and the positions of the pick-ups on the surface of the chest wall. Assuming that the medium between the source and the lung and in the chest wall were 71.5 and 29.6 m/sec, respectively. Further studies will be necessary to clarify the theory of the sound transmission through the living tissue as a viscoelastic body.

Animals↗
PubMed1998

A new versatile PC-based lung sound analyzer with automatic crackle analysis (HeLSA); repeatability of spectral parameters and sound amplitude in healthy subjects.

A versatile PC-based lung sound analyzer has been developed for short-term recording and analysis of respiratory sounds in research and clinical applications. The system consists of two sound sensors, a flow sensor, a filtering signal amplifier and a PC with a data acquisition card and software for measurement and analysis of the sounds. The analyses include phonopneumography, time expanded waveform analysis, spectral analysis with time averaged Fast Fourier Transform, frequency analysis in time domain (sonogram), and automatic detection and waveform analysis of crackles. Short-term repeatability of spectral parameters of tracheal and lung sounds was studied in 10 healthy subjects. The coefficients of variation (CoV) of the averaged quartile frequencies (F25, F50 and F75) of lung sounds during flow-controlled tidal breathing were 3.7, 4.0 and 8.9% in expiration and 2.7, 3.5 and 4.5% in inspiration, respectively. CoVs of the averaged F25, F50 and F75 of expiratory tracheal sounds were 6.9, 3.0 and 2.4%, and those of inspiratory tracheal sounds 6.3, 2.6 and 3.3%, respectively. Examples of lung sound analysis of samples containing adventitious sounds such as crackles and wheezes are presented. The results indicate that the median frequency has the best repeatability of quartile frequencies of breath sounds and they suggest that the variations of those parameters are low enough for diagnostic purposes. The results also suggest that the analyzer can be a useful new tool for pulmonary research in the fields of physiological and clinical short-term studies of respiratory sounds.

Adult↗
PubMed1984

Spectral analysis of heart sounds: relationships between some physical characteristics and frequency spectra of first and second heart sounds in normals and hypertensives.

Frequency analysis of heart sounds has been gaining recognition as a possible indicator of several heart and valve diseases, although a comprehensive study of normal heart sounds has not been published. Relating the frequency content of normal heart sounds to certain physical characteristics surrounding the generation of these sounds could lead to a valuable diagnostic tool and give a better understanding of the mechanism of heart sounds production. In this study, the first and second heart sounds from seventy-four normal, and seven hypertensive volunteers were recorded, digitized and analysed using a Fast Fourier Transform algorithm. Statistical analysis was used to relate physical characteristics (sex, blood pressure, and body surface area) of the subjects to the frequency content of normal heart sounds and to compare normal and hypertensive heart sounds. Statistical analysis showed that the major concentration of energy, for both first heart sound (S1) and second heart sound (S2), is below 150 Hertz (Hz) which may indicate that both sounds are caused by vibrations within the same structure, possibly the entire heart. However S2 spectra have greater amplitude than S1 spectra above 150 Hz, which may be due to vibrations within the aorta and pulmonary artery. Relationships observed between body surface area, sex, blood pressure, and the frequency content of heart sounds indicate that as heart size increases, the amplitude of the frequency coefficients above 150 Hz decreases. These observations were more identifiable in the S1 spectra than in the S2 spectra, possibly because the S2 higher frequency components may mask subtle changes in the S2 spectra caused by heart size changes. However, when the changes in heart size are significant, as in hypertension or increased body surface area, trends in the S2 spectra can be observed.

Adolescent↗
PubMedDate not supplied

A wavelet-based reduction of heart sound noise from lung sounds.

Heart sounds produce an incessant noise during lung sounds recordings. This noise severely contaminates the breath sounds signal and interferes in the analysis of lung sounds. In this paper, the use of a wavelet transform domain filtering technique as an adaptive de-noising tool, implemented in lung sounds analysis, is presented. The multiresolution representations of the signal, produced by wavelet transform, are used for signal structure extraction. In addition, the use of hard thresholding in the wavelet transform domain results in a separation of the nonstationary part of the input signal (heart sounds) from the stationary one (lung sounds). Thus, the location of the heart sound noise (1st and 2nd heart sound peaks) is automatically detected, without requiring any noise reference signal. Experimental results have shown that the implementation of this wavelet-based filter in lung sound analysis results in an efficient reduction of the superimposed heart sound noise, producing an almost noise-free output signal. Due to its simplicity and its fast implementation the method can easily be used in clinical medicine.

Adult↗
PubMed1990

[Study on occlusal sounds in children. 2. Fast Fourier Transform (FFT) analysis on the occlusal sounds].

The purpose of this study was to evaluate the Fast Fourie Transform (FFT) analysis of the occlusal sounds generated by tooth tapping which may apply in assisting in the functional diagnosis of occlusion in children. The fifteen subjects examined were divided into three groups: the first group with deciduous dentition, the second with mixed dentition and the third with permanent dentition. Occlusal sounds generated by tooth tapping at the rate of 76 times per minute were obtained with a micro-electronic condenser microphone placed on the infra-orbital region. For the time wave, the wave pattern of the occlusal sound was classified into two groups: 1) Impact sound, 2) Slide sound, and the ratio of appearance was examined. For the spectrum, three parameters were chosen for the measuring points such as 1) frequency range, 2) peak frequency, 3) strength of the peak frequency. The results obtained in the present study were summarized as follows: 1) Occlusal sounds in the deciduous dentition, the appearance of sliding sound was noticed in over 50% of the cases while on the permanent dentition, the sliding sound was dominant. 2) The power spectrum of the occlusal sound showed generally two or three peaks. 3) The range of frequency was recognized to be extended on the sliding sound when compared with the impact sound.

Child↗
PubMed1983

[Experimental studies on the genesis of low-frequency vibrations (M-sound) of the first heart sound using a miniature accelerometer].

We studied eight mongrel dogs, weighing 15 to 35 kg, in which an initial low-frequency vibration of the first heart sound (M-sound) was recognized on the chest wall. A miniature accelerometer weighing 0.5 gm was used to record surface velocity signals and surface acceleration signals as well as phonocardiograms over the cardiac apex of the closed chest wall and over the pericardium or epicardium. The frequency response of accelerometer was essentially flat (+/- 1.5 dB) from 1 to 200 Hz. The accelerometer mounted was such that its sensitive axis was perpendicular to the recording surface. Equisensitive phonocardiograms were obtained to compare the signal size of M-sound on the epicardium at several positions including the cardiac apex, the left ventricular anterior wall near the interventricular septum, the left ventricular antero-lateral wall and the right ventricular anterior wall. Intraventricular phonocardiograms and pressure curves were obtained by a Millar catheter directly inserted through the left ventricular wall near the apex to keep the tip near the apex. Furthermore, the relationship between M-sound and the shortening of the myocardium at the apex was investigated by means of ultrasonic dimension system and phonocardiography. Studies of M-sound were performed not only in sinus rhythm, but also in atrio-ventricular dissociation and ventricular pacing after crushing sinus node or electrical vagus stimulation. The results were as follows: The M-sounds over the chest wall, pericardium and epicardium were recorded coincidentally with the onsets of the left ventricular pressure curve, its dP/dt, low-frequency vibration of the first heart sound of intraventricular phonocardiogram, positive velocity, and acceleration of myocardial surface. The M-sound on the epicardium was maximal in intensity at or near the cardiac apex, in comparison with those recorded on the left ventricular anterior wall near the interventricular septum, left ventricular antero-lateral wall, and right ventricular anterior wall. The M-sound was observed between A and C points of the mitral valve echogram. There was no effect of atrial contraction on the M-sound in cases of atrio-ventricular dissociation. The onset of the M-sound on the epicardium at the apex was not always coincident with the onset of shortening of the myocardium at the same position.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1998

Distinct short-term memory systems for sound content and sound localization.

Short-term memory for sound content and sound localization was investigated in normal subjects using the same/different comparison of two sound stimuli separated by an interval. Auditory or visual interference tasks requiring recognition or spatial judgements were introduced in the interval. Auditory interference tasks reduced memory for sound content and sound location in a specific way. Memory for sound content was significantly more reduced by auditory recognition than by auditory spatial interference task. Visual interference tasks reduced significantly memory for sound location but not for sound content. These results suggest that (i) short-term memory for sound content and that for sound location involve partially distinct processing; and (ii) auditory spatial functions are more closely linked to visual functions than auditory recognition.

Acoustic Stimulation↗
PubMed1984

Frequency spectra of the first heart sound and of the aortic component of the second heart sound in patients with degenerated porcine bioprosthetic valves.

To determine the usefulness of the frequency of heart sounds in the assessment of porcine bioprosthetic valve degeneration, frequency spectra of phonocardiograms of the first heart sound and the aortic component of the second sound were analyzed in 31 patients with degenerated porcine bioprosthetic valves. Comparisons were made with 35 control patients whose valves were inserted 1 month or less. Among 23 patients with degenerated porcine bioprosthetic valves in the mitral position, the dominant frequency of the first heart sound was 95 +/- 11 Hz, which exceeded the first sound in 18 controls (51 +/- 3 Hz) (p less than 0.01). The degenerated mitral porcine bioprosthetic valves of 14 patients showed calcification or fibrosis and the first heart sound in these patients was 115 +/- 16 Hz, which exceeded that of control subjects (p less than 0.001). The degenerated mitral porcine bioprosthetic valves of 9 patients showed torn leaflets only, and the first heart sound in these patients was 64 +/- 9 Hz, which did not differ from that of control subjects. In the aortic position, 8 valves were degenerated and the aortic component of the second sound was 109 +/- 12 Hz, which was higher than that in 17 control subjects (63 +/- 4 Hz) (p less than 0.001). Only 2 of these degenerated valves showed tears unaccompanied by calcific deposits or fibrosis, and the frequencies were comparable to that of control subjects. These observations indicate that the frequency of heart sounds in patients with degenerated porcine bioprosthetic valves becomes abnormally elevated when degeneration is accompanied by calcification or fibrosis, which causes the cusps to stiffen.

Aortic Valve↗
PubMed1986

Sensitivity of neurons in the auditory midbrain of the grassfrog to temporal characteristics of sound. II. Stimulation with amplitude modulated sound.

The coding of fine-temporal structure of sound, especially of frequency of amplitude modulation, was investigated on the single-unit level in the auditory midbrain of the grassfrog. As stimuli sinusoidally amplitude modulated sound bursts and continuous sound with low-pass Gaussian noise amplitude modulation have been used. Both tonal and wideband noise carriers have been applied. The response to sinusoidally amplitude modulated sound bursts was studied in two aspects focussing on two types of possible codes: a rate code and a synchrony code. From the iso-intensity rate histogram five basic average response characteristics as function of modulation frequency have been observed: low-pass, band-pass, high-pass, bimodal and non-selective types. The synchronization capability, expressed in a synchronization index, was non-significant for 38% of the units and a low-pass function of modulation frequency for most of the other units. The stimulus-response relation to noise amplitude modulated sound was investigated by a non-linear system theoretical approach. On the basis of first- and second-order Wiener-Volterra kernels possible neural mechanisms accounting for temporal selectivity were obtained. About one quarter of the units had response characteristics that were invariant to changes in sound pressure level and spectral content of the carrier. These units may function as feature detectors of fine-temporal structure of sound. The spectro-temporal sensitivity range of the auditory midbrain of the grassfrog appeared not to be restricted to and showed no preference for the spectro-temporal characteristics of the ensemble of conspecific calls. Comparison of response characteristics to periodic click trains as studied in the companion paper (Epping and Eggermont, 1986) and sinusoidally amplitude modulated sound bursts revealed that the observed temporal sensitivity is due to a combination of sensitivities to sound periodicity and pulse duration. It was found that for most units the first-order kernels for Gaussian amplitude modulated stimuli and Poisson distributed click stimuli were alike. In contrast second-order kernels for the Gaussian amplitude modulated stimuli often represented only static non-linearities, while second-order kernels for Poisson distributed clicks (Epping and Eggermont, 1986) mostly revealed dynamic non-linearities.

Acoustic Stimulation↗
PubMed1999

Bilateral sound propagation characteristics in electronic TMJ sound recording.

Temporomandibular Joint (TMJ) sounds, clicking and crepitation, are important signs of possible TM disorder or dysfunction (TMD). The sound are usually recorded and observed by stethoscope auscultation or palpation. Sound from one TMJ may propagate through head tissues and be recorded on the contra lateral side misleading the examiner to classify both joints as non-silent. Errors in localization of sound source may lead to an erroneous diagnosis. Widmalm et al. (1997) suggested a mathematical model for estimation of the sound propagation characteristics through the head tissues. A modified model applying the auto-spectral density and cross-spectral density of the signal was used to estimate the bilateral sound propagation characteristics of temporomandibular joint sounds from two subjects. The result indicates that the head tissues act as a bandpass filter causing strong attenuation in some frequency areas with little attenuation in others. The phase response of the transfer function provides a good mean to estimate the latency in time between sounds.

Humans↗
PubMed1977

[Contoursonagraphic analysis of heart sound phenomena and sounds produced by various heart valve prostheses].

The normal heart sounds, murmurs, opening and closing sounds of aortic and mitral valve prostheses were recorded on a tape and analyzed in terms of contour sonagrams in order to obtain the highest frequencies which were recordable on the chest wall. The peak frequencies showed a broad range, the maximum beeing reached at about 8000 c.p.s. in the case of the sounds of prosthetic valves. Furthermore, sound level examinations of the normal first and second heart sound, as well as of the opening and closing sounds of the aortic valve prostheses were performed. The highest sound level of all of these sounds was found to lie within the low frequency range of 40 to 100 c.p.s.

Aortic Valve Insufficiency↗
PubMed1975

First heart sound and ejection sounds. Echocardiographic and phonocardiographic correlation with valvular events.

To provide additional information on the relation of valvular events to the principal components of the first heart sound (s1), combined echocardiograms and phonocardiograms were recorded in 49 subjects, chosen because of audible splitting of S1 or a combination of S1 and an ejection sound. The subjects included 14 normal persons, 16 patients with a variety of predominantly right-sided heart conditions, 7 with mitral stenosis, 3 with pulmonary stenosis and 9 with aortic valve disease or systemic hypertension. A precise relation was found between completion of closure of the atrioventricular (A-V) valves manifested in the echocardiogram and the high-frequency components of S1 (M1 and T1). The average time from the Q wave of the electrocardiogram to M1 was 0.06 plus or minus 0.003 second and the Q-T1 interval was 0.09 plus or minus 0.002 second. In mitral stenosis the Q-M1 interval was delayed to 0.10 plus or minus 0.005 second, resulting in some instances in reversed splitting of S1. In pulmonary stenosis, the ejection sound occurred 0.10 plus or minus 0.003 second from the Q wave. In 7 of the 16 patients with various right-sided abnormalities, but without valvular stenosis, an ejection sound of pulmonary origin occurred 0.18 plus or minus 0.012 second from the Q wave. In the nine patients with aortic valve disease or systemic hypertension, the time from the Q wave to the aortic ejection sound was 0.13 plus or minus 0.004 second. With only two exceptions the ejection sounds of aortic and plumonary origin coincided exactly with achievement of a fully opened position of the respective semilunar valve. Our findings support the postulate that M1, T1 and the ejection sounds occur in association with closing or opening of valves with consequent sudden deceleration or acceleration of a column of blood that, in turn, results in vibrations of the cardiohemic system and audible sounds.

Adolescent↗
PubMed1999

Long-lasting enhancement of sound discrimination ability after sound exposure in rats.

Changes in the sound discrimination ability of rats were investigated after sound exposure (SE) in a Skinner box. For estimation of the sound discrimination ability, two different amplitude-modulated (AM) sounds (S+ and S-) were presented to the rats deprived of water for 48 h. Pedal press behavior in response to only S+ was rewarded with water. The percentages of trials in which pedal press behavior occurred in response to S+ or S- were calculated separately, and test performance of the rats was determined from the difference between the percentages. Rats were exposed to AM sounds during SE of 48 h, and the sound discrimination test was carried out. Enhancement of discrimination between S+ and S- was elicited by SE in a stimulus-specific manner. Latent extinction of the pedal press behavior in response to sound stimuli was not clearly found after SE. The enhancement of test performance was detected 1-48 h after the cessation of SE, and was blocked by injection of an antagonist of N-methyl-D-aspartate receptors into the auditory cortex bilaterally, immediately before the initiation of SE. These results suggest that SE elicits enhancement of sound discrimination ability, and the responsible site is in the auditory cortex.

Acoustic Stimulation↗