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PubMed1989

Potentiation of acoustic startle by corticotropin-releasing factor (CRF) and by fear are both reversed by alpha-helical CRF (9-41).

A series of experiments were performed to investigate the effects of alpha-helical CRF [9-41] (AHCRF), a structural analogue and functional antagonist of corticotropin-releasing factor (CRF), on CRF- and fear-potentiated acoustic startle amplitude. Intracerebroventricular (ICV) administration of the CRF antagonist AHCRF reversed the potentiation of startle amplitude that was produced by ICV administration of CRF (1.0 micrograms). Doses of AHCRF that antagonized CRF-potentiated startle amplitude also reversed the potentiation of startle produced by conditioned "fear" but failed to lower startle baseline or antagonize strychnine-potentiated acoustic startle. These results suggest that CRF and "fear" may potentiate acoustic startle through overlapping neural substrates.

Acoustic Stimulation↗
PubMed2004

Transmission scanning acoustic imaging of human cortical bone and relation with the microstructure.

OBJECTIVE: To investigate and compare the spatial distribution of velocity with that of the microstructural properties (dimension of the haversian canal, percentage of porosity) on cross section of cortical bone. DESIGN: Experimental investigations permitted to quantify variation of acoustic properties related with that of the microstructural properties. BACKGROUND: Transmission ultrasonic techniques have been used in vitro and in vivo to assess the elastic and acoustic properties of Human bone, but few investigated the relationship between their variation with that of the microstructure. METHODS: Two scanning techniques (in transmission with a focused transducer at 5 MHz and an environmental scanning electronic microscope at 20 KV) enabled to obtain the spatial distribution of relative acoustic velocities and the microstructural properties (pore size and porosity). RESULTS: Increase of the velocities is related with the decrease of pore size and porosity. Around the periphery of the sections, the velocities were found to be significantly lower in the posterior side with a significant increase along the length. Radial variations are correlated to the spatial distribution of the microstructure where the endocortical region is more porous compared to the periosteal region. CONCLUSION: Significant alterations of the microstructural properties of the cortical bone reflect small variation of velocity suggesting that the velocities are not so sensitive to microstructural changes. RELEVANCE: These results are of importance for the clinicians and researchers to get a better understanding (advantages and limitation) of the use of ultrasound technique to assess material and structural properties of cortical bone. Our study suggested that velocity could be an index of porosity. Then it would be of interest to improve the clinical assessment of bone quality by describing bone both by a mineralization index and a microstructural index.

Acoustics↗
PubMed2006

Involvement of the human cerebellum in short-term and long-term habituation of the acoustic startle response: a serial PET study.

OBJECTIVE: Numerous studies have shown an involvement of the human cerebellum in motor learning, but little is known about the role of the cerebellum in learning of unspecific aversive reactions. The present study sought to distinguish which areas of the human cerebellum and brain-stem are involved in short-term habituation (STH) and long-term habituation (LTH) of the acoustic startle response. METHODS: On 5 consecutive days 42 acoustic startle stimuli were applied each day in 8 male healthy subjects. On the first and on the fifth day of the experiment [15O]H2O PET scans were performed. RESULTS: Electromyographic recordings revealed a significant decrease of the startle response within each day (STH) and across the 5 days of the experiment (LTH). On both days a decrease of regional cerebral blood flow (rCBF) across PET scans was found in the medial cerebellum most probably reflecting reduced sensory feedback during STH. Between days an increase of rCBF in the dorsomedial pons, in the mesencephalon and in an area of the medial cerebellum was observed. These activations may reflect increased inhibition of the startle response during LTH and correspond to previous animal lesion studies. Furthermore, during LTH an increase of rCBF within the lateral cerebellum in lobule HVI/Crus I was detected. CONCLUSIONS: These results suggest that distinct parts of the medial and lateral cerebellum are involved in habituation of the acoustic startle response. Lobule HVI/Crus I most likely plays a more general role in implicit learning processes considering its involvement in several conditioning paradigms. SIGNIFICANCE: The results of the present study contribute to the understanding of cerebellar involvement in learning of unspecific aversive reactions.

Acoustic Stimulation↗
PubMed2004

Acoustic rhinometry and its uses in rhinology and diagnosis of nasal obstruction.

Acoustic rhinometry is a tool that can aid in the assessment of nasal obstruction. The test is noninvasive, reliable, convenient, and easy to perform. Common clinical and practical uses of acoustic rhinometry for the rhinologic surgeon include assessment of"mixed" nasal blockage, documentation of nasal alar collapse, and preoperative planning for reduction rhinoplasty. Acoustic rhinometry can also be used to document the positive effect of surgery on nasal airway obstruction.

Airway Resistance↗
PubMed2006

Acoustic monitoring of a fluidized bed coating process.

The aim of the study was to investigate the potential of acoustic monitoring of a production scale fluidized bed coating process. The correlation between sensor signals and the estimated amount of film applied and percentage release, respectively, were investigated in coating potassium chloride (KCl) crystals with ethylcellulose (EC). Vibrations were measured with two different types of accelerometers. Different positions for placing the accelerometers and two different product containers were included in the study. Top spray coating of KCl was chosen as a 'worst case' scenario from a coating point perspective. The acoustic monitoring has the potential of summarising the commonly used means to monitor the coating process. The best partial least squares (PLS) regressions, obtained by the high frequency accelerometer, showed for the release a correlation coefficient of 0.92 and a root mean square error of prediction (RMSEP) of 5.84% (31-82.8%), and for the estimated amount of film applied a correlation coefficient of 0.95 and RMSEP of 0.52% (0.6-6%). The results of the preliminary investigation are considered promising. There is however a need for further investigations on sampling procedures and product characterisation before a final conclusion on the applicability of acoustic monitoring can be made.

Acceleration↗
PubMed2006

Acoustic and perceptual appraisal of speech production in pediatric cochlear implant users.

OBJECTIVE: The purpose of the present study was to examine the relationship between objectively measurable acoustic changes in speech production and subjective speech production accuracy and perceived intelligibility immediately following a disruption in auditory feedback normally provided to subjects from a cochlear implant. METHODS: Six children with profound sensorineural hearing loss participated in the study. Their task was to produce speech samples in two conditions: (1) with auditory feedback from their cochlear implants, and (2) without auditory feedback from their cochlear implants. Samples were subjected to both objective and subjective analyses. Objectively, measures were made of duration, fundamental frequency, and the first and second formants of the vowels. Subjectively, two groups of listeners, one familiar with the speech of children with hearing loss and the other unfamiliar, transcribed the productions and provided ratings of intelligibility. RESULTS: All the children in this study exhibited significant differences from the cochlear implant-on to the cochlear implant-off condition, although these changes were not always in the predicted direction, nor were they always perceptually salient. CONCLUSIONS: Consistent with previous studies, children in this investigation demonstrated variable acoustic voice and speech changes following deactivation of their cochlear implant device. Few of these acoustic changes affected speech intelligibility. The results of this study overall suggest that during the initial years following implantation children who are deaf rely to some extent on the auditory feedback provided by a cochlear implant to control and modify F0, duration, and vowel formant production.

Child↗
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↗
PubMed2004

Audiologic and treatment outcomes after linear accelerator-based stereotactic irradiation for acoustic neuroma.

PURPOSE: Although surgical excision is the traditional treatment modality for acoustic neuroma, radiotherapy (RT) is gaining momentum as an alternative. This is particularly evident in patients with useful hearing, in whom fractionated RT offers the potential for hearing preservation. Our objective was to determine the disease control, hearing preservation (via audiograms), and toxicity rates after linear accelerator-based stereotactic radiation for acoustic neuroma. METHODS AND MATERIALS: A total of 72 acoustic neuroma patients underwent stereotactic irradiation and had at least 6 months of follow-up between October 1997 and March 2002. Of these, 45 received single-fraction stereotactic radiosurgery (SRS) and 27 received fractionated stereotactic radiotherapy (SRT). Before treatment, all SRS patients were functionally deaf and 23 of 25 SRT patients had useful hearing in the affected ear. The minimal peripheral dose was 12 Gy and 45 Gy in all SRS and SRT patients, respectively. Tumor control, toxicity, and hearing preservation were recorded. RESULTS: The median follow-up in the SRS and SRT groups was 27 and 26 months, respectively. No tumor progression was seen after SRS and SRT. On the basis of the audiogram criteria, the 1-year and 2-year hearing preservation rate was 85% and 57%, respectively. The mean pre- and post-SRT speech recognition threshold was 20 and 38 dB, respectively. The mean proportion of pre- and post-SRT speech discrimination was 91% and 59%, respectively. CONCLUSION: Stereotactic RT achieves good local control, with acceptable toxicity. RT fractionation appears to provide encouraging rates of hearing preservation.

Adolescent↗
PubMed2004

Acoustic neuroma radiosurgery with marginal tumor doses of 12 to 13 Gy.

PURPOSE: To define tumor control and clinical outcomes of radiosurgery to marginal tumor doses of 12-13 Gy for unilateral acoustic neuroma patients. METHODS AND MATERIALS: Three hundred thirteen patients with previously untreated unilateral acoustic neuromas (vestibular schwannomas) underwent gamma knife radiosurgery between February 1991 and February 2001 with marginal tumor doses of 12-13 Gy (median, 13 Gy). Median follow-up was 24 months (maximum, 115 months; 36 patients with > or =60 months). Maximum doses were 20-26 Gy (median, 26 Gy), and treatment volumes were 0.04-21.4 mL (median, 1.1 mL). RESULTS: The actuarial 6-year clinical tumor control rate (no requirement for surgical intervention) for the entire series was 98.6 +/- 1.1%. Two patients required tumor resection; one had a complete resection for solid tumor growth and one required partial resection for an enlarging adjacent subarachnoid cyst. Six-year actuarial rates for preservation of facial nerve function, normal trigeminal nerve function, unchanged hearing level, and useful hearing were 100%, 95.6 +/- 1.8%, 70.3 +/- 5.8%, and 78.6 +/- 5.1%, respectively. The risk of developing trigeminal neuropathy correlated with increasing tumor volume (p = 0.038). CONCLUSIONS: Acoustic neuroma radiosurgery with doses of 12-13 Gy provides high rates of tumor control and cranial nerve preservation.

Adolescent↗
PubMed2004

Spatial distribution of acoustic and elastic properties of human femoral cortical bone.

The purpose of this study is to quantify the spatial distribution of acoustic velocities and elastic properties (elastic constants) on Human femoral cortical bone. Four cross sections (average thickness of 2.09+/-0.27 mm) have been cut transversally between 40% and 70% of the total length and between them parallelepiped samples in each quadrant have been cut. Ultrasonic technique in transmission with immersion focused transducers at 5 MHz and contact transducers 2.25 MHz were used on the cross sections and parallelepiped samples, respectively. The first technique allows relative spatial distribution of velocities to be obtained, meanwhile the second technique allows the direct assessment of elastic constants. For both techniques, bulk velocities were found to be lower at the posterior side with an increase along the length (from 40% to 70% total length) (p < 0.05). Densities and elastic constants show equivalent pattern of variation. These variations are mainly due the cortical porosity related to vascularisation environment. The spatial distribution of velocities exhibits significant radial variation from the endosteal to the periosteal region. This is in agreement with variation of the porosity at that location. Same range of velocities was obtained with both techniques. The range of longitudinal velocities values varies from 3548 to 3967 m/s and between 18.5 and 33.1 GPa for the bulk velocities and axial elastic constants, respectively. Our results are within the range with those found in the literature. However, it must be noted that the range of acoustic and elastic properties variation is concerning the same bone. So, our new results show the ability of the technique to quantify accurately local variation of acoustic and elastic properties (within the section and along the length) of human cortical bone. Furthermore, our immersion technique could be used to assess the spatial distribution of the elastic constants with the knowledge of spatial distribution of densities.

Acoustics↗
PubMed2006

Stuttering in adults: the acoustic startle response, temperamental traits, and biological factors.

UNLABELLED: The purpose of this study was to investigate the relation between stuttering and a range of variables of possible relevance, with the main focus on neuromuscular reactivity, and anxiety. The explorative analysis also included temperament, biochemical variables, heredity, preonset lesions, and altered auditory feedback (AAF). An increased level of neuromuscular reactivity in stuttering adults has previously been reported by [Guitar, B. (2003). Acoustic startle responses and temperament in individuals who stutter. Journal of Speech Language and Hearing Research, 46, 233-240], also indicating a link to anxiety and temperament. The present study included a large number of variables in order to enable analysis of subgroups and relations between variables. Totally 32 stuttering adults were compared with nonstuttering controls. The acoustic startle eyeblink response was used as a measure of neuromuscular reactivity. No significant group difference was found regarding startle, and startle was not significantly correlated with trait anxiety, stuttering severity, or AAF. Startle was mainly related to calcium and prolactin. The stuttering group had significantly higher scores for anxiety and childhood ADHD. Two subgroups of stuttering were found, with high versus low traits of childhood ADHD, characterized by indications of preonset lesions versus heredity for stuttering. The study does not support the view that excessive reactivity is a typical characteristic of stuttering. The increased anxiety is suggested to mainly be an effect of experiences of stuttering. LEARNING OUTCOMES: As a result of reading this article, the reader will be able to: (a) critically discuss the literature regarding stuttering in relation to acoustic startle, anxiety, and temperament; (b) describe the effect of calcium on neuromuscular reactivity; (c) discuss findings supporting the importance of early neurological incidents in some cases of stuttering, and the relation between such incidents and traits of ADHD or ADD; and (d) discuss the role of genetics in stuttering.

Acoustics↗
PubMed2006

Testing the protracted lexical restructuring hypothesis: the effects of position and acoustic-phonetic clarity on sensitivity to mispronunciations in children and adults.

Although developmental increases in the size of the position effect within a mispronunciation detection task have been interpreted as consistent with a view of the lexical restructuring process as protracted, the position effect itself might not be reliable. The current research examined the effects of position and clarity of acoustic-phonetic information on sensitivity to mispronounced onsets in 5- and 6-year-olds and adults. Both children and adults showed a position effect only when mispronunciations also differed in the amount of relevant acoustic-phonetic information. Adults' sensitivity to mispronounced second-syllable onsets also reflected the availability of acoustic-phonetic information. The implications of these findings are discussed in relation to the lexical restructuring hypothesis.

Acoustic Stimulation↗
PubMed2006

Frequency specific impairment of automatic pitch change detection by fMRI acoustic noise: an MEG study.

The loud acoustic noise produced by the magnetic resonance scanner is a major source of interference in auditory fMRI research. Whole-head magnetoencephalography (MEG) was used to investigate the interaction between the frequency range of auditory stimulation and fMRI acoustic noise. Pure tones and 3-harmonic complexes varying between 240 and 1240 Hz in frequency were presented while participants attended to a silent subtitled film. Continuous fMRI acoustic noise was presented during half of the blocks. The activity in six regions of interest was analyzed in 100-200 and 200-300 ms time windows to evaluate the magnetic counterparts of the mismatch negativity (MMN) and P3a brain responses. The results suggested that fMRI noise significantly reduced the amplitude of these responses. The effect of the noise on the automatic processing of the tones was more prominent for the tones with frequencies higher than 500 Hz. It is recommended that in the MMN protocols using continuous fMRI acquisition the sound stimuli should be spectrally separated from the fMRI scanner noise spectrum.

Acoustic Stimulation↗
PubMed2005

Metastatic lung cancer in the cerebellopontine angles mimicking bilateral acoustic neuroma.

Bilateral cerebellopontine angle (CPA) tumors identified on MRI are considered bilateral acoustic neuromas, the definitive diagnostic criterion of neurofibromatosis 2 (NF-2). We report the case of a 67-year-old man with progressive bilateral hearing loss, vertigo, and imbalance. MRI revealed bilateral enhancing CPA lesions, which were suggestive of acoustic neuromas and a diagnosis of NF-2. However, autopsy showed metastatic adenocarcinoma of the lung. Therefore, metastatic carcinoma to the CPA can mimic bilateral acoustic neuromas; imaging studies alone may be insufficient to diagnose NF-2.

Adenocarcinoma↗
PubMed2005

Facial nerve function after excision of large acoustic neuromas via the suboccipital retrosigmoid approach.

We review our results for facial nerve preservation in 105 patients with large acoustic neuromas (diameter 4.0 cm or larger) undergoing excision via the suboccipital retrosigmoid approach. Microneurosurgical techniques and facial nerve monitoring were used. Complete tumor removal was achieved in 91 cases (86.7%) and subtotal removal in 14 (13.3%). There were two postoperative deaths (1.9%). The facial nerve was preserved anatomically in 83 (79.1%) patients. Using the House-Brackmann grading system, facial nerve function was assessed immediately after surgery, at the time of discharge and 1 year after surgery. Excellent function (Grades I and II) was present in 41.0%, 41.8%, and 56.7% of patients at each time interval, respectively, with acceptable function (Grade I-IV) in 78.5% (68/87 cases) at follow-up assessment at one year. The suboccipital retrosigmoid approach resulted in good anatomical and functional preservation of the facial nerve during excision of large acoustic neuromas, with minimal other morbidity and low mortality. We recommend this approach for excision of large acoustic neuromas.

Adult↗
PubMed2004

Effects of transitory lingual nerve impairment on speech: an acoustic study of diphthong sounds.

PURPOSE: The effects of lingual nerve impairment on the phonetic quality of diphthongs were studied by analyzing changes in their main acoustic features when anesthetic was injected into the lingual nerve to partly block the normal neural feedback mechanisms in speech. PATIENTS AND METHODS: The speech material consisted of 8 diphthongs in word context produced by 7 male speakers. Every utterance was repeated 10 times using normal speech rate and intonation with and without the anesthesia (Ultracain D-Suprarenin, 0.8 mL; Aventis Pharma Deutscland GmpH, Frankfurt am Main, Germany). In addition, 1 male speaker with permanent nerve impairment was studied. The acoustic features (F1, F2, F0, and duration) were analyzed using Computerized Speech Laboratory (CSL 4300B; Kay Elemetrics, Lincoln Park, NJ). RESULTS: At the group level, no general significant acoustic changes were found between the 2 conditions. The changes were highly individual and variable across the subjects. Significant changes were observed for all the subjects, most prominently for the subject with permanent nerve impairment. CONCLUSIONS: According to the results, lingual nerve impairment has effects on the production of diphthongs. A comparison between monophthongs and diphthongs showed that the alterations are more significant for the diphthongs than for other vowels indicating the more demanding, complicated, and complex manner of articulation of diphthongs.

Adult↗
PubMed2006

Non-mineralized fibrocartilage shows the lowest elastic modulus in the rabbit supraspinatus tendon insertion: measurement with scanning acoustic microscopy.

The acoustic properties of rabbit supraspinatus tendon insertions were measured by scanning acoustic microscopy. After cutting parallel to the supraspinatus tendon fibers, specimens were fixed with 10% neutralized formalin, embedded in paraffin, and sectioned. Both the sound speed and the attenuation constant were measured at the insertion site. The 2-dimensional distribution of the sound speed and that of the attenuation constant were displayed with color-coded scales. The acoustic properties reflected both the histologic architecture and the collagen type. In the tendon proper and the non-mineralized fibrocartilage, the sound speed and attenuation constant gradually decreased as the predominant collagen type changed from I to II. In the mineralized fibrocartilage, they increased markedly with the mineralization of the fibrocartilaginous tissue. These results indicate that the non-mineralized fibrocartilage shows the lowest elastic modulus among 4 zones at the insertion site, which could be interpreted as an adaptation to various types of biomechanical stress.

Adaptation, Physiological↗
PubMed2004

Perceptual evaluation of voice quality and its correlation with acoustic measurements.

To determine whether a correlation exists between the Grade, Roughness, Breathiness, Aesthenia, Strain (GRBAS) scale (a subjective measure of voice) and the Multi-Dimensional Voice Program (MDVP) scale (an objective measure of voice). A retrospective review of 37 voice patients (12 male/25 female) was conducted. Each voice was perceptually evaluated using the GRBAS scale by an experienced speech pathologist and acoustically analyzed using the MDVP scale. Statistical analysis using a multivariate regression model identified a significant correlation between the noise-related parameters of MDVP and the components of the GRBAS scale. Grade correlated with voice turbulence index (VTI), noise harmonic ratio (NHR), and soft phonation index (SPI). Roughness correlated with NHR only. Breathiness correlated with SPI only. Aesthenia also correlated with SPI only. Of the 19 acoustic variables measured by the MDVP system, only three noise parameters significantly correlated with the GRBAS perceptual voice analysis. Perhaps "noise" is the perceived acoustical quality of the dysphonic voice. A voice quantifying measure such as a "voice index score" could be proposed using the GRBAS scoring and the three clinically relevant MDVP values following further studies.

Adult↗