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Acoustic Stimulation (acoustic + stimulation)
Selected AbstractsCervical dystonia responsive to acoustic and galvanic vestibular stimulationMOVEMENT DISORDERS, Issue 9 2006Sally M. Rosengren BSc Abstract Abstract: We examined the effects of acoustic and galvanic vestibular stimulation in a patient with cervical dystonia. Acoustic stimulation consisted of three conditions: "baseline" (no stimulation), "vestibular" (500 Hz bone-conducted tone bursts), and "control" (5,000 Hz tone bursts). Rectified electromyographic activity in the sternocleidomastoid was measured. Galvanic stimulation (1.5,2.5 mA current steps) was delivered to the mastoids, and head acceleration was measured. Vestibular acoustic stimulation reduced neck muscle activity between 16% and 44% (P < 0.001), and galvanic stimulation reduced head acceleration by 22.5% (P = 0.028). The patient reported subjective improvement in head control. Vestibular stimulation can reduce neck muscle activity in cervical dystonia and give symptomatic relief. © 2006 Movement Disorder Society [source] Development of tinnitus-related neuronal hyperactivity through homeostatic plasticity after hearing loss: a computational modelEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2006Roland Schaette Tinnitus, the perception of a sound in the absence of acoustic stimulation, is often associated with hearing loss. Animal studies indicate that hearing loss through cochlear damage can lead to behavioral signs of tinnitus that are correlated with pathologically increased spontaneous firing rates, or hyperactivity, of neurons in the auditory pathway. Mechanisms that lead to the development of this hyperactivity, however, have remained unclear. We address this question by using a computational model of auditory nerve fibers and downstream auditory neurons. The key idea is that mean firing rates of these neurons are stabilized through a homeostatic plasticity mechanism. This homeostatic compensation can give rise to hyperactivity in the model neurons if the healthy ratio between mean and spontaneous firing rate of the auditory nerve is decreased, for example through a loss of outer hair cells or damage to hair cell stereocilia. Homeostasis can also amplify non-auditory inputs, which then contribute to hyperactivity. Our computational model predicts how appropriate additional acoustic stimulation can reverse the development of such hyperactivity, which could provide a new basis for treatment strategies. [source] Double stimulation of the inner ear organs of an anuran species (Alytes cisternasii) with simple tonal advertisement callsJOURNAL OF ZOOLOGY, Issue 4 2003J. Bosch Midwife toads present one of the simplest calls in anurans, with the whole energy concentrated in a single band without frequency modulation. The tuning curves of the Iberian midwife toads Alytes cisternasii show the typical bimodal pattern in anurans, with two best excitatory frequencies at 0.412 kHz (corresponding to the amphibian papilla) and at 1.358 kHz (corresponding to the basilar papilla and matching the male call frequency). In this study, the hypothesis that complex calls arose in anurans because they were inherently more attractive to females, since they provided greater acoustic stimulation, was tested. However, our results indicate that splitting the call energy to stimulate both inner ear organs simultaneously, the male call is not more attractive to female midwife toads, but sometimes renders it unattractive. The biological role of the amphibian papilla is discussed in ecological and evolutionary terms. [source] Cervical dystonia responsive to acoustic and galvanic vestibular stimulationMOVEMENT DISORDERS, Issue 9 2006Sally M. Rosengren BSc Abstract Abstract: We examined the effects of acoustic and galvanic vestibular stimulation in a patient with cervical dystonia. Acoustic stimulation consisted of three conditions: "baseline" (no stimulation), "vestibular" (500 Hz bone-conducted tone bursts), and "control" (5,000 Hz tone bursts). Rectified electromyographic activity in the sternocleidomastoid was measured. Galvanic stimulation (1.5,2.5 mA current steps) was delivered to the mastoids, and head acceleration was measured. Vestibular acoustic stimulation reduced neck muscle activity between 16% and 44% (P < 0.001), and galvanic stimulation reduced head acceleration by 22.5% (P = 0.028). The patient reported subjective improvement in head control. Vestibular stimulation can reduce neck muscle activity in cervical dystonia and give symptomatic relief. © 2006 Movement Disorder Society [source] Effect of acute acoustic stress on anorectal function and sensation in healthy humans,NEUROGASTROENTEROLOGY & MOTILITY, Issue 2 2005S. Gonlachanvit Abstract, Little is known about the effects of acute acoustic stress on anorectal function. To determine the effects of acute acoustic stress on anorectal function and sensation in healthy volunteers. Ten healthy volunteers (7 M, 3 F, mean age 34 ± 3 years) underwent anorectal manometry, testing of rectal compliance and sensation using a barostat with and without acute noise stress on separate days. Rectal perception was assessed using an ascending method of limits protocol and a 5-point Likert scale. Arousal and anxiety status were evaluated using a visual analogue scale. Acoustic stress significantly increased anxiety scores (P < 0.05). Rectal compliance was significantly decreased with acoustic stress compared with control (P < 0.000001). In addition, less intraballoon volume was needed to induce the sensation of severe urgency with acoustic stress (P < 0.05). Acoustic stress had no effect on hemodynamic parameters, anal sphincter pressure, threshold for first sensation, sensation of stool, or pain. Acute acoustic stimulation increased anxiety scores, decreased rectal compliance, and enhanced perception of severe urgency to balloon distention but did not affect anal sphincter pressure in healthy volunteers. These results may offer insight into the pathogenesis of stress-induced diarrhoea and faecal urgency. [source] Olivocochlear Activity and Temporary Threshold Shift-Susceptibility in HumansTHE LARYNGOSCOPE, Issue 11 2005W Wagner MD Abstract Study Objectives: Animal studies (guinea pig, cat, chinchilla) have shown that activity of the medial olivocochlear efferents can exert noise-protective effects on the cochlea. It is not yet known whether such effects are also existent in humans. Olivocochlear activity can be estimated indirectly by contralateral suppression (CS) of otoacoustic emissions (OAE). Material and Methods: We measured Input/Output functions of distortion products of OAE (DPOAE), with and without contralateral acoustic stimulation by white noise, in 94 normal hearing young male subjects. Seven stimuli with L2 between 20 and 60 dB SPL and L1 = 39 dB + 0.4 L2 ("scissor paradigm") were used at f2 = 2, 3, 4, 5, and 6 kHz. The measurement was repeated 2 weeks later. In 83 subjects of the same group, pure tone audiometry was registered before and 6 minutes after shooting exercises to evaluate individual susceptibility to develop a temporary threshold shift (TTS). Results: Test-retest repeatability of CS was generally good. CS averaged 0.98 dB SPL (SD 1.19 dB, median 0.56 dB). As expected, CS was greatest at low stimulus levels (median 1.06 dB at L2 = 20 dB, as compared with 0.33 dB at L2 = 60 dB). The smallest average CS was found at 4 kHz, and the greatest CS appeared at 2 kHz. A TTS occurred in 7 of 83 (8.5%) subjects. Statistical analysis did not reveal any correlation between the amount of CS and individual TTS susceptibility. Conclusions and Outlook: 1) Measurement of CS of DPOAE using an extensive measurement paradigm revealed good test-retest repeatability, confirming the reliability of this audiologic tool. 2) CS of DPOAE does not predict individual susceptibility to mild TTS induced by impulse noise in humans. Possible explanations for the missing association are discussed. Future perspectives include longitudinal studies to further elucidate the association between medial olivocochlear bundle-activity and permanent threshold shift in humans. The goal is to develop a diagnostic tool for the prediction of individual noise vulnerability in humans, thereby preventing noise-induced hearing loss. [source] Silent Functional Magnetic Resonance Imaging (fMRI) of Tonotopicity and Stimulus Intensity Coding in Human Primary Auditory Cortex,THE LARYNGOSCOPE, Issue 3 2004F. Zerrin Yetkin MD Abstract Objectives The aims of this study were to determine the feasibility of obtaining auditory cortex activation evoked by pure tones presented at threshold and suprathreshold hearing levels, to evaluate tonotopicity of the primary auditory cortex, and to determine the effect of stimulus intensity on auditory cortex activation using silent functional magnetic resonance imaging (fMRI). Methods Sixteen subjects with normal hearing underwent silent fMRI. An audiometer was used to deliver pure tones of 1,000, 2,000, and 4,000 Hz to the left ear. Two levels of acoustic stimulation were used: 1) threshold, hearing level determined in the scanner room and 2) suprathreshold, 70 dB hearing loss (HL). Tonotopicity and stimulus intensity coding was assessed on the basis of the location, extent, and amount of the auditory cortex activation. Results The localization of activation moved to more medial and posterior regions of the primary auditory cortex as the frequency of the pure tone increased. Compared with a threshold stimulus, a suprathreshold stimulus evoked the same regions with increased spatial extent. The average increase in the right auditory cortex activation in response to suprathreshold stimulus was 57% at 1,000, 51% at 2,000, and 45% at 4,000 Hz compared with that activated by the threshold stimulus. Conclusions Silent fMRI can be used to evaluate auditory cortex activation using low-intensity stimuli. The level of stimulus intensity increases the amount of auditory cortex activation and influences the fMRI mapping of the tonotopic organization of the primary auditory cortex. [source] Electric acoustic stimulation of the auditory system: experience and results of ten patients using MED-EL's M and FlexEAS electrodesCLINICAL OTOLARYNGOLOGY, Issue 3 2010A. Lee Clin. Otolaryngol. 2010, 35, 190,197 Objective:, To evaluate the hearing preservation rate and speech perception scores in patients with profound high frequency hearing loss and acoustically aidable low frequency hearing, managed with the MED-EL electric acoustic stimulation system referenced to the insertion depth of the electrode array. Study design:, Retrospective data analysis. Participants and setting:, Ten patients implanted at the Auditory Implant Centre, Guy's and St Thomas's Hospital, London, UK. Main outcome measures:, Pure tone audiometry, speech perception tests and electrode insertion depth angle. Results:, Postoperatively, functional hearing preservation allowing electric acoustic stimulation was achieved in eight patients and total preservation of residual hearing in five patients with follow-up periods of more than 12 months. Three of four (75%) patients with an insertion depth of >360° had a threshold shift of >25 dB, and all four patients had a threshold shift of >10 dB. All patients with total hearing preservation had the electrode inserted up to 360° at maximum. Overall, speech perception outcomes increased significantly and hearing impairment was significantly reduced after electric acoustic stimulation or electric stimulation alone as compared with the preoperative scores. Conclusion:, Electric acoustic stimulation provides significant benefit to individuals with profound high frequency hearing loss. Studies with larger number of patients are needed to establish the optimal electrode insertion angle as well as to further analyse the benefit of electric acoustic stimulation. [source] | |||||||||||||