Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sound”

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 595 records · Page 33Linked to original sources
PubMed2003

Live recordings of sound levels during the use of powered instruments in ENT surgery.

Otolaryngology is one of the surgical specialities employing high-powered instruments and this study was designed in order to establish whether sound levels at work conform to HSE guidelines. No study to date has measured intra-operative noise levels in ENT operation theatres. A prospective observational study was therefore performed. Sound levels were measured during the use of bone drills for mastoid surgery and microdebriders for endoscopic sinus surgery. A SLM/IS Acos Class I sound level meter calibrated to BS 1259 was employed. A spectrum analysis of drill-generated noise was measured using a calibrated B and K precision sound level meter. Sound levels emitted varied as follows: Large burrs- 72.4 dB (A), medium size; 71.2 dB (A), small sized burrs- 68.8 dB (A) (all values for cutting burrs) and 60.8 dB (A) for diamond burs. With microdebriders, the average sound level was 60.1 dBA. Spectrum analysis revealed that the maximum intensity was at 3.15 kHz, followed by 4 kHz, while the least sound was produced at 40 kHz and 31.5 kHz. Essentially sound produced by drills was between 1.6 kHz and 6.3 kHz. Powered instruments used in ENT surgery are safe and pose no occupational hazard.

Humans↗
PubMed1996

Relationships between ambient sounds and the accuracy of pharmacists' prescription-filling performance.

Associations between ambient sounds and accuracy of pharmacists' prescription-filling performance in a pharmacy was studied. Pharmacists were videotaped as they filled prescriptions each workday for 23 days. Each filled prescription was inspected by the investigator. Deviations from the physician's written order were considered errors. Videotape analysis was used to detect unpredictable, predictable, uncontrollable, and controllable sounds. A within-subjects case control study design was employed to determine whether the frequency of ambient sounds was significantly different when prescriptions with errors, compared with those without errors, were filled. Loudness, in terms of equivalent sound levels (Leq) for each half hour, was analyzed for a relationship to dispensing error rate. A mean dispensing error rate of 3.23% was found. Unpredictable sounds, controllable sounds, and noise had a significant effect on pharmacists which resulted in a decreased dispensing error rate. These results suggest that the quality of pharmacists' performance is not adversely affected by ambient sound. As equivalent sound levels increased, the error rate increased to a point, then decreased.

Case-Control Studies↗
PubMed1977

The study of the third heart sound in relation to the left ventricular filling and wall movement by echocardiography.

The left ventricular filling and wall movement were investigated in subjects with a third heart sound or ventricular gallop by echocardiography. Nine patients with ventricular gallop, who had left ventricular volume overload disease, and 6 normal subjects with a third heart sound had higher normalized peak rate of increase of the left ventricular dimension (peak dD/dT/D) than 10 normal subjects without a third heart sound (p less than 0.01). The normalized lengthening rate in the rapid filling phase was also higher in patients with ventricular gallop than in normal subjects without a third heart sound (p less than 0.05). The time from the second heart sound to peak dD/dT/D and rapid filling time did not show statistically significant values between subjects with ventricular gallop or a third heart sound and those without a third heart sound. These results suggest that higher peak filling, larger filling volume in the rapid filling phase and more abrupt cessation of the outward movement of the left ventricular wall may be a cause of the production of ventricular gallop in patients with left ventricular volume overload and of the physiological third heart sound.

Adolescent↗
PubMed2003

Sound-producing sand in Japan: major element composition and its minerals determined by X-ray diffraction and X-ray fluorescence.

The major element composition, including two kinds of clay minerals and moisture content of sound-producing sand are reported for the first time. Sand from 33 beaches in Japan has been found to make sound. Ten sound-producing beaches were selected to compare with silent beach sand. Both sound-producing sand and silent beach sand are mostly composed of quartz and feldspar. The range of SiO2 content of sound-producing sand is not different from silent sand samples. This indicates that a high quartz content is not necessary to produce sound, although more than 60 weight percent of quartz is necessary. One silent sand recovered its sound after a 3.5 percent HNO3 treatment. Also, a small portion of clay minerals was found. A clean grain surface is a necessary factor for sand to produce sound. Illite was found in all silent sand samples.

Journal Article↗
PubMed1991

Responses of medial geniculate neurons to species-specific vocalized sounds in the guinea pig.

We obtained extracellular single-unit recordings in the medial geniculate body (MG) of guinea pigs, and studied the responses of MG neurons to pure-tone stimuli and to species-specific vocalized sounds. Of pure-tone sensitive neurons with a characteristic frequency (CF) within the frequency range of the vocalized sounds, only 29% responded to the vocalized sound, 6% were inhibited by the vocalized sound, and 30% showed no response to the vocalized sounds. The responsiveness of MG neurons to the vocalized sound was low. The majority of neurons responsive to the vocalized sounds showed discharge patterns which were not predictable from response properties to pure tones. These results suggest the presence of neurons which specifically respond to the complex feature of sound in the subcortical MG level of the guinea pig.

Acoustic Stimulation↗
PubMed1982

Listeners' identification of environmental sounds.

To determine if listeners can accurately identify various environmental sounds, a total of 40 sounds, including animal, inanimate, musical, and human sounds, were recorded, randomly arranged on a master tape, and presented to 30 judges for identification. Analysis indicated that, in general, listeners can accurately identify environmental sounds. However, their accuracy was not equal for all four classes of sounds investigated: human sounds yielded the highest accuracy, followed by musical and inanimate sounds, and animal sounds were least accurately identified. Implications and suggestions for research are discussed.

Auditory Perception↗
PubMed2000

The relationship between reaction to sudden, intermittent movements and sounds and temperament.

Casual observations indicated that some cattle are more sensitive to sudden movement or intermittent sound than other cattle. Six commercial livestock auctions in two states and a total of 1,636 cattle were observed to assess the relationship between breed, sex, and temperament score on the response to sudden, intermittent visual and sound stimuli, such as the ringman swinging his arm for a bid and the sound of him briefly yelling a bid. A 4-point temperament score was used to score each animal while it was in the ring. The scores used were 1) walks and(or) stands still, with slow, smooth body movements; 2) continuously walks or trots, and vigilant; 3) gait is faster than a trot (runs even a couple of steps), with fast, abrupt, jerky movements, and very vigilant; and 4) hits the ring fence, walls, partitions, or people with its head. Animals were observed for flinches, startle responses, or orientation toward sudden, intermittent sounds, motions, and tactile stimulation, such as being touched with a cane or plastic paddle. The cattle observed were mostly Bos taurus beef breeds and Holstein dairy cattle. Holsteins were more sound-sensitive (P = .02) and touch-sensitive (P < .01) than beef cattle. Sensitivity to sudden, intermittent stimuli (e.g., sound, motion, and touch) increased as temperament score (excitability) increased. Cattle with a temperament score of 1 were the least sensitive to sudden, intermittent movement and sound and those with a temperament score of 4 were the most sensitive (P < .01). This same relationship was sometimes observed for touch but was not statistically significant. Motion-sensitive cattle were more likely than nonsensitive cattle to score a temperament rating of 3 or 4 (P < .01). Steers and heifers were more motion-sensitive than the older bulls and cows (P = .03). Beef cattle urinated (P < .01, n = 1,581) and defecated (P < .01, n = 1,582) more often in the ring than did dairy cattle. Cattle that became agitated during handling in an auction ring were the individuals that were most likely to be startled by sudden, intermittent sounds and movements. Reactivity to sudden, intermittent stimuli may be an indicator of an excitable temperament.

Animals↗
PubMed1997

Behavioural and autonomic responses to sound in pre-term and full-term babies.

The pattern of motor (body movement) and autonomic (heart rate and respiration) responses to no sound and sound trials were compared in 20 pre-term and 22 full-term neonates. Sound levels were calibrated using neonatal ear-sized couplers to produce, in the neonatal ear, sound levels of 80, 90 and 100 dB SPL. Accelerations in heart rate (> or = beats per minute for pre-terms; > or = 7 beats per minute for full-terms) were found to be the best criterion for establishing a possible response using bandpass noise at 80, 90 or 100 dB SPL. Respiration rate decreased in response to sound stimuli, this being significant for the pre-term group for the 100 dB SPL stimulus when comparing the 5 s period post-stimulus with the stimulus period. The number of movements detected during the sound trials was higher than for the control trials, being statistically significant for the pre-term group. These changes were elicited in response to stimuli presented at levels some 20-40 dB lower than for other studies and for behavioural screening because sounds were calibrated in an appropriately sized coupler. It is concluded that the response to sound is different in the pre-term group compared with the full-term group.

Acoustic Stimulation↗
PubMed2001

Real time sound intensity measurements in an industrial complex.

The development of techniques and new tools for environmental acoustic measurements has opened up new ways and means to determine the source location, source ranking and energy flow path. The new tools posses versatile probes for different applications, better digital signal processing facilities and data presentation for sound pressure measurements--the quantity we hear, sound power measurements--the quantity emitted from a source, and the sound intensity measurements--the quantity of propogated sound power. The paper reports the results of real time sound intensity measurement carried out in an industrial complex with a portable sound intensity analyzer equipped with 1/3 octave filters and a dual microphone remote control probe for real time analysis. Extensive sound intensity measurement in the Power Plant, Ammonia Compressor House and Urea Compressor House have been carried out. The results are useful for sound power determination of various sources.

Acoustics↗
PubMed2004

Automated lung sound analysis in patients with pneumonia.

OBJECTIVE: To determine whether objectively detected lung sounds were significantly different in patients with pneumonia than those in asymptomatic subjects, and to quantify the pneumonia findings for teaching purposes. METHODS: At a community teaching hospital we used a multi-channel lung sound analyzer to examine a learning sample of 50 patients diagnosed with pneumonia and 50 control subjects. Automated quantification and characterization of the lung sounds commonly recognized to be associated with pneumonia were used to generate an "acoustic pneumonia score." These were examined in the learning sample and then prospectively tested in 50 patients and 50 controls. RESULTS: The acoustic pneumonia score averaged 13 in the learning sample and 11 in the test sample of pneumonia patients. The scores were 2 and 3 in the controls. The positive predictive value of a score higher than 6 was 0.94 in the learning sample and 0.87 in the test sample. The sensitivities in the 2 groups were 0.90 and 0.78, and the specificities were 0.94 and 0.88, respectively. Adventitious sounds were more common in pneumonia patients (inspiratory crackles 81% vs 28%, expiratory crackles 65% vs 9%, rhonchi 19% vs 0%). CONCLUSION: Our lung sound analyzer found significant differences between lung sounds in patients with pneumonia and in asymptomatic controls. Computerized lung sound analysis can provide objective evidence supporting the diagnosis of pneumonia. We believe that the lung-sound data produced by our device will help to teach physical diagnosis.

Aged↗
PubMed1992

The fetal sound environment during vibroacoustic stimulation in labor: effect on fetal heart rate response.

Nine pregnant women near term, with medical indications for internal monitoring during labor, were studied to determine the transmission of sound across maternal soft tissues during vibroacoustic stimulation with an electronic artificial larynx. A miniaturized hydrophone was placed transcervically at the level of the fetal neck under ultrasound guidance. Intrauterine sound pressure levels were measured before and during stimulation applied at 1 and 0 cm from the surface of the maternal abdomen. When the electronic artificial larynx was placed at a distance of 1 cm from the maternal abdomen, the intrauterine sound pressure level averaged 75 dB at frequencies between 0-5000 Hz. However, when the electronic artificial larynx was firmly applied on the maternal abdomen, intrauterine sound pressure levels were enhanced by more than 20 dB (P less than .001) and averaged 95 dB at all frequencies between 87-20,000 Hz. Baseline intrauterine sound pressure levels consisted of low-frequency sound with intensity of 85 dB at 12.5 Hz, decreasing to 60 dB at 100 Hz and less than 40 dB above 200 Hz. There was a significant correlation (r = 0.78, P less than .02) between the duration of the first fetal heart rate (FHR) acceleration following stimulus and the overall intrauterine sound pressure level at the time of the stimulus. Our data suggest that a threshold of 94 dB intrauterine sound pressure level is necessary to produce a consistent FHR response during active labor.

Acoustic Stimulation↗
PubMed1991

Inability to assess breath sounds during air medical transport by helicopter.

This study assessed the capabilities of a traditional and an amplified stethoscope used by flight nurses to assess breath sound during air medical transport in an MBB BO-105 helicopter. We developed a normal breath sound model using a prerecorded tape of breath sounds interspersed with segments without breath sounds; the recorder had been placed in the chest wall of a resuscitation training manikin. Flight nurses completed control listening sessions in a quiet environment and experimental sessions during flight using a traditional stethoscope for half of the sessions and an amplified stethoscope for the remaining half. In the quiet environment, flight nurses accurately reported the presence or absence of breath sounds in 110 (92%) of 120 trials. During helicopter flight, none of the flight nurses heard breath sounds during any of the recorded segments with either the traditional stethoscope or the amplified stethoscope. We conclude that flight nurses are unable to hear normal breath sounds using a traditional or amplified stethoscope during flight in a medically configured MBB BO-105 helicopter. Improved stethoscopes, innovative methods of listening, and reduction of aircraft noise are potential solutions to the problems of breath sound assessment during air medical transport.

Aircraft↗
PubMed1986

Normal and pathological bowel sound patterns.

The purpose of this study was to determine the usefulness of auscultation of bowel sounds in evaluating patients with total and subtotal small intestinal obstruction and immediately after operation. The study was based on ten healthy volunteers, seven patients with documented mechanical obstruction, one patient with chronic subtotal mechanical obstruction and twelve patients undergoing an emergency laparotomy. Bowel sounds varied markedly in all individuals studied. The most striking finding in mechanical obstruction was the regular occurrence of clustered bowel sounds. These were defined as 3-10 regular sounds, occurring one every five seconds, preceded and followed by at least one minute of silence. The associated periods of quiescent motor activity may account for the unexpectedly reduced frequency and motility index after a meal in obstructed patients compared with normal subjects. The different bowel sound patterns occurred in the patient with subtotal mechanical obstruction before and after a meal respectively i.e. infrequent and low-amplitude bowel sounds and clustered bowel sounds. The technique is probably not more sensitive than radiological procedures, and the abnormalities that are detected by an auscultation of bowel sounds are not specific.

Adult↗
PubMed1998

The functional anatomy of sound intensity discrimination.

The human neuroanatomical substrate of sound intensity discrimination was investigated by combining psychoacoustics and functional neuroimaging. Seven normal subjects were trained to detect deviant sounds presented with a slightly higher intensity than a standard harmonic sound, using a Go/No Go paradigm. Individual psychometric curves were carefully assessed using a three-step psychoacoustic procedure. Subjects were scanned while passively listening to the standard sound and while discriminating changes in sound intensity at four different performance levels (d' = 1.5, 2.5, 3.5, and 4.5). Analysis of regional cerebral blood flow data outlined activation, during the discrimination conditions, of a right hemispheric frontoparietal network already reported in other studies of selective or sustained attention to sensory input, and in which activity appeared inversely proportional to intensity discriminability. Conversely, a right posterior temporal region included in secondary auditory cortex was activated during discrimination of sound intensity independently of performance level. These findings suggest that discrimination of sound intensity involves two different cortical networks: a supramodal right frontoparietal network responsible for allocation of sensory attentional resources, and a region of secondary auditory cortex specifically involved in sensory computation of sound intensity differences.

Adult↗
PubMed1997

Chest surface mapping of lung sounds during methacholine challenge.

Wheeze as an indicator of airway obstruction during bronchoprovocation lacks sensitivity. We therefore studied whether induced airway narrowing is revealed by changes in normal (vesicular) lung sounds. Fifteen subjects with asthma and nine healthy controls, aged 8-16 years, performed a standardized methacholine challenge. Respiratory sounds were recorded with eight contact sensors, placed posteriorly over the right and left superior and basal lower lobes, and anteriorly over both upper lobes, the right middle lobe, and the trachea. Average spectra of normal inspiratory and expiratory sounds, excluding wheeze, were characterized in 12 asthmatics and 9 controls at flows of 1 +/- 0.2 L/sec. Airway narrowing was accompanied by significant changes in lung sounds, but not in tracheal sounds. Lung sounds showed a decrease in power at low frequencies during inspiration and an increase in power at high frequencies during expiration. These changes already occurred at a decrease in forced expiratory volume in 1 sec of less than 10% from baseline and were fully reversed after inhalation of salbutamol. Thus, lung sounds were sensitive to changes in airway caliber, but were not specific indicators of bronchial hyperresponsiveness.

Adolescent↗
PubMed2002

Pneumothorax detection using computerised analysis of breath sounds.

The primary objective of the study was to investigate the effects of pneumothorax (PTX) on breath sounds and to evaluate their use for PTX diagnosis. The underlying hypothesis is that there are diagnostic breath sound changes with PTX. An animal model was created in which breath sounds of eight mongrel dogs were acquired and analysed for both normal and PTX states. The results suggested that pneumothorax was associated with a reduction in sound amplitude, a preferential decrease in high-frequency acoustic components and a reduction in sound amplitude variation during the respiration cycle (p<0.01 for each, using the Wilcoxson signed-rank test). Although the use of diminished sound amplitude for PTX diagnosis assumes availability of baseline measurements, this appears unnecessary for high-frequency reduction or sound amplitude changes over the respiratory cycle. Further studies are warranted to test the clinical feasibility of the method in humans.

Animals↗
PubMed1981

The phonochrome: a coherent spectro-temporal representation of sound.

Representation of simple stationary sounds can be given either in the temporal form by display of the waveform as function of time or in the spectral form by intensity and phase as function of frequency. For complex nonstationary sounds, e.g. animal vocalisations and human speech, a combined spectro-temporal representation is more directly associated with auditory perception. The well-known sonogram or dynamic power spectrum has a fixed spectro-temporal resolution and neglects phase relations of different spectral and temporal sound components. In this paper the complex spectro-temporal intensity density CoSTID) is presented as a coherent spectro-temporal image of a sound, based on the analytic signal representation. The CoSTID allows an arbitrary form of the spectro-temporal resolution and preserves phase relations of different sound components. Since the CoSTID is a complex function of two variables, it leads naturally to the use of colour images for the spectro-temporal representation of sound: the phonochrome. The phonochromes are shown for different technical and natural sounds. Applications of this technique for study of phonation and audition and for biomedical signal processing are indicated.

Acoustics↗
PubMed2004

Illusory sound shifts induced by the ventriloquist illusion evoke the mismatch negativity.

The ventriloquist illusion arises when sounds are mislocated towards a synchronous but spatially discrepant visual event. Here, we investigated the ventriloquist illusion at a neurophysiological level. The question was whether an illusory shift in sound location was reflected in the auditory mismatch negativity (MMN). An 'oddball' paradigm was used whereby simultaneously presented sounds and flashes coming from the same location served as standard. The deviant consisted of a sound originating from the same source as the standard together with a flash at 20 degrees spatial separation, which evoked an illusory sound shift. This illusory sound shift evoked an MMN closely resembling the MMN evoked by an actual sound shift. A visual-only control condition ruled out that the illusory-evoked MMN was confounded by the visual part of the audiovisual deviant. These results indicate that the crossmodal interaction on which the ventriloquist illusion is based takes place automatically at an early processing stage, within 200 ms after stimulus onset.

Acoustic Stimulation↗