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 1,315 records · Page 73Linked to original sources
PubMed1992

[Processing steps in perception of speech sounds].

The aim of this study is to investigate whether speech sounds--as is stated by the widely accepted theory of categorical perception of speech--can be perceived only as instances of phonetic categories, or whether physical differences between speech sounds lead to perceptual differences regardless of their phonetic categorization. Subjects listened to pairs of synthetically generated speech sounds that correspond to realizations of the syllables "ba" and "pa" in natural German, and they were instructed to decide as fast as possible whether they perceived them as belonging to the same or to different phonetic categories. For 'same'-responses reaction times become longer when the physical distance between the speech sounds is increased; for 'different'-responses reaction times become shorter with growing physical distance between the stimuli. The results show that subjects can judge speech sounds on the basis of perceptual continua, which is inconsistent with the theory of categorical perception. A mathematical model is presented that attempts to explain the results by postulating two interacting stages of processing, a psychoacoustical and a phonetic one. The model is not entirely confirmed by the data, but it seems to deserve further consideration.

Adult↗
PubMed2003

Developing optimal search strategies for detecting sound clinical prediction studies in MEDLINE.

BACKGROUND: The gaining interest in the use of clinical prediction guides as an aid for helping clinicians make effective front-line decisions, together with the increasing emphasis on evidence-based practice, underscores the need for accurate identification of sound clinical prediction studies. Despite the growing use of clinical prediction guides, little work has been done on identifying optimal literature search filters for retrieving these types of studies. The current study extends our earlier work, on developing optimal search strategies, to include clinical prediction guides. OBJECTIVE: To develop optimal search strategies for detecting methodologically sound clinical prediction studies in MEDLINE in the publishing year 2000. DESIGN: Comparison of the retrieval performance of methodologic search strategies in MEDLINE with a manual review ("gold standard") of each article for each issue of 162 core health care journals for the year 2000. METHODS: 6 experienced research assistants who had been trained and intensively calibrated reviewed all issues of 162 journals for the publishing year 2000. Each article was classified for format, interest, purpose, and methodologic rigor. Search strategies were developed for all purpose categories, including studies of clinical prediction guides. MAIN OUTCOME MEASURES: The sensitivity (recall), specificity, precision, and accuracy of single and combinations of search terms. RESULTS: 39% of original studies classified as a clinical prediction guide were methodologically sound. Combinations of terms reached peak sensitivities of 95%. Compared with the best single term, a three-term strategy increased sensitivity for sound studies by 17% (absolute increase), but with some loss of specificity when sensitivity was maximized. When search terms were combined to optimize sensitivity and specificity, these values reached or were close to 90%. CONCLUSION: Several search strategies can enhance the retrieval of sound clinical prediction studies.

Causality↗
PubMedDate not supplied

The nano-hardness and elastic modulus of carious and sound primary canine dentin.

This study measured the nanohardness and elastic modulus- of carious and sound primary canine dentin and compared the values obtained under the lesion and in sound regions of incisal, center and cervical areas, and outer, middle and inner layers. Six extracted or exfoliated primary canines (three with dentin caries on both proximal surfaces and three sound teeth) were mesiodistally sectioned parallel to the long axis of the tooth and polished. The hardness (H), plastic hardness (PH) and Young's modulus (Y) were measured by a nano-indentation tester. Ten indentations at intervals of 10 microm on all regions, areas and layers were made using a load of 1 gf for one second. All indentations were observed using a microscope attached to the tester. All data were statistically analyzed using ANOVA and Scheffe's test at p < 0.05. For sound teeth, the H, PH and Y values of the inner layer were significantly lower than the outer and middle layers in all areas. The H, PH and Y values of the cervical area were significantly lower than the incisal area in almost all of the outer, middle and inner layers. For carious teeth, the H, PH and Y values of the inner layer were significantly lower than the outer and middle layers in the center area. For the center area, the H, PH and Y values under the lesion were significantly lower than sound teeth in the outer and middle layers. Dentin under the lesion, near the pulp and cervical areas showed significantly lower nanohardness and elasticity.

Analysis of Variance↗
PubMed2004

The pattern of tongue pressure against the palate during articulating glossal sounds in normal subjects and glossectomy patients.

The purpose of the present study was to measure tongue pressure with the aim of characterizing the pattern of linguopalatal contact during articulating glossal sounds in normal subjects and glossectomy patients. Tongue pressures against the palate were evaluated in 13 normal subjects and 5 glossectomy patients by using three parameters: the duration from the onset of linguopalatal contact to the time of maximum pressure, the maximum pressure, and anterior posterior ratio of the maximum pressure. Three glossal sounds, [ti], [t [symbol: see text] i], and [[symbol: see text] i], which have tendency of mishearing in glossectomy patients, were selected for test sounds. A unique characteristic was demonstrated in normal subjects. The score of the maximum pressure showed an apparent order among the three sounds, while the durations revealed the opposite order. Anterior posterior ratio of the maximum pressure also showed some relationship among three sounds. In glossectomy patients, these characters were not found. The loss of tongue volume or deterioration of tongue mobility causes these results.

Adult↗
PubMedDate not supplied

Bonding to sound vs caries-affected dentin using photo- and dual-cure adhesives.

This study aimed to evaluate the microtensile bond strength (microTBS) of photo- and dual-cure adhesives to sound and caries-affected dentin using total- and self-etch techniques. Human third molars with occlusal caries were prepared as previously described by Nakajima and others (1995). Dentin surfaces were bonded with Optibond Solo Plus (Kerr; photo-cure adhesive) or Optibond Solo Plus + Dual-cure activator (Kerr; dual-cure adhesive) with total- and self-etch technique. Clearfil AP-X (Kuraray) was used for composite buildups. Following storage in distilled water at 37 degrees C for 24 hours, the teeth were sectioned into 0.7-mm thick slices to obtain sound and caries-affected dentin slabs, then trimmed to form hour glass shapes with a 1 mm2 cross-sectional area. The specimens were subjected to microtensile testing using EZ-test (Shimadzu) at 1 mm/minute. Data were analyzed using three-way ANOVA and Student's t-Test (p<0.05). Bond strengths to sound dentin with photo- and dual-cure adhesives using total- and self-etch techniques were significantly higher than those to caries-affected dentin. Dual-cure adhesive significantly decreased bond strengths both to sound and caries-affected dentin. The total-etch technique showed no beneficial effect on caries-affected dentin compared with the self-etch technique. Scanning electron microscopic observation of the resin-dentin interfaces revealed that hybrid layers in caries-affected dentin were thicker than those observed in sound dentin with photo- and dual-cure adhesives. Resin infiltration into dentinal tubules of caries-affected dentin was hampered by the presence of mineral deposits.

Acid Etching, Dental↗
PubMed2005

[Experimental study on conduction of Gong tonality vibromusic sound wave in the healthy human body].

OBJECTIVE: To study the conduction of Gong tonality vibromusic sound wave along meridians in healthy human body, and investigate differences of the sensitivity of different meridians and genders to this vibromusic message. METHODS: Emit the Gong tonality music signal under the water and then investigate the responses of different acupoints and control points at the tissue of the same level to the vibromusic sound wave. RESULTS: There were differences of sensitivity to music waves at source acupoints on the foot, sensitivity of Zusanli (ST 36) was significantly higher than its control point (P < 0.05), and there was difference between genders in the sensitivity of Sanyinjiao (SP 6) and Yinlingquan (SP 9) to music sound wave. CONCLUSION: Gong tonality vibromusic sound wave can conduct along meridians in healthy human body, and there are differences between different meridians and different genders in the sensitivity to the music sound wave.

Acupuncture Points↗
PubMed1990

[Experimental examinations about the influence of prosthetic therapeutic remedies for players on a wind-instrument as to the quality of the instrumental sound].

In 20 professional players on a wind-instrument (10 musicians on wood wind-instruments, 10 ones on brass wind-instruments) the condition was examined if there are significant connections between the meanwhile applied prosthetic therapeutic remedies (imitated by measuring bodies) and the instrumental sound produced by them. The sound quality was analysed as to the quality as well as to the quantity by an appropriate narrow band spectrometer, and a sound index was figured out. By this method we succeeded in demonstrating the use of a maxillary plate in the anterior third of the palate and that one of back-ground splints in the upper front tooth region of players on brass wind-instruments to cause significant sound changes. Additionally, a significant change in sound impression was stated by placing a maxillary plate into the middle of the third of the palate. Thus we succeeded to point out the prosthetic-critical zones of players on a wood wind- and a brass wind-instrument.

Adolescent↗
PubMed1989

Evaluation of maternal perception of sound-provoked fetal movement as a test of antenatal fetal health.

Maternal perception of sound-provoked fetal movement was correlated with the results of nonstress cardiotocography in 1097 women with obstetric or medical antenatal risk factors. Ninety-two percent of the mothers felt fetal movements with the stimulus; all but three had a reactive non-stress test (NST). These three women were taking multiple antihypertensive drugs and were less than 33 weeks' gestation. Of 88 patients with no maternal perception of sound-provoked fetal movement, ten had nonreactive NSTs. Ultrasound confirmed the absence of fetal movement to the stimulus. The outcome in nine of these ten cases suggested some evidence of fetal compromise. Maternal perception of sound-provoked fetal movement correlated well with the results of the NST; the sensitivity (76.9%), specificity (92.8%), and negative predictive value (99.7%) were all high, although the positive predictive value was only 11.4%. Maternal perception of sound-provoked fetal movement may suffice as an inexpensive and simple method of evaluating antenatal fetal well-being in risk situations. When the mother is doubtful or does not feel the sound-provoked fetal movement, NST is indicated to evaluate the fetal health.

Acoustic Stimulation↗
PubMed1984

Sound pickup utilizing an implantable piezoelectric ceramic bimorph element: application to the cochlear implant.

The degree of sound pickup possible with a piezoelectric ceramic bimorph element ( PCBE ) was tested as part of research on a total implantation system for a cochlear prosthesis. The PCBE functions as an electromechanical transducer and can be utilized as a device to sense vibration in the tympanic membrane by touching it to the malleus head. This method lends itself to the miniaturization and simplification required by an implantable device for sound pickup. The ability of the PCBE to function as a device to pick up sound was investigated using three normal human temporal bones. The sensitivity of the PCBE when coupled to the malleus was calculated as the ratio of the voltage generated by the PCBE to the sound pressure in front of the tympanic membrane, when these factors were processed with a spectrum analyzer. The best sensitivities registered with the three temporal bone specimens were -63, -61, -59 dB re 1 V/Pa, respectively, at 1 kHz. The frequency response curves had resonant frequencies at about 2 kHz and declined beyond 5 kHz. These results indicate that a PCBE coupled to the malleus head performs satisfactorily in regard to sound pickup and shows promise as a component of a totally implanted hearing system.

Bone Conduction↗
PubMed1983

[Neuronal reactions of the fastigial nucleus in the cat to sound signals].

28 out of 67 neurones of the fastigial nucleus responded to sound signals in anesthetized cats. Thresholds of the responses were over 72 dB in most of the neurones. Changes in intensity or duration of the sound signals were followed by insignificant changes in neuronal activity. An insignificant frequency selectivity (Q less than 0.2) was found in 8 (29%) neurones out of the 28. A considerable sensitivity was revealed in respect to the signals simulating spatial location or moving of the sound source. 13 out of 16 neurones (81%) responded to changes in interaural differences of the stimulation in time. Half of these neurones revealed the maximal changes of activity in interaural differences lesser than 50 microseconds (i.e. with the delays simulating the situation of the sound source near the midline of the head). 7 out of 18 neurones (39%) proved to be sensitive to "movement" of the sound source, each neuron having a preferential sensitivity to the movement with a certain speed.

Acoustic Stimulation↗
PubMed1978

Stimulus factors which influence the perceived externalization of sound presented through headphones.

Several experimental conditions were arranged to study the influence of binaural difference cues on the externalization of sound. Broadband, high- and low-pass noise bursts were generated in a sound-treated but not echo-free room and tape recorded from electret microphones placed at the entrance to the ear canals in a live model. The tapes were processed in special ways in an attempt to dissociate the binaural differences in time, intensity, and spectrum which normally appear together and congruently when listening to a sound 90 degrees off midline. These variously processed tapes of trains of noise bursts were played back via headphones to 12 normal-hearing Ss; they were asked to estimate the apparent distance of the acoustic image. No significant differences in distance judgments were found among listening conditions which consisted of: (1) interaural differences in time, intensity, and spectrum (i.e., simulating free-field listening); (2) interaural differences in time and spectrum only; and (3) interaural differences in time only. With respect to interaural time differences, it was found in a second experiment with 16 normal-hearing Ss that differences in time of stimulus arrival promoted externalization of sound, since when these were eliminated (leaving only interaural differences in the ongoing aspects of the fine structure of the stimuli) all sounds appeared significantly nearer the head. A consistent finding was that high-pass noise bursts appeared nearer the head than low-pass noise bursts irrespective of the conditions of stimulus presentation.

Acoustic Stimulation↗
PubMed1998

Lack of habituation of the pattern of cardiovascular response evoked by sound in subjects with primary Raynaud's disease.

1. The vasospasm of primary Raynaud's disease can be triggered by acute emotional stress. We have studied the pattern of cardiovascular response evoked by acute emotional stress, a sound stimulus of 90 dB, 2 kHz for 30 s, in eight subjects with primary Raynaud's disease and in eight age- and sex-matched controls, the sound being repeated five times on each of days 1, 3 and 5. 2. In controls, the first sound evoked the pattern of the alerting response that is characteristic of acute emotional stress: a rise in arterial pressure and heart rate, a decrease in vascular conductance in the cutaneous circulation of the digit, assessed by laser Doppler recording of erythrocyte (red cell) flux in the digit divided by arterial pressure, and an increase in forearm muscle vascular conductance, assessed from forearm blood flow recorded by venous occlusion plethysmography divided by arterial pressure. 3. In the subjects with primary Raynaud's disease, baselines of arterial pressure, digital cutaneous vascular conductance and forearm vascular conductance were not significantly different from those of the controls and they too showed the alerting response to the first sound, the magnitudes of the changes being comparable to those of the controls. 4. In both the controls and subjects with primary Raynaud's disease, the evoked responses were consistent on repetition of the sound on day 1. In contrast, judging from the means of the changes evoked on each day, the controls showed habituation of the individual components of the alerting response over days 1, 3 and 5, whereas the subjects with primary Raynaud's disease showed no habituation of either the forearm muscle vasodilatation or the digital vasoconstriction. Conversely, the decrease in digital cutaneous vascular conductance evoked by a single deep breath was fully reproducible in both controls and subjects with primary Raynaud's disease when tested at the beginning and end of each experimental day. 5. These results allow the novel conclusion that subjects with primary Raynaud's disease have an abnormality of the central neural modulation of the brain stem areas that integrate the cardiovascular components of the alerting response to acute emotional stress, such that habituation of the vasodilator and vasoconstrictor components of the response on repetition of the stimulus is impaired. We propose that such persistence of vasoconstrictor responses to stressful stimuli predisposes to vasospasm, particularly if neurally mediated vasoconstriction is reinforced by locally released vasoconstrictor factors.

Adult↗
PubMed1990

A low-cost, high-fidelity FM wireless precordial radiostethoscope for continuous monitoring of heart and breath sounds.

We constructed and tested an inexpensive (less than $50) FM wireless, acoustically shielded, precordial radiostethoscope that enables the anesthetist to follow the heart tones and breath sounds of the patient regardless of the anesthetist's location in the operating room. We compared our acoustically shielded device with a similar, but acoustically unshielded, commercially available device. We found the sound quality of our radiostethoscope to be superior to that of the commercial device; the signal-to-noise ratio of our device was 7.6 for heart tones and 8.4 for breath sounds, whereas the commercial device had a signal-to-noise ratio of 2.7 and 3.9 for heart tones and breath sounds, respectively. Our device offers all of the advantages of a radiostethoscope and has the added advantages of low cost and high fidelity.

Equipment Design↗
PubMed1982

Directionality of sound pressure transformation at the cat's pinna.

The directionality of the cat's pinna was studied by using the amplitude of the cochlear microphonic (CM) as a quantitative indicator of tympanic sound pressure level (SPL). It was found that tympanic SPL varied with the location of a free field stimulator in anechoic space. For high (tonal) frequencies, there was a circumscribed optimal area for tympanic SPL in the frontal ipsilateral sound field, in confirmation of previous findings with other techniques that the pinna has an acoustical axis. The directionality of the pinna, determined from the solid angle enclosed by the 5 dB isointensity-decrement line with respect to the optimal position, increased with frequency. For low tonal frequencies, no circumscribed optimal area in the frontal sound field could be distinguished, and tympanic SPL fell by only 10-12 dB for displacements of 90 degrees into the contralateral sound field. Excision of the pinna abolished the circumscribed optimal areas for tympanic SPL and revealed the pinna produces up to 28 dB amplification of acoustic signals delivered 'on-axis'.

Animals↗
PubMed2005

Visual localization of sounds.

Circumscribed hemispheric lesions in the right hemisphere have been shown to impair auditory spatial functions. Due to a strong crossmodal links that exist between vision and audition, in the present study, we have hypothesized that multisensory integration can play a specific role in recovery from spatial representational deficits. To this aim, a patient with severe auditory localization defect was asked to indicate verbally the spatial position where the sound was presented. The auditory targets were presented at different spatial locations, at 8 degrees, 24 degrees, 40 degrees, 56 degrees to either sides of the central fixation point. The task was performed either in a unimodal condition (i.e., only sounds were presented) or in crossmodal conditions (i.e., a visual stimulus was presented simultaneously to the auditory target). In the crossmodal conditions, the visual cue was presented either at the same spatial position as the sound or at 16 degrees or 32 degrees, nasal or temporal, of spatial disparity from the auditory target. The results showed that a visual stimulus strongly improves the patient's ability to localize the sounds, but only when it was presented in the same spatial position of the auditory target.

Acoustic Stimulation↗
PubMed1999

The localisation of spectrally restricted sounds by human listeners.

The two principal binaural cues to sound location are interaural time differences (ITDs), which are thought to be dominant at low frequencies, and interaural level differences (ILDs), which are thought to dominate at mid to high frequencies. The outer ear also filters the sound in a location dependent manner and provides spectral cues to location. In these experiments we have examined the relative contribution of these cues to the auditory localisation performance by humans. Six subjects localised sounds by pointing their face toward the perceived location of stimuli presented in complete darkness in an anechoic chamber. Control stimuli were spectrally flat (400 Hz to 16 kHz), while the relative contribution of location cues in the low frequency channels was determined using noise high passed at 2 kHz and in the high frequency channels using stimuli low passed at 2 kHz. The removal of frequencies below 2 kHz had little effect on either the pattern of systematic errors or the distribution of localisation estimates with the exception of an increase in the size of the standard deviations associated with a few rear locations. This suggests considerable redundancy in the auditory localisation information contained within a broadband sound. In contrast, restricting the target spectrum to frequencies below 2 kHz resulted in a large increase in the cone-of-confusion errors as well as a subject dependent biasing of the front-to-back or back-to-front confusions. These biases and the reduction in localisation accuracy for high pass stimuli at some posterior locations are consistent with a contribution of spectral information at low frequencies.

Acoustic Stimulation↗
PubMed2000

When a "wheeze" is not a wheeze: acoustic analysis of breath sounds in infants.

Epidemiological studies indicate that the prevalence of "wheeze" is very high in early childhood. However, it is clear that parents and clinicians frequently use the term "wheeze" for a range of audible respiratory noises. The commonest audible sounds originating from the lower airways in infancy are ruttles, which differ from classical wheeze in that the sound is much lower in pitch, with a continuous rattling quality and lacking any musical features. The aim of this study was to clearly differentiate wheeze and ruttles objectively using acoustic analysis. Lung sounds were recorded in 15 infants, seven with wheeze and eight with ruttles, using a small sensitive piezoelectric accelerometer, and information relating to the respiratory cycle was obtained using inductive plethysmography. The acoustic signals were analysed using a fast fourier transformation technique (Respiratory Acoustics Laboratory Environment programme). The acoustic properties of the two noises were shown to be quite distinct, the classical wheeze being characterized by a sinusoidal waveform with one or more distinct peaks in the power spectrum display; the ruttle is represented by an irregular nonsinusoidal waveform with diffuse peaks in the power spectrum and with increased sound intensity at a frequency of <600 Hz. It is important for clinicians and epidemiologists to recognize that there are distinct types of audible respiratory noise in early life with characteristic acoustic properties.

Fourier Analysis↗
PubMed2001

Loudness constancy with varying sound source distance.

At a listener's ears, sound source power and sound source distance are confounded in measures of acoustic intensity, a physical property long thought to be the primary determinate of loudness. Although the relationship between sound source loudness and power is well known when source distance is fixed, relatively little is known about source loudness under conditions of varying distance. Here we show a robust loudness constancy, similar in many ways to visual size constancy, that results under distance-varying conditions that produce inaccurate estimates of source distance. Our results suggest that the auditory system does not require accurate distance estimates to judge source loudness, even when distance is variable. We offer an alternative explanation of loudness constancy based solely on a reverberant sound energy cue.

Acoustic Stimulation↗