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At least 73 records · Page 4Linked to original sources
PubMed2001

The stimulated acoustic relaxation emission of maize starch tablets.

Stimulated acoustic relaxation emissions from maize starch tablets after compression were detected and recorded in the audible region. Stimulation was found to enhance the detected acoustic emission and to maintain recordable acoustic emission level longer. Based on the fact, that the stimulation by a halogen lamp and a preheated chamber produced similar results, the effect of stimulation on acoustic relaxation emission is proposed to be connected to the temperature rather than the visible emission. A mathematical model of acoustic activity and its dependence on stimulation temperature is also introduced.

Hot Temperature↗
PubMed1993

Effects of contralateral acoustic stimulation on otoacoustic emissions following vestibular neurectomy.

This study demonstrates that, following unilateral vestibular neurectomy, the inhibitory effect of contralateral acoustic stimulation on evoked otoacoustic emissions is absent. The patient acts as her own control in that the unoperated side shows normal suppression of otoacoustic emission amplitude with contralateral acoustic stimulation. The lack of interaural suppression of otoacoustic emissions on the sectioned side, in the presence of normal acoustic reflex threshold levels, provides evidence that observed phenomena are not merely a function of middle ear reflex activity. It is concluded that the lack of inhibition in the operated ear is due to the sectioning of the olivocochlear bundle within the inferior vestibular nerve, removing the efferent control of the receptor cells. Otoacoustic emissions recorded during contralateral acoustic stimulation may thus provide a rapid, non-invasive means of investigating the functional of the efferent auditory system.

Acoustic Stimulation↗
PubMed1991

The significance of amniotic fluid volume during intrapartum fetal acoustic stimulation.

The relationship of intrapartum fluid volume to the fetal response to acoustic stimulation was investigated in 112 patients who were in the latent phase of labor. Amniotic fluid volume appears to play an insignificant role in the genesis of fetal heart rate decelerations that occur after fetal acoustic stimulation, regardless of the amount of amniotic fluid present.

Acoustic Stimulation↗
PubMedDate not supplied

Fetal bradycardia following vibratory acoustic stimulation: a sign of distress?

In two cases the application of vibratory acoustic stimulation, at term, resulted in severe fetal bradycardia of 4 and 5 min duration. The spontaneous return to a normal fetal heart rate pattern allowed normal vaginal deliveries of healthy neonates. Transient fetal bradycardias that follow vibratory acoustic stimulation should not be regarded as an unequivocal sign of fetal distress.

Acoustic Stimulation↗
PubMed2004

Photo-acoustic stimulation increases the amount of 70 kDa heat shock protein (Hsp70) in human whole saliva. A pilot study.

Long-term photo-acoustic stimulation leads to changes in the composition of saliva, which may have a key contribution to the effectivity of this technique in easing mucosal symptoms of psychosomatic patients. In the present study a significant (P <or= 0.01) increase in salivary 70 kDa heat shock protein, Hsp70 was demonstrated in human whole saliva after repeated photo-acoustic stimulation. Increased salivary chaperones may contribute to the effectivity of photo-acoustic stimulation, because of their cytoprotective extracellular actions.

Acoustic Stimulation↗
PubMed2001

Short fetal acoustic stimulation test for rapid antepartum assessment of fetal well-being.

Short fetal acoustic stimulation test (FAST) was prospectively studied in 604 high risk pregnancies after 28 weeks of gestation. Fetal heart rates were recorded 3 minutes before and 5 minutes after fetal acoustic stimulation. The results of the tests performed within a week of delivery were compared with perinatal outcomes. Reactive response to short FAST occurred in 597 cases (98.8%) while nonreactive response was found in 7 cases (1.2%). Nine fetuses were considered poor outcomes. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of short FAST to predict poor fetal outcomes were 66.7, 99.8, 85.7, 99.5, and 99.3 per cent, respectively. Short FAST has high specificity, negative predictive value and accuracy for prediction of poor perinatal outcome. This rapid test should be used as a screening method for antepartum assessment of fetal well-being in a busy antenatal clinic.

Acoustic Stimulation↗
PubMed1989

Vibro-acoustic stimulation of the human fetus: effect on behavioural state organization.

Vibro-acoustic stimulation of the human fetus in being increasingly performed both antenatally and during labour, to differentiate between poor and good fetal health in cases of flat or otherwise suspect fetal heart rate patterns. In a controlled study we investigated the effect of the electronic artificial larynx (EAL) on fetal behavioural state organization. In 10 healthy women with normal pregnancies of 38-40 weeks of gestation, recordings of fetal heart rate, body movements and eye movements, with a duration of 120-210 min, were carried out during two consecutive days. In each fetus, 3-4 episodes of state 1F and consecutive state 2F were studied, one of which served as a control observation. EAL stimulation during state 1F was associated with excessive fetal movements and with a state change in 7 out of 9 observations (four times into 2F; three times into 4F). Stimulation during state 2F was associated with a change into 4F in four of the nine observations. On days with EAL stimulation the fetuses spent more time in state 4F or in an episode not classifiable (because of an atypical FHR pattern with tachycardia and small accelerations) than control fetuses (21% vs. 3% of time). Disorganized states or periods of state 4F sometimes lasted for more than 1 h following the stimulation. It is concluded that stimulation with the EAL induces excessive fetal movements, a prolonged tachycardia, non-physiological state changes and a disorganisation and change in the distribution of fetal behavioural states. Until more is known regarding the safety and risks of vibro-acoustic stimulation, it should not be used in a routine clinical setting.

Acoustic Stimulation↗
PubMed2006

Electrocortical effects of MDMA are potentiated by acoustic stimulation in rats.

BACKGROUND: 3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is known for its toxicological, psychopathological and abuse potential. Some environmental conditions, e.g. acoustic stimulation typical of the "rave scene" can influence the toxicity of this drug. RESULTS: We investigated the effects of low doses of MDMA in vivo using Wistar rats in the absence of acoustic stimulation (white noise; 95 Db) demonstrating that ecstasy is able to induce a significant activation (reduction of Electrocortical total power) of the telencephalic cortex that spontaneously reverts in the absence of sensorial stimuli, whereas it persists for several days if, in addition to MDMA, the animals are exposed to acoustic stimulation. CONCLUSION: Our data demonstrate that low doses of MDMA are able to reduce electrocortical total power, and that this effect is potentiated by sensorial stimuli commonly present in certain environments, such as rave parties.

Acoustic Stimulation↗
PubMed1991

[Vibration and acoustic stimulation during labor with external monitoring. Pathology of fetal heart rate].

Vibratory acoustic stimulation was done in patients with an abnormal fetal heart rate tracing in external continuous electronic monitoring during labor, correlating with Apgar score, meconium staining and umbilical cord pH, describing a 83.3% sensitivity, 81.3% specificity and 62.5% positive predictive value. The authors recommend the use of vibratory acoustic stimulation in those cases with an abnormal fetal heart rate tracing in external continuous electronic monitoring, when we can not install internal electronic monitoring or obtain a fetal blood pH on assessment of fetal well-being.

Acoustic Stimulation↗
PubMed1992

Loudness balance between electric and acoustic stimulation.

Binaural loudness balance between electric and acoustic stimulation is obtained in auditory brainstem implant listeners who had substantial acoustic hearing in one ear. The data are well described by a linear relationship between acoustic decibels and electric microamps. Based upon this linear relationship, we propose an exponential model of loudness growth in electric stimulation. The exponential model predicts that the loudness growth function can be determined solely by the threshold and the uncomfortable loudness level in electric stimulation. This prediction is consistent with previous psychophysical data on loudness functions. Implications of this finding for speech processor designs are discussed.

Acoustic Stimulation↗
PubMed1991

The response to acoustic stimulation and the changes in brain amine levels after repeated administration of beta-phenylethylamine in rats.

Reverse tolerance to stereotyped behavior was induced after repeated administration of beta-phenylethylamine (PEA) (50 mg/kg, i.p., daily for 10 days) in rats. The reverse tolerance was maintained for at least 4 weeks after the last administration. We studied the effects of acoustic stimulation on locomotor activity 2 days and 4 weeks after withdrawal from PEA and measured the changes in brain monoamine levels 4 weeks after the withdrawal. Locomotor activity during acoustic stimulation was increased in the saline treated group, and this response was unaffected after repeated PEA treatment. Four weeks after withdrawal, significant increases in noradrenaline levels in the cerebral cortex and decreases in 5-hydroxytryptamine levels in the hypothalamus were found. The effects of acoustic stimulation on locomotor activity and the changes in brain monoamine levels were different from those of methamphetamine treatment obtained in our previous study. In conclusion, it may be suggested that the response to acoustic stimulation after repeated PEA administration in rats cannot be a model for abnormal responsiveness to environmental stimulation that is observed in chronic paranoid schizophrenics.

Acoustic Stimulation↗
PubMed2005

Ultra-high-frequency ultrasonic external acoustic stimulation for tinnitus relief: a method for patient selection.

We proposed a method for patient selection and application of criteria for predicting success with bone-conduction external acoustic stimulation using high-audio-frequency sound in the ranges of 10-20 kHz and 20-26 kHz for individuals with subjective idiopathic tinnitus (SIT) of the severe disabling type. Ultra-high-frequency (UHF) stimulation for tinnitus relief has been found to be most effective when residual neuronal function exists in the acoustic ranges of 10-14 kHz, with thresholds no greater than 40-50 dB sound pressure level (SPL). Ultrasonic (US) acoustic stimulation is recommended for patients with audiometric thresholds greater than 50-60 dB SPL for frequencies of 10-14 kHz. Fifty-two consecutive patients seen for the primary complaint of SIT of the severe disabling type received a trial of either UHF or US bone-conduction acoustic stimulation. Tinnitus relief was reported in 22 of the 52 patients. The application of criteria for patient selection predicted tinnitus relief in 20 of the 22.

Acoustic Stimulation↗
PubMed1991

[Fetal heart rate patterns in response to acoustic stimulation].

Fetal heart rate response to fetal acoustic stimulation (FAST) during the antepartum period after 25 weeks of gestational age was studied in 157 cases of normal pregnancy, 22 cases of fetal distress, 12 cases of SFD, 10 cases of fetal malformation, 9 cases of placental dysfunction, 4 cases of oligohydramnios, 12 cases of toxemia of pregnancy, and 15 cases of SLE. Five different types of response were observed: Type I through type V. 1. FAST was available to evaluate fetal well-being from 27 weeks of gestational age, although a nonstress test (NST) has been used after 31 weeks of gestational age. 2. Type IV was observed frequently in the case of coiling of the umbilical cord. 3. In acute fetal distress abnormality was detected by NST prior to FAST, but in latent fetal distress abnormality was detected by FAST prior to NST. 4. Cases classified as FAST types III and IV, which remained unchanged or deteriorated to III, IV or V were almost all characterized by poor fetal outcome.

Acoustic Stimulation↗
PubMed1990

Fetal acoustic stimulation as a possible adjunct to diagnostic obstetric ultrasound: a preliminary report.

Unfavorable fetal position during diagnostic obstetric ultrasound can interfere with visualization of certain structures, leading to prolonged or repeated examination. Fetal acoustic stimulation induces a fetal startle reflex and an increase in fetal movements. This report describes our experience with fetal acoustic stimulation to prompt fetal movement in an effort to improve fetal visualization. At gestational ages of 28 weeks or more a 94.1% success rate was noted, in 30 seconds or less in 70.6% of the cases. We conclude that fetal acoustic stimulation may be a valuable adjunct to diagnostic obstetric ultrasound.

Acoustic Stimulation↗
PubMed2002

Can spontaneous movements be modulated by visual and acoustic stimulation in 3-month-old infants?

BACKGROUND: The assessment of the quality of general movements (GMs) in infants proves to be a reliable and valid diagnostic tool for detecting brain dysfunction early in life. Of special interest, particularly for the prediction of cerebral palsy, is the fidgety kind of GMs, the so-called fidgety movements (FMs) observable in 3- to 5-month-old infants. GMs are part of an infant's spontaneous motor repertoire and as such endogenously generated by the nervous system itself. AIM: The question was raised as to what extent the temporal organisation of FMs can be modulated by visual and acoustic stimulation. STUDY DESIGN: Spontaneous motility in supine position with and without stimulation was recorded on video and the data were semiquantitatively analysed. We studied the effect of visual stimulation (red ring, red puppet), unanimated acoustic stimulation (68, 77, 88 dB) and of the mother, approaching her infant in a talkative manner after an absence of a quarter of an hour. SUBJECTS: Twenty-nine healthy infants at the age of 12 weeks who all showed normal FMs. RESULTS: Visual stimulation demonstrated that only the presentation of a red puppet elicited a significant level of focussed attention and led to a decrease of FMs. A red ring, unanimated acoustic stimulation as well as the interaction with the mother had no influence on the temporal organisation of FMs. CONCLUSION: This study demonstrated that in 3-month-old infants, FMs is a predominant motor pattern and that it is possible to assess FMs during (playful) social interaction.

Acoustic Stimulation↗
PubMed1988

Continuing experience with the fetal acoustic stimulation test.

Antepartum fetal heart rate testing remains a useful method with which to assess fetal well-being in high-risk pregnancies. Recently the adjunctive use of transabdominal acoustic stimulation was proven effective in reducing the number of nonreactive nonstress tests (NSTs) without changing the predictive reliability of the test. Our continuing experience with this method involved 1,503 women undergoing 3,935 tests. A reactive test occurred in 93%, and the fetal death rate was 1.3/1,000. In an attempt to evaluate the incidence of mortality in a large population, data from the current investigation were pooled with those from other reports from our institution. In our aggregate experience of 7,763 tests, fetal death occurred within seven days of a reactive test with an incidence of 1.9/1,000 in patients receiving acoustic stimulation. This finding contrasts favorably with a death rate of 1.6/1,000 in fetuses with spontaneous reactivity. Fetal acoustic stimulation testing seems to offer advantages over the more traditional NST, and the predictive values of normal tests seem to be equivalent.

Acoustic Stimulation↗
PubMed1993

[Changes in human spontaneous otoacoustic emissions with contralateral acoustic stimulation].

According to current cochlear concepts, spontaneous otoacoustic emissions (SOAEs) are thought to be the product of outer hair cell (OHCs) movement. Furthermore, efferent neurofibers from the olivocochlear bundle primarily innervate OHCs. Thus, we designed this investigation to determine changes in SOAE under conditions of contralateral acoustic stimulation. Fouty-two normal ears of 34 subjects with uni- or bilateral SOAEs were examined. The sound pressure level (SPL) of SOAE was measured 3 times in each subject and was initially averaged. The white noises of 30 or 40dBSPL, believed not to affect the other side, were then loaded contralaterally and the SPL of SOAEs were measured and compared with the non-loaded data. The SPL of single SOAEs were actually suppressed with 40dBSPL stimulation while the SPL of multiple SOAEs showed typical changes. Interestingly, no significant suppression of SOAEs was noticed under conditions of contralateral acoustic stimulation of the impaired ear. These data suggest that contralateral acoustic stimulation could affect OHC function via the olivocochlear bundle.

Acoustic Stimulation↗