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PubMed1990

Acoustic emission from trabecular bone during mechanical testing: the effect of osteoporosis and osteoarthritis.

This study examines the relation between the nature of acoustic emission signals emitted from cancellous bone under compression and the mechanical properties of the tissue. The examined bone specimens were taken from 12 normal, 31 osteoporotic and six osteoarthritic femoral heads. The mechanical behaviour of the osteoporotic bone specimens was found to be significantly different from that of the normal specimens both in the pre-yield and post-yield ranges. In the osteoarthritic bones only the elastic behaviour was significantly different. The rates of acoustic events before yield and beyond it were found to be significantly higher both in the osteoporotic and osteoarthritic bone specimens. The average peak amplitude of the signals was also significantly higher in the diseased bones. Stepwise regression analysis showed that a combination of the acoustic emission parameters could significantly predict some mechanical properties of the bone. The energy absorbed during compression and the ultimate compressive stress of the specimens could be estimated from the rate of pre-yield acoustic events, the average amplitude of the signals and the rate of post-yield events. However, the explanation power of the acoustic emission parameters was only moderate. The nature of acoustic emission signals was thus demonstrated to be a potential tool for assessing bone quality.

Acoustics↗
PubMed2001

Mapping of soil insect infestations sampled by excavation and acoustic methods.

Geostatistical analysis was used to map traditionally and acoustically sampled populations of soil invertebrates at two different times in a hayfield at Grove Hill, AL, and once in an Auburn, AL, hayfield. The distributions of nearly all the soil invertebrates and their sounds were nonrandom in all three mapping studies. The maps constructed by excavation and acoustic sampling methods were compared by correlating the estimated (kriged) soil invertebrate counts with the estimated (kriged) counts of sounds per minute (pulse rate). Acoustic and traditional estimates were positively correlated in the Auburn study. Kriged estimates for green June beetle grub counts overlapped significantly with kriged estimates of sound pulse rate (R2 = 0.47). Overlap with sound pulse rates increased slightly when other soil organisms were counted along with green June beetle grubs: estimates of sound pulse rates were significantly correlated with counts of all white grubs (R2 = 0.50), all white grubs with earthworms (R2 = 0.52), all white grubs with earthworms and earwigs (R2 = 0.59), and total invertebrates (R2 = 0.59). The correlation between acoustic and traditional estimates was not significant at Grove Hill in either year, possibly because of a lack of experience in signal analysis or because the soil invertebrates may not have generated enough sounds to be detected above the background noise levels. These results suggest that acoustic technology is a promising tool for detecting insect pests in soil, but that further study and additional analysis are needed to improve interpretation of acoustic data obtained in the field.

Acoustics↗
PubMedDate not supplied

Evaluation of human middle ear function via an acoustic power assessment.

Measurements of middle ear (ME) acoustic power flow (power reflectance, power absorption, and transmittance) and normalized impedance (acoustic resistance, acoustic reactance, and impedance magnitude) were compared for their utility in clinical applications. Transmittance, a measure of the acoustic power absorbed by the ME, was found to have several important advantages over other measures of acoustic power flow. In addition to its simple and audiologically relevant physical interpretation (absorbed power), the normal transmittance curve has a simple shape that is visually similar to the ME transfer function. The acoustic impedance measures (resistance and reactance) provided important additional information about ME status and supplemented transmittance measurements. Together these measurements can help identify unusual conditions such as eardrum perforations. While this article is largely a review of the development of a commercial power reflectance measurement system, previously unpublished experimental results are presented.

Acoustic Impedance Tests↗
PubMed2003

Dynamic-acoustic variation causes differences in evaluations of laughter.

Exposure to laughter has striking effects on human listeners and may facilitate positive emotional and behavioural responses. The acoustic signal pattern of laughter vocalisations is particularly suitable to elicit these reactions. However, little is known about factors that lead to differences in reactions of listeners. The acoustic quality of laughter, the social context, and the disposition of the listener are possible variables in differences in evaluation. We conducted experiments using playback techniques in which human laughter elicited in a natural setting was evaluated by listeners (N=90). Listeners evaluated several phrases of laughter produced by different laughing targets. We investigated the role of the characteristics of voice, dynamic-acoustic characteristics, and order of playback sequence on the evaluation of laughter. The dynamic-acoustic characteristics of laughter significantly affected evaluations by listeners, whereas voice and the playback order did not. An acoustic analysis allowed us to identify acoustic parameters that contribute to such differences in evaluation.

Adult↗
PubMedDate not supplied

Accuracy of measurement of acoustic rhinometry applied to small experimental animals.

Nasal obstruction is one of the major symptoms of allergic rhinitis. In the study of the mechanism of nasal obstruction, experiments on animal are useful. In adult humans, acoustic rhinometry has been used to evaluate nasal obstruction by determining nasal cavity dimensions in terms of cross-sectional areas as a function of the distance from the nostril. We modified the equipment used on humans to assess dimensions of nasal airway geometry of small experimental animals. The purpose of this study was to investigate the accuracy of measurement of the modified acoustic rhinometry applied to small experimental animals using nasal cavity models and guinea pigs. Measurement of the nasal cavity models (made of cylindrical silicone tubes) showed that the acoustic rhinometry estimated 85.5% of actual area and 79.0% of actual volume. In guinea pigs, nasal cavity volume determined by the acoustic rhinometry was 73.7 +/- 20.0% of actual volume. The actual volume was estimated by impression material instilled into the nasal cavity of the animals (IM volume), and volume determined by acoustic rhinometry significantly correlated with IM volume. Furthermore, there was a significant negative correlation between the volume and nasal airway resistance in guinea pigs. Measurement of the nasal airway resistance is the method frequently used in the evaluation of the nasal obstruction in guinea pigs. These results suggest that acoustic rhinometry is useful in evaluating nasal obstruction in small experimental animals.

Acoustics↗
PubMed1984

Implications of DNA characterization of human acoustic neuromas.

Based on in vitro detection of cell-mediated immunity against human acoustic neuroma extract, a malignant potential of acoustic neuromas could be surmised, as malignant DNA patterns have been demonstrated in benign pituitary tumours. Flow-cytofluorometric characterization of the DNA content in 10 human acoustic neuromas, however, only revealed diploid cell lines and normal distributions of cells in different cell cycle phases. All acoustic neuromas were histopathology benign. The percentage of cells in S-phase (range: 1.8-8.3%, median: 3.6%) reflected a slow growth rate correlated neither to age, size of tumour, nor length of case history at time of surgery. These findings may in part be due to the analytical variation in the determinations of the S-phases. The investigation has not offered any explanation for the observed cell-mediated immunity against acoustic neuromas, and confirms that acoustic neuromas are benign tuours.

DNA↗
PubMed1995

Facial nerve involvement in patients with acoustic neurinomas. Examination with magnetic single- and bi-stimulation.

The diagnosis of acoustic neurinomas is usually made by auditory and vestibular testing and magnetic resonance imaging. As clinical involvement of the facial nerve is infrequent, occurring only in large tumours, only little is known about the subclinical involvement of the facial nerve. Transcranial magnetic stimulation of the VIIth cranial nerve in the temporal bone, adjacent to acoustic neurinoma growth, seems to be an adequate instrument for electrophysiological measurements of minimal nerve lesions without clinically obvious facial palsy. In 70% out of 97 patients with surgically and histologically confirmed acoustic neurinomas, obvious elongation of the intratemporal conduction time of the facial nerve was found. This affection was dependent on tumour size. No correlation was found to preoperative or postoperative facial nerve function and hearing function. The latencies of the conduction time showed a tendential increase in patients with a more difficult grade of surgery and of facial nerve preparation due to fibrous adhesions and nerve spreading on the tumour capsule. A completely new stimulation modality, the application of two magnetic stimuli in quick succession, was applied for the first time in acoustic neurinoma patients, and revealed facial nerve involvement by acoustic neurinoma growth. Facial nerve involvement in acoustic neurinoma can be detected by transcranial magnetic stimulation even in patients with small and medium sized tumours but with clinically normal facial function.

Cranial Nerve Neoplasms↗
PubMed1996

Auditory performance and acoustic reflexes in young adults reporting listening difficulties.

We aimed to determine whether reported difficulties in speech understanding are associated with abnormal acoustic reflex thresholds (ARTs). The acoustic reflex has been shown to have a role in the understanding of speech at high intensities by ensuring that the strong low-frequency components of sound do not excessively mask the higher-frequency components, which are important for speech understanding. There is also wide variance in individual ARTs. Hence, the possibility arises that subjects reporting listening difficulties in noise have abnormal acoustic reflex function. In this investigation, a questionnaire to 2395 university students was used to obtain 20 subjects reporting listening difficulties in background noise and requesting advice about their hearing problems; it also screened out significant histories of middle ear disease in childhood. These subjects, and 20 control subjects reporting no listening difficulties, received a battery of performance tests and measures of acoustic reflex thresholds. Results showed significant differences in auditory performance between subjects reporting listening difficulties and those with no such difficulties, but no differences in acoustic reflex thresholds. These findings extend the relationship between reported listening difficulties and auditory performance within the "normal hearing' range, but this relationship is unlikely to be due to abnormal acoustic reflex thresholds.

Auditory Threshold↗
PubMed1997

Perceiving the causes of coarticulatory acoustic variation: consonant voicing and vowel pitch.

Coarticulatory acoustic variation is presumed to be caused by temporally overlapping linguistically significant gestures of the vocal tract. The complex acoustic consequences of such gestures can be hypothesized to specify them without recourse to context-sensitive representations of phonetic segments. When the consequences of separate gestures converge on a common acoustic dimension (e.g., fundamental frequency), perceptual parsing of the acoustic consequences of overlapping spoken gestures, rather than associations of acoustic features, is required to resolve the distinct gestural events. Direct tests of this theory were conducted. These tests revealed mutual influences of (1) fundamental frequency during a vowel on prior consonant perception, and (2) consonant identity on following vowel stress and pitch perception. The results of these converging tests lead to the conclusion that speech perception involves a process in which acoustic information for coarticulated gestures is parsed from the stream of speech.

Humans↗
PubMed1993

[An evaluation of nasal patency with acoustic rhinometry--preop. and postop. comparisons].

Changes in nasal patency after nasal surgeries were evaluated with acoustic rhinometry. Fourteen cases (20 sides) were included in the evaluation and the following types of nasal surgery were performed: 2 partial maxillectomies, 11 Caldwell-Luc operations, 4 endonasal ethmoidectomies, 1 endonasal maxillary sinusectomy and 2 septoplasties. The evaluation with acoustic rhinometry was routinely performed on two occasions; the day before and 7-14 days after the surgery. The preop. and postop. results of the evaluations of nasal volume (6.9-14.1 cm by the area-distance curve) and nasal area (averaged areas at 11.0 cm and 13.4 cm by the area-distance curve) were compared. Postop. results in all but one case demonstrated increases in both nasal volume and nasal area, indicating that acoustic rhinometry has practical applications in preop. and postop. evaluations of nasal patency. Three aspects remain to be clarified. The first is the influence of the nasal cycle, which varies considerably at the time of both preop and postop evaluations. The second is the influence of the paranasal sinuses. When the results of cases who had undergone endonasal ethmoidectomy or septoplasty were compared to those who had received partial maxillectomy or Caldwell-Luc operation, the latter showed greater increases in nasal patency, suggesting that the cavities of paranasal sinuses, especially of the maxillary sinus, influence the results of acoustic rhinometry. The third is the size of the anterior entrance of the middle meatus. When the entrance is narrow, the acoustic pulse generated by acoustic rhinometry will not reach up to the paranasal sinuses so that the size of the entrance will again influence the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustics↗
PubMed1993

[Acoustic rhinometry as method for evaluating paranasal sinuses--experimental studies].

The potential application of acoustic rhinometry for evaluating paranasal sinuses was evaluated experimentally. In order to assess the influence of paranasal sinus volume in acoustic rhinometry, three model studies were performed. A tube made of acryle (20 cm in length, 2 cm in diameter) with a side hole was used for the first experiment. In the experiment measuring this tube with acoustic rhinometry, a difference between cases with a side hole (ex. 2 mm in diameter) and these without a side hole was observed. In the former, a more posterior tube position gave rise to an increase in the acoustic curve. In the second experiment, a syringe was was fixed to the side hole of the tube, so as that no leakage of sound wave would occur. A change in the volume of the syringe could be detected by acoustic rhinometry, even with changes as small as 1 ml. In the third experiment, the relationship between the size of the side hole and the volume of the syringe was evaluated. When the volume was less than 20 ml, the value was almost equal to the theoretical value even if the diameter of the side hole was as small as 4 mm. A larger size hole was required when the volume was increased. It was concluded that acoustic rhinometry is of possible value in assessing the paranasal sinuses, if the nasal cavity communicates with the paranasal sinuses via a large opening (e.g. in post-operative cases).

Acoustics↗
PubMed1992

[Concentration-effect and underestimation of time by acoustic stimuli].

This experiment is to examine emotional effects induced by acoustic loading on time-estimation and degree of concentration on tasks. Subjects were ten college students, who were asked to produce five second periods (estimation of time), under acoustic loading for 15 minutes. Acoustic stimuli were (1) koto-music, (2) classical music, (3) sound effect, and (4) FM-noise, with different power spectra, expected to induce different emotions in the subjects. Time-estimation and EEG alpha-rhythm were used as parameters of concentration. The main results were as follows. In general, time was underestimated when the subjects' attention was concentrated on the tasks. Acoustic stimuli with 1/f-fluctuation and pleasant emotions induced underestimation of time. Gradient of fluctuation in time-estimation also showed the same effects. With increase in acoustically induced pleasant emotions, alpha-rhythm increased, in parallel with the underestimation of time. These results suggest that emotions induced by the physical characteristics of acoustic stimuli affect mental concentration and eventually affect time-estimation.

Acoustic Stimulation↗
PubMed1999

Genetic association between chronic ethanol withdrawal severity and acoustic startle parameters WSP and WSR mice.

BACKGROUND: The present study examined the genetic association between chronic ethanol withdrawal severity and acoustic startle response (ASR) in replicated lines of mice selected for high (Withdrawal Seizure-Prone; WSP) and low (Withdrawal Seizure-Resistant; WSR) susceptibility to handling-induced convulsions after withdrawal from chronic exposure to ethanol. Any differences on a nonselected (correlated) trait between the opposite-selected lines is strong evidence for pleiotropic effects of the genes fixed by selection. METHODS: Naive WSP and WSR mice of both replicates were placed in startle chambers and exposed to a series of white noise stimuli of different intensities. In Experiment 1, two parameters [the maximal acoustic startle response (Rmax), and the sound intensity necessary to produce 50% of the maximal startle response (dB50)] were obtained from a least-squares nonlinear regression by fitting data for each subject to a sigmoidal function that best described the relationship between sound intensity and mean ASR. Response habituation of WSP and WSR mice to a repeated acoustic stimulus of high intensity was examined in Experiment 2. RESULTS: When ASR amplitude was plotted versus sound intensity, the sigmoid intensity-response curves of both WSP replicates were shifted to the right relative to the responses of WSR mice, which suggested decreased startle sensitivity in the WSP animals. Statistical analysis showed that naive WSP mice were less sensitive (higher dB50) to acoustic stimulation than Seizure-Resistant animals whereas Rmax was similar for both lines. The selected lines also differed in their responses to repeated acoustic stimulation, with WSP mice demonstrating greater habituation. CONCLUSION: Results of the present study suggest some common genetic mechanisms underlying behavioral responsiveness to acoustic stimulation and severity of ethanol withdrawal.

Acoustic Stimulation↗
PubMed2002

[Acoustic microscopy methods in studies of the filling materials microstructure].

The structure of filling materials (kemfil, polyacrylate cement, and Dentis, material produced by Stomadent Firm in Russia) at the interface with human dentin was studied in teeth subjected to retrograde filling with preliminary appendectomy. A prototype of table wide-field short pulse scanning acoustic microscope (50 mHz) (Acoustic Microscopy Center, Institute of Biochemical Physics of Russian Academy of Sciences) and Elsam acoustic microscope (200 mHz) (Leitz, Germany) were used. The results indicate that analysis of acoustic characteristics, including the data of acoustic microscopy, helps investigate the cement microstructure and evaluate the compactness and elasticity of samples; moreover, structural elements of the material, which are undetectable by other methods, are seen on acoustic images. These data can be used for evaluating the relationship between the microstructure and formation of mechanical properties, and, maybe, the patterns of cement interactions with dental tissues.

Acoustics↗
PubMed1992

The acoustic filter: an ultrasonic blood filter for the heart-lung machine.

Cardiopulmonary bypass-associated encephalopathy is thought to be due in part to continuous microembolization of the brain with gas microbubbles more than 40 microns in diameter during bypass. Current barrier filter technology cannot effectively remove such small microbubbles in fragile fluids such as blood. The design concepts for a new nonbarrier ultrasound-based fluid filtration system (an "acoustic filter") capable of filtering small microbubbles from blood are presented. The acoustic filter uses a field of high-intensity ultrasound to push microbubbles down an acoustic gradient, where they can be collected and removed. To test the filtration efficiency of the system, a Doppler ultrasound bubble detector was built. By monitoring the prefilter and postfilter Doppler signal an assessment of filtration efficiency was made. A suspension of stable albumin-encapsulated microbubbles (4 to 32 microns) were used as a model of the microbubble contaminants that might be found in the arterial return line of the heart-lung machine. Inactivated, the acoustic filter neither removed nor added microbubbles to the fluid. Activated, the acoustic filter provided total or near-total clearing of microbubbles. We conclude that the acoustic filter can remove microbubbles from a cardiopulmonary bypass-like apparatus.

Acoustics↗
PubMed2004

GABA mediaties the inhibitory effect of lateral amygdaloid nucleus stimulation on the acoustic response of neurons in A I cortex: An in vivo microiontophoretic study.

Experiments were performed on Sprague Dawley rats with multibarrel microelectrode technique. The effects of acoustic response of A I cortex neurons produced by electrical stimulation of lateral amygdaloid nucleus (LA) and the influence of GABA were observed. Experimental results showed that iontophoretic administration of GABA caused a pronounced inhibition of the electrical activity of A-I neurons. Blockade of GABA(A) with bicuculline (BIC) facilitated the acoustic response. The acoustic response of A-I neurons was inhibited when the LA was stimulated. Iontophoretic application of GABA resulted in a similar inhibitory effect as that of LA stimulation. Blockade of GABA(A) with bicuculline reversed the inhibitory effect of LA stimulation on the acoustic response of A-I neurons. In contrast, application of strychnine, a glycine receptor antagonist, could not reverse the inhibitory effect of LA. Baclofen, a GABA(B) agonist, did not affect the acoustic response of the auditory neurons. These results indicate that GABA is the ultimate transmitter which mediates the LA stimulation-induced inhibition of the acoustic response of A-I neurons in rats, possibly via the GABA(A) receptor.

Acoustic Stimulation↗
PubMed1990

Immunohistochemical localization of vimentin and S-100 antigen in small acoustic tumors and adjacent cochlear nerves.

To clarify the involvement of cochlear nerves in small acoustic tumors, we used immunoperoxidase techniques to determine the presence and distribution of vimentin and S-100 antigens in two acoustic tumor specimens and a transected vestibular nerve. Schwann cells and acoustic tumor cells failed to react positively with monoclonal antibody to vimentin. Reaction was observed in mesenchymal-appearing cells within both the normal nerve and the acoustic tumors, predominantly in association with blood vessels. Normal schwann cells and acoustic tumor cells reacted with polyclonal antibody to S-100 antigen with a similar, uniform distribution. Mesenchymal-appearing cells did not react with antibody to S-100. Immunostaining of a vestibular nerve from a Meniere's disease patient, used as a control, did not differ significantly from nerves adjacent to acoustic tumors. Because tumor cells and normal schwann cells stained similarly with antibody to S-100, it was not possible to establish with certainty if tumor cells invaded adjacent nerves.

Antigens, Neoplasm↗
PubMed1985

Acoustic reflex abnormalities in behaviorally disturbed and language delayed children.

Contralateral and ipsilateral acoustic reflex thresholds were measured in 62 subjects referred for suspected delays in development of language, learning disabilities, or disorders of auditory processing, with normal peripheral hearing thresholds and normal tympanometry. Thirty-two percent of the subjects in this study showed abnormal contralateral and ipsilateral acoustic reflex thresholds. Both contralateral and ipsilateral acoustic reflex thresholds were involved when subjects showed abnormal reflex thresholds. Although a high percentage of abnormal acoustic reflexes occurred in this population, no strong correlation could be found with specific areas of language delay. A slight positive correlation was found between abnormal acoustic reflexes and delayed psychomotor development. Increased or absent acoustic reflex thresholds are usually associated with peripheral or low brain stem pathologies. While not conclusive, these results suggest brain stem involvement in this population.

Adolescent↗