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PubMed1986

Predicting children's oral reading proficiency from selected acoustic and perceptual measures.

In contrast to the amount of information available on acoustic characteristics of adults' effective speech, little data are available on children's vocal effectiveness. A study, therefore, has been initiated to examine the relationship between some acoustic characteristics and listener judgments of children's vocal effectiveness. This article is a sequel to the first one, which reported some acoustic characteristics of oral reading by 36 10- to 12-year-old children. It describes results of perceptual analyses of oral reading proficiency on a five-point scale, of reading error analysis, and results of multiple regression analysis for testing predictability of the oral reading proficiency from the perceptual and acoustical measures. Some sex differences in oral reading proficiency are also discussed.

Child↗
PubMed1991

Contributions of occipital and temporal brain regions to visual and acoustic imagery--a spect study.

Regional cerebral blood flow (rCBF) was assessed by means of HMPAO-SPECT in two experimental groups. In a control condition both groups listened to abstract words, in the experimental condition they heard five names of objects. One group was advised to form visual images of the objects, the other group was advised to form acoustic images of the sounds made by these objects. Post-experimental questionnaires revealed that most of the subjects in the acoustic imagery condition had had visual images in addition to the acoustic ones. Both imagery conditions lead to approximately equal increases of rCBF in the left inferior occipital region and in the left thalamus. Flow increases in both hippocampal regions and the right inferior and superior temporal regions were larger in the acoustic than in the visual imagery condition. It is concluded that only the activation of left inferior occipital and left thalamic regions can be interpreted as being related to modality-specific visual aspects of imagery.

Auditory Perception↗
PubMed1984

Effects of two pyrethroid insecticides on motor activity and the acoustic startle response in the rat.

To better characterize the behavioral toxicity of pyrethroid insecticides, comparisons were made of the effects of cismethrin and deltamethrin exposure on motor activity and the acoustic startle response in male Long-Evans rats. Acute dose-effect, acute time course, and 30-day repeated-exposure determinations of 1-hr motor activity were made using figure-eight mazes. The acoustic startle response was measured to a 13-kHz, 120-dB(A), 40-msec tone at each of three background white noise levels (50, 65, and 80 dB). Deltamethrin (0, 2, 6, or 8 mg/kg) or cismethrin (0, 6, 12, 18, or 24 mg/kg) were administered po in 0.2 ml/kg corn oil. Cismethrin and deltamethrin produced similar dosage-dependent decreases in motor activity. The time course of onset and recovery for this decreased activity was rapid (1 to 4 hr) No cumulative effects on motor activity of a 30-day exposure to 2 mg/kg/day deltamethrin or 6 mg/kg/day cismethrin were found. The effects of cismethrin and deltamethrin on the acoustic startle response were dissimilar: deltamethrin produced a dosage-dependent decrease in amplitude and an increase in latency, and cismethrin produced an increase in amplitude and no change in latency. The differential effects of cismethrin and deltamethrin on the acoustic startle response may be related to the contrasting effects previously shown with neurophysiological and/or neurochemical techniques.

Administration, Oral↗
PubMed1994

Correlation of histology and acoustic parameters of liver tissue on a microscopic scale.

The correlation of several acoustic parameters with histological features was investigated in healthy White New Zealander rabbit liver (n = 10). Thin sections (10 microns) were studied by means of a light microscope in combination with a digital image processing system. Adjacent thick sections (250 microns) were studied by means of a custom-designed acoustic microscope. Markers of black silk suture material, that could be identified both optically and acoustically, enabled the spatial correlation of both imaging modalities. Acoustic images were reconstructed from the velocity of ultrasound, the attenuation at the central frequency (30 MHz), the attenuation spectral slope, the backscatter spectral slope and the backscatter at the central frequency. The measurements comprised the frequency range from 10 to 50 MHz, yielding a resolution of approximately 50 microns. From the thin sections (10 microns) the local histological composition was obtained by digital segmentation techniques. The features that were segmented are: the collagen rich fibrous tissue content, the area lumina, the area interstitial spaces, the number density of nuclei and the area parenchymal tissue. Correlation techniques revealed that the main feature responsible for attenuation is collagen. There was a fair correlation between area lumina and attenuation, but this was caused by a high correlation between the collagen that surrounds the lumina, and attenuation. No correlation was found between any histological feature and backscatter parameters or velocity.

Animals↗
PubMed1986

Noradrenergic influence on the prepulse inhibition of acoustic startle.

Oral administration of p,p'-1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), a chemical believed to increase neuronal membrane excitability increased the acoustic startle responsiveness of rats. Inhibition of the acoustic startle response with a brief, prepulse white-noise stimulus was evident at 12.5 to 25 mg/kg of p,p'-DDT, but not at 50 mg/kg. Pretreatment of rats with phenoxybenzamine, an adrenergic receptor antagonist, attenuated the effects of 12.5 mg/kg of p,p'-DDT on the acoustic startle reflex, and decreased the maximum magnitude reduction produced by the prepulse stimulus in DDT-exposed rats. These data extend previous work showing that p,p'-DDT augments startle reactivity in rats and is in accord with the existence of an excitatory norepinephrine(NE)-containing pathway modulating motor outflow in the acoustic startle reflex arc.

Analysis of Variance↗
PubMed1987

Acoustic distortion products in rabbit ear canal. I. Basic features and physiological vulnerability.

In contrast to evoked otoacoustic emissions, acoustic distortion products (DPs) recorded from the ear canal are present at predictable frequencies with respect to their primary tones, f1 and f2. Such specificity may provide detailed frequency-place information concerning the functional state of limited regions of the organ of Corti following experimental intervention. However, to date, it is not clear whether emitted DPs solely reflect activity at the basilar-membrane regions of primary tones or if the remote DP site makes a significant contribution to the emitted signal measured in the ear canal. We have investigated a number of the general features of acoustic-DP generation in the rabbit so that, in later experiments, the contributions of specific basilar-membrane regions involved in generating these DPs can be identified using techniques designed to manipulate their normal properties. The first report describes the outcome of systematic manipulations of a number of stimulus conditions and alterations to the physiological state of the cochlea by exposure to fatiguing sound or anoxia. Experimental findings for the 2f1-f2 DP showed that, in general, the relations of the levels and frequency of the primary tones to DP magnitude were consistent with previously published data from other mammalian species. Additional observations for other odd-order intermodulation DPs at the 3f1-2f2 and 2f2-f1 frequencies suggested that the basic attributes of the acoustic DPs were similarly affected by systematic manipulation of the basic parameters of the primary tones and the general metabolic state of the cochlea. General anesthesia, however, did not affect DP amplitude. A companion paper describes the results of a series of subsequent experiments using response-suppression, interfering-tone, and temporary threshold shift techniques which address more directly the issue of which basilar-membrane sites contribute to the generation of different acoustic DPs.

Anesthesia, General↗
PubMed1987

Acquisition of acoustic startle response in relation to growth and thyroid function in rats.

Thiourea was administered by gavage to pregnant and lactating rats from gestational day 18 until postnatal day 10, at doses of 100 or 250 mg per day (approximately 350 or 900 mg/kg/day). From the day after birth until postnatal day 14 the neonates were weighed, and beginning on postnatal day 10 acquisition of acoustic startle reflex was assessed. Serum thyroxine and thyrotropin were measured on postnatal day 14. High dose thiourea severely inhibited thyroid function in pups, significantly depressed body growth, and retarded development of the acoustic startle response. At the low dose there was a significant reduction in growth, but no effect on acquisition of acoustic startle reflex. Low dose pups appeared to be functionally euthyroid (free T4 and thyrotropin were not significantly different from control). In conjunction with other studies, these results strongly suggest that, while development of acoustic startle is dependent upon thyroid hormone, it is not readily affected by retarded body growth.

Animals↗
PubMed2006

Immune cell recruitment following acoustic trauma.

Acoustic trauma induces cochlear inflammation. We hypothesized that chemokines are involved in the recruitment of leukocytes as part of a wound healing response. The cochleas of NIH-Swiss mice, exposed to octave-band noise (8-16 kHz, at 118 dB) for 2h, were examined after the termination of exposure. Leukocytes were identified immunohistochemically with antibodies to CD45 and F4/80. Gene array analysis followed by RT-PCR was performed on cochlear tissue to identify up-regulation of chemokine and adhesion molecule mRNA. The expression of the adhesion molecule ICAM-1 was also investigated immunohistochemically. Few CD45- or F4/80-positive leukocytes were observed in the non-exposed cochlea. Following acoustic trauma however, the number of CD45-positive cells was dramatically increased especially after 2 and 4 days, after which time the numbers decreased. F4/80-positive cells also increased in number over the course of a week. Gene array analysis indicated increased expression of monocyte chemoattractant protein 5 (MCP-5), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein-1beta (MIP-1beta) and ICAM-1. RT-PCR, performed using primers for the individual mRNA sequences, confirmed the increased expression of MCP-1, MCP-5, MIP-1beta, and ICAM-1 relative to non-exposed mice. In the normal cochlea, ICAM-1 immunohistochemical expression was observed in venules, spiral ligament fibrocytes and in endosteal cells of the scala tympani. Expression increased to include more of the spiral ligament and endosteal cells after acoustic trauma. A cochlear inflammatory response is initiated in response to acoustic trauma and involves the recruitment of circulating leukocytes to the inner ear.

Animals↗
PubMed2006

Turbulent inertial gelation and acoustic quasi-gelation of submicron aerosol particles.

Inertial turbulent and acoustic orthokinetic particle coagulation mechanisms have physical similarity. We consider analytically and numerically coagulation of discrete compact and fractal submicron agglomerated particles, governed by these mechanisms via Smoluchowski equation. Existence of the inertial turbulent coagulation is mathematically proven. A new gelation scenario is revealed for both of the above coagulation mechanisms. Turbulent inertial gelation is manifested by means of a multi-modal relay-type run-away particle size growth, including formation of infinite set of secondary maxima in volume fraction distribution. When acoustic coagulation mechanism is much stronger than the Brownian coagulation, acoustic coagulation occurs as a quasi-gelation process, with a run-away particle size growth, characterized, however, by a finite set of secondary maxima. The effect of acoustic field on coagulation is shown to be more pronounced for fractal agglomerates than that for compact agglomerated particles.

Journal Article↗
PubMed2005

Normative standards for vocal tract dimensions by race as measured by acoustic pharyngometry.

SUMMARY: Acoustic pharyngometry evaluates the geometry of the vocal tract with acoustic reflections and provides information about vocal tract cross-sectional area and volume from lip to the glottis. Variations in vocal tract diameters are needed for speech scientists to validate various acoustic models and for medical professionals since the advent of endoscopic surgical techniques. Race is known to be one of the most important factors affecting the oral and nasal structures. This study compared vocal tract dimensions of White American, African American, and Chinese male and female speakers. One hundred and twenty healthy adult subjects with equal numbers of men and women were divided among three races. Subjects were controlled for age, gender, height, and weight. Six dimensional parameters of the speakers' vocal tract cavities were measured with acoustic reflection technology (AR). Significant gender and race main effects were found in certain vocal tract dimensions. The findings of this study now provide speech scientists, speech-language pathologists, and other health professionals with a new anatomical database of vocal tract variations for adult speakers from three different races.

Adult↗
PubMed2005

fMRI-acoustic noise alters brain activation during working memory tasks.

Scanner noise during functional magnetic resonance imaging (fMRI) may interfere with brain function and change blood oxygenation level dependent (BOLD) signals, a problem that generally worsens at the higher field strengths. Therefore, we studied the effect of increased acoustic noise on fMRI during verbal working memory (WM) processing. The sound pressure level of scanner noise was increased by 12 dBA from "Quiet" to "Loud" echo planar imaging (EPI) scans by utilizing resonant vibration modes of the gradient coil. A WM paradigm with graded levels of task difficulty was used to further access WM load. Increased scanner noise produced increased BOLD responses (percent signal change) bilaterally in the cerebellum, inferior (IFG), medial (medFG), and superior (SFG) frontal, fusiform (FusG), and the lingual (LG) gyri, and decreased BOLD responses bilaterally in the anterior cingulate gyrus (ACG) and the putamen. This finding suggests greater recruitment of attention resources in these brain regions, probably to compensate for interference due to louder scanner noise. Increased working memory load increased the BOLD signals in IFG and the cerebellum, but decreased the BOLD signals in the putamen and the LG. These findings also support the idea that brain function requires additional attention resources under noisier conditions. Load- and acoustic-noise-related changes in BOLD responses correlated negatively in the WM network. This study demonstrates that MR noise affects brain activation pattern. Future comparisons between studies performed under different acoustic conditions (due to differing magnetic field strengths, pulse sequences, or scanner manufacturers) might require knowledge of the sound pressure level of acoustic noise during fMRI.

Adult↗
PubMed2004

Kynurenate in the pontine reticular formation inhibits acoustic and trigeminal nucleus-evoked startle, but not vestibular nucleus-evoked startle.

The startle reflex is elicited by acoustic, trigeminal or vestibular stimulation, or by combinations of these stimuli. Acoustic startle is mediated largely by ibotenate-sensitive neurons in the ventrocaudal pontine reticular formation (PnC). In these studies we tested whether startle elicited by stimulation of different modalities is affected by infusion of the non-selective glutamate antagonist, kynurenate, into the PnC. In awake rats, startle responses evoked by either acoustic or spinal trigeminal nucleus stimulation were inhibited by kynurenate, but not saline, infusions, with the most effective placements nearest PnC. In chloral hydrate-anesthetized rats, kynurenate in the PnC reduced trigeminal nucleus-evoked hindlimb EMG responses, but not vestibular nucleus-evoked startle. Kynurenate in the vestibular nucleus had no effect on trigeminal nucleus-evoked startle. These results indicate that trigeminal nucleus stimulation evokes startle largely through glutamate receptors in the PnC, similarly to acoustic startle, but vestibular nucleus-evoked startle is mediated through other pathways, such as the vestibulospinal tract.

Animals↗
PubMed2006

Two-dimensional analysis of the effect of an electrode layer on surface acoustic waves in a finite anisotropic plate.

The effect of a metal layer over an elastic substrate on surface acoustic wave propagating in the structure can be evaluated precisely for semi-infinite solids and infinite plates, but there is no accurate analytical solution if the finite size of the plate has to be considered. By expanding displacements with eigensolutions of surface acoustic waves in a semi-inifite solid, a set of two-dimensional equations similar to the Mindlin plate theory are obtained. Then for a thin electrode layer, the effect is considered through the approximation of displacements in the metal layer with the ones in the substrate, and an integration over the thickness incorporated the properties of the metal layer into equations through the modification of material properties with the decaying indices of surface acoustic waves and the thickness of the metal layer. Using AT-cut quartz crystal as the substrate, we present the effect of silver electrode layers of finite thickness on the phase velocity of propagating surface acoustic waves.

Journal Article↗
PubMed2006

Influence of overlying soft tissues on trabecular bone acoustic measurement at various ultrasound frequencies.

Ultrasound (US) has been introduced as a promising tool for osteoporosis diagnostics. However, soft tissues overlying the bones affect reliability of the ultrasound (US) techniques. In this in vitro study, the effect of soft tissues on bone US measurements was investigated numerically and experimentally. Particularly, the dependence of the error induced by soft tissues on the applied US frequency (0.3 to 6.7 MHz) was addressed. For these aims, human trabecular bone samples (n = 25) were measured using acoustic, dual energy x-ray absorptiometry (DXA) and mechanical techniques. US attenuation, speed, reflection and backscattering were determined from the through-transmission and pulse-echo measurements. Numerical correction, based on the inclusion of acoustic characteristics of specific soft tissue components, i.e., adipose and lean tissues, was derived for the analysis of experimental measurements. Values of US parameters, interrelationships between the US parameters and mechanical properties, as well as the errors induced by the soft tissues, were significantly dependent on the US frequency. The errors induced by the soft tissues on the US measurement were typically reduced by approximately 50% after introduction of the numerical correction technique. Thereby, the acoustic prediction of mechanical properties of trabecular bone was also improved. We conclude that the numerical correction of the contribution of overlying soft tissues on acoustic measurements can reduce uncertainties related to in vivo US measurements.

Absorptiometry, Photon↗
PubMed2005

Effect of surface acoustic waves on the catalytic decomposition of ethanol employing a comb transducer for ultrasonic generation.

The effect of surface acoustic waves, generated on a silver catalyst using a comb transducer, on the catalytic decomposition of ethanol is examined. The comb transducer employs purely mechanical means for surface acoustic wave (SAW) transduction. Unlike interdigital SAW transducers on piezoelectric substrates, the complicating effects of heat generation due to electromechanical coupling, high electric fields between adjacent electrodes, and acoustoelectric currents are avoided. The ethanol decomposition reactions are carried out at 473 K. The rates of acetaldehyde and ethylene production are retarded when acoustic waves are applied. The rates recover to varying degrees when acoustic excitation ceases.

Journal Article↗
PubMed1997

Comparison of echocardiographic acoustic quantification system and radionuclide ventriculography for estimating left ventricular ejection fraction: validation in patients without regional wall motion abnormalities.

Echocardiographic automated border detection of blood-endocardium interface is made on the basis of the principle of acoustic quantification. The automated border system is capable of providing on-line left ventricular (LV) cavity area and function. Recently, ABD algorithms have been devised to estimate LV volume on line from a long-axis image, calculated by established area-length method or Simpson's formula. To test the clinical validity of this newly developed echocardiographic method, LV volumes and ejection fraction measured by real-time acoustic quantification were compared with radionuclide ejection fraction in 24 subjects on the same day. Patients were included in the study if > or = 75% of their endocardium was visualized with conventional two-dimensional echocardiography. Sixteen (66%) of 24 patients had a technically adequate conventional echocardiogram with a broad range of ventricular dimensions and systolic function. None of the study patients had regional wall motion abnormalities. Echocardiographic measurements were obtained from the LV apical four-chamber, long-axis view. Ejection fraction, determined by the acoustic quantification and by radionuclide ventriculography, showed a strong linear relation (r = 0.92, standard error of the estimate = 4.4, p < 0.05). However, acoustic quantification overestimated the radionuclide ejection fraction with rather wide limits of agreement (3.8% +/- 16.4%; bias +/- 2 SD). Thus echocardiographic automated border detection technique is a reasonably accurate method for on-line assessment of LV function.

Adult↗
PubMed2000

Evaluating the protective role of the olivocochlear bundle against acoustic overexposure in rats by using Fos immunohistochemistry.

Efferent inhibition on the cochlea is suggested as a possible function of the olivocochlear bundle (OCB). Substantial evidence supports the finding that the OCB may protect the inner ear from noise-induced damage. However, there is relatively less known about the effects of noise on the central auditory transmission compared to the effects on the periphery. In the present animal study, two experimental paradigms were designed to analyze the influence of OCB lesion on the central auditory transmission following acoustic overexposure. In order to evaluate the animal's auditory function, its hearing threshold and the tone-evoked Fos expression shown in auditory nuclei were examined. Fos is a protein product of proto-oncogene c-fos. Via appropriate acoustic stimulation, Fos expression reveals the activated neuronal elements along the ascending auditory pathway. Thus, in experiment 1, no exposure sound was introduced and therefore no significant differences were shown in hearing thresholds and Fos expression among all rats, regardless of the status of their OCB. This result indicates that, without acoustic overexposure, OCB lesion caused no significant effect on brainstem auditory transmission. In contrast, in experiment 2, rats were exposed to continuous 8 kHz tones at 85 dB sound pressure level (SPL). A significantly increasing threshold was observed in rats with OCB lesion following an exposure period of 5 or 10 days. In addition, Fos expression was invisible first in rats with OCB lesion following 5-day exposure and almost no Fos expression could be examined in all rats after 10-day exposure. Taken together, the present data demonstrate that damaging the OCB renders an animal more easily vulnerable to acoustic damage than that of rat with intact OCB, and then reduces its cochlear activities, which eventually leads to increasing difficulty to induce tone-evoked Fos expression along the ascending auditory pathway.

Animals↗
PubMed2002

Probing acoustic nonlinearity on lengths scales comparable to material grain dimensions.

The focus of this presentation is to describe our efforts at laser generation of high frequency surface acoustic waves and detection of the nonlinear contribution in the acoustic near-field of the source. Narrow band acoustic generation is accomplished by interfering two pulsed laser beams at the surface of the sample. A Michelson interferometer, that incorporates a high power microscope objective, is used to detect the acoustic disturbance. Detection near the source combined with high frequency generation (approximately 0.1 GHz) facilitates investigation of fundamental processes of harmonic generation on length scales comparable to grain size dimensions.

Journal Article↗