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PubMed2001

[Psychoacoustic scaling of acoustic voice parameters by multicenter voice ratings].

BACKGROUND: The purpose of the study was to analyze if perceptual voice quality ratings of the well-known RBH rating procedure (a 4-point scale of roughness, breathiness, and hoarseness) covary with acoustical voice parameters. METHODS: 120 voice samples from subjects with healthy and hoarse voices were rated on the RBH-index in a multicenter study with 31 raters. Multivariate regression tree analysis classified the perceptual ratings as "gold standard". Voice samples were acoustically analyzed with a feature extraction method. Feedforward-networks were trained to selected acoustical parameters having highest "relative importance" in the regression trees. Based on the best classifier, a computer program consisting of 50 simultaneous working networks was developed. RESULTS: Mean probabilities for correct classifications were found at 0.65-0.85, implying a significance level over chance (0.25). Classifications of the program matched in 40% with a priori values in the categories roughness combined with breathiness, and in 65% in at least one domain. CONCLUSIONS: The new method described here provides a psychoacoustically based "objective" classification of hoarse voices, which seems to enable future analysis of new parameters (like GNE), which may even improve the present results.

Acoustics↗
PubMed2001

[Radiosurgery of recurrent acoustic neurinoma or: the elegant solution of a surgical problem?].

BACKGROUND: Stereotactic radiosurgery has proved to be an effective alternative to microsurgical resection in treatment of acoustic neuroma. Still, microsurgery is considered by many to be the therapy of choice. In case of recurrence microsurgical resection is much more difficult because of scarring and has a higher risk of complications. Therefore in cases of recurrence the role of radiosurgery needed to be evaluated. PATIENTS AND METHODS: From April 1992 to July 1997 135 patients suffering from acoustic neuroma were treated at the Neurosurgical Department of the University Medical School of Graz by means of the gamma-Knife. 12 patients had recurrence after a single or several microsurgical resections. The age distribution was between 38 and 71 years with a mean of 57 years. The diameter of the tumors varied between 10.5 and 31.2 mm. RESULTS: In all 12 cases the tumors could be inactivated biologically in a mean follow-up period of 58.8 months by means of stereotactic radiosurgery. Tumor shrinkage was achieved in 3 cases (25%), central necrotic areas were observed in 8 cases (67%). No additional cranial nerve palsies occurred. CONCLUSIONS: Stereotactic radiosurgery has proven to be a safe and effective treatment option instead of repeated microsurgery. Stereotactic radiosurgery should be considered as the therapy of choice in cases of recurrent acoustic neuromas.

Adult↗
PubMed2002

Determination of the modulus of elasticity of bone material by an acoustical approach at the forearm distinguishes women with and without vertebral fractures independent of bone mineral density.

The modulus of elasticity is a parameter characterizing fracture stability of bone independent of bone mineral density. Measurement of acoustical properties of the forearm by determination of the resonant frequency of the ulna in longitudinal direction as a function of sound transmission velocity after adjustment of the measuring result by ulna length yields information about the modulus of elasticity. It was the aim of this study to investigate whether this parameter may distinguish between subjects with and without vertebral fractures independent of bone mineral density. Fifty females (61.1 +/- 9.1 years) were enrolled into the study, 25 with, and 25 age-matched without prevalent osteoporotic vertebral fracture(s). Especially low bone mineral density was not considered an exclusion criteria for enrollment into the control group. Resonant frequency of the ulna multiplied by ulna length was significantly lower in the group with prevalent fractures (53.6 +/- 6.8 m/s versus 56.8 +/- 5.2 m/s) after adjustment for age and after additional adjustment for forearm bone mineral density. Linear regression analysis showed complete independence of the acoustical parameter from bone mineral density. This study demonstrates that the modulus of elasticity of bone material is an independent risk factor for osteoporotic fractures. Acoustical measurement at the forearm by analyzing the resonant frequency of the ulna and correcting it by ulna length as geometrical parameter is capable of determining the modulus of elasticity in vivo.

Acoustics↗
PubMed1995

Correlation of fetal heart rate decelerations following acoustic stimulation with perinatal outcome.

This was a retrospective study of acoustic stimulation response and perinatal outcome of 688 fetuses undergoing nonstress testing. Acoustic stimulation was performed within 7 days of delivery, and responses were classified based on the presence of an acceleration, deceleration, or both. Responses were correlated with perinatal outcome. Abnormal outcome was defined as: cesarean section for nonreassuring fetal heart rate patterns with an acidotic umbilical artery cord gas; delivery at less than 32 weeks for nonreassuring antenatal fetal testing; meconium aspiration syndrome or mechanical ventilation at 36 weeks or greater; neonatal seizures; 5-minute Apgar score less than 7; and stillbirth. Fetuses who demonstrated deceleration responses were significantly more likely to have abnormal perinatal outcomes when compared with those with acceleration responses (p < 0.001). Although combination acceleration-deceleration responses were more often associated with abnormal perinatal outcome when compared with pure acceleration responses, differences were not significant. A deceleration response following acoustic stimulation is associated with increased risk for adverse perinatal outcome and may merit further evaluation.

Acoustic Stimulation↗
PubMed1997

[Acoustic and mechanical properties of tympanic membrane transplants].

BACKGROUND: The human tympanic membrane has reasonably good sound transmission properties and withstands high static pressure loads. Destruction of the tympanic membrane resulting from middle ear diseases or trauma may be repaired by different types of grafts. Middle ear surgery mostly uses autologous temporal fascia, cartilage, or cartilage perichondrium transplants which differ in their acoustical characteristics and mechanical strength. METHODS: We have investigated the acoustical and mechanical properties of these materials and compared them with human tympanic membranes by constructing an ear canal-tympanic membrane model. Fresh human tympanic membrane, fascia, perichondrium, and cartilage preparations were exposed to static pressures up to 4 kPa and white noise sound pressure levels of 70 dB. The vibrational amplitudes and displacements due to static pressure were measured by laser Doppler vibrometry. RESULTS: The temporal fascia and perichondrium show similar amplitude frequency responses compared to the tympanic membrane for dynamic excitation. The displacement of these materials at static pressures above 4 kPa indicates a higher compliance than the tympanic membrane. The acoustical and mechanical properties of cartilage transplants are determined by the thickness of the slices. Thin cartilage slices are less stable although their frequency response is comparable to the intact tympanic membrane. Layer thickness above 500 microns result in a decrease of vibration amplitudes. CONCLUSIONS: Cartilage is an excellent transplant material which provides a better prognosis than soft materials in cases of ventilation disorders with long-term middle ear pressure problems. Large cartilage slice transplants should not exceed layer thickness of 500 microns in order to minimize transmission loss.

Acoustic Impedance Tests↗
PubMed1990

Effect of vibratory acoustic stimulation on the duration of fetal heart rate monitoring tests.

The ability of vibratory acoustic stimulation to shorten the duration of antepartum fetal heart rate monitoring was investigated by a randomized controlled trial. Vibratory acoustic stimulation did not shorten the overall duration of testing. This failure to improve the performance of antepartum monitoring appeared to result from prolonged accelerations, which complicated one third of the tests in which vibratory acoustic stimulation was employed. Further investigation is warranted using less profound methods of fetal stimulation.

Acoustic Stimulation↗
PubMed1986

[Magnetic resonance tomography in suspected acoustic neurinoma: technic and differential diagnosis].

Sixty-five patients with suspected acoustic neuromas were examined by CT and MR; the optimal diagnostic procedures are discussed. Extrameatal acoustic neuromas (11 cases) were all diagnosed by CT and MR, but only 82% of intrameatal tumours could be diagnosed by CT combined with air cisternography. Using special surface coils and the paramagnetic contrast medium Gd-DTPA, the accuracy of MR was 100%. All tumours greater than 4 mm were demonstrated. Following clinical and neurological examination, MR is the primary diagnostic method in the investigation of acoustic neuromas.

Diagnosis, Differential↗
PubMed1998

Long-term outcomes after radiosurgery for acoustic neuromas.

BACKGROUND: Stereotactic radiosurgery is the principal alternative to microsurgical resection for acoustic neuromas (vestibular schwannomas). The goals of radiosurgery are the long-term prevention of tumor growth, maintenance of neurologic function, and prevention of new neurologic deficits. Although acceptable short-term outcomes have been reported, long-term outcomes have not been well documented. METHODS: We evaluated 162 consecutive patients who underwent radiosurgery for acoustic neuromas between 1987 and 1992 by means of serial imaging tests, clinical evaluations, and a survey between 5 and 10 years after the procedure. The average dose of radiation to the tumor margin was 16 Gy, and the mean transverse diameter of the tumor was 22 mm (range, 8 to 39). Resection had been performed previously in 42 patients (26 percent); in 13 patients the tumor represented a recurrence of disease after a previous total resection. Facial function was normal in 76 percent of the patients before radiosurgery, and 20 percent had useful hearing. RESULTS: The rate of tumor control (with no resection required) was 98 percent. One hundred tumors (62 percent) became smaller, 53 (33 percent) remained unchanged in size, and 9 (6 percent) became slightly larger. Resection was performed in four patients (2 percent) within four years after radiosurgery. Normal facial function was preserved in 79 percent of the patients after five years (House-Brackmann grade 1), and normal trigeminal function was preserved in 73 percent. Fifty-one percent of the patients had no change in hearing ability. No new neurologic deficits appeared more than 28 months after radiosurgery. An outcomes questionnaire was returned by 115 patients (77 percent of the 149 patients still living). Fifty-four of these patients (47 percent) were employed at the time of radiosurgery, and 37 (69 percent) remained so. Radiosurgery was believed to have been successful by all 30 patients who had undergone surgery previously and by 81 (95 percent) of the 85 who had not. Thirty-six of the 115 patients (31 percent) described at least one complication, which resolved in 56 percent of those cases. CONCLUSIONS: Radiosurgery can provide long-term control of acoustic neuromas while preserving neurologic function.

Adult↗
PubMed2001

Normal standard curve for acoustic pharyngometry.

Pharyngeal size, compliance, and the dynamic behavior of the upper airway are important factors in the production of obstructive sleep apnea. Assessment of the upper airway for possible site(s) of obstruction is one of the keys to a successful management of the condition. Acoustic pharyngometry has the potential for localizing such sites, however, standardizing the operating technique and producing a standard normal curve is a prerequisite before exploring the potential of this equipment. A total number of 350 normal volunteers (271 males and 79 females) were examined by acoustic pharyngometry and a coefficient of variance of 5% to 7% was obtained from each of them. Mean and standard deviation of pharyngeal area at each point of X-axis (distance) was obtained and analyzed statistically to produce a general standard curve. Using special techniques during examination, the oropharyngeal junction and glottis were located, and thus a mapped acoustic pharyngogram was produced. Mean pharyngeal area was 3.194 cm(2) in males (SD 0.311) and 2.814 cm(2) in females (SD 0.331). Mean glottic area was 1.06 cm(2) in males (SD 0.119) and 0.936 cm(2) in females (SD 0.108). A minimal pharyngeal area is probably needed as a "golden standard" to evaluate patients with obstructive sleep apnea.

Acoustics↗
PubMed2002

Lung volume dependence of pharyngeal cross-sectional area by acoustic pharyngometry.

Pharyngeal size and the dynamic behavior of the pharynx may be important factors in the modulation of pharyngeal airflow. There are two measures of pharyngeal function: changes in pharyngeal area with lung volume and changes in pharyngeal area in response to externally applied positive pressure. Both measurements have been used for the assessment of pharyngeal function, and both reflect pharyngeal "floppiness." The aim of the present study was to examine the relationship between pharyngeal cross-sectional area, using acoustic reflection technique, and different lung volumes (tidal volume, inspiratory reserve volume, and expiratory reserve volume), to determine whether there are differences in mechanical properties of the pharynx of normal volunteers in response to changes in intrapharyngeal pressure. The acoustic technique was used to assess the pharyngeal cross-sectional area of 40 healthy volunteers (29 men and 11 women) at tidal volume, inspiratory reserve volume, and expiratory reserve volume. In men, the mean pharyngeal area at tidal volume was 3.191 cm2, the mean pharyngeal area at inspiratory reserve volume was 2.976 cm2, and the mean pharyngeal area at expiratory reserve volume was 2.975 cm2. In women, the corresponding pharyngeal area measurements were 2.832, 2.484, and 2.492 cm2. Statistical analysis of results showed that men have a larger pharyngeal cross-sectional area and the pharyngeal airways of men and women act in a similar manner in response to changes in intrapharyngeal pressure, with men having a greater change. Examination of the pharyngeal compliance by acoustic pharyngometry adds to the potential of this technique as a tool for the evaluation of the pharyngeal airway in terms of area and dynamic behavior assessment. This may be of relevance in promotion of the development of upper airway assessment in patients with obstructive sleep apnea.

Acoustics↗
PubMed2002

Hydroxyapatite cement cranioplasty in translabyrinthine acoustic neuroma surgery.

OBJECTIVES: Hydroxyapatite cement cranioplasty (HAC) after translabyrinthine resection of acoustic neuroma is a promising new technique for wound reconstruction. This study reviews the efficacy of HAC for the prevention of cerebrospinal fluid (CSF) leakage and the long-term wound outcomes of HAC versus abdominal fat graft (AFG) reconstruction. METHODS: This retrospective study of l08 consecutive acoustic neuromas operated on by Pittsburgh Ear Associates uses chart review, telephone interview, and mail questionnaire data. Fifty-four patients received AFG dural repair, and 54 patients received HAC. RESULTS: Seven AFG patients (12.5%) had CSF leaks versus 2 (3.7%) of the overall group of 54 HAC patients. However, none (0%) of the 47 HAC patients had CSF leakage with current HAC techniques. HAC also produced significantly less postauricular wound depression and superior cosmetic results in comparison with AFG. Although HAC patients experienced less postoperative discomfort, wound complications requiring medical or surgical intervention were extremely uncommon in both groups. CONCLUSION: HAC offers significant CSF leakage control and long-term cosmetic and comfort advantages over AFG alone. We recommend HAC as the standard closure technique for translabyrinthine acoustic neuroma surgery.

Abdomen↗
PubMed2002

Viral titers and delayed facial palsy after acoustic neuroma surgery.

OBJECTIVE: Delayed facial palsy (DFP) after acoustic neuroma surgery has been reported to occur in up to one third of cases. Reactivation of latent virus has been proposed as an etiology for DFP. However, only retrospective case reports and case series have offered data to support this theory. The objective of this study was to correlate DFP with change in viral titers. PATIENTS AND METHODS: Twenty consecutive patients who underwent acoustic neuroma surgery were prospectively evaluated for viral titers immediately preoperatively and at 3 weeks postoperatively. Viral titers measured included herpes simplex virus 1 (HSV-1), herpes simplex virus 2 (HSV-2), and varicella zoster virus (VZV) and included both IgG and IgM titers. The status of facial nerve function was documented preoperatively and throughout the postoperative period. Patients were categorized according to the presence or absence of DFP. RESULTS: Seven patients developed DFP after acoustic neuroma surgery, while the remaining 13 patients did not. There was no difference in preoperative and 3-week postoperative IgG titers for any of the 3 viruses tested. However, IgM titers were much higher postoperatively in DFP patients for all 3 viruses tested. The average HSV-1 IgM titer rose 92% in DFP patients compared with only 4.5% in the patients who did not develop DFP. Average HSV-2 IgM titers rose 70% compared with a decline of 8.5% in non-DFP patients. Most strikingly, VZV IgM titers rose an average 495% postoperatively among DFP patients compared with a decline of 14% in the non-DFP patients. CONCLUSION: Elevation of the IgM titers of the viruses measured in this study implies that recrudescence of the virus has occurred. The absence of this rise among patients who did not develop DFP implies that viral recrudescence plays a role in the etiology of DFP. These findings support treatment or prophylaxis of DFP with antiviral therapy.

Facial Paralysis↗
PubMed2003

Effects of vocal training on the acoustic parameters of the singing voice.

Vocal training (VT) has, in part, been associated with the distinctions in the physiological, acoustic, and perceptual parameters found in singers' voices versus the voices of nonsingers. This study provides information on the changes in the singing voice as a function of VT over time. Fourteen college voice majors (12 females and 2 males; age range, 17-20 years) were recorded while singing, once a semester, for four consecutive semesters. Acoustic measures included fundamental frequency (F0) and sound pressure level (SPL) of the 10% and 90% levels of the maximum phonational frequency range (MPFR), vibrato pulses per second, vibrato amplitude variation, and the presence of the singer's formant. Results indicated that VT had a significant effect on the MPFR. F0 and SPL of the 90% level of the MPFR and the 90-10% range increased significantly as VT progressed. However, no vibrato or singers' formant differences were detected as a function of training. This longitudinal study not only validates previous cross-sectional research, ie, that VT has a significant effect on the singing voice, but also it demonstrates that these effects can be acoustically detected by the fourth semester of college vocal training.

Acoustics↗
PubMed2000

Value of acoustic rhinometry in environmental medicine.

It is a weak point of environmental medicine that health disturbances, e.g. functional affections of the upper respiratory tract, cannot be objectively judged by physicians resp. researchers. In this study, the validity of acoustic rhinometry, a method giving information on cross-sectional areas of the upper airways by means of ultrasound probing, was tested in 40 volunteers seven times during one year. Furthermore, using a simplified model of the nose the accuracy of this method to measure the minimal cross-sectional area (MCA) in the nose was tested. The measurements were extremely confounded by the mode of connection to the nose (e.g. selected adapter, direction of application) and by the MCA in the nasal cavity. Statistical analyses showed a good reproducibility of measurements repeated within minutes, but suggested an intrapersonal variability over the analyzed examination phases due to apparatus independent factors. However, this variability could not be explained by influencing and confounding factors obtained by questionnaire, medical history, and physical examination. The test model showed little to great errors (1.5 to 568.5%) between the actual and the measured MCA, depending on the diameter. It is concluded that the method of acoustic rhinometry has to be standardized before it's value for environmental medicine can finally be judged. Further studies are necessary that should focus among others on factors influencing the variability of MCA and the effect of MCA on the measurement of the area behind the MCA. So far, the use of acoustic rhinometry for the evaluation of nasal function cannot be recommended.

Acoustics↗
PubMed2000

Contrast-enhanced magnetic resonance imaging of the cranial nerves in patients with acoustic schwannoma: correlation with surgical findings.

Eighteen patients with acoustic schwannoma were examined on a 1.5-T magnetic resonance imaging (MRI) unit with precontrast and postcontrast T1-weighted spin-echo sequences. Each abnormality was assessed in terms of the size, location, extensions and signal intensity of the lesions. If a nerve was enhanced and was involved by the tumor around the fundus of the internal auditory canal (IAC), the nerve was interpreted to be the originating nerve. The postcontrast T1-weighted images revealed enhanced masses of the cerebellopontine angle and/or the IAC in all cases. In 11 of the 19 operated patients with shwannomas, the site of tumor origin (or origin nerve) was confirmed by surgery. In 2 of the 11 cases (18%), surgical findings coincided with the T1-weighted image findings. Facial nerve enhancement on the ipsilateral side of the tumor was noted in 10 cases (53%) and the contralateral facial nerve enhancement was demonstrated in 7 (70%). The enhancement of facial nerve associated with acoustic schwannoma was not correlated to the degree of nerve compression by the tumor. These results demonstrate that it was possible, although infrequent, to predict the site of origin of acoustic schwannoma before surgery in some patients. Improvement of the imaging matrix or multiplanar reconstruction techniques with three-dimensional data acquisition may make it possible to overcome the limitations of MRI.

Adult↗
PubMed2000

Aerodynamic and acoustic parameters in CO2 laser posterior transverse cordotomy for bilateral vocal fold paralysis.

The aim of this prospective study was to analyse airway improvement and acoustic and aerodynamic parameters after CO2 laser posterior transverse cordotomy (LPTC) in bilateral vocal fold paralysis (BVFP). Four patients (2 males, 2 females) were recorded pre- and post-operatively at 1, 3, 6, 12 and 24 months. Forced inspiratory volume during the first second (FIV), vital capacity, peakflow, and forced expiratory volume during the first second (FEV) were measured with the Gould II spirometer. Acoustic frequency features (average fundamental frequency, standard deviation, jitter, shimmer and harmonic-to-noise ratio) and speech duration parameters (maximum phonation time, number of words read per minute, and number of words per breath) were measured. Aerodynamic parameters were measured with the Aerophone II. Three tasks were completed. Pneumo-phonatory parameters in "maximum sustained phonation" and in "comfortable phonation", and laryngeal aerodynamic parameters (intraoral air pressure, oral airflow and sound pressure level) were measured non-invasively. Glottal resistance and vocal efficiency were calculated. FIV increased significantly after LPTC (p = 0.01). Postoperatively, frequency features were undetectable by standard commercialized algorithms. Acoustic and aerodynamic parameters improved in the measures obtained at the 6th postoperative month. These results were stable 2 years postoperatively in all cases. We conclude that laryngeal aerodynamic parameters can be used objectively to follow patients longitudinally after LPTC.

Aged↗
PubMed2005

Quality of life after unilateral acoustic neuroma surgery via middle cranial fossa approach.

CONCLUSIONS: Patients with acoustic neuroma experienced reduced quality of life (QOL) after surgery. Individual factors did not have a significant effect on QOL. In the future, QOL should be a basic factor in the outcome evaluation of different therapeutic regimens in the treatment of acoustic neuroma. OBJECTIVE: To measure the QOL of patients who underwent unilateral acoustic neuroma surgery via the middle cranial fossa approach. MATERIAL AND METHODS: The Short Form-36 (SF-36) Health Survey and a self-designed disease-specific questionnaire were used during follow-up examinations to assess health-related QOL. The pure-tone average was used to specify hearing ability. Facial nerve function was described using the House-Brackmann grading system. A total of 28 male and 14 female patients who underwent surgery between 1997 and 2001 were included in the study. RESULTS: Patients' QOL scores revealed significant reductions in QOL in comparison to normative German QOL data. Gender, age, tumor size or location and clinical symptoms such as hearing loss and restricted facial nerve function did not have an effect on QOL. The SF-36 scales physical functioning, role functioning-physical, bodily pain, general health, social functioning and role functioning-emotional demonstrated significant QOL reductions.

Adult↗
PubMed1998

Towards an ecological audiology: stereophonic listening chamber and acoustic environmental tests.

An acoustic laboratory for reproduction of speech and acoustic environments is presented along with two sound field tests. Its design has been inspired by the LEDE (Living End Dead End) principle for construction of radio and music control rooms. The equipment and the 12 loudspeakers can simultaneously reproduce several stereophonic and monophonic recordings. The interesting feature is that the delayed first reflex in the LEDE room allows for a realistic perception of the recording room. A preliminary presentation of two newly developed tests for sound field listening is given. In DSIN. Directional Speech In Noise, the JFC (just follow conversation) threshold for continuous discourse is determined in 12 directions in quiet and in noise from +/- 60 degrees azimuth. In SEIT (Sound Environmental Identification Test), stereophonic acoustic environments are presented and the subject is asked to identify specific components and to characterize each environment as closely as possible. Results from tests with normal hearing subjects and examples of results with hearing impaired subjects are presented. The potential of the technique for use in aural rehabilitation, functional definition of auditory communication and quality assessment of hearing aids is discussed. It is pointed out that the term ecological audiology is suitable for describing the interaction between the communicating individual and the environment in a broad sense.

Acoustics↗

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