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At least 685 records · Page 38Linked to original sources
PubMed1995

The effect of methacholine-induced acute airway narrowing on lung sounds in normal and asthmatic subjects.

The association between lung sound alterations and airways obstruction has long been recognized in clinical practice, but the precise pathophysiological mechanisms of this relationship have not been determined. Therefore, we examined the changes in lung sounds at well-defined levels of methacholine-induced airway narrowing in eight normal and nine asthmatic subjects with normal baseline lung function. All subjects underwent phonopneumography at baseline condition and at > or = 20% fall in forced expiratory volume in one second (FEV1), and in asthmatic subjects also at > or = 40% fall in FEV1. Lung sounds were recorded at three locations on the chest wall during standardized quiet breathing, and during maximal forced breathing. Airflow-dependent power spectra were computed using fast Fourier transform. For each spectrum, we determined the intensity and frequency content of lung sounds, together with the extent of wheezing. The results were analysed using analysis of variance (ANOVA). During acute airway narrowing, the intensity and frequency content of the recorded sounds, as well as the extent of wheezing, were higher than at baseline in both groups of subjects. At similar levels of obstruction, both the pitch and the change in sound intensity with airflow were higher in asthmatics than in normal subjects. Wheezing, being nondiscriminative between the subject groups at baseline, was more prominent in asthmatics than in normal subjects at 20% fall in FEV1. We conclude that, at given levels of acute airway narrowing, lung sounds differ between asthmatics and normal subjects. This suggests that airflow-standardized phonopneumography is a sensitive method for detecting abnormalities in airway dynamics in asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1999

Communication signals and sound production mechanisms of mormyrid electric fish.

The African weakly electric fishes Pollimyrus isidori and Pollimyrus adspersus (Mormyridae) produce elaborate acoustic displays during social communication in addition to their electric organ discharges (EODs). In this paper, we provide new data on the EODs of these sound-producing mormyrids and on the mechanisms they use to generate species-typical sounds. Although it is known that the EODs are usually species-specific and sexually dimorphic, the EODs of closely related sound-producing mormyrids have not previously been compared. The data presented demonstrate that there is a clear sexual dimorphism in the EOD waveform of P. isidori. Females have a multi-phasic EOD that is more complex than the male's biphasic EOD. In this respect, P. isidori is similar to its more thoroughly studied congener P. adspersus, which has a sexually dimorphic EOD. The new data also reveal that the EODs of these two species are distinct, thus showing for the first time that species-specificity in EODs is characteristic of these fishes, which also generate species-specific courtship sounds. The sound-generating mechanism is based on a drumming muscle coupled to the swimbladder. Transverse sections through decalcified male and female P. adspersus revealed a muscle that envelops the caudal pole of the swimbladder and that is composed of dorso-ventrally oriented fibers. The muscle is five times larger in males (14.5+/-4.4 microl, mean +/- s.d.) than in females (3.2+/-1.8 microl). The fibers are also of significantly larger diameter in males than in females. Males generate courtship sounds and females do not. The function of the swimbladder muscle was tested using behavioral experiments. Male P. adspersus normally produce acoustic courtship displays when presented with female-like electrical stimuli. However, local anesthesia of the swimbladder muscle muted males. In control trials, males continued to produce sounds after injection of either lidocaine in the trunk muscles or saline in the swimbladder muscles.

Air Sacs↗
PubMed1999

Resonators in insect sound production: how insects produce loud pure-tone songs.

In a resonant vibration, two reactive elements, such as a mass and a spring, interact: the resonant frequency depends on the magnitude of these two elements. The build-up and decay of the vibration depend on the way the resonator is driven and on the damping in the system. The evidence for the existence of resonators in insect sound production is assessed. The mechanics of different types of sound-producing system found in insects is described. Mechanical frequency-multiplier mechanisms, which convert the relatively slow contraction of muscles to the higher frequency of the sound, are commonly used to convert the comparatively slow muscle contraction rate to the higher frequency of the sound. The phasing and rate of mechanical excitation may also affect the frequency and duration of the sound that is produced. Although in many insects the song may appear to be produced by the excitation of a simple resonator, the song frequency may not be constant, suggesting that other factors, such as the mechanism of excitation, or variation of the effective mass or elasticity of the system during sound production, may be additional determinants of the song frequency. Loud, and hence efficient, transduction of the energy of a mechanical resonator into sound may involve a second stage of transduction which, by damping the resonator, may compromise tonal purity. Some insect singers resolve this problem by tuning both stages of transduction to the same frequency, thereby maintaining tonal purity.

Animals↗
PubMed1984

Marked paradoxical septal motion associated with an early diastolic heart sound.

The findings in four patients with marked paradoxical septal motion and an unusual early diastolic sound are presented. Each patient had markedly abnormal right ventricular function. Phonocardiograms, apexcardiograms, and echocardiograms showed the sound to precede the expected timing of a third heart sound and to coincide with the peak leftward displacement of the paradoxically moving septum in early diastole. In two patients the sound was also accompanied by third and fourth heart sounds, revealing a total of five heart sounds on phonocardiographic studies. The sound appeared to originate from the sudden deceleration of the septal mass as it moved leftward during ventricular relaxation.

Adult↗
PubMed1989

Digital respirosonography. New images of lung sounds.

We used tape recordings from normal subjects and from patients with lung disease to generate spectrographic images of respiratory sounds on a personal computer. These digital respirosonograms presented timing and frequency content of lung sounds, with the sound intensities displayed on a color scale. Respiratory sounds during inspiration and expiration could be recognized by their association with concurrent respiration curves. Contributions of low-frequency cardiac sounds were visually identified by their relationship to simultaneously recorded ECGs. Typical characteristics of normal and adventitious lung sounds were documented and displayed both in the time and the frequency domain. Digital respirosonography provides an easy way to assess lung sound amplitudes, frequencies and timing over several breaths.

Adolescent↗
PubMed2006

Rapid brain discrimination of sounds of objects.

Electrical neuroimaging in humans identified the speed and spatiotemporal brain mechanism whereby sounds of living and man-made objects are discriminated. Subjects performed an "oddball" target detection task, selectively responding to sounds of either living or man-made objects on alternating blocks, which were controlled for in their spectrogram and harmonics-to-noise ratios between categories. Analyses were conducted on 64-channel auditory evoked potentials (AEPs) from nontarget trials. Comparing responses to sounds of living versus man-made objects, these analyses tested for modulations in local AEP waveforms, global response strength, and the topography of the electric field at the scalp. In addition, the local autoregressive average distributed linear inverse solution was applied to periods of observed modulations. Just 70 ms after stimulus onset, a common network of brain regions within the auditory "what" processing stream responded more strongly to sounds of man-made versus living objects, with differential activity within the right temporal and left inferior frontal cortices. Over the 155-257 ms period, the duration of activity of a brain network, including bilateral temporal and premotor cortices, differed between categories of sounds. Responses to sounds of living objects peaked approximately 12 ms later and the activity of the brain network active over this period was prolonged relative to that in response to sounds of man-made objects. The earliest task-related effects were observed at approximately 100 ms poststimulus onset, placing an upper limit on the speed of cortical auditory object discrimination. These results provide critical temporal constraints on human auditory object recognition and semantic discrimination processes.

Adult↗
PubMed2003

Sound levels in classrooms and effects on self-reported mood among school children.

The principle of this field study is an investigation of recorded sound levels in 24 classrooms and relations between sound level measures and aspects of children's rated annoyance, task orientation, and inattentiveness. The background sound-exposure levels were distributed within the interval of 33-42 dB(A)eq and the activity sound level exposure ranged between 47-68 dB(A)eq. The recorded levels must be considered as high for work environments where steady concentration and undisturbed communication is essential. Results do not support the hypothesis that lower background-sound level and fewer students per class would improve the sound environment by generating a lower activity noise or the hypothesis that higher sound levels should increase annoyance and inattentiveness as well as deteriorate task orientation ratings.

Acoustics↗
PubMed1998

Spectral analysis of heart valve sound for detection of prosthetic heart valve diseases.

The spectral analysis of heart valve sound is a noninvasive diagnostic method known to be useful in evaluating the state of the heart valve function. This may provide early detection of valve calcification, thrombus or destruction, since previous studies have shown that the dominant frequency peak moved to a high frequency area when natural heart valve leaflets were calcified, stiffened or destroyed. However, it is important for a heart valve sound diagnostic system to find a proper spectral analysis method on phonocardiography. Until now, conventional frequency analyses such as the Fourier transform or autoregressive spectral estimation technique have been used to estimate spectral components of a phonocardiogram, but they are inappropriate because the signal frequency is assumed to remain constant during the transform interval. To overcome this problem, in this study, FOS (Fast Orthogonal Search) & MUSIC (MUltiple SIgnal Classification), which both appeared suitable for the analysis of biological data, were applied to prosthetic heart valve sound as the new heart valve sound spectral analysis methods. Five subjects with normally functioning mechanical heart valves and a patient with a malfunctioning one were selected to collect the heart valve sound signals. As a result, the second dominant peak frequency proved to be important along with the first dominant peak frequency in identifying the valve function. This study showed that the new heart valve sound spectral analysis method presented in this paper may be an effective method in heart valve sound analysis. Further study using this system in a large population of patients will aid in providing a diagnostic method in the early detection of valve failure.

Female↗
PubMed2000

[A simple personal computer-based system for lung sound analysis].

Although lung sounds provide important information about the respiratory system, the analysis of lung sounds has not been widely used in clinical practice because of the complicated procedure involved. However, personal computer technology has made impressive strides in recent years. Today, practically all personal computer models on the market are equipped with the capacity for audio signal input and output. We developed a new computer system for lung sounds acquisition and analysis. The system hardware comprises only a personal computer and a microphone, and the software was developed for a widely used operating system (Windows 95). Our system can record, save, and replay lung sounds and analyze their time and frequency domains. To verify the accuracy of sound acquisition, we examined the frequency characteristics of the system as installed and utilized on 4 different machines. The characteristics were essentially flat throughout the 200-2,000 Hz spectrum within which almost all lung sounds were contained. We feel our system can serve as a simple and useful tool for lung sound analysis.

Humans↗
PubMed1996

Fetal heart sound analysis: a preliminary evaluation.

The aim of this study, is to determine whether the fine characteristics of the fetal heart sounds could be used to identify intrauterine growth retarded fetuses. A preliminary evaluation, was conducted to compare these characteristics between intrauterine growth retarded fetuses and normal fetuses in the antenatal period after 36 weeks of gestation. Altogether, 7 IUGR fetuses were compared with 12 normal fetuses. An instrument named the Fetal Frequency Phonocardiogram was designed for this purpose. When connected to a personal computer and with a software programme specially written, the fetal heart sound characteristics were analysed. After detailed analysis, there were 3 significant differences between IUGR and normal fetuses, all of which gave a p-value of < 0.01. The frequency of the first heart sound was significantly higher in the IUGR fetuses compared to normal fetuses. The ratio of the amplitude of the first heart sound over the second heart sound was higher in the IUGR group. Finally, the ratio of the time between the first and second heart sound over the cardiac cycle was shorter in the IUGR fetuses. Fetal heart sound analysis, may provide a simple non-invasive method of detecting and monitoring fetuses at risk in the antenatal period.

Fetal Growth Retardation↗
PubMedDate not supplied

Spectral analysis of /s/ sound with changing angulation of the maxillary central incisors.

PURPOSE: The aim of the study was to measure the influence of the maxillary central incisors free from adaptation phenomena using spectral analysis. MATERIALS AND METHODS: The maxillary dentures of 18 subjects were duplicated. The central incisors were fixed in a pivoting appliance so that their position could be changed from labial to palatal direction. A mechanical push/pull cable enabled the incisor section to be handled extraorally. Connected to the control was a sound generator producing a sinus wave whose frequency was related to the central incisor angulation. This acoustic signal was recorded on one channel of a digital tape recorder. After calibration of the unit, the denture duplicate was inserted into the subject's mouth, and the signal of the /s/ sounds subsequently produced by the subject was recorded on the second channel during alteration of the inclination angle simultaneously with the generator signal. Spectral analysis was performed using a Kay Speech-Lab 4300B. RESULTS: Labial displacement in particular produced significant changes in spectral characteristics, with the lower boundary frequency of the /s/ sound being raised and the upper boundary frequency being reduced. CONCLUSION: Maxillary incisor position influences /s/ sound production. Displacement of the maxillary incisors must be considered a cause of immediate changes in /s/ sound distortion. Therefore, denture teeth should be placed in the original tooth position as accurately as possible. Our results also indicate that neuromuscular reactions are more important for initial speech sound distortions than are aerodynamic changes in the anterior speech sound-producing areas.

Acoustics↗
PubMed2004

Sequential sound therapy in tinnitus.

Sequential sound therapy, which uses wide-band white noise distinguished by some unique characteristics, is applied in the treatment of tinnitus. The methodology is described, as are the differences from and similarities to tinnitus retraining therapy. We have performed sequential sound therapy in 26 patients from 2002 through part of 2003. Thirty-eight generators of sounds were adapted for use in this therapy and, of these, 34 incorporated an earphone. The results of sequential sound therapy in our 26 patients were compared with the results of tinnitus retraining therapy in 15 patients treated during the years 2000 and 2001. Satisfactory results obtained with sequential sound therapy totaled 100%, whereas only 33% of subjects treated with tinnitus retraining therapy obtained satisfactory results. In 6 patients who received sequential sound therapy, tinnitus disappeared altogether. In addition, no patient receiving sequential sound therapy has left the treatment protocol, whereas 53% of patients receiving tinnitus retraining therapy abandoned the treatment protocol.

Acoustic Stimulation↗
PubMed1991

Multigated blood-pool imaging using heart sounds.

A method to trigger multigated blood-pool (MGBP) acquisition using both the first and second heart sound has been developed. The heart sound gating (HSG) circuitry identifies, individually, both the first (S1) and second (S2) heart sounds from their timing relationship alone, and provides two trigger points during the cardiac cycle. First heart sound gating may be performed to assess the systolic ejection portion of the cardiac cycle, with S2 gating utilized for reproduction of the diastolic filling portion of the cycle. Heart sound gating has been applied to twenty patients who underwent analysis of left ventricular function, and compared to conventional ECG-gated MGBP. Left ventricular ejection fractions calculated from MGBP studies using a first and a second heart sound trigger correlated well with conventional ECG gated acquisitions in patients adequately gated by HSG and ECG. Heart sound gating may be utilized in patients with rapidly changing heart rates, as S1 and S2 precisely define end-diastole and end-systole, respectively, and in situations when the ECG is inadequate for gating purposes.

Electrocardiography↗
PubMed1991

Muscle sounds from evoked twitches in the hand.

Skeletal muscle emits acoustic signals during voluntary contraction and during twitches produced by electric stimulation of peripheral nerves. Supramaximal, percutaneous electric stimulation was applied to the median or ulnar nerve, while electric and sound signals were recorded from the abductor pollicis brevis or abductor digiti minimi muscles, respectively, in 27 volunteers without known disease. Reproducible waveforms were obtained with the following means and standard deviations: (1) latency from stimulus to onset of sound, median = 6.9 +/- 0.8msec, ulnar = 6.6 +/- 1.0msec; (2) latency from stimulus to peak of sound, median = 15.1 +/- 1.5msec, ulnar = 13.1 +/- 1.5msec; (3) latency from onset of surface electric to onset of sound, median = 3.6 +/- 1.0msec, ulnar = 3.9 +/- 1.1msec; (4) baseline-to-peak amplitude of sound, median = 860 +/- 270mV, ulnar = 640 +/- 230mV; and (5) baseline-to-peak amplitude of surface electric, median = 11.4 +/- 3.0mV, ulnar = 10.1 +/- 2.4mV. Stimulated muscle sounds are useful when artifacts, such as tremor, interfere with voluntary muscle sound recordings, or when quantitative information is needed to relate electric to contractile muscle activity.

Electric Stimulation↗
PubMed1989

The effects of conservative treatment on temporomandibular joint sounds and mandibular deviation during opening and closing movement of the mandible.

This study was undertaken to examine changes in temporomandibular joint (TMJ) sounds and mandibular deviations on opening and closing movements subsequent to conservative treatment of twelve patients presenting with mandibular dysfunction. A comparison of synchronous records indicated that two thirds of TMJ sounds were directly related to minor deviations in the path of movement of the mandible on opening and closing. TMJ sounds decreased significantly following flat plane splint therapy in all types, qualities and positions of sounds with the exception of those occurring near occlusal contact and those of a soft character. TMJ sounds related to minor mandibular deviations decreased significantly in all types, qualities and position of sounds except those of a soft nature. Fast Fourier Transform analysis of joint sounds consistently present before and after treatment revealed that the dominant frequencies were at the lower end of the acoustic range and that hard clicks have dominant frequencies higher than soft clicks.

Auscultation↗
PubMed1988

[Effects of the intersensory action of sound on the performance of a simple motor reaction to light in the cat].

In 6 alert cats, placing responses to light and their latencies with added sound stimuli were investigated. The latency recovery cycles demonstrated that in cases of sound-light intervals 750-0 ms and light-sound intervals 0-75 ms the latencies to light were reduced, the maximum of this effect being at sound-light intervals 250-200 ms. Latency to light was enhanced at light-sound intervals 100-350 ms, the maximum being at 100-200 ms. Spatial location of sound source affected the latencies: when the sound source spatially coincided with the light source, the effect of latency shortening was most obvious.

Acoustic Stimulation↗
PubMed1987

Spectral analysis of cough sounds recorded with and without a nose clip.

The voluntary cough sounds of healthy volunteers, patients with chronic rhinitis, chronic rhinitis with bronchial asthma and asthma were recorded with and without a nose clip. A gated series of signals of the first cough sound lasting 200 ms was analysed by a system with a 20 ms delay of the first signal. In the case of filtered cough sounds, low-cut digitally, the mean values of averaged spectra of the healthy volunteers showed a first peak around 350 Hz, similar to the expiratory spectra of respiratory sounds. Second and third harmonics were also identified. The mean values of averaged spectra from the patients with airway disease differed significantly in the range of low frequency components. The upper airways work as narrow-band acoustic filters determining the harmonic contents of speech as well as those of cough sounds. To minimize these effects for acoustic analytical purposes, the application of a nose clip is suggested to find the cough harmonics related to those of pulmonary sounds. The voluntary cough sounds contain diagnostic information, but to build up a quantitative, diagnostic, decision-making system, further investigations as well as standardization of recording and analysis are necessary.

Adolescent↗
PubMed1977

[The 6th heart sound].

The author describes a new sound in systole which he calls the V1th heart sound. This sound can be recorded in patients with pure aortic incompetence, but also in healthy subjects. It is not sufficiently loud to be heard on auscultation. It is visible only on the low frequency bands at 35 Hz, and rarely at 70 Hz. It is maximal at the apex and the endapex. It is characterised by 1 or 2 oscillations at the end of mesosystole and at the beginning or middle of end-systole. This sound may be physiological: it will then be of low amplitude, and further from the 2nd sound than in cases of pure aortic incompetence, in which it is pathological, and closer to the 2nd sound. The author puts forward two hypotheses for the origin of the VIth sound.

Adolescent↗