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At least 883 records · Page 49Linked to original sources
PubMed1994

Abnormal lung sounds in patients with asthma during episodes with normal lung function.

Even in patients with clinically stable asthma with normal lung function, the airways are characterized by inflammatory changes, including mucosal swelling. In order to investigate whether lung sounds can distinguish these subjects from normal subjects, we compared lung sound characteristics between eight normal and nine symptom-free subjects with mild asthma. All subjects underwent simultaneous recordings of airflow, lung volume changes, and lung sounds during standardized quiet breathing, and during forced maneuvers. Flow-dependent power spectra were computed using fast Fourier transform. For each spectrum we determined lung sound intensity (LSI), frequencies (Q25%, Q50%, Q75%) wheezing (W), and W%. The results were analyzed by ANOVA. During expiration, LSI was lower in patients with asthma than in healthy controls, in particular at relatively low airflow values. During quiet expiration, Q25% to Q75% were higher in asthmatics than in healthy controls, while the change of Q25% to Q75% with flow was greater in asthmatic than in normal subjects. The W and W% were not different between the subject groups. The results indicate that at given airflows, lung sounds are lower in intensity and higher in pitch in asthmatics as compared with controls. This suggests that the generation and/or transmission of lung sounds in symptom-free patients with stable asthma differ from that in normal subjects, even when lung function is within the normal range. Therefore, airflow standardized phonopneumography might reflect morphologic changes in airways of patients with asthma.

Adult↗
PubMed1996

Posture-dependent change of tracheal sounds at standardized flows in patients with obstructive sleep apnea.

BACKGROUND: The ability of awake subjects with obstructive sleep apnea (OSA) to dilate their pharynx during inspiration may be defective. Airflow through a relatively more narrow pharyngeal passage should lead to increased flow turbulence and hence to louder respiratory sounds. We therefore studied the increase of tracheal sound intensity (TSI) in the supine position as an indicator of abnormal pharyngeal dynamics in patients with documented OSA. SUBJECTS AND METHODS: Sound was recorded with a contact sensor at the suprasternal notch in 7 patients with OSA (age, 52 +/- 8 years; body mass index, 29.0 +/- 3; apnea-hypopnea index, 58 +/- 17; means +/- SD), and in 8 control subjects, including obese subjects and snorers (age, 39 +/- 8 years; body mass index, 28.6 +/- 4). Subjects breathed through a pneumotachograph and aimed at target flows of 1.5 to 2 L/s, first sitting, then supine. Flow and sound signals were digitized at a 10-KHz rate. Fourier analysis was applied to sounds within the target flow range and average power spectra were obtained. Spectral power was calculated for frequency bands 0.2 to 1, 1 to 2, and 2 to 3 KHz. RESULTS: In the supine position, OSA patients had a significantly greater increase of inspiratory TSI than control subjects: 7.5 +/- 1.2 dB vs 1.7 +/- 3.4 dB (p < 0.001); 6.6 +/- 1.7 dB vs 1.3 +/- 3.9 dB (p < 0.005); and 12.2 +/- 3.2 dB vs 5.6 +/- 3.1 dB (p < 0.001) at low, medium, and high frequencies, respectively. Expiratory TSI also increased in supine subjects, but the change was significantly greater in OSA subjects only at high frequencies. These findings confirm our earlier observations that did not include obese subjects or snorers among control subjects. SUMMARY: Measuring posture effects on tracheal sounds is noninvasive and requires little time and effort. The greater increase of inspiratory TSI in supine OSA patients compared to subjects without OSA suggests a potential value for daytime acoustic screening.

Adult↗
PubMed1987

Nomenclature used by health care professionals to describe breath sounds in asthma.

We studied the spontaneous, uninstructed description by 40 health care professionals of breath sounds in asthmatic patients, and their use of lung sound terminology following current recommendations. Tape play-back auscultation of recorded tracheal and lung sounds was performed by ten observers in each group of residents, nurses, staff physicians and physiotherapists. They repeated the test after two weeks to three months. Individual descriptions were compared to computer-aided characterization of the breath sound recordings. We found significant differences in the preferred terms for description of adventitious lung sounds between the groups of health care professionals. There was considerable intraobserver variability, with less agreement when suggestions for a more complex characterization were followed. Our observations indicate the importance of teaching a standardized nomenclature for lung sounds to health care professionals, using only terms which are clearly informative of pulmonary disease.

Allied Health Personnel↗
PubMed2001

Echo suppression in the human cortex is affected by the spatial and temporal proximity of the primary sound and echo.

Echo suppression in the human auditory cortex was studied with auditory middle latency evoked potentials (AMEP) using virtual reality acoustic stimuli, including distance and elevation cues, presented by earphones. The purpose of the study was to assess the effect of proximity of the source sound and echo on the degree of echo suppression. Sixteen subjects were presented with source-echo pairs in which the preceding source sound was always at the vertex, and the echo varied among ten positions on the coronal plane. Positions varied in elevation, distance and time lag between source and echo. The psychoacoustic location judgment of the fused source-echo pair was closer to the source sound (more echo suppression) the nearer the echo drew to the source in its elevation and time. The equivalent dipole magnitudes of the cortical components of AMEP were significantly reduced (more suppression) with shorter echo lags and when echo elevation was similar to that of the source sound. The distances used in this study did not significantly affect echo suppression. These results indicate that echo suppression in the auditory cortex is more pronounced the closer are the primary sound and echo in locational attributes and timing. As source sound and echo draw apart, echo suppression in the cortex decreases and the perceived localization of the fused source-echo is more biased toward the echo.

Acoustic Stimulation↗
PubMed1977

On the function of the aortic valve and the mechanism of the first and second sounds.

Studies are reported on the exact timing of the aortic component of the second sound in relationship to aortic pressure and flow velocity, and also to aortic valve closure. These studies were performed in animals by means of catheter-tip probes and an electric contact introduced into the aortic valve. They were supplemented by echocardiographic stuides of the aortic valve, and impedance cardiograms in man. Opening of the aortic valve and its relationship to the first heart sound were also studied. It was observed that the second component of the first heart sound grossly coincides with the opening of the aortic valve. The aortic component of the second sound starts a few milliseconds after aortic valve closure. It starts after the incisura of the aortic pressure tracing and the drop of the velocity curve to the zero line; it then increases attaining its maximum at the peak of the rapid rebound of the aortic pressure, which coincides with the trough of the velocity tracing. The final interpretation on the mechanism of the second sound agrees in principle with the studies of Luciani, Wiggers, and Rushmer attributing the sound vibrations to release of the energy stored in the aortic wall, which accelerates the flow and causes deceleration of numerous structures (aortic and valvar) as well as of the blood. Studies of the rate of change of acceleration of pressure confirm this interpretation.

Adolescent↗
PubMed1982

Pseudo-knock sound in a patient with nephrotic syndrome and massive ascites.

A patient with markedly elevated diaphragm due to massive ascites secondary to nephrotic syndrome demonstrated an intense early diastolic sound with low- and medium-pitch. This abnormal sound coincided closely with the "D" point of the anterior mitral valve echogram. This sound remarkably diminished in intensity during inspiration with lowering of diaphragm, and after removing ascites it completely disappeared. Noninvasive study with phonoechocardiograms showed neither constrictive pericarditis nor large pericardial effusion. These findings lead us to believe that the sound may be related to an abnormal ventricular recoil striking the extracardiac structures at the end of the isovolumetric relaxation time. To our knowledge, the fact that the elevated diaphragm itself can produce an early diastolic sound ("pseudo-knock sound") has not been previously reported.

Diastole↗
PubMed2003

Analysis of the cough sound frequency in adults and children with bronchial asthma.

It is well known that the frequency distribution of cough sound varies in different pathological conditions. Its identification could have diagnostic value. In this study the cough sound frequency in adults (n=20, 51.7 +/- 11 yrs), children (n=21, 11.8 +/- 0.4 yrs) asthmatics and healthy volunteers (n=25, 21 yrs) was explored. All patients were suffering from bronchial asthma. They were on a stable therapeutic regime and in a quiet status. Voluntary cough sound was recorded by a microphone and a tape recorder an ddigitally processed. Overlapping technique and Fast Fourier Transform were used to estimate the sound spectra. The records were smoothed by the method of Pascal triangle. They demonstrate the mean values of cough sound spectra. The registered pseudo three-dimensional plots of cough sound frequency (1 K spectra as function in time) of adults showed that the intensity of frequencies increased from 100 to 900 Hz in 3-4 waves. These frequencies afterwards decreased and between 1 to 2 kHz a smaller elevation was present. The spectra of children resembled to the spectrum of adults but had a smoother course. The spectra of asthmatics had some specificity and differed from the spectrum of healthy volunteers.

Adult↗
PubMed1998

Discrimination of productive and non-productive cough by sound analysis.

There are two types of coughs, productive and non-productive; the former is caused by excess airway secretions. The analysis of cough may provide important clues not only to aid diagnosis, but also for the selection of drugs for treatment. In this study, cough sounds recorded in a free acoustic field from patients with productive cough and non-productive cough due to chronic airway diseases were compared with those of voluntary cough of healthy subjects and were analyzed by sound spectrogram and time-expanded waveform. All cough sounds could be separated into two or three phases. The implementation of the novel technique to record cough sounds in the free acoustic field and to analyze the sounds of the high frequency range enable recognition of the characteristics of the cough sounds in phase 2 of the cough.

Acoustics↗
PubMed1994

A study of temporomandibular joint sounds; Part 1. Relationship with articular disc displacements.

The relationship between complaints about temporomandibular joint (TMJ) sounds and the prevalence of disc displacements was studied. The rate of incidence of TMJ sounds was 42% in the 50 subjects investigated. In the subjects with TMJ sounds, 19% were diagnosed as having articular disc displacements. In the 58% sound-free subjects, 14% were found to have disc displacements. Therefore, it seems that patients with TMJ sounds do not always have disc displacements, and that a sound-free state does not necessarily indicate a healthy TMJ.

Adult↗
PubMed1999

Dynamic capture of sound motion by light stimuli moving in three-dimensional space.

A moving light stimulus produced a sensation of motion for a stationary sound stimulus presented simultaneously, which was called the dynamic visual capture by Mateeff, Hohnsbein, and Noack in 1985. The present study examined whether the moving light stimulus might induce a perceptual shift in the velocity, that is, the speed and the direction, of a moving sound stimulus. This type of the visual capture was explored in the directions where the sound stimulus moved along the motion tracks of the light stimulus: first in a horizontal and a vertical orientation and secondly in a depth orientation. Moreover, perceptual distortion of the direction of movement of the sound stimulus was investigated when the direction from which a sound stimulus moved deviated from the motion tracks of a light stimulus. It was found that the dynamic visual capture was inducible in all of three orientations, appearing more strongly in the vertical and the depth orientations than in the horizontal orientation. The perceived direction of the moving sound stimulus was greatly influenced by the direction where the light stimulus moved simultaneously and was often the same as the physical direction of the light stimulus, even when the physical motion directions of those two stimuli were perpendicular or opposite each other.

Acoustic Stimulation↗
PubMed1979

Physiological aspects of the effects of sound on man and animals.

A review of some short-term and long-term physiological effects of sound on non-auditory body functions is given. It is pointed out that the short-term effects depend closely on the acoustic properties of the sound. Habituation is rapid for steady signals but slow for interrupted ones. Irrelevant, meaningless sound, presented to rats over their life-time in such a way as to simulate an industrial acoustic environment, did not affect blood pressure, life-span or morbidity incidence. As far as the injurious effect of sound on the inner ear is concerned, it was shown that spontaneously hypertensive rats were considerably more susceptible to such impairment than were normotensive ones. Hence sound does not produce hypertension, but susceptibility to ear injury may be greater in hypertensive individuals. The protential role which individual variability in physiological properties of the sound conduction system might play for the observed individual variability in noise-induced hearing loss is also discussed.

Animals↗
PubMed1992

Effects of frequency and intensity of sound on cochlear blood flow.

Laser Doppler flowmetry demonstrates that loud sound induces a decrease of blood flow in the cochlea of the guinea pig. In this experiment, we observed the effects of frequency and intensity of sound on cochlear blood flow using 15 guinea pigs. In the first 5 guinea pigs, a Doppler probe was attached to the basal turn of the cochlea and sounds of 6, 7, 8, 9 and 10 kHz were delivered to the ear serially from lower to higher frequency, i.e. from 6 kHz to 10 kHz. In the next 5 guinea pigs, the sound was delivered from higher to lower frequency, i.e. from 10 kHz to 6 kHz. The sound intensity delivered to the ear was changed from lower to higher intensity (80 to 120 dB SPL by 10 dB width) at each frequency. In the last 5 guinea pigs, the blood flow in the basal, second, third, and fourth turns of the cochlea was measured at 120 dB SPL of 10 kHz. No change of blood flow was seen in the cochlear basal turn at 6 and 7 kHz up to 120 dB SPL, but a decrease of blood flow was found at 110 and 120 dB SPL at 8, 9, and 10 kHz. On the other hand, the sound of 120 dB SPL at 10 kHz induced a decrease of blood flow only in the basal turn of the cochlea. Our results suggest that there is a corresponding blood flow area which is sensitive to specific frequency in the cochlea.

Animals↗
PubMedDate not supplied

Arousing effect of sounds for testing infants hearing ability.

In order to identify the sounds that best produce orienting reflexes, 38 infants were examined. The infants' ages ranged from 6 to 21 months. Altogether, 42 different calibrated sounds were presented to the infants in random order at 45 dB (A). The sounds were recorded on tapes and were given through loudspeakers placed on each side of the infant. The best sounds proved to be human voice, bird song and chime. The most effective human voice was an infant's crying. An infant is more apt to react to complicated sounds than to pure tones or warble tones. In order to be audiologically acceptable, the sounds must be well calibrated.

Female↗
PubMed2005

A tutorial on complex sound fields for audiometric testing.

A fundamental understanding of soundfield characteristics in enclosed spaces is required in order to appreciate and predict the behavior of complex sound fields (i.e., sound fields created with at least two uncorrelated sound sources on different axes) used in auditory tests for evaluating hearing aid performance, especially speech-in-noise tasks. This article is a tutorial starting with idealized definitions of acoustical spaces. Next is an exploration of the interactions between practical sound fields and the enclosures that contain them, based on a synthesis of ideas formed from a review of classical acoustical theory combined with direct observation. Finally, the discussion turns to the application of complex sound fields for speech-in-noise testing in typical audiometric test rooms and a practical realization of such a sound field with consideration given to the limitations imposed by factors covered in the foregoing discussions.

Acoustic Stimulation↗
PubMed2006

The use of cortical auditory evoked potentials to evaluate neural encoding of speech sounds in adults.

There has been considerable recent interest in the use of cortical auditory evoked potentials (CAEPs) as an electrophysiological measure of human speech encoding in individuals with normal as well as impaired auditory systems. The development of such electrophysiological measures such as CAEPs is important because they can be used to evaluate the benefits of hearing aids and cochlear implants in infants, young children, and adults that cannot cooperate for behavioral speech discrimination testing. The current study determined whether CAEPs produced by seven different speech sounds, which together cover a broad range of frequencies across the speech spectrum, could be differentiated from each other based on response latency and amplitude measures. CAEPs were recorded from ten adults with normal hearing in response to speech stimuli presented at a conversational level (65 dB SPL) via a loudspeaker. Cortical responses were reliably elicited by each of the speech sounds in all participants. CAEPs produced by speech sounds dominated by high-frequency energy were significantly different in amplitude from CAEPs produced by sounds dominated by lower-frequency energy. Significant effects of stimulus duration were also observed, with shorter duration stimuli producing larger amplitudes and earlier latencies than longer duration stimuli. This research demonstrates that CAEPs can be reliably evoked by sounds that encompass the entire speech frequency range. Further, CAEP latencies and amplitudes may provide an objective indication that spectrally different speech sounds are encoded differently at the cortical level.

Acoustic Stimulation↗
PubMed1999

Coding of sound pressure level in the barn owl's auditory nerve.

Rate-intensity functions, i.e., the relation between discharge rate and sound pressure level, were recorded from single auditory nerve fibers in the barn owl. Differences in sound pressure level between the owl's two ears are known to be an important cue in sound localization. One objective was therefore to quantify the discharge rates of auditory nerve fibers, as a basis for higher-order processing of sound pressure level. The second aim was to investigate the rate-intensity functions for cues to the underlying cochlear mechanisms, using a model developed in mammals. Rate-intensity functions at the most sensitive frequency mostly showed a well-defined breakpoint between an initial steep segment and a progressively flattening segment. This shape has, in mammals, been convincingly traced to a compressive nonlinearity in the cochlear mechanics, which in turn is a reflection of the cochlear amplifier enhancing low-level stimuli. The similarity of the rate-intensity functions of the barn owl is thus further evidence for a similar mechanism in birds. An interesting difference from mammalian data was that this compressive nonlinearity was not shared among fibers of similar characteristic frequency, suggesting a different mechanism with a more locally differentiated operation than in mammals. In all fibers, the steepest change in discharge rate with rising sound pressure level occurred within 10-20 dB of their respective thresholds. Because the range of neural thresholds at any one characteristic frequency is small in the owl, auditory nerve fibers were collectively most sensitive for changes in sound pressure level within approximately 30 dB of the best thresholds. Fibers most sensitive to high frequencies (>6-7 kHz) showed a smaller increase of rate above spontaneous discharge rate than did lower-frequency fibers.

Acoustic Stimulation↗
PubMed1999

Auditory perception of walls via spectral variations in the ambient sound field.

Individuals with visual disabilities often use their hearing in order to maintain a line of travel parallel to walls, such as when walking down a hallway or along the side of a building. Previous studies established that this ability depends on the sense of hearing, but the specific acoustic information has not been investigated. The present paper describes a model of how sound pressure builds up within a meter or so in front of a wall, particularly in the low frequency end of the sound spectrum. This buildup of sound pressure is based on ambient or "background" sound, not self-produced sound such as footsteps. The model leads to a prediction that walls are detected by means of a spectral shift toward low frequencies. This prediction was tested in three experiments, in which sighted adults listened for such spectral shifts. In each experiment, a threshold value was obtained corresponding to the farthest simulated distance from a wall that could be detected. Threshold values were in good agreement with previous observations of the distance at which pedestrians can utilize acoustic information from walls. There was no evidence that simulated listener motion enhanced perception of walls. The model underlying these experiments implies that the term echolocation carries inappropriate connotations about the auditory processes that are involved in walking along walls. It is suggested that a more apt description is that pedestrians listen for spatial variations in the structure of the ambient sound field.

Adult↗
PubMed1999

Automatic recognition of the source of temporomandibular joint sounds.

Sounds evoked in the temporomandibular joint (TMJ) during jaw movements may indicate pathology. They are in dental clinics usually recorded by auscultation and noted in protocols by verbal, subjective descriptions. Time-frequency analysis of electronically recorded TMJ sounds makes possible a more objective and sophisticated analysis. Such sounds were recorded from four subjects and grouped into two sets. One was used for training a classifier, while the other was used for testing its ability to relate a given sound to the subject from which it was recorded. Both scale and time-shift invariant representations, as well as only time-shift invariant representations of the Reduced Interference Distributions of the TMJ sounds were used for pattern recognition. The nearest neighbor, zero-subspace and nearest constrained linear combination classification methods were employed. It was observed that TMJ sound patterns could be very typical for a given person. This indicates that our classification approach can be developed into a useful diagnostic tool by obtaining training sets from patients where a definitive diagnosis of TMJ pathology has been obtained.

Humans↗