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PubMedDate not supplied

Voice acoustic patterns of patients diagnosed with vibroacoustic disease.

BACKGROUND: Long-term low frequency noise exposure (LFN) (< or = 500 Hz, including infrasound) may lead to the development of vibroacoustic disease (VAD), a systemic pathology characterized by the abnormal growth of extra-cellular matrices. The respiratory system is a target for LFN. Fibrosis of the respiratory tract epithelia was observed in VAD patients through biopsy, and confirmed in animal models exposed to LFN. Voice acoustic analysis can detect vocal fold variations of mass, tension, muscular and neural activity. Frequency perturbation (jitter), amplitude perturbation (shimmer) and harmonic-to-noise ratio (HNR) are used in the evaluation of the vocal function, and can be indicators of the presence and degree of severity of vocal pathology. Since the respiratory system is the energy source of the phonation process, this raises questions about the effects of VAD on voice production. The purpose of this study was to determine if voice acoustic parameters of VAD patients are different from normative data. METHODS: Nine individuals (5 males and 4 females) diagnosed with VAD were recorded performing spoken and sung tasks. The spoken tasks included sustaining vowels and fricatives. The sung tasks consisted of maximum phonational frequency range (MPFR). Voice acoustic parameters ana- lysed were: fundamental frequency (F0), jitter, shimmer, HNR and temporal measures. RESULTS: Compared with normative data, both males and females diagnosed with VAD exhibited increased F0, shimmer and HNR. Jitter, MPFR and one temporal measure were reduced. CONCLUSIONS: VAD individuals presented voice acoustic parameter differences in spectral, temporal and perturbation measures, which may be indicative of small morphological changes in the phonatory system.

Acoustics↗
PubMedDate not supplied

Acoustic neuroma.

The National Institutes of Health Consensus Development Conference on Acoustic Neuroma brought together neurosurgeons, radiosurgeons, otologists, neurologists, audiologists, otolaryngologists, and other health care professionals as well as the public to reach agreement (1) on defining the clinical types of acoustic neuroma, (2) on which procedures are useful for screening and diagnosis, (3) on the options available for managing the disorder as well as the complications of treatment, and (4) on the key clinical and biological areas for future research. Following 2 days of presentations by experts and discussion by the audience, a consensus panel weighed the evidence and prepared their consensus statement. Among their findings, the panel concluded that (1) the term vestibular schwannoma is preferred over acoustic neuroma as these tumors are composed of Schwann cells and typically involve the vestibular rather than the acoustic division of the 8th cranial nerve; (2) treatment for vestibular schwannoma must be individualized and requires an experienced, well-integrated, multidisciplinary team approach; (3) surgery remains the treatment of choice, but research is needed on the relative benefits and risks of all management options, including pharmaceutical and other alternative medical treatments such as tumor suppressing agents; (4) routine intraoperative monitoring of the facial nerve should be included in surgical therapy for vestibular schwannoma; (5) neurofibromatosis 2 (NF2) should be carefully considered in all patients newly diagnosed with vestibular schwannoma, and, when found, genetic evaluation and counseling should be provided for all relevant family members; and (6) a registry for all patients with vestibular schwannoma, whether undergoing observation or active management, should be established.

Forecasting↗
PubMed1991

[Evaluation of acoustic conditions in hospitals of provincial capital cities].

The hospital environment comprises various noise sources of high intensity and changeable character, creating a risk to health and general feeling of patients. Apart from traffic noise and from that caused by medical apparatus and sanitary installations, the acoustic climate of hospitals mainly depends on intrahospital nose. Acoustic conditions are most adverse during morning hours in operation rooms, intensive therapy, maternity and pediatric wards. Corridors belong among the most noisy premises in hospitals; they are a source of disturbances for ca. 64% of patients' rooms. Only 22% of patients' rooms. Only 22% of patients' rooms in morning hours and 47% in the afternoon display acoustic parameters complying with the norms. In as many as 21% of patients' rooms in the morning and in 13% of them in the afternoon, the noise exceeds 45 dB. Acoustic conditions in hospitals can be improved by complex activities aimed at limitation of external noise and at wider application of building-related preventive measures, as well as by reduction of the noise created by medical equipment and transport push-carts, and by changes in work organization and behaviour of the staff.

Acoustics↗
PubMed1991

Impedance tympanometry and acoustic reflectometry at myringotomy.

A total of 220 ears undergoing myringotomy and pressure-equalizing tube placement were studied with impedance tympanometry and acoustic reflectometry in a direct comparison for detection of middle-ear effusion. Impedance tympanometry and acoustic reflectometry were equally accurate, detecting the presence or absence of middle-ear effusion in 73% and 72% of ears, respectively. The presence of effusion in ears with tympanographic patterns other than type A and type B was not consistently and reliably predicted. The higher sensitivity of impedance tympanometry (90%) compared with that for acoustic reflectometry (58%) contrasted with the opposite findings for specificities (54% vs 88%). It is concluded that impedance tympanometry and acoustic reflectometry measure different events at the tympanic membrane and their utility lies in the fact that they complement each other. These instruments can aid the experienced otoscopist in confirming a clinical impression and assist the less experienced clinician in validating or improving otoscopic skills.

Acoustic Impedance Tests↗
PubMedDate not supplied

Acoustic discrimination of three types of infant cries.

The ability of acoustic characteristics, both separately and in linear combination with others, to differentiate among procedural pain-induced, hungry, and fussy crying was explored using audiorecordings of cries from healthy 2 to 4-month-old infants. Fussy cries were less tense than hungry or pain-induced cries and pain-induced cries had significantly stronger second formant amplitudes than fussy or hungry cries. Formants and tenseness were important contributors to a linear combination of acoustic measures, derived from discriminant function analysis, which correctly classified 74% of the procedural pain-induced crying specimens. The inability of this linear combination of acoustic measures to identify correctly approximately one-third of the cry specimens suggests that the discrete acoustic differences among the three situationally defined types of crying is not large.

Acoustics↗
PubMed1990

[Acoustic neurinoma in a child].

A case is reported of acoustic neurinoma unrelated to Von Recklinghausens' disease in a child. A 14-year-old boy had suddenly become aware of impaired hearing associated with tinnitus, in August, 1988. He was admitted to our department in October, 1988. On admission, he had no neurological deficits except for right tinnitus. Acoustic tumor was found on air CT and MRI. Total removal of the tumor was achieved through a suboccipital craniotomy. The tumor had originated in the superior vestibular nerve. The size of the tumor was about 1 X 2 cm. The histological diagnosis was neurinoma. The facial and cochlear nerves were anatomically preserved. Twenty-two reported cases of acoustic neurinoma in children less than 15 years of age were reviewed. Based on these reports, it was concluded that acoustic neurinoma may grow rapidly in children, and they should be diagnosed and treated at an early stage.

Adolescent↗
PubMed1989

An intrasubject comparison of electric and acoustic middle latency responses.

The middle components of the auditory evoked response (middle latency response, MLR) were evoked by acoustic clicks from the normal-hearing ear and by charge-balanced biphasic current pulses from the severe-to-profoundly hearing-impaired ears of patients undergoing labyrinthectomy for the management of intractable vertigo. A vertex-positive peak with a latency ranging from 27 msec to 38 msec (Pa) was characteristic of both the electric and the acoustic MLR. In subjects, the electric Pa always preceded the acoustic Pa in latency. In addition, the electric Pa had a sharper appearance than did the acoustic Pa. The electric MLRs were elicited by a range of stimulus intensities and persisted after the completion of labyrinthectomy.

Acoustic Stimulation↗
PubMed1989

[Ultrasonic tissue characterization of parotid tumors--analysis with the acoustic microscope].

The purpose of this study was to investigate acoustic properties of parotid tumors in detail by using the mechanically scanned acoustic microscope. The frequency of ultrasound was fixed at 200MHz. The amplitude images and the phase contrast images were taken in pictures. Mean attenuation, mean velocity, microscopic variation of the attenuation and that of the sound velocity were also measured and analyzed. The results are summarized as follows: 1) The acoustic properties of the tissue were optically displayed in the amplitude image and the phase contrast image. 2) The mean attenuation of malignant tumors was stronger than that of benign ones. 3) Microscopic variation of the attenuation was greater for malignant tumors than for benign ones. 4) No difference in velocity was found when malignant tumors and benign ones were compared as a whole, although the mean velocities are known to vary depending on the histological types. 5) The microscopic variation of the velocity was greater for malignant tumors than for benign ones. 6) Values of mean attenuation and mean velocity were strongly affected by the number of collagenous fiber. Microscopic variation of attenuation and that of velocity were affected by the arrangement of the tissue materials. 7) It is concluded that mean attenuation, mean velocity, microscopic variation of attenuation and that of velocity were useful parameters in investigating the acoustic properties of the tissue.

Acoustics↗
PubMed1988

[Changes in the compound action potential in patients with acoustic neuroma].

Thirty-eight patients with proven acoustic neuroma were divided into three groups: 13 patients with normal threshold on pure tone audiogram, 15 patients with a hearing loss of 40 dB-80 dB (HL) in the low and middle frequencies, and 10 totally or almost deaf patients. Results of the first two groups are reported, using intra-tympanic electrodes with alternating clicks of 90 dB (nHL) intensity and a stimulus rate of 20/s. A total of 500 sweeps were averaged. Widening of the CAP complex by a mean of 1.6 ms, compared to 1.1 ms in normal hearing subjects, was the most striking finding. Summation potentials (ratio of SP amplitude to CAP amplitude) were enlarged to 0.6, compared to 0.2 in healthy persons and 0.9 in patients suffering from Ménière's disease. CAP amplitudes as well as CM amplitudes were reduced to almost one-third of normal values. The most noticeable result was the loss of amplitude using very short interstimulus intervals. With a stimulus rate of 97/s amplitudes of acoustic neuroma patients were reduced by 49.9% - reduction in normal and Ménière patients was 41.6% and 41.3%. Acoustic neuroma patients show pathological inner ear potentials. Increased summation potentials are often found with Ménière patients, which are said to be caused by endolymphatic hydrops. For tumours of the acoustic nerve the hydrops theory does not seem likely; the loss of amplitude due to ++adaptation++ within the first neuron seems to point to mechanical reasons due to the pressure of the tumour itself.

Auditory Threshold↗
PubMed1988

Respiratory acoustical impedance: a new technique to measure airway response during bronchial inhalation challenges.

Respiratory acoustical impedance, a new method to measure airway obstruction during quiet breathing, was compared with plethysmography and spirometry in 19 asthmatics undergoing a bronchial inhalation challenge with an allergen. Respiratory acoustical impedance and plethysmography were both more sensitive than spirometry in detecting bronchoconstriction. Respiratory acoustical impedance is easily measured during quiet breathing, even in uncooperative subjects; forced expirations, which may alter bronchial tone, are avoided. Respiratory acoustical impedance is sensitive and reliable in measuring acute airway obstruction.

Acoustic Impedance Tests↗
PubMed1988

Uni-lateral hearing-loss with acoustic neuroma patients: electrocochleographic findings.

38 patients with proven acoustic neuroma were examined. Intratympanic electrocochleography was performed with alternating clicks of 90 dB (nHL) intensity and a stimulus rate of 20 per second; 500 sweeps were averaged. Widening of the Cochlear Action Potential (CAP)-complex by a mean of 1.6 ms was the most striking finding. Summating potentials (ratio of SP-amplitude to CAP-amplitude) were enlarged to 0.6, compared to 0.2 in healthy persons and 0.8 in patients suffering from Meniere's disease. The most noticeable result was the loss of amplitude using very short interstimulus intervals. With a stimulus-rate of 97 per second amplitudes of acoustic neuroma patients were reduced by 49.9%. Acoustic neuroma patients show pathological inner ear potentials. Some of the changes such as increased SP are found in patients with Meniere's disease, supposingly caused by endolymphatic hydrops. For tumours of the acoustic nerve the hydrops theory does not seem likely; the loss of amplitude due to adaptation within the first neuron seems to point to mechanical reasons due to the pressure of the tumour itself.

Audiometry, Evoked Response↗
PubMed1988

Effects of tracheal intubation on laryngeal acoustic waveforms.

To assess the feasibility of noninvasive detection of laryngeal injury after tracheal intubation through acoustic waveform measurements, we studied the effects of intubation on "time-expanded" acoustic waveforms of the larynx in 16 patients given general anesthesia, 9 with and 7 without tracheal intubation. Recordings of several utterances were obtained by means of a microphone and an accelerometer attached to the skin at the midpoint of the suprasternal notch. Recordings were taken the day before induction of general anesthesia, 20 minutes after extubation, and 2 and 4 days after extubation. Waveforms of the recordings were subsequently assessed visually for features different from those of normal phonation as determined in preliminary studies. Waveforms in several of the recordings taken soon after extubation showed marked intraperiod and interperiod irregularities. These abnormalities improved and disappeared over the following 4 days. No changes were observed in the acoustic waveforms of seven patients given general anesthesia without tracheal intubation. The analysis of time-expanded acoustic waveforms of the larynx indicates that this technique has considerable potential as a sensitive, noninvasive technique that helps to evaluate the effects of tracheal intubation on laryngeal function, a technique that warrants further study and evaluation.

Adult↗
PubMed1988

[Magnetic resonance imaging in the study of acoustic neurinoma].

Exploration of acoustic neurinoma, the most frequent benign tumor of posterior fossa, now includes magnetic resonance imaging, and an C.G.R. supraconductor apparatus (0.5 Tesla) has been in use since March 1986. This equipment provides high resolution frontal sections, not only of posterior fossa but of the two pontocerebellar angles and even the contents of the two IAC (thin, contiguous 4 mm sections in 256 x 256 matrix). A total of 43 patients were examined, 37 with surgically confirmed acoustic neurinoma and 2 with tumor recurrence. The neurinoma appears on the first echo as a hyposignal in relation to brain stem in sequences predominant in T1 and as a hypersignal in relation to peripontic CSF in sequences predominant in T2. Short sequences predominant in Tl (partial saturation or short ET and RT spin-echos) appear to be most effective for detection of acoustic neurinoma. Comparison of MRI and CT scan imaging showed that firstly, all cases detected by conventional scanography were correctly analyzed by MRI, with superiority for MRI for preoperative screening due to the frontal sections obtained without interference and, secondly, the non-invasive confirmation of diagnosis in doubtful or negative cases requiring computerized gaz meatocisternography. No false negative or false positive results were reported in our series or those documented in the literature using this new imaging technique, but high performance apparatus is necessary (thin sections ans powerful principal magnetic field of at least 0.5 resla). Improvements in this method could be obtained by the availability of more rapid programmes, the use of surface coils and the injection of paramagnetic substances (galodinium chelates) presently under study. NMR imaging is a reliable and non-invasive imaging method capable of replacing the scanner for study of acoustic neurinoma as soon as more apparatuses become available.

Humans↗
PubMed1987

Acoustic tumor in a young adult: documented growth rate.

The diagnosis of acoustic neuroma is being made more easily with the advent of late-generation, high-resolution computed tomography. It is known that acoustic tumor growth in the elderly is often slow. On the other hand, it is believed that an acoustic tumor can grow very rapidly in the young. A case of acoustic neuroma in a young man with computed tomographic evidence of extremely rapid growth over a period of fifteen months is presented.

Adult↗
PubMed1986

Reduction of acoustic annoyance in school dining halls.

The sound levels in dbA and the reverberation times in sec were measured in 18 school dining areas in and around Rennes. Of these, 12 had had acoustic treatment, 6 had not. The range of levels in all schools exceeded those recommended in the literature for the avoidance of noise-induced fatigue, while the reverberation times were acceptable (less than 0.8 sec) only in those spaces acoustically treated. There was a clear relation between sound level and reverberation times, but it was not directly proportional, as other parameters influenced sound level. Suggestions for acoustic treatment of surfaces were made, together with suggestions for treatment and placement of furniture and for compartmenting the interior space. An example was given of a large dining area (2,280 m3) in which the beneficial effects of acoustic treatment of ceiling and of walls separately was demonstrated, the sound level being reduced by 4-8 dbA. It was recommended that persons at all levels, from administrators to the children themselves become aware of the necessity to lower noise levels to facilitate relaxation and communication at meal time and to control noise to innocuous levels.

Acoustics↗
PubMed1986

An acoustic approach to diver navigation.

Three experiments were carried out to assess the capability of divers to localize acoustic signals underwater and to navigate by them. In the first experiment, divers attempted to determine the correct distance to several underwater transducers projecting acoustic stimuli on a horizontal plane. The second experiment consisted of two related studies where the diver/subjects attempted to discover which of many possible stimuli would produce the most robust perception of underwater "sound movement," or the Underwater Auditory Phi Phenomenon (UAPP). A third experiment consisted of navigational swims by divers; the acoustic stimuli utilized were based on those identified in prior experiments as the most preferred. The results demonstrated that divers are able to discriminate among signals emanating from acoustic sources at various distances underwater and to do so at levels well above chance. Second, divers judged 500-Hz square waves to be the signal which best facilitated an acceptable UAPP; thermal noise and 1-kHz square waves followed in that order. However, these differences were only slight and, in practice, divers maintained that the noise signal was the most useful. Third, it was found that divers apparently can effectively navigate by means of auditory signals alone--at least within certain limits. Finally, a significant decrease in the discrimination abilities of divers for frequencies above 6 kHz suggests that intensity cues may not be as robust as time-of-arrival information with respect to underwater sound localization.

Acoustic Stimulation↗
PubMed1986

[Origin of acoustic neuroma].

Acoustic neurinomas are vestibular schwannomas. Ultramicroscopic examination of the root of these tumors, removed using a petrosal approach (translabyrinthic, suprapetrosal) in 20 cases, investigated the site of origin of the schwannoma. Tumoral capsule was absent between Scarpa's ganglion cells and tumoral cells, these two types of cells being intermingled. The fact that the very small tumors, 3 to 5 mm in diameter, were all derived from Scarpa's ganglion and were separated by a capsule from the other structures of internal auditory canal prove that acoustic neurinoma arises from Scarpa's vestibular ganglion. Other studies have shown the absence of myelin surrounding bodies of Scarpa's ganglion cells in humans, inversely to findings in other vertebrates. Since on the one hand the appearance in humans is similar to that observed during development of Scarpa's ganglion in the rat, and on the other hand acoustic neurinoma has never been demonstrated in the animal, it can be suggested that acoustic neurinoma development in humans corresponds to cellular immaturity of Scarpa's ganglion.

Cranial Nerve Neoplasms↗
PubMed1985

Some acoustic evidence for vocal abuse in adult speakers with repaired cleft palate.

Acoustic evidence for vocal abuse in adult speakers with cleft palate and hypernasality has not been reported. This study was undertaken to determine if there was acoustic evidence of inappropriate vocal fold adduction during stop consonant production in this population. The results indicated that spectrograms of speakers without cleft palate and severe hypernasality exhibited acoustic characteristics different from spectrograms of speakers without cleft palate and speakers with cleft palate and mild hypernasality. Specifically, voiceless stop productions of severe hypernasal speakers resembled voiced stop productions. Their vocal folds were inappropriately adducted to provide a constriction inferior to the inadequately functioning velopharyngeal port to minimize the nasal air leak. The acoustic evidence supports the hypothesis that a cause of vocal abuse in the cleft palate population is due to compensatory laryngeal valving activities secondary to severe hypernasality.

Adolescent↗