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PubMed1995

Acoustic enhancement of electrically evoked otoacoustic emissions reflects basilar membrane tuning: a model.

A simple model for the acoustic enhancement of electrically evoked otoacoustic emissions (EEOEs) is presented in this paper. The model is based on the assumption that the enhancement is a result of the local interaction between the electrical current spreading in the scala media and the basilar membrane (BM) response to acoustic input. The analytical, steady-state response of the 1-dimensional linear cable to sinusoidal current injection is derived and is used to predict the current spreading in the cochlea. Acoustic enhancement at an emission generator is modeled as a magnitude change that is a sigmoid function of the local BM motion. The model results are in good agreement with the experimental findings and support our interpretation that the acoustic enhancement of EEOEs reflects BM tuning.

Acoustic Stimulation↗
PubMed1995

Middle latency responses to acoustical and electrical stimulation of the cochlea in cats.

The middle latency responses (MLR) to acoustical stimulation (A-MLR) as well as to electrical stimulation (E-MLR) of the inner ear were recorded in pentobarbital-anaesthetised cats. Monopolar and bipolar MLR recordings were performed with electrodes located at different places on the primary auditory cortex (AI). The cochlea was electrically stimulated (ES) through a single round-window electrode or through a multichannel intracochlear implant. The slope of amplitude-intensity functions of the A-MLR was steeper when the stimulus frequency of the acoustical stimuli corresponded to the tonotopical recording place on the auditory cortex. Other response properties (waveshape, thresholds and latencies) were related to the recording site and stimulus frequency in only two-thirds of animals. Parameters of E-MLRs evoked by high-frequency ( > 4 kHz) and low-intensity ES in hearing cats, which produced an electrophonic effect, were similar to parameters of acoustically evoked MLRs. In deafened cats, the properties of responses to extracochlear ES were different from those recorded to acoustical stimulation and they were almost uniform in all cortical places. Variations in thresholds, in latencies and in the slope of the amplitude-intensity functions of the E-MLRs recorded in individual tonotopical cortical places were observed when the auditory nerve was stimulated with different configurations of electrodes through a multichannel intracochlear implant.

Acoustic Stimulation↗
PubMedDate not supplied

Different behavioral and electrographic effects of acoustic stimulation and dibutyryl cyclic AMP injection into the inferior colliculus in normal and in genetically epilepsy-prone rats.

The behavioral and electrographic effects of acoustic stimulation (100 dB) and injection of dibutyryl cyclic AMP (cAMP, 10 nmol) into the inferior colliculus were studied in normal and genetically epilepsy-prone (GEPR-9) rats. Acoustic stimulations induced behavioral seizures only in GEPR-9 rats; the seizures were associated with electrographic epileptiform discharges recorded from the inferior colliculus. Injections of dibutyryl cAMP into the inferior colliculus caused wild running episodes resembling the initial phase of audiogenic seizures in both groups. However, in GEPR-9 rats these episodes progressed to significantly more severe seizures than in normal rats and the convulsions culminated into status epilepticus. During drug-induced seizures, epileptiform activity was present in the inferior colliculus in both groups. The seizure generalization latency was markedly shorter in GEPR-9 rats than in normals. Furthermore, in GEPR-9 rats, the seizure generalization latency was in the same range with either acoustic stimulation-induced or dibutyryl cAMP-induced seizures. The data suggest that the increased susceptibility of genetically epilepsy-prone rats to acoustic stimuli may be related to a malfunction of the cyclic AMP system within the inferior colliculus.

Acoustic Stimulation↗
PubMed2004

Voice acoustical measurement of the severity of major depression.

A number of empirical studies have documented the relationship between quantifiable and objective acoustical measures of voice and speech, and clinical subjective ratings of severity of Major Depression. To further explore this relationship, speech samples were extracted from videotape recordings of structured interviews made during the administration of the 17-item Hamilton Depression Rating Scale (HDRS; ). Pilot data were obtained from seven subjects (five males, two females) from videotapes that have been used to train expert raters on the administration and scoring of the HDRS. Several speech samples were isolated for each subject and processed to obtain the acoustic measurements. Acoustic measures were selected on the basis that they were correlated with HDRS ratings of symptom severity as seen under ideal voice recording conditions in previous studies. Our findings corroborate earlier reports that speaking rate is well correlated (negatively) with HDRS scores, with a strong correlation and nearly significant trend seen for the measure of pitch variability. A moderate pairwise correlation between percent pause time and HDRS score was also revealed, although this relationship was not statistically significant. The results from this cross-sectional study further demonstrate the ability of voice and speech signal analyses to objectively track severity of depression. In the present case, it is suggested that this relationship is robust enough to be found despite the less than ideal recording conditions and equipment used during the original videotape recording. Voice acoustical analyses may provide a powerful compliment to the standard clinical interview for depression. Use of such measures increases the range of techniques that are available to explore the neurobiological substrates of Major Depression, its treatment, and the dynamic interplay of the systems that govern the motor, cognitive, and emotional aspects of speech production.

Adult↗
PubMed2005

Immediate early gene expression following exposure to acoustic and visual components of courtship in zebra finches.

Sensory driven immediate early gene expression (IEG) has been a key tool to explore auditory perceptual areas in the avian brain. Most work on IEG expression in songbirds such as zebra finches has focused on playback of acoustic stimuli and its effect on auditory processing areas such as caudal medial mesopallium (CMM) caudal medial nidopallium (NCM). However, in a natural setting, the courtship displays of songbirds (including zebra finches) include visual as well as acoustic components. To determine whether the visual stimulus of a courting male modifies song-induced expression of the IEG ZENK in the auditory forebrain we exposed male and female zebra finches to acoustic (song) and visual (dancing) components of courtship. Birds were played digital movies with either combined audio and video, audio only, video only, or neither audio nor video (control). We found significantly increased levels of Zenk response in the auditory region CMM in the two treatment groups exposed to acoustic stimuli compared to the control group. The video only group had an intermediate response, suggesting potential effect of visual input on activity in these auditory brain regions. Finally, we unexpectedly found a lateralization of Zenk response that was independent of sex, brain region, or treatment condition, such that Zenk immunoreactivity was consistently higher in the left hemisphere than in the right and the majority of individual birds were left-hemisphere dominant.

Acoustic Stimulation↗
PubMed2004

Acoustic cell filter: a proven cell retention technology for perfusion of animal cell cultures.

This article is a review highlighting the application of the acoustic filter as a reliable cell retention device during the long-term perfusion of animal cell cultures. Critical operating parameters such as duty cycle, perfusion and re-circulation flow rates, acoustic power and backflush frequency are discussed with regard to influence on the separation efficiency and optimal operating ranges have been identified. Perfusion data gathered from the literature have been complemented with original data from a series of perfusion experiments carried out in the context of industrial projects for industrially relevant cell lines including NS0, HEK-293, SP2-derived hybridoma and insect cells in different serum-supplemented and serum-free media at different perfusion rates and acoustic chamber volumes. Finally, scale-up potential of the acoustic filter for large-scale industrial applications is discussed.

Acoustics↗
PubMed2005

Stress hormones in Ménière's disease and acoustic neuroma.

Stress has been postulated to trigger or contribute to inner ear pathologies but there is little objective evidence. We investigated stress hormones in Ménière's patients and patients with acoustic neuroma. Data were compared with those from a control group of patients with facial spasm. We assayed classic stress hormones including adrenocorticotropic hormone, cortisol, growth hormone and prolactin. We found a strong positive correlation between cortisol and adrenocorticotropic hormone in Ménière patients and patients with acoustic neuroma but no correlation in patients with facial spasm. The data also revealed in female patients with Ménière's disease or with acoustic neuroma an unexpected significant positive correlation between cortisol and prolactin. The data showed the expected negative correlation or no correlation between cortisol and prolactin associated with males and females in the other patient groups. Both cortisol and prolactin increases are known to represent alternative strategies to cope with stress, and our data point to prolactin being possibly more dominant in Ménière's disease and cortisol in acoustic neuroma. These data provide further evidence for modification of different stress hormones in audiovestibular pathologies, which might provide a valuable diagnostic or prognostic tool in the future.

Adrenocorticotropic Hormone↗
PubMed2006

Representation of acoustic signals in the human cochlea in presence of a cochlear implant electrode.

BACKGROUND: In subjects with remaining low frequency hearing, combined electric-acoustic stimulation (EAS) of the auditory system is a new therapeutic perspective. Intracochlear introduction of a cochlear implant electrode, however, may alter the biomechanical properties of the inner ear and thus affect perception of acoustic stimuli. STUDY DESIGN: Based on histological observations of morphologic changes after cochlear implantation in cadaveric and post mortem studies the effects of basilar membrane (BM) stiffening in the ascending basal and middle turns of the cochlea due to close contact of the BM with the electrode were simulated in a 3D-computational finite element model of the inner ear. To verify our simulated results, pre- and postoperative pure-tone audiograms of 13 subjects with substantial residual hearing, who underwent cochlear implantation, were evaluated. RESULTS: In the scenario of partial BM-fixation, acoustic energy of middle (2 kHz) and high (6 kHz) frequency was focused basally and apically to the fixed section, increasing BM displacement amplitudes up to 6 dB at a stimulation level of 94 dB (SPL). Lower frequencies were not affected by fixation in the basal and middle turn of the cochlea. In implanted subjects, a small but significant decrease of thresholds was observed at 1.5 kHz, a place in tonotopy adjacent to the tip region of the implanted electrode. CONCLUSION: Our model suggests that stiffening of the basilar membrane adjacent to an implanted electrode into the basal and middle cochlear turn did not affect BM movement in the low frequency area. Focussing of acoustic energy may increase perception in regions adjacent to the fixed section. Observations in implanted subjects were concordant with our model predictions. High frequencies, however, should not be amplified in patients using EAS to avoid disturbances in discrimination due to tonotopically incorrect frequency representation.

Acoustic Stimulation↗
PubMed2004

Effect of intranasal triamcinolone acetonide on bronchial hyper-responsiveness in children with seasonal allergic rhinitis and comparison of perceptional nasal obstruction with acoustic rhinometric assessment.

OBJECTIVE: Many patients with allergic rhinitis (AR) have bronchial hyper-responsiveness (BHR), and seasonal variation of BHR has been demonstrated in these patients. We aimed to investigate how BHR in children with seasonal AR is modified by triamcinolone acetonide aqueous nasal spray (TANS) therapy during the pollen season. A secondary aim was to assess the efficacy of TANS on nasal congestion by acoustic rhinometry and symptom scores. METHODS: A total of 34 children aged 7-18 years with grass pollen-induced AR and 18 age and sex-matched healthy controls were included in study. The patients were divided into the following two subgroups: 22 patients who had AR only; and 12 patients who had AR and asthma. All of them had a baseline BHR (PC20FEV1 methacholine < 8mg/ml). All patients received 220 microg TANS once daily for 4 weeks following a 1-week run-in period. Nasal patency was measured by acoustic rhinometry and patients recorded their nasal obstruction scores in a diary. RESULTS: There was no significant difference at baseline pulmonary function test parameters between the patients and the healthy control children. None of the control subjects had BHR. Asthmatic children with AR had significantly reduced baseline PC20FEV1 when compared with the AR only group [mean +/- S.E.M., (1.60 +/- 0.57 mg/ml versus 2.93 +/- 0.42 mg/ml, P = 0.021)]. The mean PC20FEV1 values increased slightly at the end of treatment in both group (from 1.60 +/- 0.57 mg/ml to 3.25 +/- 1.11 and from 2.93 +/- 0.42 mg/ml to 3.93 +/- 1.41 mg/ml), but the change was not statistically significant. TANS produced substantial symptomatic recovery in nasal obstruction according to patients' daily diary assessments, and significantly improved all objective acoustic rhinometry parameters. CONCLUSIONS: Once-daily intranasal TANS 220 microg effectively controlled nasal obstruction in children with seasonal AR according to subjective and objective assessments, and blocked the increase in BHR to methacholine after high-load natural pollen exposure. There was no correlation between patients' own subjective assessment of nasal obstruction and objective acoustic rhinometric assessment.

Administration, Intranasal↗
PubMed2005

Acoustic rhinometry in the objective evaluation of childhood septoplasties.

OBJECTIVE: The aim of this study was to evaluate results of septoplasty during childhood objectively with the help of acoustic rhinometry (AR). METHODS: Twenty-six children aged between 6 and 15 years who had septoplasty for nasal septal deviation during year 2002 were included in this study. Twenty-one patients who had no nasal septal deformities and nasal symptoms were included as control group. The study group was divided into two subgroups: Group 1 with only anterior septal deviation (8 patients) and Group 2 with both anterior and posterior septal deviations (18 patients). Acoustic rhinometry was performed one day preoperatively and 4 months postoperatively. Preoperative and postoperative minimal cross-sectional areas (MCSA), total volumes (TV), MCSA and TVs on pathologic side were compared. Acoustic rhinometry was performed 2 months interval in control group. Patients and parents were asked about the effectiveness of surgery subjectively. RESULTS: There was a statistical significance between preoperative and postoperative MCSAs of Groups 2 and 1+2. There was no statistical significance for Group 1. There was statistical significance between control group and Groups 1, 2, 1+2 in terms of MCSAs, MCSAs on pathologic side and TVs on pathologic side. There was statistical significance in terms of preoperative and postoperative MCSAs, TVs, MCSAs and TVs on pathologic side in patients with subjective well being postoperatively. There was no statistical significance in patients without any subjective postoperative improvement in terms of preoperative and postoperative MCSAs and MCSAs on pathologic side while TVs and TVs on pathologic side were statistically significant. CONCLUSIONS: Surgery is successful in children. But it should be restricted to only the pathologic area and should be conservative. Acoustic rhinometry is an objective method for the evaluation of nasal septal deformities and surgical success. Further studies are needed to see long-term success of septal surgery in children.

Adolescent↗
PubMed2005

Acoustic rhinometric measurements in children undergoing rapid maxillary expansion.

OBJECTIVE: To evaluate geometric changes of nasal cavities in children undergoing rapid maxillary expansion and to assess the effect of this procedure on nasal airway size by means of acoustic rhinometry. METHOD: We recruited 14 mouth-breather children (mean age 8.2 years) presenting constricted maxillary arches and scheduled for rapid maxillary expansion in the orthodontics department of our hospital. Clinical history did not reveal any allergic diseases and ENT examination was completely normal with a well-aligned nasal septum. Nasal measurements were obtained using acoustic rhinometry, which was performed before the expansion treatment and after 1-year follow-up. A postero-anterior radiograph of the skull was also performed in all patients for cephalometric analysis before and 3 months after the treatment. RESULTS: We observed a satisfactory increment in the transverse dimension of the maxilla in all patients but one who manifested a relapse after 4 months from the treatment and required a second procedure. Similarly, acoustic rhinometric measurements and cephalometric tracings showed a statistically significant increase respectively in decongested total nasal volumes (p=0.047) and in binasal cavity width (p=0.001). However, only eight children switched their respiration from oral to nasal breathing mode. CONCLUSIONS: Rapid maxillary expansion is an effective method for increasing the width of narrow maxillary vault and it is also associated with a significant increment in nasal volumes and in the transverse diameter of the maxilla. With regard to breathing posture, the role of this procedure still remains debatable. To date this is the first study aimed at analysing the effects of rapid maxillary expansion on nasal dimensions by means of acoustic rhinometry.

Airway Resistance↗
PubMedDate not supplied

Acoustic and perceptual characteristics of vowels produced during simultaneous communication.

UNLABELLED: This study investigated the acoustical and perceptual characteristics of vowels in speech produced during simultaneous communication (SC). Twelve normal hearing, experienced sign language users were recorded under SC and speech alone (SA) conditions speaking a set of sentences containing monosyllabic words designed for measurement of vowel duration, formant frequencies, and fundamental frequency in consonant-vowel-consonant (CVC) syllables and 60 listeners audited the speech samples. Although results indicated longer sentence and vowel durations for SC than SA, the data showed no difference in spectral characteristics of vowels produced during SC versus SA, indicating no degradation of vowel spectrum by rate alteration during SC. Further, no difference was found in listeners' ability to identify vowels produced during SC versus SA, indicating no degradation of vowel perceptual cues during SC. These conclusions are consistent with previous research indicating that temporal alterations produced by SC do not produce degradation of segmental acoustical characteristics of spoken English. LEARNING OUTCOMES: As a result of this activity, the participant will be able to (1) describe simultaneous communication; (2) explain the role of simultaneous communication in communication with children who are deaf; (3) describe vowel acoustics in English speech; (4) discuss methods of measuring vowel perception; (5) specify the acoustic characteristics of vowels produced during simultaneous communication; and (6) specify the ability of listeners to perceive vowels in speech produced during simultaneous communication.

Adult↗
PubMed2005

Acoustic-perceptual correlates of voice quality in elderly men and women.

UNLABELLED: Common perceptual characteristics of the elderly voice include hoarseness, breathiness, instability, and a change in the pitch of the voice. Although research is available concerning changes in the elderly voice, little research has been completed to examine the relationship between the perception of voice quality and acoustic measures. The purpose of this study was to examine the relationship between perceived breathiness and hoarseness and selected acoustic variables. The results of the study revealed significant age-related differences in fundamental frequency standard deviation, amplitude perturbation quotient, and noise-to-harmonic ratio. No significant difference in perceived hoarseness was found between the young and elderly speakers. However, the young women were perceived as significantly more breathy than the elderly women. Moderate correlations were found between the perceptions of hoarseness and breathiness and the acoustic measures. These findings are discussed relative to age-related laryngeal changes that may contribute to the perception of aging. LEARNING OUTCOMES: (1) To understand the perceptual attributes of the aging voice in men and women. (2) To understand the relation between the perception of voice quality and acoustic measures of voice production in the aging voice.

Adult↗
PubMed2006

Acoustic comparison of vowel sounds produced before and after orthognathic surgery for mandibular advancement.

PURPOSE: The effects of orthognathic surgery on the phonetic quality of speech were studied by analyzing the main acoustic features of vowel sounds. PATIENTS AND METHODS: Five men with dentofacial deformities undergoing surgical operation for correction of malocclusion were enrolled in the study. The speech material consisted of 8 vowels in sentence context. Every utterance was repeated 10 times in 3 different sessions: before the operation, 6 weeks after the operation, and 30 weeks after the operation. The acoustic features (F1, F2, F0, duration) of vowels were measured and analyzed. RESULTS: At the group level, no significant acoustic changes were found between the 3 different sessions in any parameter measured (all F values <1). The results show that the operation had individual and variable effects on vowel quality, ranging from slightly affected to completely unaffected. The 2 lowest vocal-tract resonances changed in frequency for 2 of the subjects, and 1 subject had short-term changes returning to the presurgical level. Significant changes of F0 were observed for 1 subject, and 3 of the subjects had short-term changes. No significant changes were found for duration. One subject had no significant changes in any parameter measured. CONCLUSIONS: No long-lasting perceptually significant changes were identified in vowel production in patients undergoing a variety of orthognathic procedures. The facial skeleton (consisting of palate, maxilla, mandible, dentition, nasal cavity, etc) imposes direct limits on the morphology of the resonating vocal tract cavities, and is therefore of immediate relevance to both speech articulation and acoustics.

Adult↗
PubMed2006

Detection of significant variation in acoustic output of an electromagnetic lithotriptor.

PURPOSE: We describe the observation of significant instability in the output of an electromagnetic lithotriptor. This instability had a form that was not detected by routine assessment, but rather was observed only by collecting many consecutive shock waves in nonstop regimen. MATERIALS AND METHODS: A Dornier DoLi-50 lithotriptor used exclusively for basic research was tested and approved by the regional technician. This assessment included hydrophone measures at select power levels with the collection of about 25 shock waves per setting. Subsequent laboratory characterization used a fiberoptic hydrophone and storage oscilloscope for data acquisition. Waveforms were collected nonstop for hundreds of pulses. RESULTS: Output was typically stable for greater than 1,000 shock waves but substantial fluctuations in acoustic pressures were also observed. For example, output at power level 3 (mean peak positive acoustic pressure +/- SD normally 44 +/- 2 MPa) increased dramatically to greater than 50 MPa or decreased significantly to approximately 30 MPa for hundreds of shock waves. The cause of instability was eventually traced to a faulty lithotriptor power supply. CONCLUSIONS: Instability in lithotriptor acoustic output can occur and it may not be detected by routine assessment. Collecting waveforms in a nonstop regimen dramatically increases sampling size, improving the detection of instability. Had the instability that we observed occurred during patient treatment, the energy delivered may well have exceeded the planned dose. Since the potential for adverse effects in lithotripsy increases as the dose is increased, it would be valuable to develop ways to better monitor the acoustic output of lithotriptors.

Acoustics↗
PubMed2005

Acoustic prediction of voice type in women with functional dysphonia.

The categorization of voice into quality type (ie, normal, breathy, hoarse, rough) is often a traditional part of the voice diagnostic. The goal of this study was to assess the contributions of various time and spectral-based acoustic measures to the categorization of voice type for a diverse sample of voices collected from both functionally dysphonic (breathy, hoarse, and rough) (n=83) and normal women (n=51). Before acoustic analyses, 12 judges rated all voice samples for voice quality type. Discriminant analysis, using the modal rating of voice type as the dependent variable, produced a 5-variable model (comprising time and spectral-based measures) that correctly classified voice type with 79.9% accuracy (74.6% classification accuracy on cross-validation). Voice type classification was achieved based on two significant discriminant functions, interpreted as reflecting measures related to "Phonatory Instability" and "F(0) Characteristics." A cepstrum-based measure (CPP/EXP ratio) consistently emerged as a significant factor in predicting voice type; however, variables such as shimmer (RMS dB) and a measure of low- vs. high-frequency spectral energy (the Discrete Fourier Transformation ratio) also added substantially to the accurate profiling and prediction of voice type. The results are interpreted and discussed with respect to the key acoustic characteristics that contributed to the identification of specific voice types, and the value of identifying a subset of time and spectral-based acoustic measures that appear sensitive to a perceptually diverse set of dysphonic voices.

Adult↗
PubMed2005

Adverse effects of environmental noise on acoustic voice quality measurements.

An accurate analysis of voice quality is imperative when using acoustic measurements to diagnose vocal pathologies. It is known that noise has a significant effect on the reliability and validity of acoustic voice measurements, but the precise relationship has not been established. The purpose of this study was to investigate the influence of noise on the accuracy, reliability, and validity of acoustic voice quality measurements while balancing for gender, age, intersubject and intrasubject variability, microphones, computer hardware, analysis software, and type of noise. Level of noise was precisely controlled. The specific focus of interest was to determine the critical levels of noise that can invalidate voice quality measurements and to generate practical recommendations. Results suggest that the recommended, acceptable, and unacceptable levels of noise in the acoustic environment are above 42 dB, above 30 dB, and below 30 dB signal-to-noise ratio, respectively.

Acoustics↗
PubMed2006

Functional analysis of voice using simultaneous high-speed imaging and acoustic recordings.

We present a comprehensive, functional analysis of clinical voice data derived from both high-speed digital imaging (HSDI) of the larynx and simultaneously acquired acoustic recordings. The goals of this study are to: (1) correlate dynamic characteristics of the vocal folds derived from direct laryngeal imaging with indirectly acquired acoustic measurements; (2) define the advantages of using a combined imaging/acoustic approach for the analysis of voice condition; and (3) identify new quantitative measures to evaluate the regularity of the vocal fold vibration and the complexity of the vocal output -- these measures will be key to successful diagnosis of vocal abnormalities. Image- and acoustic-based analyses are performed using an analytic phase plot approach previously introduced by our group (referred to as 'Nyquist' plot). Fast Fourier Transform (FFT) spectral analyses are performed on the same data for a comparison. Clinical HSDI and acoustic recordings from subjects having normal and specific voice pathologies, including muscular tension dysphonia (MTD) and recurrent respiratory papillomatosis (RRP) were analyzed using the Nyquist plot approach. The results of these analyses show that a combined imaging/acoustic analysis approach provides better characterization of the vibratory behavior of the vocal folds as it correlates with vocal output and pathology.

Humans↗