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PubMed1990

Variation of breath sound and airway caliber induced by histamine challenge.

Inspiratory breath sounds were recorded from the chest wall during histamine challenge in five subjects with mild asthma (baseline FEV1 greater than 60% of predicted normal). The median frequency of the power spectrum of the breath sounds was found to correlate with the percentage change in FEV1 induced by histamine and with FEF50. The analysis suggests that for a decrease in FEV1 of 20%, the median frequency of breath sound would increase by 80 Hz. Variation in airway caliber produced a consistent alteration in the distribution of energy in inspiratory breath sound in the absence of wheeze. Spectral analysis of breath sound may be a useful addition to conventional spirometry in identifying changes in airway diameter.

Adult↗

PubMed2002

Some critical developments in acquiring native language sound organization during the first year.

Although infants are born with rather sophisticated capacities for discriminating and categorizing speech sounds, they still must learn about the sound organization of their native language. Before 6 months, infants show relatively little sensitivity to native language versus non-native language sound organization. Shortly thereafter, infants recognize which sounds and sound sequences and rhythmic patterns are likely to appear in native language words. Knowledge of these features plays a critical role in how and when infants segment words from fluent speech. Word segmentation abilities develop rapidly between 7.5 and 10.5 months. Initially, English-learners segment words using stress cues. Soon after, they learn to use other potential cues to word boundaries. As their lexicons develop during the second year, they begin to use information about known words in segmenting and learning new words.

Age Factors↗

PubMed1987

The spectral properties of temporomandibular joint sounds.

Spectral analyses were performed on sounds recorded from TMJ's that had previously been classified into different intracapsular categories, in an attempt to determine whether the inherent properties of these sounds were unique for each different disorder. A total of 55 joints was studied: 32 were diagnosed as displaced disc with reduction [DDR], 10 were diagnosed as displaced disc without reduction [DDN], and 13 were diagnosed as degenerative joint disease [DJD]. The spectral analysis for each recorded joint sound was performed using a Fast Fourier transform routine, the results of which were plotted as a frequency vs. amplitude envelope. These analyses showed that different intracapsular TMJ disorders were characterized by sounds whose energy distribution patterns, while showing certain across-group differences, usually shared significant common spectral properties. The joint-propagated noises associated with DDR, DDN, and DJD were each characterized by a spectral envelope whose primary band of energy was centered around a peak at approximately 1 kHz, and which dropped off from that point to background levels. These patterns presumably reflect the resonance characteristics of the disordered joint as defined by the mass and stiffness of its articulating surfaces. Based on the findings of this study, it would appear that comparisons of the spectral envelopes of joint-propagated sounds would have only limited application in the differential diagnosis of intracapsular TMJ disorders.

Adolescent↗

PubMed1994

The reliability of clinical methods for recording temporomandibular joint sounds.

Measurement errors in recording temporomandibular joint sounds may originate from variation between observers and from variation in the phenomenon. Laboratory settings enable various procedures to be used to minimize both sources of variation. These procedures yield some excellent intra- and inter-examiner reliabilities, but this does not imply that dentists in a clinical setting are likely to evaluate temporomandibular joint sounds in a comparable way. This study was designed to evaluate clinical joint sound assessment methods (palpation and stethoscopy) without using special precautions to minimize variance. An attempt was made to quantify the signal variance. Within- and between-examiners agreement is estimated for both methods in a sample of 44 non-patients. The results show that two clinically experienced craniomandibular disorders specialists were able to reach fair to good agreement on the identification of (the number of) temporomandibular joint sounds. There was some disagreement with respect to the number of reciprocal clicks. Compared with the palpation technique, stethoscopy is more sensitive, especially with regard to crepitation. Based on the electronically recorded sounds, both examiners appeared to be overconsistent. It is concluded that the use of both palpation and stethoscopy in clinical settings can be justified but that both methods have limitations. When, in a given clinical setting, these limitations are acceptable, there appears to be no need for extra-sensitive but expensive electronic recording devices.

Auscultation↗

PubMed2005

Identification of endotracheal tube malpositions using computerized analysis of breath sounds via electronic stethoscopes.

Endotracheal tube (ETT) malpositioning into a mainstem bronchus or the esophagus may result in significant hypoxemia. Current methods to determine correct ETT position include auscultation, radiography, and bronchoscopy, although the current acceptable standard procedure for proper endotracheal (versus esophageal) intubation is detection of end-tidal carbon dioxide (ETco(2)) by capnography, capnometry, or colorimetric ETco(2) devices. Unfortunately, capnography may be unavailable or unreliable in nonhospital/emergency settings or in low cardiac output states, and it does not detect endobronchial intubation. The purpose of this study was to quantify and assess breath sound characteristics using electronic stethoscopes placed over each hemithorax and epigastrium to determine their ability to detect ETT malposition. We recorded breath sounds in 19 healthy, non-obese adults before general surgical procedures. After intubation of the trachea, the ETT was bronchoscopically positioned 3 cm above the carina, after which 3 breaths of 500 mL were given and breath sounds were recorded. A second ETT was placed in the esophagus and the same series of breaths and recordings were performed. Finally, the tracheal ETT was advanced into the right mainstem bronchus and breath sounds were recorded. Using computerized analysis, breath sounds were digitized and filtered to remove selected frequencies, and acoustic signals and energy ratios were obtained for all 3 positions. Total energy ratios using band-pass filtering of the acoustic signals accurately identified all esophageal and endobronchial intubation (P < 0.001). These preliminary results suggest that this technique, when incorporated into a 3-component, electronic stethoscope-type device, may be an accurate, portable mechanism to reliably detect ETT malposition in adults when ETco(2) may be unavailable or unreliable.

Blood Gas Analysis↗

PubMed2006

Sound production mechanism in carapid fish: first example with a slow sonic muscle.

Fish sonic swimbladder muscles are the fastest muscles in vertebrates and have fibers with numerous biochemical and structural adaptations for speed. Carapid fishes produce sounds with a complex swimbladder mechanism, including skeletal components and extrinsic sonic muscle fibers with an exceptional helical myofibrillar structure. To study this system we stimulated the sonic muscles, described their insertion and action and generated sounds by slowly pulling the sonic muscles. We find the sonic muscles contract slowly, pulling the anterior bladder and thereby stretching a thin fenestra. Sound is generated when the tension trips a release system that causes the fenestra to snap back to its resting position. The sound frequency does not correspond to the calculated resonant frequency of the bladder, and we hypothesize that it is determined by the snapping fenestra interacting with an overlying bony swimbladder plate. To our knowledge this tension release mechanism is unique in animal sound generation.

Air Sacs↗

PubMed2006

Acoustic communication in territorial butterflyfish: test of the sound production hypothesis.

Butterflyfishes are conspicuous members of coral reefs and well known for their visual displays during social interactions. Members of the genus Chaetodon have a unique peripheral arrangement of the anterior swim bladder that connects with the lateral line (the laterophysic connection) and in many species projects towards the inner ear. This morphology has lead to the proposal that the laterophysic connection and swim bladder system may be a specialized structure for the detection of sound. However, the relevant stimuli, receiver mechanisms and functions for these putative hearing structures were unknown because butterflyfishes were previously not recognized to produce sounds during natural behavior. We performed field experiments to test the hypothesis that Chaetodon produces sounds in natural social contexts. Acoustic and motor behaviors of the monogamous multiband butterflyfish, C. multicinctus, were evoked and recorded by placement of bottled fish into feeding territories of conspecific pairs. We demonstrate that territory defense includes the production of agonistic sounds and hydrodynamic stimuli that are associated with tail slap, jump, pelvic fin flick and dorsal-anal fin erection behaviors. In addition, grunt pulse trains were produced by bottled intruders and are tentatively interpreted to function as an alert call among pair mates. Acoustic behaviors include low frequency hydrodynamic pulses <100 Hz, sounds with peak energy from 100 Hz to 500 Hz, and a broadband high frequency click (peak frequency=3.6 kHz), which is produced only during the tail slap behavior. These results provide a biological framework for future studies to interpret the proximate function of the acoustico-lateralis sensory system, the evolution of the laterophysic mechanism and their relevance to butterflyfish social behavior.

Animal Communication↗

PubMed1997

The effects of seasonal hypertrophy and atrophy on fiber morphology, metabolic substrate concentration and sound characteristics of the weakfish sonic muscle.

Male weakfish Cynoscion regalis possess highly specialized, bilateral, striated sonic muscles used in sound production associated with courtship. Androgen-driven hypertrophy of the muscles during the late spring spawning period results in a tripling of sonic muscle mass followed by post-spawning atrophy. This study examined the morphological and biochemical changes underlying seasonal changes in sonic muscle mass and the functional effects of these on contraction as measured by sound production. Sonic muscle fiber cross-sectional area (CSA) increased significantly during the period of hypertrophy and then decreased by nearly 60%. Both the CSA of the contractile cylinder and that of the peripheral sarcoplasm decreased significantly by late summer, with the peripheral ring of sarcoplasm virtually disappearing. Muscle protein content followed a similar trend, suggesting a major loss of structural elements during atrophy. Muscle glycogen and lipid content decreased precipitously in early June during the period of maximal sound production. Sound pressure level increased and sound pulse duration decreased with increasing sonic muscle mass, indicating that sonic muscle fibers contract with greater force and shorter duration during the spawning season. Neither the pulse repetition rate nor the number of pulses varied seasonally or with muscle mass, suggesting that the effects of steroids on the acoustic variables are more pronounced peripherally than in the central nervous system. Seasonal sonic muscle hypertrophy, therefore, functions as a secondary sexual characteristic that maximizes vocalization amplitude during the spawning period.

Androgens↗

PubMed1990

Airflow-generated sound in a hollow canine airway cast.

We examined the distribution of airflow-generated sound within a flexible model of canine airways. Sounds were picked up by a microphone adapted to a glass conical probe which was introduced through puncture holes in the wall of the model. We acquired 341 measurements in 31 airways between 2.0 and 19.0 mm in diameter at airflow rates from 0 to 2.5 L/s in the inspiratory and expiratory directions. We found that in the expiratory direction, the sound amplitude was approximately linearly related to airway cross-sectional area, with the greatest amplitude occurring in the largest airway. In the inspiratory direction the greatest amplitude occurred in airways of 5 to 8 mm in diameter. At all levels within the model, sound amplitude was approximately linearly related to the square of the airflow. Our findings suggest that in canine airways, the predominant vesicular lung sound-producing locations are the large airways for the expiratory component and the medium-sized airways for the inspiratory component.

Animals↗

PubMed1990

Lung sound nomenclature survey.

We report the terms used by 223 pulmonary physicians and 54 physicians in other specialties to describe eight recorded examples of lung sounds. The participants listened to the lung sounds at the 1988 American College of Chest Physicians annual convention and wrote "free form" answers. Pulmonary physicians used the terms "crackles" and "rales" with equal frequency to describe discontinuous adventitious lung sounds (ALS) and not at all to describe continuous ALS. Other physicians preferred the term "rales" in describing discontinuous ALS. The terms "wheeze" and "stridor" were used only in describing continuous ALS; however, the term "rhonchi" was frequently used to describe continuous and discontinuous ALS. The majority of participants recognized the normal breath sounds but not the pleural friction rub. Most did not use a qualifying adjective to describe ALS, and there was little agreement among those who did. The lung sound terminology used by physicians is not well standardized and the recommendations of the ATS/ACCP nomenclature subcommittee are not widely accepted.

Data Collection↗

PubMed2003

[Effect of subcutaneous fatty tissue on normal respiratory sounds].

Auscultation is an important, non-invasive and simple measure in the diagnosis of lung diseases that can detect sometimes pathological processes prior to radiography. Attempts have already been made to automatically detect characteristic pathological sounds, but a knowledge of potential influencing factors is a must for correct interpretation. In this study we have investigated the effect of the subcutaneous fat layer on normal lung sounds. This is of importance to determine corrective factors for the automatic detection of bronchial breathing in pneumonia. The lung sounds of 125 healthy people (55f, 70m) were digitally recorded at four different positions of the thorax (3. ICR paravertebral, 7. ICR medioscapular, all left and right). Evaluation was done separately for gender. The subcutaneous fat layer was measured with a Holtain Skinfold Caliper at the identical four recording positions. For a quantitative evaluation of the sounds we calculated the relative power of frequency bands 330-600 Hz and 60-330 Hz and their ratio. The relation between these parameters and the subcutaneous fat layer was analyzed with the Pearson correlation. The results of this study show that the influence of subcutaneous fat layer is negligible and can be ignored in the automatic detection of lung sounds.

Adipose Tissue↗

PubMed1989

Sound speed, density and total protein concentration of blood.

The sound speed and the density of a series of blood samples was measured in a temperature range from 20 degrees C to 40 degrees C. An expression was derived from a least square fit which related the sound speed in human blood in this temperature range to the blood density and to the total protein concentration, respectively. The data were obtained from the measurement of sound speed and density by means of a newly developed Density and Sound Analyzer (DSA-48, A. Paar K.G., 8054 Graz, Austria). The relationship of sound speed, density and temperature permits the calculation of the total protein concentration with an accuracy of 1 g/kg. The resolution of the measurement is in the order of 0.1 g/kg.

Blood Proteins↗

PubMed2004

Dynamic sound localization during rapid eye-head gaze shifts.

Human sound localization relies on implicit head-centered acoustic cues. However, to create a stable and accurate representation of sounds despite intervening head movements, the acoustic input should be continuously combined with feedback signals about changes in head orientation. Alternatively, the auditory target coordinates could be updated in advance by using either the preprogrammed gaze-motor command or the sensory target coordinates to which the intervening gaze shift is made ("predictive remapping"). So far, previous experiments cannot dissociate these alternatives. Here, we study whether the auditory system compensates for ongoing saccadic eye and head movements in two dimensions that occur during target presentation. In this case, the system has to deal with dynamic changes of the acoustic cues as well as with rapid changes in relative eye and head orientation that cannot be preprogrammed by the audiomotor system. We performed visual-auditory double-step experiments in two dimensions in which a brief sound burst was presented while subjects made a saccadic eye-head gaze shift toward a previously flashed visual target. Our results show that localization responses under these dynamic conditions remain accurate. Multiple linear regression analysis revealed that the intervening eye and head movements are fully accounted for. Moreover, elevation response components were more accurate for longer-duration sounds (50 msec) than for extremely brief sounds (3 msec), for all localization conditions. Taken together, these results cannot be explained by a predictive remapping scheme. Rather, we conclude that the human auditory system adequately processes dynamically varying acoustic cues that result from self-initiated rapid head movements to construct a stable representation of the target in world coordinates. This signal is subsequently used to program accurate eye and head localization responses.

Acoustic Stimulation↗

PubMed2006

Monkey sound localization: head-restrained versus head-unrestrained orienting.

The sound localization abilities of three rhesus monkeys were tested under head-restrained and head-unrestrained conditions. Operant conditioning and the magnetic search coil technique were used to measure eye and head movements to sound sources. Whereas the results support previous findings that monkeys localize sounds very poorly with their heads restrained, the data also reveal for the first time that monkeys localize sounds much more accurately and with less variability when their heads are allowed to move. Control experiments using acoustic stimuli known to produce spatial auditory illusions such as summing localization confirmed that the monkeys based their orienting on localizing the sound sources and not on remembering spatial locations that resulted in rewards. Overall, the importance of using ecologically valid behaviors for studies of sensory processes is confirmed, and the potential of the rhesus monkey, the model closest to human, for studies of spatial auditory function, is established.

Acoustic Stimulation↗

PubMed1977

Recording of the fourth heart sound by the signal averaging method. Preliminary report.

The fourth heart sound was clearly recorded by using the signal averaging method. Furthermore, the simultaneous recording of the Doppler signal with the fourth heart sound was performed. Thus, it was demonstrated that the Doppler signal started after the P wave and followed by the fourth heart sound. In 2 cases, the effect of the double Master's test and taking a bath was studied on the computer averaged phonocardiogram. After the exercise, the amplitude of the fourth heart sound was increased, whereas after taking a bath it was almost unchanged. The above results show that the simultaneous recordings of a computer averaged phonocardiogram and Doppler signal that is associated with cardiac activity can greatly facilitate the interpretation of small vibrations such as the fourth heart sound.

Activities of Daily Living↗

PubMed1982

Laryngeal narrowing measured with low frequency sound.

We measured laryngeal resistance with 800 Hz sound in human subjects. 800 Hz sound was forced into the mouth and the intensities of sound above and below vocal cord were detected by two microphones on the anterior neck. Respiratory resistance (Rrs) was simultaneously measured by an oscillation method. When the subject voluntarily controlled the glottis aperture at functional residual capacity, the percent increase of difference of intensity of sound between two microphones (Y %) was curvilinearly proportional to the increase of Rrs (X) from the control state; Y = 20.8 X X 1.24. Since Rrs below the larynx was constant at a given lung volume, we could estimate the increase of laryngeal resistance from the control state by knowing the percent increase of difference of intensity of sound. The present method would be clinically applicable to measure Rrs independent from laryngeal artifact.

Adult↗

PubMed1991

Audible pedestrian traffic signals: Part 2. Analysis of sounds emitted.

This project evaluated audible pedestrian traffic signals from three perspectives: 1) the patterns of use and the impact of these signals on pedestrian travel; 2) the physical characteristics of the sound emitted by these devices; and, 3) the detection of their emitted sounds in the presence of various traffic noise levels. This paper, the second of three companion articles (2, 3), examines the sounds emitted by the Nagoya/Traconex audible traffic signal, the unit most commonly found in the western United States and almost exclusively in California. The sounds emitted by the north-south and east-west Traconex audible signals were analyzed for their loudness, directionality, frequency spectrum, and temporal characteristics using standard engineering tools including an anechoic chamber, sound level meters, spectrum analyzers, and signal analyzers.

Accidents, Traffic↗

PubMed1982

Stimulus-presentation probability influences newborns' head orientation to sound.

Although newborn infants are capable of turning their heads toward laterally-presented sounds, the incidence of such responding varies across studies. Previous work suggests that as the probability of a laterally-presented sound increases head-turning performance improves. To test this "lateral-stimulus-presentation probability" hypothesis, we presented 30 alert newborns with a rattle sound from a lateral source on either 1/4, 2/4, or 3/4 of all sound trials. On remaining sound trials the rattle came from a loudspeaker located above the infant's head. For 12 infants all lateral trials were presented consecutively; these trials were spaced across the session for the other infants. The likelihood of correct head turning increased linearly as the lateral-stimulus-presentation probability increased. The distribution of lateral trials did not influence the incidence of correct head turning.

Acoustic Stimulation↗