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At least 1,297 records · Page 72Linked to original sources
PubMed1975

Sound localization by the bottlenose porpoise Tursiops truncatus.

1. Sound localization was measured behaviourally for the Atlantic bottlenose porpoise (Tursiops truncatus) using a wide range of pure tone pulses as well as clicks simulating the species echolocation click. 2. Measurements of the minimum audible angle (MAA) on the horizontal plane give localization discrimination thresholds of between 2 and 3 degrees for sounds from 20 to 90 kHz and thresholds from 2-8 to 4 degrees at 6, 10 and 100 kHz. With the azimuth of the animal changed relative to the speakers the MAAs were 1-3-1-5 degrees at an azimuth of 15 degrees and about 5 degrees for an azimuth of 30 degrees. 3. MAAs to clicks were 0-7-0-8 degrees. 4. The animal was able to do almost as well in determining the position of vertical sound sources as it could for horizontal localization. 5. The data indicate that at low frequencies the animal may have been localizing by using the region around the external auditory meatus as a detector, but at frequencies about 20 kHz it is likely that the animal was detecting sounds through the lateral sides of the lower jaw. 6. Above 20 kHz, it is likely that the animal was localizing using binaural intensity cues. 7. Our data support evidence that the lower jaw is an important channel for sound detection in Tursiops.

Animals↗
PubMed2004

Modulation power and phase spectrum of natural sounds enhance neural encoding performed by single auditory neurons.

We examined the neural encoding of synthetic and natural sounds by single neurons in the auditory system of male zebra finches by estimating the mutual information in the time-varying mean firing rate of the neuronal response. Using a novel parametric method for estimating mutual information with limited data, we tested the hypothesis that song and song-like synthetic sounds would be preferentially encoded relative to other complex, but non-song-like synthetic sounds. To test this hypothesis, we designed two synthetic stimuli: synthetic songs that matched the power of spectral-temporal modulations but lacked the modulation phase structure of zebra finch song and noise with uniform band-limited spectral-temporal modulations. By defining neural selectivity as relative mutual information, we found that the auditory system of songbirds showed selectivity for song-like sounds. This selectivity increased in a hierarchical manner along ascending processing stages in the auditory system. Midbrain neurons responded with highest information rates and efficiency to synthetic songs and thus were selective for the spectral-temporal modulations of song. Primary forebrain neurons showed increased information to zebra finch song and synthetic song equally over noise stimuli. Secondary forebrain neurons responded with the highest information to zebra finch song relative to other stimuli and thus were selective for its specific modulation phase relationships. We also assessed the relative contribution of three response properties to this selectivity: (1) spiking reliability, (2) rate distribution entropy, and (3) bandwidth. We found that rate distribution and bandwidth but not reliability were responsible for the higher average information rates found for song-like sounds.

Acoustic Stimulation↗
PubMed1981

Peculiarities of the first heart sound in bundle branch blocks. A new interpretation based on graphic analysis.

A phonocardiographic study in a medium frequency range was made over various areas of the precordium in 27 cases of right bundle branch block (RBBB), 28 cases of left bundle branch block (LBBB), and 30 normal subjects of the same age. The various components of the first heart sound plus the pulses at the suprasternal notch and the right carotid artery were studied in regard to timing, relationship with the ECG and the arterial pulses, intervals between components, and amplitude. The timing and intervals of the three components of the first sound were found normal in RBBB and so were the arterial pulses; apparent wide splitting was occasionally noted, due to recording of the first (a) and third (c) components, the latter being larger, as frequently observed in old age. All three components of the first sound were found small and delayed in LBBB; a delay of the arterial pulses was also noted. No additional component that might be attributed to the right heart preceded the delayed first sound. This study confirms that the first heart sound recorded on the chest wall originates only in the left heart and aorta.

Aged↗
PubMed2004

Natural sound archives: past, present and future.

Recordings of wild animals were first made in the Palearctic in 1900, in the Nearctic in 1929, in Antarctica in 1934, in Asia in 1937, and in the Neotropics in the 1940s. However, systematic collecting did not begin until the 1950s. Collections of animal sound recordings serve many uses in education, entertainment, science and nature conservation. In recent years, technological developments have transformed the ways in which sounds can be sampled, stored and accessed. Now the largest collections between them hold altogether around 0.5 million recordings with their associated data. The functioning of a major archive will be described with reference to the British Library Sound Archive. Preserving large collections for the long term is a primary concern in the digital age. While digitization and digital preservation has many advantages over analogue methods, the rate of technology change and lack of standardization are a serious problem for the world's major audio archives. Another challenge is to make collections more easily and widely accessible via electronic networks. On-line catalogues and access to the actual sounds via the internet are already available for some collections. Case studies describing the establishment and functioning of sound libraries in Mexico, Colombia and Brazil are given in individually authored sections in an Appendix.

Analog-Digital Conversion↗
PubMed1997

A simple method for relative assessment of the sound propagation velocity in breast tumors: technique and diagnostic efficacy.

OBJECTIVE: The purpose of this study was to describe and evaluate a method for assessing the sound propagation velocity in breast tumors relative to the velocity in adjacent tissue. SUBJECTS AND METHODS: Sixty-six patients with palpable breast tumors were studied. The scanning plane was aligned so that it transected the tumor and depicted the front of a rib or the pleura-lung interface behind the tumor. This contour was evaluated for distortion, and the height of the distortion and the height of the tumor were used to calculate the relative sound propagation velocity. RESULTS: A posterior reference line was revealed behind 62 of 66 tumors. Of these 62 tumors, an elevation was seen behind 49 tumors, and no distortion was seen behind 13 tumors. A depression was never observed. The median relative sound propagation velocity of 1.07 that was calculated in 42 carcinomas (range, 1.00-1.14) was insignificantly higher (p = .079) than the median relative sound propagation velocity of 1.04 obtained in 20 fibroadenomas (range, 1.00-1.15). CONCLUSION: Although assessment of relative sound propagation velocity in breast tumors was successful, the relative velocities differed only insignificantly between benign and malignant lesions.

Biopsy, Needle↗
PubMed1997

Sound quality evaluation of anti-saturation circuitry in a hearing aid.

Loud sounds amplified by conventional hearing aids produce saturation distortion. This paper presents a comparison between a Class D hearing aid that was allowed to amplify into saturation and a Class D hearing aid that contained circuitry to prevent saturation distortion. The study was performed to determine whether users judged the conventional hearing aid or the anti-saturation hearing aid to have better sound quality. Seventeen subjects with hearing losses performed sound quality judgments at two sites. At low input levels, where the measured distortion was low, the subjects rated both hearing aids equal in sound quality. At high input levels, the subjects preferred the anti-saturation hearing aid, which had significantly lower distortion than the standard hearing aid. Though these data do not correlate the measured distortion to the subjective sound quality, the relationship revealed between the two in this testing warrants further investigation.

Correction of Hearing Impairment↗
PubMed1995

Perceived sound quality of three bone-anchored hearing aid models.

Eighteen patients judged the sound quality of the new Classic 300 and the existing HC 100 or HC 200 on 4 five-stage sound quality scales. Two of the scales relate to the perceptual dimensions softness and clarity, one relates to interference or noise and one relates to the overall impression. The evaluations were made, based on a questionnaire, in the patients' own homes and comprised the listening situations: TV news, music, conversation with two to three people in a noisy environment and one optional choice. The patients also stated which hearing aid was best in each situation and made a confidence rating for their selection. The patients were accustomed to wearing the HC 100 or HC 200. In these comparisons of the different bone-anchored hearing aid models, the Classic 300 received the best ratings overall. Seventeen patients changed their previously fitted hearing aid to a Classic 300 and satisfactory sound quality was undoubtedly one of the principal reasons. When it came to the confidence rating for their selections, some two-thirds of the patients stated that it was without hesitation or with little hesitation. Our overall conclusion is that the sound quality of bone-anchored hearing aids is satisfactory when it comes to clarity and overall impression. However, it may be expected that these patients with conductive losses get a better sound quality than other patients with sensorineural losses if the same type of aid is used.

Adolescent↗
PubMed2001

The roles of letter names and letter sounds in connecting print and speech.

Three experiments were carried out to examine the cues that are used in learning to read and spell new words. In a reading task (Experiment 1), even preschoolers who could not read simple real words were able to benefit from print-sound relationships that were based on letter names. They found it easier to learn that the made-up word TM was pronounced as 'team" (name condition) than that TM was pronounced as "tame" (sound condition) or as "wide" (visual condition). The letter-name strategy persisted among college students (Experiment 2). In a spelling task (Experiment 3), prereaders and novice readers again did better in the name condition than in the sound condition. The ability to use relationships based on letter sounds emerged later than the ability to use relationships based on letter names. However, sound-based relationships were used to a greater extent in spelling than in reading.

Adult↗
PubMed1994

Impression of smoothness of a sound stream in relation to legato in musical performance.

Physically continuous sounds do not always produce the subjective impression of legato. In the present study, the effect of temporal factors on the impression of smoothness of a sound stream was systematically investigated in relation to the dynamic characteristics of hearing. The results showed that decaying sounds, successively presented, were perceived as being marginally connected when the sounds physically overlapped, while steady-state sounds were perceived as being marginally connected when they were physically separated. It was also shown that judgments by the subjects agreed quite well with the effect intended by the pianist when the passage was given in different temporal interpretations.

Adolescent↗
PubMed1989

[Effect of sound stress on immune response].

This study was undertaken to assess the effect of sound stress on humoral and cellular immune responses to thymus-dependent and independent antigens in mice. After mice were exposed to 4 hr daily sound stressors (83 dB) for 4 days before or after immunization, the primary and/or secondary immune response to sheep red blood cells (SRBC), polyvinylpyrroridone (PVP) or picryl chloride (TNCB) were assayed. When mice were exposed to sound stressor before or after immunization, delayed-type hypersensitivity reaction and contact sensitivity to TNCB was remarkably depressed compared with those of the unstressed control mice. However, the primary and secondary hemagglutinin response of the stressed mice to SRBC showed a pronounced increase compared with that of the unstressed mice. In contrast to antibody response to SRBC, the primary antibody response of the stressed mice to PVP was almost not detected, surprisingly, the secondary antibody response to PVP of the mice receiving the secondary sound stress was markedly increased when the immune-depressed mice received the secondary immunization with PVP at 46 days after the primary immunization. The susceptibility of mice to intravenously infected Candida albicans was not changed by the sound stress.

Acoustic Stimulation↗
PubMed1999

Comparison of air-conduction and bone-conduction hearing thresholds for pure tones and octave-band filtered sound effects.

The purpose of this study was to measure air-conduction (AC) and bone-conduction (BC) hearing thresholds with pure-tone and filtered sound effect stimuli using standard audiometric equipment. A group of 20 young, normal-hearing listeners participated in the study. Pure-tone stimuli were 250, 500, 1000, 2000, and 4000 Hz. Sound effect stimuli were 12 natural sounds that were spectrally limited to an octave bandwidth centered at either 250, 500, 1000, 2000, or 4000 Hz. The AC and BC detection thresholds were measured using a clinical audiometer (Madsen Orbiter 922) with a B-71 bone oscillator and TDH-50 earphones. Results indicated that detection thresholds for the pure-tone and corresponding octave-band sound effect stimuli were within 3 to 4 dB of each other for both AC and BC testing. The findings support the notion that octave-filtered sound effects are a viable alternative to pure-tone stimuli for use in audiology clinics.

Adolescent↗
PubMed2000

[The mismatch negativity as an index of the perception of speech sounds by the human brain].

The present article outlines the contribution of the mismatch negativity (MMN), and its magnetic equivalent MMNm, to our understanding of the perception of speech sounds in the human brain. MMN data indicate that each sound, both speech and non-speech, develops its neural representation corresponding to the percept of this sound in the neurophysiological substrate of auditory sensory memory. The accuracy of this representation, determining the accuracy of the discrimination between different sounds, can be probed with MMN separately for any auditory feature or stimulus type such as phonemes. Furthermore, MMN data show that the perception of phonemes, and probably also of larger linguistic units (syllables and words), is based on language-specific phonetic traces developed in the posterior part of the left-hemisphere auditory cortex. These traces serve as recognition models for the corresponding speech sounds in listening to speech.

Brain↗
PubMed1992

The NASA Sounding Rocket Program and space sciences.

High altitude suborbital rockets (sounding rockets) have been extensively used for space science research in the post-World War II period; the NASA Sounding Rocket Program has been on-going since the inception of the Agency and supports all space science disciplines. In recent years, sounding rockets have been utilized to provide a low gravity environment for materials processing research, particularly in the commercial sector. Sounding rockets offer unique features as a low gravity flight platform. Quick response and low cost combine to provide more frequent spaceflight opportunities. Suborbital spacecraft design practice has achieved a high level of sophistication which optimizes the limited available flight times. High data-rate telemetry, real-time ground up-link command and down-link video data are routinely used in sounding rocket payloads. Standard, off-the-shelf, active control systems are available which limit payload body rates such that the gravitational environment remains less than 10(-4) g during the control period. Operational launch vehicles are available which can provide up to 7 minutes of experiment time for experiment weights up to 270 kg. Standard payload recovery systems allow soft impact retrieval of payloads. When launched from White Sands Missile Range, New Mexico, payloads can be retrieved and returned to the launch site within hours.

Research↗
PubMed1975

Sound production by Simochromis diagramma (Günther) (Pisces, Cichlidae).

Two types of sounds produced by the cichlid fish Simochromis diagramma, are recorded and analysed. A br-r-r sound, with a main frequency of 200 Hz and a chewing sound with a main frequency of 6,000-10,000 Hz are produced during threatening; the former sound can also be heard during quivering. No sound was recorded with fighting or anxious fishes.

Aggression↗
PubMed1975

[Proceedings: Right bundle-branch block without a wide split of the 2nd sound].

In a series of 38 complete right bundle branch blocks (RBBB) (17 "idiopathic" and 21 cardiopathies), auscultation and phonocardiograms disclosed a normal split second heart sound (S2 = A2-P2 less than or equal to 0.045 sec) in 27 and a wide split S2 (A2-P2 greater than or equal to 0.06 sec) in only 11 cases. Analysis of the initial and terminal vectors constructed from ECGs recorded at 250 mm/sec shows no valid correlation between a transseptal mode of depolarization of the right ventricle and the presence of either a normal or wide split of the 2nd heart sound. A review of the mechanisms generating the 2nd sound and discussion of the additional factors which may influence the duration of A2-P2 in RBBB (start of activation, length and quality of right ventricular systole, impedance of pulmonary arterial bed, possible delay of 2nd aortic sound) explain why wide splitting of the 2nd sound in RBBB is the exception rather than the rule.

Bundle-Branch Block↗
PubMedDate not supplied

The MYSound Project: building an estuary-wide monitoring network for Long Island Sound, USA.

A network of five water quality monitoring stations has been established in Long Island Sound, measuring temperature, salinity, and dissolved oxygen since 1999. The stations are located in areas of extreme water quality degradation (western Long Island Sound) as well as in pristine areas (eastern Long Island Sound). The data from these stations are collected every 15 minutes and posted to the project web site in real time as provisional data. After subsequent quality assurance procedures, the data are archived to the project File Transfer Protocol (FSP) site for downloading by the user community. The network of stations is in part supported logistically by a number of partners, including state and local agencies, schools, and non-governmental organizations. Data from the monitoring programs of some of these partners are also published to the project website providing a more comprehensive and complete picture of the status of the Sound than can be provided independently. This repository of information is used by marine educators, resource managers, scientists, and the general public, each with a different end purpose. We use the data from two of the stations to show that these high frequency time series measurements can be used to complement and enhance other monitoring programs within the Sound, documenting in greater detail the occurrence and duration of hypoxic events.

Automation↗
PubMed1999

Sound-Induced Cochlear Ischemia/Hypoxia as a Mechanism of Hearing Loss.

This review will briefly examine evidence supporting the hypothesis that sound causes changes in cochlear blood flow, intracochlear oxygen levels, and the morphology of cochlear blood vessels. A survey of the literature shows that traditional histopathological studies provided such evidence and that decreased cochlear blood flow can be demonstrated and measured by laser Doppler flowmetry and by direct observation of cochlear microvessels. Oxygen levels also decline and possibly to a greater degree than blood flow. There is also evidence that in certain circumstances sound can increase blood flow. Reduced blood flow, or reduced oxygenation, is critically important in an organ system with high energy needs like the cochlea. Therefore, a second hypothesis, that sound-induced reduction in CBF represents a functional ischemia, will be explored in examining the relevance of traditional ischemia/reperfusion models to cochlear damage. It is found that reactive oxygen species (free radicals and oxidizing ions) are present in sound-induced hearing loss and thus there is evidence that an ischemia/reperfusion type of injury occurs during loud sound exposures.

Journal Article↗
PubMed1992

The effects of ocean sounds on sleep after coronary artery bypass graft surgery.

OBJECTIVE: To investigate the influence of ocean sounds (white noise) on the night sleep pattern of postoperative coronary artery bypass graft (CABG) patients after transfer from an intensive care unit. DESIGN: A before and after trial with an experimental and a control group was used in this intervention study. SETTING: A large public hospital with primary, secondary, and tertiary care facilities. PATIENTS: A consecutive sample of 60 first-time CABG patients was systematically assigned to the experimental or the control group. INTERVENTION: For the experimental group, the sounds were played on the Marsona Sound Conditioner (Marpac Corporation, Wilmington, NC) for three consecutive nights posttransfer from the ICU. No control of environment, except for the elimination of white noise, was done for the control group. MAIN OUTCOME MEASURES: The Richards-Campbell Sleep Questionnaire, a visual analog scale, provided self-reported sleep scores on six variables. Analysis of covariance was used to test the difference between the posttest scores of the groups, with the pretest used as the covariate. RESULTS: There were significant differences in sleep depth, awakening, return to sleep, quality of sleep, and total sleep scores; the group receiving ocean sounds reported higher scores, indicating better sleep. There was no difference in the falling asleep scores. CONCLUSION: The use of ocean sounds is a viable intervention to foster optimal sleep patterns in postoperative CABG patients after transfer from the ICU.

Adult↗