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At least 19 recordsLinked to original sources
PubMed1984

Antepartum fetal heart rate response to sound stimulation: the acoustic stimulation test.

The fetal heart rate acceleration response to an acoustic stimulation was compared to the traditional nonstress test in regard to pregnancy outcome, as reflected by the incidence of intrapartum fetal distress, meconium staining of the amniotic fluid, 1- and 5-minute Apgar scores, and perinatal mortality. Fetuses with spontaneous or sound-generated reactivity had comparably good outcomes with respect to all outcome measures investigated. Fetuses who lacked spontaneous or sound-stimulated reactivity had an increased risk for intrapartum fetal distress. The acoustic stimulation test is a safe and rapid test of fetoplacental sufficiency that appears to perform comparably to the nonstress test. The acoustic stimulation test significantly shortens total antepartum testing time and expense.

Acoustic Stimulation↗
PubMed2003

Echo-enhanced color Doppler cystosonography of vesicoureteral reflux in children. Improvement by stimulated acoustic emission.

PURPOSE: To prospectively evaluate the potential of echo-enhanced color Doppler sonography (ee-CDS) using the acoustic stimulated emission technique in the diagnosis of vesicoureteral reflux (VUR) in children. MATERIAL AND METHODS: 30 children (age: 0-9 years) with suspicion of VUR were submitted for echo-enhanced cystosonography (ee-CS) and conventional voiding cysto-urethrography (VCU). Conventional US and then color Doppler sonography (CDS) were performed after instillation of Levovist into the catheterized urinary bladder that had been prefilled with saline. Finally, output gain was increased in order to 'burst' the bubbles (= stimulated acoustic emission, burst-CS). Thereafter VCU was performed in the same session. The results of conventional ee-CS and burst-CS were compared to VCU findings. RESULTS: Twenty-four refluxing systems were found in a total of 66 collecting systems by both techniques. Ee-CS and burst-CS detected VUR in four systems not seen by VCU (grades 1-4), but missed low-degree VUR in 2 cases. In low-degree VUR, burst-CS was particularly helpful in 9 patients with equivocal results on conventional ee-CS. In 6 of them, VUR was proven by burst-CS, the other 3 showed VURs neither on VCU nor on burst-CS. CONCLUSION: Levovist ee-CS is feasible in the pediatric bladder. It enables reliable visualization of VUR in the renal collecting system. Burst-CS improves visualization of contrast reflux, particularly in non-dilative or minimally dilative VUR, which is sometimes difficult to depict with conventional ee-CS.

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PubMed1985

Fetal acoustic stimulation testing: a retrospective experience with the fetal acoustic stimulation test.

The nonstress test is of accepted value in the surveillance of high-risk pregnancies. In order to improve the efficiency of testing, the authors retrospectively evaluated the adjunctive use of acoustic stimulation testing (FAS-TEST) in 1241 patients who underwent 3464 antepartum fetal heart rate tests. The results were compared to those in the previous 6 months during which time 1307 patients underwent 3573 nonstress tests. The frequency of nonreactive tests was 12.6% in the nonstress test group and 6.1% in those patients who underwent the FAS-TEST. The antepartum fetal death rates were not significantly different when the two groups were compared. The FAS-TEST decreases the percentage of nonreactive tests in a high-risk population and, as a consequence, may reduce the testing time.

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PubMedDate not supplied

[The prognostic value of the acoustic stimulation test for fetal wellbeing and neonatal status. Controlled acoustic stimulation of the fetus in the last pregnancy trimester].

Fetal heart frequencies and fetal movements were examined in 57 cases simultaneously by antepartal cardiotocogram and by mothers in the third trimenon of their pregnancy. 163 CTGs were monitored and two different groups defined. One group of 34 healthy newborns was compared with a group of 18 small for gestational age fetuses (birth weight less than 25th percentile of birth weight). The fetal heart rate and movements response to sound stimulation was studied. Fetuses appropriate for gestational age showed significantly higher activity in heart rate accelerations and movements following sound stimulation (1-2 kHz, 120 dB, 20 sec.) compared with the group of SGA fetuses. The study showed that the maternal perception of fetal activity is a suitably complementary method to assess fetal wellbeing. Measuring by maternal perception, it could be demonstrated that fetuses appropriate to gestational age reached a higher activity (16.5 p.c. monitoring period) as compared with 8.0 p.c. of fetal movements registered by mothers in the group of small for gestational age fetuses.

Acoustic Stimulation↗
PubMedDate not supplied

[Influence of the contralateral acoustic stimulation on the acoustic otoemissions: response modulation by the efferent olivocochlear system].

We have correlated in 16 patients (32 ears), the modifications de EOEs before and after sound stimulation of the contralateral ear. The recording of the EOEs has been performed in a sound proof room with ILO 88 from Otodynamics Ltd., the analysis has been made with the ILO 88 V.3.5 software. We have tried to study the modulator rol of the medial efferent coclear system on the external ciliated cells. In the results we observe a decrease of the amplitude in the EOEs when the contralateralmears is stimulated a white noise, in relation with the nonstimulation situation. When pures tones are used contralateral stimulation the decrease in the EOEs amplitude takes place in the same frequency spectrum as the pure tone used.

Acoustic Stimulation↗
PubMed1987

Fetal heart rate response to vibratory acoustic stimulation predicts fetal pH in labor.

Vibratory acoustic stimulation was performed during labor in 188 instances 60 seconds before fetal scalp puncture was done to determine fetal scalp blood pH. The fetal heart rate response was recorded for both vibratory acoustic stimulation and fetal scalp puncture. No instance of fetal acidosis occurred in the presence of an acceleration to either vibratory acoustic stimulation or fetal scalp puncture. Vibratory acoustic stimulation was more likely to elicit an acceleration than fetal scalp puncture in the nonacidotic fetus. Vibratory acoustic stimulation is less invasive and may be used in some instances in which fetal scalp blood puncture for pH determination is technically impossible.

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PubMed1998

Hypothalamic neurons preferentially respond to female nest coo stimulation: demonstration of direct acoustic stimulation of luteinizing hormone release.

Avian vocalizations are generally understood to play a pivotal role in reproductive functions. The role of the hypothalamus in gonadotropin release in higher vertebrates including birds is well established. To date, however, a direct linkage between the neuronal processing of vocal input and the contingent luteinizing hormone (LH) response has not been demonstrated. In this study, using female ring doves, we recorded neuronal activity from hypothalamic nuclei that, as we have shown previously, receive acoustic inputs from the auditory thalamic relay. Concurrently with recording single-unit responses to stimulation with species-specific coo vocalizations, we sampled LH levels in blood from the pituitary veins. LH concentration in the plasma was significantly elevated in birds hearing species-typical coos but not in birds exposed to experimentally altered coos or white noise or in birds that received no vocal stimulation. We found two types of neurons in the preoptic and anterior hypothalamus that selectively responded to the female nest coo: excitatory units and inhibitory units. Among the excitatory neurons are units characterized by two bursts separated by a period of slow spiking or complete silence, in a pattern approximately corresponding temporally to the two-note coo. We designate them as female-nest-coo-specific units. Most neurons in the posterior hypothalamus were nonselective in their response. Female nest coo and male nest coo stimulation evoked an equal magnitude of discharge changes from responsive units in the preoptic-anterior hypothalamic area. We found, however, that the LH increment was three times greater for birds hearing female nest coos than for birds hearing male nest coos. These observations suggest that feature-detecting neurons such as the female-nest-coo-specific units are involved in gonadotropin-releasing hormone output. The present findings are consistent with the well established behavioral evidence that female nest coos mediate ovarian growth.

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PubMed2005

Using fetal acoustic stimulation to shorten the biophysical profile.

PURPOSE: To determine whether fetal acoustic stimulation can decrease the time required to achieve a reassuring biophysical profile. METHODS: Patients scheduled for a biophysical profile were prospectively assigned to study and control groups. The study group received 3 seconds of acoustic stimulation if fetal breathing, tone, or movement were not present during the first 5 minutes of the study. The biophysical profile was completed in the standard fashion, for both groups. RESULTS: A total of 870 patients were enrolled (458 control, 412 with stimulation). The fetal acoustic stimulation group had decreased testing time (3 minutes) and fewer non-reassuring tests (5%). The fetal acoustic stimulation group had fewer studies without breathing, potentially reducing the need for further testing or intervention. CONCLUSIONS: Fetal acoustic stimulation can be used to decrease the biophysical profile testing time and to reduce the number of non-reassuring tests.

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PubMed1993

The effect of fetal acoustic stimulation on fetal swallowing and amniotic fluid index.

OBJECTIVE: To determine the effect of fetal acoustic stimulation on fetal swallowing and amniotic fluid (AF) index in an attempt to understand the potential mechanism for fetal compromise following fetal acoustic stimulation. METHODS: Fetal swallowing movements and AF index were assessed in 90 full-term fetuses before and after fetal acoustic stimulation. Fetal swallowing movements were identified on a video monitor and measured in terms of the percentage of time they occurred during 30 minutes of observation. The fetal heart rate was recorded 30 minutes before and 30 minutes after fetal acoustic stimulation. RESULTS: The mean (+/- standard deviation) percentage of time spent by the fetus in swallowing increased from 16.1 +/- 6% before to 44.3 +/- 10.3% after stimulation (P < .005). The AF index decreased from 14.6 +/- 8.4 cm before acoustic stimulation to 12.8 +/- 6.8 cm afterward (not statistically significant). Seven of 17 patients (41%) with borderline AF indexes developed oligohydramnios after the fetal acoustic stimulation; two of these demonstrated persistent variable decelerations that required obstetric intervention. CONCLUSIONS: Fetal acoustic stimulation is associated with increased fetal swallowing activity, which can lead to diminution of AF volume. The AF index should be assessed in fetuses before acoustic stimulation and if the volume is low, acoustic stimulation should be used with extreme caution.

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PubMed1997

A randomized controlled trial of a new fetal acoustic stimulation test for fetal well-being.

OBJECTIVES: Our purpose was to determine (1) whether a fetal acoustic stimulation test results in more palpable fetal movement compared with a mock test (control) and (2) whether palpated fetal movements after a fetal acoustic stimulation test are accompanied by a reactive nonstress test. STUDY DESIGN: In a randomized controlled trial we studied women seen in the labor and delivery suite for various indications. Women were excluded for multiple gestation, < 31 weeks' gestational age, treatment with magnesium sulfate or narcotics, or ruptured membranes. Informed consent was obtained from eligible women, who were then randomized to a test or control group. We placed an acoustic stimulator on the abdomen of each woman, but only the test group was stimulated. We assessed fetal movement by a grading system: 0 = no fetal movement felt by patient or tester, 1 = fetal movement felt by patient only, 2 = fetal movement felt by tester, 3 = visual movement seen by tester. A positive fetal acoustic stimulation test result was defined as one with any fetal movement felt or seen by the tester (grades 2 or 3). We then performed a nonstress test. We compared rates of a positive fetal acoustic stimulation test in the test and control groups with the chi 2 test. A p value < 0.05 was considered significant. RESULTS: We randomized 297 women to the test group and 280 women to the control (mock test) group. Of women tested with the fetal acoustic stimulation test. 81% had fetal movement by palpation or visualization (grades 2 or 3) compared with 19% of the control group (p < 0.0001, odds ratio 19.29, 95% confidence interval 12.42 to 30.07). Of the test group, 283 (95%) had a reactive nonstress test and 14 (5%) had nonreactive tests; the control group had 267 (95%) reactive and 13 (5%) nonreactive nonstress tests. Of 242 patients in the test group with a positive fetal acoustic stimulation test, 236 (98%) had a reactive nonstress test. Of those in the test group with fewer than three contractions per 10 minutes. 164 (89%) had a positive fetal acoustic stimulation test. Of these, 162 (99%) had a reactive nonstress test. CONCLUSION: The fetal acoustic stimulation test evokes significantly more palpated or visualized fetal movement than in controls. Palpated or visualized fetal movement after acoustic stimulation was almost always accompanied by a reactive nonstress test.

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PubMed1991

No evidence of hearing loss due to fetal acoustic stimulation test.

The fetal acoustic stimulation test is used increasingly for fetal assessment. To evaluate the possibility of acoustic trauma, 465 children who had been exposed to vibroacoustic stimulation in utero were screened at 4 years of age for high-frequency hearing loss. A hand-held audiometer with test tones at 25 dB for 1000 and 4000 Hz was used because responses at this level indicate hearing within normal limits for middle and high frequencies. Thirty-one children failed the test. Failure to respond was followed by inspection of the ear canal for wax, tympanometry, and reflex measurement to assess the tympanic membrane, middle ear, and eustachian tube. Hearing was retested across the full frequency range using conventional audiometric technique, and referral for otolaryngologic examination and treatment was made if necessary. The causes of hearing loss were impacted wax in 12, current or recent upper respiratory tract infection with eustachian tube dysfunction and middle ear effusion in 15, and unresolved middle ear effusion after treatment with antibiotics for otitis media in two. Profound bilateral sensorineural hearing loss of unknown origin was found in one and slight bilateral gently sloping hearing loss in another. Retesting of all children with conductive hearing loss indicated that hearing had returned to normal after treatment. None of the children showed evidence of hearing loss.

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PubMed2000

Facilitation of electric forepaw stimulation-induced somatosensory activation in rats by additional acoustic stimulation: an fMRI investigation.

The influence of scanner acoustic noise on somatosensory activation pattern in rat cortex was investigated by functional magnetic resonance imaging (fMRI) using the blood oxygenation level-dependent (BOLD) contrast. This was achieved by two approaches. The first approach was to compare a conventional, loud fMRI sequence with a new sequence, in which the noise level was reduced by about 30 dB. In the second approach, the inner ear of the animal was destroyed, resulting in deafness. We compared the activation patterns obtained with both sequences before and after cochleotomy. The activated area was larger when data were sampled with background noise, and was also larger before cochleotomy than after. Thus, facilitation of somatosensory activation is induced by additional acoustic stimulation. Magn Reson Med 44:317-321, 2000.

Acoustic Stimulation↗
PubMed1985

A mechanism for stimulated acoustic emissions in the cochlea.

Stimulated acoustic emissions in the cochlea are explained in terms of its hydraulic properties. The mathematical model predicts that these 'echoes' are caused by reflections which result from a discontinuity in the resistive and reactive components of the impedance which occurs at resonance. This discontinuity is a direct result of the wavelength-dependent nature of the fluid inertance and occurs without the consideration of non-linearities. Calculations of the time delay of tone bursts to and from the places of reflection by determination of the group velocity agree with observations of the response latencies for the frequencies concerned.

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PubMed1989

Preterm and term fetal cardiac and movement responses to vibratory acoustic stimulation.

To assess fetal response to vibratory acoustic stimulation, 24 preterm (group A; less than 36 weeks' gestation) and 30 term (group B; greater than or equal to 36 weeks' gestation) pregnancies were studied. Study variables were perceived fetal movement, fetal heart rate, and fetal heart rate pattern. Observer- and patient-perceived fetal movement responses were noted in most cases but were slightly more common in term patients (group A: + fetal movement, patient 87.5%/observer 87.5%) group B: + fetal movement, patient 96.7%/observer 90%). Baseline changes in fetal heart rate (greater than or equal to 10 beats/min) were observed in 46% of preterm fetuses and 70% of term fetuses. Tachycardia (fetal heart rate greater than 160 beats/min) was a common finding in both groups. In group A, tachycardia after vibratory acoustic stimulation persisted more than 1 minute in 29.2% and more than 5 minutes in 12.5% of patients. In group B tachycardia beyond 1 and 5 minutes was noted in 73.3% and 50% of patients, respectively. A significant shift to "awake" fetal heart rate patterns occurred in both groups; 29% to 79% was noted in group A (p less than 0.001) and 46.7% to 90% in group B (p less than 0.001). When vibratory acoustic stimulation was used, the high occurrence of increased baseline, tachycardia, and emergence of unusual fetal heart rate patterns must be recognized to adequately interpret fetal heart rate tracings.

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PubMed1992

Acoustic stimulation as a diagnostic test: comparison with oxytocin challenge test.

The usefulness of an acoustic stimulation test as a marker of fetal well-being was evaluated in a randomized controlled study of 121 pregnant women exhibiting a non-reactive fetal non-stress test at term. The women were randomly divided into two groups; those in the first group (n = 62) underwent an acoustic stimulation test immediately prior to an oxytocin challenge test, while those in the second (n = 59) underwent an oxytocin challenge test only. Fetal response to the acoustic stimulation was non-reactive in 22.5% of the women tested in the first group. The incidence of abnormal oxytocin challenge test among the women who were previously subjected to an acoustic stimulation was somewhat lower than among those who did not (14.5% vs. 23.7%), but the difference was not significant. In the prediction of an abnormal oxytocin challenge test, a non-reactive acoustic stimulation test had a sensitivity of 100%, a positive predictive value of 64% and a specificity of 91%. As a single test for the prediction of fetal distress in labor (n = 62), the acoustic stimulation test had a specificity and a positive predictive value similar to those of the oxytocin challenge test (n = 121), and its sensitivity was even higher (88% vs. 71%). We conclude that the acoustic stimulation test is at least as reliable as the oxytocin challenge test in the evaluation of fetal well-being in women exhibiting a non-reactive non-stress test at term.

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PubMed2000

[The use of photo-acoustic stimulation in dental practice].

Photo-acoustic stimulation provides a powerful stimulation of the central nervous system, whereas it relaxes the body. Authors found it useful to eliminate simple anxiety, and to reduce salivary secretion in the oral cavity. The combination of photo-acoustic stimulation with hypnotic techniques has been found as an excellent method to treat oro-facial psychogenic symptoms and denture intolerance. In the case of odonto-phobic patients, the combined method has been found less effective than hypnotic techniques alone.

Acoustic Stimulation↗
PubMed1995

Fetal acoustic stimulation, an adjunct to external cephalic version: a blinded, randomized crossover study.

OBJECTIVE: Our purpose was to determine whether fetal acoustic stimulation can improve the chance of successful external cephalic version in patients at 36 to 38 weeks' gestation with fetal midline spine position. STUDY DESIGN: A randomized, blinded crossover trial was performed. In this "N of 1" study, the patient served as her own control. RESULTS: Twenty-six patients were enrolled in the study, and three were excluded due to engagement of the fetal breech. In the initial trial with fetal acoustic stimulation to the maternal abdomen, 12 of 12 (100%) changed position to spine lateral and 11 of 12 (92%) were successfully verted. In the control group (fetal acoustic stimulation to nurse's arm), none of 11 (0%) changed position to spine lateral and one of 11 (9%) were successfully verted (p < 0.0001). In the crossover trial eight of 10 (80%) of the original placebo (control) patients were successfully verted after fetal acoustic stimulation to the maternal abdomen and none of 1 (0%) from the original treatment group were successfully verted after placebo fetal acoustic stimulation (p < 0.0001). Combined data from the original and crossover trials indicates 19 of 22 (86%) successful versions after fetal acoustic stimulation to maternal abdomen compared with one of 12 (8%) that had successful external cephalic version after placebo fetal acoustic stimulation. CONCLUSION: Fetal acoustic stimulation shifts fetal position to spine lateral, which increases successful version of fetuses with midline fetal spine presentations.

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PubMed1989

The effects of vibratory acoustic stimulation on baseline fetal heart rate in term pregnancy.

Fetal heart rate responses to vibratory acoustic stimulation have been studied in normal and complicated pregnancies. To determine the precise nature of these responses, we studied 50 normal term fetuses with 60 minutes of electronic antepartum fetal heart rate monitoring divided in two 30-minute segments separated by 3 seconds of vibratory acoustic stimulation. All tracings were analyzed by a programmed microcomputer. Comparison of grouped mean 30-minute values before and after vibratory acoustic stimulation showed significant increases in baseline fetal heart rate, fetal heart rate variation, frequency of accelerations exceeding 10 and 15 beats/min, duration of accelerations exceeding 15 beats/min, and frequency of decelerations after vibratory acoustic stimulation. Mean baseline fetal heart rate elevation greater than 10 beats/min occurred within 7.6 +/- 4.4 seconds in 42 of 50 fetuses and lasted for 596 +/- 531 seconds. Reactive tests increased from 35 (70%) to 47 (94%) after vibratory acoustic stimulation. Most healthy term fetuses exhibit fetal heart rate responses after differing in frequency or magnitude from spontaneous fetal heart rate changes. Vibratory acoustic stimulation may be a valid fetal assessment tool but cannot be considered the physiologic equivalent of nonstress testing.

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