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PubMed1984

[Semantic scales for the evaluation of noise (II). Subjacent dimensions in subjective judgments of sound stimuli].

Second stage of a research in which Osgood's Diferential Semantic Technique was used in two experiments with the following aims: a) to find out the subyacent dimensions of subjective evaluation of sound stimuli; b) to know if Osgood's Evaluation, Potency and Activity dimensions appear when sound stimuli are judged; c) to obtain a group of semantic scales that represent the found dimensions, which can be used in other researches in the same field. In the first experiment 37 scales were used by 98 Ss for judging 10 sound stimuli. In the second, 120 Ss performed the same task through 46 scales and 40 sound stimuli. Data of both experiments were processed by factor analysis method and a Varimax rotation was done. Having obtained 12 similar factors in both experiments the results were analized in a comparative way. Eight dimensions that explain the subject-sound stimuli relation were found. The other dimensions deal with the stimulis control, cognitive experience and structural caracteristics of sound stimuli, being the affective component also present in some of their scales. In the third stage the sound stimuli used will be analized through the found dimensions.

Acoustic Stimulation↗
PubMed1981

Newborns' orientation toward sound: possible implications for cortical development.

The precedence effect is an auditory illusion produced by presenting the same signal through 2 loudspeakers, with 1 leading the other by several milliseconds. Adults perceive a sound localized exclusively on the leading side and directionally equivalent to a single source sound. Because the precedence effect is thought to involve cortical functions, newborns were expected not to respond with directional head turning toward these sounds. Newborns were presented with a tape-recorded rattle sound produced in 3 ways: through a single loudspeaker located right or left, through both loudspeakers with 1 onset leading the other by 7 msec, and control stimuli in which both loudspeakers sounded simultaneously, resulting in an apparent center location of the sound. Newborns turned toward the single source sound, but neither to precedence effect stimuli nor control stimuli. These results were related to maturation of the auditory cortex.

Auditory Cortex↗
PubMed1980

Sound transfer function of the congested canine lung.

Alterations of sound transfer function of the lung in pre-congested and congested states were studied in a canine model as an index of the accumulation of lung liquids. Pulmonary congestion was produced by graduated inflations of a balloon in the left atrium. Different degrees of pulmonary congestion were documented by post-mortem wet to dry lung weight ratios. Sound transfer function of the lung was determined utilizing passive sound transmission in the audio freqency range consisting of sinusoidal oscillations swept from 50 Hz to 2 kHz. Sound transfer function in dB was defined as 20 times the logarithm of sound output divided by sound input. These functions were computed for pre-congested and congested states of the lung and the differential values correlated with the post-mortem wet to dry weight ratios of the lung. The magnitude of sound transfer function of the lung correlated well with increasing accumulation of intravascular and extravascular lung liquids and provided a quantitative index of pulmonary congestion.

Animals↗
PubMed1993

A study of the influence of arrangement of upper posterior artificial teeth on pronunciation: Japanese sounds articulated on the posterior palate.

To clarify the standard of bucco-lingual tooth arrangement in complete denture construction, the influence of the bucco-lingual position of upper posterior artificial teeth on pronunciation was investigated. Wearing 7 kinds of experimental artificial teeth with the upper posterior ones arranged in 7 different positions, patients pronounced 5 test sounds: "ka", "ki", "kw", "ke" and "ko". Resultant sounds were evaluated in terms of how the bucco-lingual position of posterior artificial teeth influenced pronunciation as determined with by aural pronunciation judgment test and frequency analysis using a 1/3 octave-band real-time analyzer. Pronunciation disorders caused by the arrangement of the upper posterior artificial teeth in complete dentures occur when the lingual surfaces of the upper molars is located more than 1/4 inward of the distance between the right and left denture border from the buccal denture border or less than 1/10 of that distance outward from the buccal denture border. Results of the aural pronunciation judgment test indicated that the influence of the arrangement of the upper posterior artificial teeth on pronunciation depends on the vowel following the consonant of the sound. When the vowel following the consonant is a back vowel, as in "ka", "kw" and "ko" the sound was barely influenced, but when the vowel is a front vowel. as in "ke" and "ki", the sound was markedly influenced. We established the frequency spectrum of the consonant of the normally pronounced 5 test sounds as the standard frequency spectral range and compared distorted and misheard sounds with it.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1996

Variation in artificial heart acceleration and sound production with prosthetic valve selection in vitro.

In an attempt to explore methods to reduce total artificial heart (TAH) acceleration and sound production, in vitro measurements of TAH acceleration and sound were made when using a variety of prosthetic valves in a test ventricle. A miniature, uniaxial, high fidelity accelerometer was glued to the housing of a UTAH-100 left ventricle adjacent to the inflow and outflow ports and parallel to the axis of diaphragm excursion. A miniature, high fidelity contact microphone was glued to the opposite side of the ventricular housing between the inflow and outflow ports. Data was collected over a range of heart rates, ventricular filling volumes and control modes while using tilting disc valves (TDV) and polymer trileaflet valves (PTV). For both valve types, the peak systolic acceleration impulse was lower (approximately equal to 50%) when the ventricle was fully rather than partially filled and the peak diastolic acceleration impulse was lower (approximately equal to 50%) when the ventricle was fully rather than partially ejected. The magnitude of the acceleration with PTVs was approximately equal to 20x less than the TDVs (0.5 to 2.2 g vs. 10 to 49g). The magnitude of the sound production was also considerably less with the PTVs (28 to 49 db vs. 50 to 64 db). Diastolic acceleration and sound production was approximately twice the systolic value for the TDVs; the reserse was true for PTV sound production. These data demonstrate the substantial reduction in TAH impulse acceleration and sound production by selecting PTVs over TDSs. With PTVs, the TAH impulse acceleration is the same as the natural heart. Consequently, this ability to lower TAH acceleration and sound production to the level of the natural heart may lead to a reduction in component wear, patient discomfort and other undesirable consequences of TAH implantation.

Aorta↗
PubMed1997

Protection against noise trauma by sound conditioning.

Sound conditioning provides protection against a subsequent noise trauma. The sound conditioning paradigm consists of a low-level, long-term, non-damaging acoustic stimulus (1 kHz, 81 dB SPL x 24 days). Morphological and physiological alterations are not induced by the sound conditioning stimulus alone. In addition, the middle ear muscles have been shown not to be influenced by sound conditioning. It has been shown that after exposure to a traumatic stimulus, sound conditioning protects the outer hair cell morphology (fewer missing outer hair cells), as well as physiology (distortion product otoacoustic emissions) compared to an unconditioned group exposed only to the traumatic stimulus. Further studies are needed in order to establish the underlying mechanisms for the phenomenon of sound conditioning. Nevertheless, since sound-conditioning experiments have been successfully applied to human subjects our understanding of hearing impaired individuals has been enhanced.

Adaptation, Physiological↗
PubMed1997

The 'sail sound' and tricuspid regurgitation in Ebstein's anomaly: the value of echocardiography in evaluating their mechanisms.

We describe a patient with Ebstein's anomaly in whom Doppler echocardiography was used to clarify the mechanism responsible for 'sail sound' and tricuspid regurgitation associated with this condition. Phonocardiography revealed an additional early systolic heart sound, consisting of a first low-amplitude component (T1) and a second high-amplitude component (T2, 'sail sound'). In simultaneous recordings of the tricuspid valve motion using M mode echocardiography and phonocardiography, the closing of the tricuspid valve occurred with T1 which originated at the tip of the tricuspid leaflets, while T2 originated from the body of the tricuspid leaflets. Using color Doppler imaging, the tricuspid regurgitant signal was detected during pansystole, indicating a blue signal during the phase corresponding to T1 and a mosaic signal during the phase corresponding to T2 at end-systole. Thus, 'sail sound' in patients with Ebstein's anomaly is not simply a closing sound of the tricuspid valve, but a complex closing sound which includes a sudden stopping sound after the anterior and/or other tricuspid leaflets balloon out at systole.

Diagnosis, Differential↗
PubMed1997

Higher-order statistics: a robust vehicle for diagnostic assessment and characterisation of lung sounds.

The use of higher-order statistics for diagnostic assessment and characterisation of lung sounds is presented in this article. The parametric approach of bispectrum estimation, which is a third-order spectrum, based on a non-Gaussian white noise driven autoregressive (AR) model, reveals information about lung sounds that is not contained in the ordinary power spectrum, such as the degree of nonlinearity and deviations from normality. Characterisation of source and transmission of lung sounds is achieved using an AR model based on third-order statistics. Furthermore, harmonic analysis of lung sounds is combined with the bicoherence index in order to obtain information regarding possible quadratic phase coupling among harmonic components of musical lung sounds. Experiments have shown that higher-order statistics can offer reliable evaluation of lung sounds characteristics, since their general properties and robustness in noiseless or noisy environments (lung sounds contaminated with additive symmetrical noise, e.g., Gaussian) proved to have superior advantages in objective analysis of pulmonary dysfunction.

Humans↗
PubMed1998

Sound lateralization and speech discrimination in patients with sensorineural hearing loss.

Sound lateralization and speech discrimination abilities are both closely related to central auditory system function. In this study, we investigated the relationship between sound lateralization and speech discrimination in patients with sensorineural hearing loss (SNHL) of unknown aetiology or presbycusis. Interaural intensity difference (IID) and interaural time difference (ITD) discriminations were measured using a self-recording apparatus for dichotic sound presentation, and the means of bilateral maximum scores in speech discrimination tests were calculated. Subjects with normal sound lateralization had good speech discrimination scores above 70%, while those with abnormal sound lateralization had poor scores below 70%. Some patients, however, had good speech discrimination but abnormal sound lateralization. These findings were obtained in both IID and ITD discrimination tests. Furthermore, some subjects could not discriminate ITD, although all could discriminate IID. These findings suggest that sound lateralization ability may be affected more than speech discrimination in SNHL of unknown aetiology or in presbycusis.

Adult↗
PubMed2000

Motor unit sound in needle electromyography: assessing normal and neuropathic units.

Motor unit action potentials (MUPs) recorded by a monopolar needle electrode in normal and neuropathic muscles were computer-simulated. Five experienced electromyographers acted as examiners and assessed the firing sounds of these MUPs without seeing them on a display monitor. They judged whether the sounds were crisp or close enough to accept for the evaluation of MUP parameters and whether, when judged acceptable, they were neuropathic-polyphasic. The examiners recognized motor unit (MU) sound as crisp or polyphasic when the MUP obtained was 0.15-0.2 mm from the edge of the MU territory. When the intensity of the sound decreased, they were unable to perceive it as crisp. When the intensity exceeded the saturation level of loudspeaker output, the sound was perceived as polyphasic, but the wave form of the MUP was not. When the frequency of the neuropathic MUP was lowered, the examiners were unable to determine whether the MUP was polyphasic. MUPs recognized as acceptable for evaluation can be distinguished by listening to MU sounds. The audio amplifier gain must be appropriately adjusted for each MUP amplitude in order to assess whether an individual MU sound is crisp or polyphasic before MUP parameters are measured on a display monitor.

Adult↗
PubMed1991

Erythrocyte micronuclei in winter flounder (Pseudopleuronectes americanus): results of field surveys during 1980-1988 from Virginia to Nova Scotia and in Long Island Sound.

Erythrocyte micronuclei (MN) frequencies of 280 winter flounder (Pseudopleuronectes americanus) from Chesapeake Bay to the southern Scotian Shelf including Long Island Sound were measured. The MN data were combined with data previously reported for 224 flounder and the combined data sets were analyzed. Incidences of MN were elevated sixfold in flounder from the New York Bight Apex as compared to frequencies for fish from the inshore Gulf of Maine and Block Island Sound, and twice those found in Georges Bank and Long Island Sound flounder. Inshore New Jersey fish had higher MN frequencies than those from inshore Gulf Of Maine and Block Island Sound. The occurrence of MN in flounder from inshore Virginia was higher than in flounder from inshore Gulf of Maine and Block Island Sound. The large subset of stations from Long Island Sound indicated higher frequencies of MN in flounder from Hempstead and Shoreham as compared to most other sites in the Sound. There was no significant difference in the frequency of MN between males and females, but males had significantly more MN than sexually immature flounder. Flounder over the entire sampling area had increased levels of MN during the fall months of the year. This is probably influenced by the maternal cycle of gonadal maturation.

Animals↗
PubMed1996

Cocaine's effects on speech sound identification and reaction times in baboons.

The effects of cocaine on speech sound discriminations was examined to determine whether cocaine's previously demonstrated effect in reducing speech sound discriminability was dependent upon either the type of stimuli employed (simple tones versus complex speech) or the procedure (stimulus detection versus stimulus discrimination). Because of demonstrated similarities in the way that baboons and humans discriminate speech, and in the way the CNS is thought to encode and process speech sounds in these two species, baboons were trained to perform a choice procedure to identify the occurrence of different synthetic vowel sounds (see text). Animals held down a lever and released the lever only when one of four target vowels sounded, and not when a fifth, standard vowel sounded. Acute IM administration of cocaine (0.0032-1.0 mg/kg) produced dose-dependent decreases in vowel discriminability that were mostly due to elevations in false alarms (i.e., releases to the standard vowel) following cocaine. Cocaine also shortened reaction times to the stimuli in two of three baboons, but to a much lesser extent than observed previously. These results suggest that cocaine may interfere with the ability of the CNS to process the acoustic cues in speech sounds, and that the effects of cocaine on reaction times may depend upon the complexity of the reaction time procedure employed.

Animals↗
PubMed1997

Auscultation revisited: the waveform and spectral characteristics of breath sounds during general anesthesia.

Although auscultation is commonly used as a continuous monitoring tool during anesthesia, the breath sounds of anesthetized patients have never been systematically studied. In this investigation we used digital audio technology to record and analyze the breath sounds of 14 healthy adult patients receiving general anesthesia with positive pressure ventilation. Sounds recorded from inside the esophagus were compared to those recorded from the surface of the chest, and corresponding airflow was measured with a pneumotachograph. The sound samples associated with inspiratory and expiratory phases were analyzed in the time domain (RMS amplitude) and frequency domain (peak frequency, spectral edge, and power ratios). There was a positive linear correlation (R2 > 0.9) between inspiratory flow and sound amplitude in the precordial and esophageal samples of all patients. The RMS amplitude of the inspiratory and expiratory sounds was approximately 13 times greater when recorded from inside the esophagus than from the surface of the chest in all patients at all flows (p < 0.001). The peak frequency (Hz) was significantly higher in the esophageal recordings than the precordial samples (298 +/- 9 vs 181 +/- 10, P < 0.0001), as was the 97% spectral edge (Hz) (740 +/- 7 vs 348 +/- 16, P < 0.0001). In the adult population esophageal stethoscopes yield higher frequencies and greater amplitude than precordial stethoscopes. Quantification of lung sounds may provide for improved monitoring and diagnostic capability during anesthesia and surgery.

Adolescent↗
PubMed2005

Image-to-sound conversion: experience-induced plasticity in auditory cortex of blindfolded adults.

The ability to adapt to environmental changes is based on the impressive capacity of the central nervous system for plasticity changes. A better understanding of the requirements of neuroplasticity will help to apprehend and predict the success of sensory prostheses. To investigate neuroplastic changes associated with (1) blindfolding and (2) the use of a mobile visual-auditory substitution system, five normally sighted adults underwent weekly measurements of neuromagnetic activity using a 122-channel whole head neuromagnetometer. The substitution device converted visual images into sound patterns. During measurements subjects listened to "geometric sounds" converted from images of geometric shapes, "natural sounds" representing photographs of everyday objects, as well as to original "environmental sounds". To assess the role of visual deprivation, three individuals were blindfolded throughout a 3-week testing period. To assess the effect of extended exposure to "visual sounds", three subjects-two blindfolded, one sighted-had free use of the substitution device. Neuromagnetic responses were restricted to the auditory cortex across all measurements. Activity at 100 ms after presentation of "natural sounds", but not other auditory stimuli, showed a significant enhancement over time only in blindfolded subjects using the substitution system, indicating that the combination of visual deprivation and practice facilitated intra-modal plasticity. The fact that changes occurred only in response to "natural sounds" probably reflects the increased behavioural relevance of this category evident only for blindfolded subjects using the substitution device.

Acoustic Stimulation↗
PubMed2001

The effect of sound intensity on duration-tuning characteristics of bat inferior collicular neurons.

Previous studies have shown that inferior collicular neurons of the big brown bat, Eptesicus fuscus, serve as short-, band-, long- and all-pass filters for sound durations. Neurons with band-, short- and long-pass filtering characteristics discharged maximally to a specific sound duration or a range of sound durations. In contrast, neurons with all-pass filtering characteristics do not have duration selectivity. To determine if duration-tuning characteristics of collicular neurons were tolerant to changes in sound intensity, we examined the duration-tuning characteristics of collicular neurons using a wide range of sound intensities. Duration-tuning characteristics examined included the type, bandwidth and slope of duration-tuning curves. Sound intensity delivered within 20 dB of minimum threshold did not affect duration-tuning characteristics of all collicular neurons studied. Sound intensities at still higher levels did not affect the tuning characteristics of two-thirds of collicular neurons but decreased the duration selectivity and changed the duration-tuning curves of the remaining one-third of neurons from one type to another. However, these two groups of duration-tuning collicular neurons were not separately organized inside the inferior colliculus. The biological relevance of these findings to bat echolocation is discussed.

Acoustic Stimulation↗
PubMed1990

Increases in the activity of tryptophan hydroxylase from rat cortex and midbrain in response to acute or repeated sound stress are blocked by adrenalectomy and restored by dexamethasone treatment.

Exposure of male Sprague-Dawley rats to acute sound stress (2 s, 110 dB sound pulses presented randomly every minute for 1 h) increases the in vitro activity of cortical and midbrain tryptophan hydroxylase by an alkaline phosphatase-reversible mechanism. Repeated exposure to sound stress on three separate days produces a stable increase in enzyme activity that persists 24 h after the termination of the stress and is insensitive to alkaline phosphatase. Adrenalectomy abolishes both increases in enzyme activity to acute or repeated sound stress but does not change baseline levels of enzyme activity. The synthetic glucocorticoid, dexamethasone, (500 micrograms/day i.p.) given for 3 days or 5 out of 6 days, starting day 3 after adrenalectomy, restores the increases in enzyme activity in adrenalectomized rats exposed, respectively, to acute or repeated sound stress. The mineralocorticoid, aldosterone (5 micrograms/day s.c.), does not substitute for dexamethasone in acutely sound-stressed, adrenalectomized rats. Dexamethasone does not alter control levels of enzyme activity in either adrenalectomized rats or rats with intact adrenals (sham-adrenalectomized), but is required to allow the increase in enzyme activity in response to acute or repeated sound stress to be expressed. The effect of the glucocorticoid, thus, appears to be a permissive one.

Acoustic Stimulation↗
PubMed2006

Intense sound-induced plasticity in the dorsal cochlear nucleus of rats: evidence for cholinergic receptor upregulation.

Previous studies in a number of species have demonstrated that spontaneous activity in the dorsal cochlear nucleus (DCN) becomes elevated following exposure to intense sound. This condition of hyperactivity has aroused considerable interest because it may represent an important neural correlate of tinnitus. There is some evidence that neurons in the superficial DCN, such as cartwheel, stellate and fusiform cells, may contribute to the level of hyperactivity induced by intense sound, although the relative importance of these different cell types is unknown. In the present study, we sought to determine the effect of intense sound exposure on multiunit spontaneous activity both at the DCN surface and in the fusiform cell layer and to examine the influence of cholinergic input to DCN circuits on the level of activity in the fusiform cell layer. Rats were studied in two groups, one of which had been exposed to a continuous intense sound (10 kHz 127 dB SPL) for 4h while the other group served as unexposed controls. Between 30 and 52 days post-exposure, recordings of multiunit activity were performed at the DCN surface as well as in the middle of the fusiform cell layer. Changes in fusiform cell layer activity were also studied in response to superficial applications of the cholinergic agonist, carbachol, either alone or following pre-application of the cholinergic antagonist, atropine. The results demonstrated that multiunit spontaneous activity in the rat DCN was generally much higher in both control and exposed animals relative to that which has been observed in other species. This activity was significantly higher at the DCN surface of sound-exposed animals than that of controls. In contrast, hyperactivity could not be demonstrated in the fusiform cell layer of sound-exposed animals. Carbachol administration most commonly caused suppression of fusiform cell layer activity. However, this suppression was considerably stronger in the DCN of sound-exposed animals than in controls. These findings suggest that, hyperactivity at the DCN surface of exposed rats may arise as a consequence of more highly activated neurons in the molecular layer, such as cartwheel and/or stellate cells, and that the lack of hyperactivity in the fusiform cell layer may be the result of inhibition of fusiform cells by these inhibitory interneurons. Although this finding does not rule out fusiform cells as possible sources of hyperactivity in other species, or even in the rat after short post-exposure recovery periods, the enhanced sensitivity of the fusiform cell layer to cholinergic stimulation suggests that in the rat, at least after prolonged post-exposure recovery periods, increased inhibition of activity in this layer by more superficially located neurons may result from an upregulation of receptors for cholinergic input. This upregulation may be greater in rats than in other species due to the relatively heavy cholinergic input that exists in the cochlear nucleus of this species.

Acoustic Stimulation↗
PubMed2006

Fringed sound fields and their interaction with liquid-solid interfaces.

On the one hand, it is well known that Gaussian beams possess the ability to stimulate Rayleigh waves, resulting in the Schoch effect, a lateral beam displacement. This effect, often characterized by a reflected sound pattern consisting of two anti-phase beams, is due to the re-radiation of sound because of the stimulation of leaky Rayleigh waves. On the other hand, fringed sound beams are characterized by the fact that they consist of a number of neighboring anti-phase narrow beams. They are a first approximation of a sound field originating from a phased array of harmonic vibrating crystals in which each crystal vibrates in anti-phase compared to its neighbor. The individual lobes within the fringed sound pattern diverge much less than standard Gaussian beams of the same size. The current study investigates the interaction of fringed beams with a liquid-solid interface. It is found that under certain conditions, a fringed beam, incident at the Rayleigh angle, produces a reflected sound pattern that contains a wide lobe that is not fringed. It is also shown that under other conditions, contrary to the famous forward displacement of the reflected sound for incident Gaussian beams, a strong backward displacement occurs for fringed beams.

Journal Article↗