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At least 19 recordsLinked to original sources

PubMed1992

[Interaction between acoustic environment and landscape--the effect of acoustic environment on perceived landscape and the effect of landscape on perceived acoustic environment].

The effect of acoustic environment on the impression of the landscape and the effect of the landscape on the impression of the acoustic environment were investigated by a multivariate technique using a semantic differential method. The resulting five dimensions were interpreted as "Calmness", "Activity", "Naturalness", "Uniqueness", and "Volume (Magnitude)" for both landscape and sound evaluations. These common psychological qualities are considered to be the intermodalities of visual and auditory processing. Further, the consonance phenomenon through the intermodalities, a kind of interaction between auditory and visual processing which changes the psychological qualities to the same direction, was observed when the combination of the acoustic environment and landscape was evaluated to be matched. These results may be the basis of the soundscape design under various kinds of landscape.

Auditory Perception↗

PubMedDate not supplied

Pressure-induced modifications of the acoustic nerve. Part I: The acoustic reflex.

It is commonly thought that as an acoustic neuroma grows it exerts pressure on the acoustic nerve resulting in alterations of the acoustic reflex and brain stem audiometry. This hypothesis has not been confirmed. In this study in an animal model, acute pressure was applied to the nerves of the internal auditory canal, and changes in the acoustic reflex were measured. Our results support the theory that pressure on the acoustic nerve causes an increase in the rate of adaptation and a decrease in the amplitude of the acoustic reflex. The contralateral reflex appears to be the most sensitive indicator of these effects. We feel that this animal model can be useful to investigate the effects of pressure on the acoustic nerve.

Acoustic Impedance Tests↗

PubMed1991

Changes in EEG power, acoustic evoked potentials and heart rate after mildly arousing non-acoustic priming stimuli in carp (Cyprinus carpio).

1. Changes in EEG power spectrum of carp to a priming non-acoustic stimulus followed by acoustic clicks were compared to those due to acoustic clicks delivered alone. Recordings were made from the telencephalon, midbrain and medulla. Acoustic evoked potentials (AEPs) to the clicks were also recorded. 2. EEG power changes to non-acoustic stimuli occurred over the whole 1-40 Hz frequency range and were regionally specific and consistent. 3. The changes in the EEG midfrequency 12-24 Hz power spectrum to non-acoustic stimuli were significantly correlated with changes in the AEP to subsequent clicks. An elevated medullary AEP amplitude and reduced duration were correlated with increased medullary EEG power and increased midbrain AEP duration. 4. Telencephalic EEG power changes were inversely related to changes in medullary and midbrain AEP amplitude.

Acoustic Stimulation↗

PubMed1990

Influence of acoustic deprivation on recovery of hair cells after acoustic trauma.

The purpose of this study was to investigate how the recovery of the cochlea, after acoustic trauma, might be influenced by acoustic stimulation or deprivation. In anaesthetized adult chinchillas, both ears were simultaneously exposed to a traumatizing acoustic stimulus (2 kHz tone, at 117 dB SPL for 15 min). Probe microphones positioned in both bullae were used to ensure identical exposure to the two ears; this was important because the experiment relies on within-animal controls. Cochlear action potential thresholds across frequency (CAP audiograms) were used to verify the similarity of threshold shifts to the two ears. Immediately following, a unilateral ossiculectomy was performed which resulted in one cochlea being acoustically deprived during the recovery period, whilst the other was not. In groups of animals with recovery periods of 1, 3, 6, and 12 weeks, both the acoustically deprived and the normally stimulated cochleas were examined with scanning electron microscopy. To quantify hair cell damage, we used a damage scale based on stereociliar integrity; for each cochlea, a standard region 5.5-8.5 mm from the apex was studied in detail. We found that after acoustic trauma, hair cell damage to the cochlea which is deprived of sound during the recovery period, is significantly greater compared with that in the normally stimulated, contra-lateral cochlea. Our results suggest that mechanical activation of the inner ear acts to inhibit long-term degenerative processes, or influence repair of partially damaged hair cells.

Action Potentials↗

PubMed1989

Effects of alcohol on the acoustic-phonetic properties of speech: perceptual and acoustic analyses.

This report summarizes the results of a series of studies that examined the effects of alcohol on the acoustic-phonetic properties of speech. Audio recordings were made of male talkers producing lists of sentences under a sober condition and an intoxicated condition. These speech samples were then subjected to perceptual and acoustic analyses. In one perceptual experiment, listeners heard matched pairs of sentences from four talkers and were required to identify the sentence that was produced while the talker was intoxicated. In a second perceptual experiment, Indiana State Troopers and college undergraduates were required to judge whether individual sentences presented in isolation were produced in a sober or an intoxicated condition. The results of the perceptual experiments indicated that groups of listeners can significantly discriminate between speech samples produced under sober and intoxicated conditions. For acoustic analyses, digital signal processing techniques were used to measure acoustic-phonetic changes that took place in speech production when the talker was intoxicated. The results of the acoustical analyses revealed consistent and well-defined changes in speech articulation between sober and intoxicated conditions. Because speech production requires fine motor control and timing of the articulators, it may be possible to use acoustic-phonetic measures as sensitive indices of sensory-motor impairment due to alcohol consumption.

Adult↗

PubMed1989

Acoustic rhinometry: evaluation of nasal cavity geometry by acoustic reflection.

To study the geometry of the nasal cavity we applied an acoustic method (J. Appl. Physiol. 43: 523-536, 1977) providing an estimate of cross-sectional area as a function of distance. Acoustic areas in a model constructed from a human nasal cast, in the nasal cavity of a cadaver and in 10 normal subjects and two patients with well-defined afflictions of the nasal cavity, were compared with similar areas obtained by computerized tomography (CT) scans, a specially developed water displacement method, and anterior rhinomanometry. We found a coefficient of variation of the areas of less than 2% by the acoustic method compared with 15% for the rhinomanometric measurements. Acoustic areas correlated highly to similar areas obtained by CT scanning (r = 0.94) and by water displacement (r = 0.96). In two patients the acoustic method accurately outlined, respectively, a tumor in the nose and a septum deviation. It is concluded that this method provides an accurate method for measuring the geometry of the nasal cavity. It is easy to perform and is potentially useful for investigation of physiological and pathological changes in the nose.

Acoustics↗

PubMed1979

Factors influencing the acoustic-immittance characteristics of the acoustic reflex.

Measurements of the aural acoustic-immittance (admittance and impedance) characteristics of the middle-ear transmission system in humans during the quiescent (static) and reflexive states were made (N = 36) utilizing a signal-averaging technique. Three pure tones (750, 1000, and 2000 Hz) and broadband noise stimuli elicited the acoustic reflex in 2-dB steps at sound-pressure levels from 84-116 dB (tones) and 66-116 dB (noise) during ascending- and descending-intensity level runs. The contralateral middle-ear activity was monitored with a 220-Hz probe by digitizing the conductance and susceptance outputs of an admittance meter. A computer corrected for the ear-canal volume utilizing measurements made at ear-canal pressures of 0 and --350 daPa and then converted the conductance and susceptance values into admittance and impedance units. The results were reported in absolute and relative immittance units, including components, as a function of both stimulus sound-pressure level and intensity level above the acoustic-reflex threshold. The static immittance of the middle ear changed nonlinearly over time to lower admittance or higher impedance values. The influence of this static-immittance shift on the reflex magnitude was discussed. The largest mean reflex magnitude and the slowest rate of growth were observed with broadband noise, although eight of the 36 subjects demonstrated the largest reflex magnitude in response to one or more of the tonal stimuli. Although static-immittance values and acoustic-reflex thresholds were poorly correlated, the reflex magnitudes were proportional to static immittance. The variability of the reflex measures was similar to the variability of the static-immittance values. Finally, bi-directional changes in resistance during the reflexive state were observed and discussed.

Acoustic Impedance Tests↗

PubMedDate not supplied

Cerebellopontine angle tumours, other than acoustic neuromas. A report on 34 cases. A presentation of 7 bilateral acoustic neuromas.

The symptoms, preoperative diagnostic results and histological findings in 34 cerebellopontine angle tumour cases, other than acoustic neuromas, are presented. The meningeomas dominate by far this group of tumours. The symptomatology is much less uniform than that of the acoustic neuromas, where the VIII nerve is dominant. The facial nerve is less involved, whereas the other cranial nerves give symptoms more frequently. One remarkable sign is the presence of severe trigeminal neuralgia, which we have not encountered in acoustic neuromas. Only 35% of the 'non-neuroma' patients had elevated spinal fluid protein, compared with 100% in our acoustic neuroma cases. Furthermore, 7 patients with bilateral acoustic neuromas are presented. The connection with von Recklinghausens disease and multiple meningeomas is discussed.

Adult↗

PubMed1991

Sustained potential shifts and changes in acoustic evoked potentials after presentation of a non-acoustic priming stimulus to carp (Cyprinus carpio).

1. Recordings were made from the region of the midbrain tectum and torus semicircularis of sustained potential shifts (SPS) to a non-acoustic priming stimulus and the change in subsequent acoustic evoked potentials (AEPs) to a train of six clicks after a long rest. 2. In the absence of priming stimuli (a jet of saline or water to the flank) the AEP to the first click in a train had the highest amplitude; with these stimuli it became the most attenuated. 3. The SPS to both non-acoustic stimuli was initially (ca 4 sec) negative, then became positive for a similar time period. 4. After saline jet the tectal and the torus AEP amplitude was significantly correlated with the torus SPS; after water jet, the tectal and the torus AEP durations were correlated with the SPS. 5. Application of alumina gel to the posterior telencephalic border caused elevation of the torus AEP amplitude after some 5 hr.

Acoustic Stimulation↗

PubMed1988

Transmission acoustic microscopy of tissue sections (1 GHz). Histoacoustics and acoustic staining.

The acoustic microstructure of mouse small intestine has been studied with a transmission acoustic microscope working at 1 GHz and the influence of the histologic processing on the microacoustic pattern has been tested. Unstained thin sections provide pictures rich in details and highly contrasted. Gelatin has been used as hydrosoluble embedding medium and has been compared to paraffin. The former embedding procedure retained the viscoelastic properties of the specimen far more and provided the most detailed pictures. Osmiun tetroxide has been used to demonstrate acoustic staining.

Animals↗

PubMed1990

Spectral analysis and acoustic transmission of mitral and aortic valve closure sounds in dogs. Part 1. Modelling the heart/thorax acoustic system.

A system model based on the simultaneous recording and analysis of the intracardiac and thoracic phonocardiograms to estimate the time-varying properties of the heart/thorax acoustic system of the dog is described. The presence of instrumental noise in the recording of intracardiac phonocardiograms is characterised, and it is demonstrated that its effect on the estimate of the transfer and coherence functions of the system can be quantified and corrected. Application of the model to study the spectral characteristics and the acoustic transmission properties of the mitral component M1 of the first heart sound and of the aortic component A2 of the second heart sound in the dog shows that the heart/thorax acoustic system acts like a bandpass filter having a higher attenuation for A2 than for M1. Between 20 and 100 Hz, the mean attenuation of M1 is 30 dB while that of A2 is 46 dB. Above 100 Hz, the attenuation slope is -12 dB per octave for M1 and -6 dB per octave for A2.

Animals↗

PubMed1989

Comments on "Effects of Noise on Speech Production: Acoustic and Perceptual Analyses" [J. Acoust. Soc. Am. 84, 917-928 (1988)].

The effect of background noise on speech production is an important issue, both from the practical standpoint of developing speech recognition algorithms and from the theoretical standpoint of understanding how speech is tuned to the environment in which it is spoken. Summers et al. [J. Acoust. Soc. Am. 84, 917-928 (1988]) address this issue by experimentally manipulating the level of noise delivered through headphones to two talkers and making several kinds of acoustic measurements on the resulting speech. They indicate that they have replicated effects on amplitude, duration, and pitch and have found effects on spectral tilt and first-formant frequency (F1). The authors regard these acoustic changes as effects in themselves rather than as consequences of a change in vocal effort, and thus treat equally the change in spectral tilt and the change in F1. In fact, the change in spectral tilt is a well-documented and understood consequence of the change in the glottal waveform, which is known to occur with increased effort. The situation with F1 is less clear and is made difficult by measurement problems. The bias in linear predictive coding (LPC) techniques related to two of the other changes-fundamental frequency and spectral tilt-is discussed.

Humans↗

PubMed1992

[Changes in otoacoustic emissions with simultaneous acoustic stimulation of the contralateral ear in normal probands and patients with unilateral acoustic neurinoma].

Contralateral white noise alters the amplitude of transitory evoked otoacoustic emissions (TEOAE). 27 students between 20 and 28 years of age with no history of ear disease or dizziness were tested for normal hearing by pure tone audiogram. OAE evoked by nonlinear stimuli were measured with and without contralateral stimulation by 40, 50 and 60 dB white noise. The contralateral stimulation resulted in a statistically significant diminution of the amplitude of the TEOAE under contralateral acoustic stimulation. This diminution is probably caused by the effect of the crossed bundle of the efferent innervation on the outer hair cells resulting in altered vibratory properties of the basilar membrane. In patients with unilateral acoustic neuroma and measurable TEOAE a diminution of the amplitude of the TEOAE under contralateral sound stimulation was not found. The testing can easily be performed with the routine measurement of TEOAE. It could be useful in the diagnostic of lesions of the cerebello pontine angle and the brain stem.

Acoustic Stimulation↗

PubMed1989

Comments on "Acoustic Transfer Characteristics in Human Middle Ears Studied by a SQUID Magnetometer Method" [J. Acoust. Soc. Am. 82, 1646-1654 (1987)].

The study by Brenkman et al. [J. Acoust. Soc. Am. 82, 1646-1654 (1987)] of malleus umbo and anterior crus of stapes displacement in 14 human temporal bones shows a mean -7.3-dB/oct slope above 1.0 kHz for stapes displacement in response to a 80-dB SPL input at the eardrum. The slope they obtained for midfrequency (1.0-4.0 kHz) stapes displacement is significantly flatter than what was found previously [Gyo et al., Acta Otolaryngol. 103, 87-95 (1987); Gundersen, Prostheses in the Ossicular Chain (University Park, Baltimore, MD, 1971); Kringlebotn and Gundersen, J. Acoust. Soc. Am. 77, 159-164 (1985); Vlaming and Feenstra, Clin. Otolaryngol. 11, 353-363 (1986a)]; in these studies, stapes displacement rolled off at -12.0 to -14.9 dB/oct above 1.0 kHz. It appears that their mean midfrequency stapes displacement slope has been flattened by some unusual results in a small number of ears. Possible reasons for these results are discussed.

Acoustic Stimulation↗

PubMed1991

Acoustic microcavitation: its active and passive acoustic detection.

In this work acoustic microcavitation in water is studied primarily at 0.75 MHz and 1% duty cycle. To detect cavitation, two kinds of acoustic detectors are used. The first one is an unfocused, untuned 1-MHz receiver transducer that serves as a passive detector. The other one is a focused 30-MHz transducer that is used in pulse-echo mode and is called the active detector. Cavitation itself is brought about by a focused PZT-8 crystal driven in pulse mode. The active detector is arranged confocally with respect to the cavitation transducer. Both the interrogating pulse and the cavitation pulse arrive simultaneously at the common focus, which is the region of cavitation. With the test chamber filled with clean water, no cavitation is observed, even when the cavitation transducer is driven to give its peak output of 22 bar peak negative. Cavitation is, however, observed when polystyrene microparticles are added to the host water. Our view of how these smooth, spherical, monodispersed microparticles give rise to cavitation is described with some estimates. An attempt has been made to understand whether the presence of "streaming" affects the thresholds, and it has been found that the active detector field affects the cavitation process.

Acoustics↗

PubMed1992

The feasibility of using oto-acoustic emissions to monitor cochlear function during acoustic neuroma surgery.

The feasibility of using evoked oto-acoustic emission (EOAE) measurement for intra-operative monitoring of cochlear function was assessed during removal of an acoustic neuroma in a 53-year-old woman with normal hearing on the operated side prior to surgery. The high level of noise in the operating theatre was the only material problem encountered and this was not sufficient to prevent recording of identifiable waveforms. During manipulation of the brainstem, damage to the cochlea was indicated by an increase in EOAE latency and its eventual disappearance. A total hearing loss in the operated ear was revealed after surgery. Monitoring cochlear function with EOAEs is probably best considered at present as an adjunct to auditory brainstem response monitoring of the composite cochlea and eighth nerve, thus providing differential information.

Cochlea↗

PubMed1989

[What should be expected of oto-acoustic emissions? A critical analysis of clinical applications of oto-acoustic emissions].

The aim of this article is to carry out a critical analysis of the clinical applications of acoustic oto-emissions based on analysis of more than 1,000 adult and pediatric audiometric records. The principal technical and clinical properties of acoustic oto-emissions are described. The clinical value would seem to be very limited in adult audiology, whereas this examination would appear to be a reliable and non invasive method for screening in children at risk of cochlear deafness. In this respect, the investigation is principally limited by middle ear pathology and involvement of the central auditory pathways.

Acoustic Stimulation↗

PubMed1976

Acoustic reflex test in neuro-otologic diagnosis. A review of 24 cases of acoustic tumors.

Acoustic and other tumors of the cerebellopontine angle are not uncommon, and they usually have otologic symptoms or findings. Early diagnosis depends on a high index of suspicion and a thorough evaluation of patients with suspected tumors. This is a report of 24 cases selected from a group of 184 surgically confirmed tumors. Had the cases been evaluated only on the basis of pure tone or speech audiometry or on the basis of plain roentgenograms, the diagnosis might not have been made. Audiological examination should include the acoustic reflex test. The results of this test indicated a retrocochlear problem (absence or decay of the reflex) in 19 of 24 cases (80%). The test was positive in 11 of 12 patients with normal or near normal hearing and in seven of eight patients with normal x-ray films.

Adolescent↗