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PubMed1996

[Acoustic trauma and development of endolymphatic hydrops among the personnel in the self defense forces].

An investigation was carried out among the military personnel in the Self Defense Forces to assess acoustic trauma in association with the onset of endolymphatic hydrops (ELH). Four hundred seventy servicemen were offered general physical examinations in an inpatient setting prior to their discharge from the SDF for mandatory age retirement. A questionnaire on the history of intense acoustic exposure and of dizzy spells was given to the same individuals. A routine ENT examination and audiography were performed for each of them. The following results were noteworthy: five men had a history of Ménière's disease, and 32.5 percent of those questioned had experienced dizzy spells. Hearing thresholds in those who reported that they had had dizzy spells were considerably higher than those who had not had such spells. Although a quantitative analysis as well as a well-established control study seems necessary to implicate acoustic trauma as one of the etiological factors of ELH, this study strongly suggests a relationship between acoustic trauma and development of ELH among the SDF personnel examined.

Endolymphatic Hydrops↗
PubMed2003

Lipochoristomas (lipomatous tumors) of the acoustic nerve.

CONTEXT: Lipochoristomas (lipomatous choristomas) are rare tumors of the acoustic nerve (cranial nerve VIII/vestibulocochlear nerve) within the internal acoustic canal and sometimes the cerebellopontine angle, and are histogenetically believed to be congenital malformations. Their clinically indolent behavior has recently prompted a more conservative management protocol in a quest for maximal nerve/hearing preservation. This approach contrasts sharply with that for the common internal acoustic canal/cerebellopontine angle tumors, the neuroepithelial neoplasms (acoustic schwannomas and meningiomas), which behave more aggressively and have more prominent clinical manifestations. Owing to their rarity, the clinicopathologic features of cranial nerve VIII lipochoristomas have been obtained mainly through case reports. OBJECTIVE: We present the clinicopathologic features of 11 cases of lipochoristomas of cranial nerve VIII. DESIGN: The 11 cases were documented between 1992 and 2003. We performed complete clinical reviews with histologic, histochemical, and immunohistochemical analyses of formalin-fixed, paraffin-embedded tumor samples. RESULTS: The patients were 8 men and 3 women with hearing loss of the right ear (5 patients) or the left ear (6 patients). No patient had bilateral tumors. All lipochoristomas histologically possessed mature adipose tissue admixed with varied amounts of mature fibrous tissue, tortuous thick-walled vessels, smooth muscle bundles, and skeletal muscle fibers, the latter verified with immunohistochemistry. CONCLUSIONS: The histomorphologic and immunophenotypic evidence showed that these tumors are better characterized as choristomas than as simple "lipomas," as they have been labeled in the past. Their overall nonaggressive clinical nature in addition to the characteristic radiologic and histomorphologic findings are important clinicopathologic features for the pathologist to recognize and differentiate, especially during frozen section evaluations, in order to direct the neurosurgeon to a more appropriate conservative therapeutic intervention.

Adult↗
PubMed2006

Acoustic techniques for assessing the Optison destruction threshold.

OBJECTIVE: The purpose of this study was to identify the pressure threshold for the destruction of Optison (octafluoropropane contrast agent; Amersham Health, Princeton, NJ) using a laboratory-assembled 3.5-MHz pulsed ultrasound system and a clinical diagnostic ultrasound scanner. METHODS: A 3.5-MHz focused transducer and a linear array with a center frequency of 6.9 MHz were positioned confocally and at 90 degrees to each other in a tank of deionized water. Suspensions of Optison (5-8x10(4) microbubbles/mL) were insonated with 2-cycle pulses from the 3.5-MHz transducer (peak rarefactional pressure, or Pr, from 0.0, or inactive, to 0.6 MPa) while being interrogated with fundamental B-mode imaging pulses (mechanical index, or MI,=0.04). Scattering received by the 3.5-MHz transducer or the linear array was quantified as mean backscattered intensity or mean digital intensity, respectively, and fit with exponential decay functions (Ae-kt+N, where A+N was the amplitude at time 0; N, background echogenicity; and k, decay constant). By analyzing the decay constants statistically, a pressure threshold for Optison destruction due to acoustically driven diffusion was identified. RESULTS: The decay constants determined from quantified 3.5-MHz radio frequency data and B-mode images were in good agreement. The peak rarefactional pressure threshold for Optison destruction due to acoustically driven diffusion at 3.5 MHz was 0.15 MPa (MI=0.08). Furthermore, the rate of Optison destruction increased with increasing 3.5-MHz exposure pressure output. CONCLUSIONS: Optison destruction was quantified with a laboratory-assembled 3.5-MHz ultrasound system and a clinical diagnostic ultrasound scanner. The pressure threshold for acoustically driven diffusion was identified, and 3 distinct mechanisms of ultrasound contrast agent destruction were observed with acoustic techniques.

Albumins↗
PubMed1999

Case report and discussion of hearing preservation after translabyrinthine excision of small acoustic tumors.

OBJECTIVE: Since 1991, three separate reports have shown how hearing may be salvaged after translabyrinthine excision of small acoustic tumors. The authors submit yet another report of a complete translabyrinthine excision of a 1.4-cm intracanalicular acoustic tumor with modest hearing preservation. An attempt is made to retrace the steps of the operation and recognize and discuss what particular events may have safeguarded the viability of the cochlea. With the availability of cochlear implantation, there should be added incentive to preserve the cochlear neurones if hair cells cannot be saved. STUDY DESIGN: The study design was a retrospective case review. SETTING: The study was conducted at a primary care hospital. INTERVENTION: Therapeutic and rehabilitative measures were performed. MAIN OUTCOME MEASURES: Hearing preservation was measured. CASE REPORT: A 55-year-old woman presented with a left-sided hearing loss and a 1.4-cm left acoustic tumor completely filling the internal auditory canal (speech reception threshold [SRT] 30 dB, discrimination [Pb] 28%). A successful translabyrinthine excision of the tumor was performed in November 1995. A 1-year postoperative audiogram showed a mixed hearing loss in the left ear with SRT 85 dB and Pb 0%. Average pure-tone threshold for 500 Hz, 1 kHz, and 3 kHz was 50 dB and aided SRT 40 dB with Pb 64%. Postoperative magnetic resonance imaging confirmed complete excision of the tumor. CONCLUSION: An exceptional case of hearing preservation after translabyrinthine excision of a small acoustic tumor illustrates how it may be possible to preserve cochlear hair cells and neurones simultaneously in certain selected cases. A review of the surgical events shows the value of sealing the cochlear duct with bone wax, selectively removing the vestibular nerves with the tumor by sharp dissection, and safeguarding the meatal segment of the anterior inferior cerebellar artery by a limited dural incision.

Cranial Nerve Neoplasms↗
PubMed1999

[Physiological-occupational assessment of acoustic load with equal energy but different time and informational characteristics].

The article deals with results of experimental study comparing effects of 4 types of acoustic load--noise (constant and impulse) and music (electronic symphonic one and rap)--on hearing sensitivity, processes in nervous system and subjective evaluation. All types of acoustic load were equal in energy (on evaluation according to equivalent level during the experiment). The study included 2 levels of load--90 and 95 dB. The differences revealed demonstrate importance of impulse parameters of noise and musical load for reactions of acoustic analyzer and central nervous system. The experiments show that evaluation of harm caused by temporary and impulse noises should be based not only on assessment of specific (hearing) function, but also on parameters of central nervous system state. The authors found that music of certain acoustic and informational parameters may harm hearing function.

Hearing Loss, Noise-Induced↗
PubMed2000

[Malignant peripheral nerve sheath tumor with divergent cartilage differentiation from the acoustic nerve: case report].

Malignant peripheral nerve sheath tumors(MPNSTs) of the acoustic nerve are very rare. Only seven cases of MPNST arising from the acoustic nerve have been reported. The authors present a case of MPNST with divergent cartilage and melanotic differentiation of the acoustic nerve. The patient was a 69 year old man admitted to our neurosurgical service in January 1999 complaining of left facial nerve palsy and hearing difficulty of his left ear. The initial CT showed a tumor at the left cerebellopontine angle region. On MRI the tumor was depicted as low intensity on T 1-weighted image and high intensity on T 2-weighted image, the mass was heterogeneously enhanced after administration of Gd-DTPA. The partial removal of the tumor was performed in January 1999. He was discharged February 1999. But he was admitted again because of progressive cerebellar ataxia. MRI showed the rapid regrowth of the residual tumor. In March 1999, complete removal of the tumor was performed. Histopathological analysis revealed a malignant spindle cell neoplasm with divergent cartilage and melanotic differentiation. We review the relevant literature concerning MPNST of the acoustic nerve and discuss the clinical features of malignant eighth cranial nerve tumor.

Aged↗
PubMed1975

Bilateral hearing loss as a sequel to unilateral acoustic trauma.

Within the framework of a study on the natural history of acoustic trauma, over 600 soldiers were examined. A higher rate of bilateral acoustic trauma was observed among soldiers with longer service. Comparison between unilateral and bilateral acoustic trauma showed a greater severity of damage in both ears of the latter group. Comparison of the progression of the damage in the same persons on two consecutive examinations suggested the same trend. It is suggested that bilateral acoustic trauma may be a later and more severe stage in some types of noise-induced damage.

Adult↗
PubMed2001

[Acoustic characteristics of resonance after cavity surgery on the ear and their usage in variants of reconstructive operations].

Acoustic measurements were made of the external and middle ear resonance in health and disease in patients after radical surgery on the ear and in chronic perforative otitis media. It is shown that the absence of the posterior wall of the acoustic meatus deteriorates hearing acuity in the frequency 4000 Hz. Reconstructive surgery of this wall normalizes acoustic resonance of the ear. The value of bone-air interval on pure tone audiogram is different after cavity operation and perforation of the tympanic membrane. Characteristics of acoustic resonance of the ear are decisive for choice of reconstructive surgery.

Audiometry, Pure-Tone↗
PubMed2004

Mechano-acoustic determination of Young's modulus of articular cartilage.

The compressive stiffness of an elastic material is traditionally characterized by its Young's modulus. Young's modulus of articular cartilage can be directly measured using unconfined compression geometry by assuming the cartilage to be homogeneous and isotropic. In isotropic materials, Young's modulus can also be determined acoustically by the measurement of sound speed and density of the material. In the present study, acoustic and mechanical techniques, feasible for in vivo measurements, were investigated to quantify the static and dynamic compressive stiffness of bovine articular cartilage in situ. Ultrasound reflection from the cartilage surface, as well as the dynamic modulus were determined with the recently developed ultrasound indentation instrument and compared with the reference mechanical and ultrasound speed measurements in unconfined compression (n=72). In addition, the applicability of manual creep measurements with the ultrasound indentation instrument was evaluated both experimentally and numerically. Our experimental results indicated that the sound speed could predict 47% and 53% of the variation in the Young's modulus and dynamic modulus of cartilage, respectively. The dynamic modulus, as determined manually with the ultrasound indentation instrument, showed significant linear correlations with the reference Young's modulus (r(2)=0.445, p<0.01, n=70) and dynamic modulus (r(2)=0.779, p<0.01, n=70) of the cartilage. Numerical analyses indicated that the creep measurements, conducted manually with the ultrasound indentation instrument, were sensitive to changes in Young's modulus and permeability of the tissue, and were significantly influenced by the tissue thickness. We conclude that acoustic parameters, i.e. ultrasound speed and reflection, are indicative to the intrinsic mechanical properties of the articular cartilage. Ultrasound indentation instrument, when further developed, provides an applicable tool for the in vivo detection of cartilage mechano-acoustic properties. These techniques could promote the diagnostics of osteoarthrosis.

Animals↗
PubMed2004

Evaluation of various therapeutic schemes in the treatment of tinnitus due to acute acoustic trauma.

OBJECTIVES: We evaluated the effectiveness of various pharmaceutical therapeutic schemes in the treatment of tinnitus due to acute acoustic trauma. PATIENTS AND METHODS: This prospective study included 108 military personnel (all males; mean age 22 years; range 18 to 31 years) with complaints of tinnitus due to acute acoustic trauma following firearm use. Involvement was in the left ear in 61 patients, the right ear in nine patients, and in both ears in 38 patients. The mean duration from trauma to treatment was 26 days (range 1 to 110 days). Before and after treatment, complaints of tinnitus were evaluated using a questionnaire and a visual analog scale. Treatment was carried out for 15 days in four randomized groups: oral administration of trimetazidine, prednisolone, and vitamin B complex; trimetazidine alone; prednisolone and vitamin B complex; and intravenous piracetam and prednisolone. Unresponsive patients were further treated with trimetazidine for a month. Evaluations were made 15 days and 45 days after the institution of treatment. RESULTS: Thirteen patients (12%) had complete remission and 28 patients (25.9%) showed significant improvement. Further treatment with trimetazidine was beneficial in only seven (9.5%) patients. No significant differences were found between the groups in terms of tinnitus remission and improvement in hearing (p>0.05). Initiation of treatment, especially within the first week following acoustic trauma was significantly linked with higher rates of tinnitus regression (p<0.05). The degree of hearing improvement after medication did not correlate with improvement in tinnitus. Intravenous treatment was not advantageous over oral treatment. CONCLUSION: A timely initiation of therapy, especially within the first week following acoustic trauma, increases the chance of improvement in tinnitus patients.

Administration, Oral↗
PubMed2005

[Horizontal glottectomy--oncological and functional results. Part II. Morphology of the glottis and perceptive-acoustics characteristic of the voice and speech after horizontal glottectomy].

INTRODUCTION: The authors showed findings concerning glottis morphology and perceptual-acoustic characteristics of voice and speech after partial classical (PCGLg) and extended glottic partial laryngectomy (PEGLg). MATERIAL AND METHODS: 10 patients (9 M., 1 F. average age 56 (min. 47 max. 65) were examined. All patients were undergone glottic partial laryngectomy: a) classical (n = 5) b) extended of vocal process (n = 3) with (n = 2) or without (n = 1) the removal of the mucous false folds, c) extended of part of arytenoid cartilage with (n = 2) or without (n = 1) the removal of the mucous of the false folds. The following examinations were executed: phoniatric, videolaryngoscopic and perceptual-acoustic analysis. RESULTS: After PCGLg and one extended of vocal process, voice and speech has mostly characterized of features of hypofunction dysphonia. Hyperfunction was found in patients after removal of the mucous of the false folds due to leucoplakia. In case of removing of a part of arythenoid cartilage the notable or entire standstill or lack of full phonatory closure were found. The phonetical-acoustic analysis showed that in patients using melodious voice, the character of the source of actuating was periodically-noise, with the component of noise in all range of the course of the acoustic signal of voice. The parameters such as F0, jitter, shimmer does not make coherent conclusions and are less useful in the assessment of the quality of voice. CONCLUSIONS: In case of the resection of the part of the arythenoid cartilage during glottis laryngectomy, we take into account lack of full phonatory closure and using whisper by the patients. Obtaining the reliable conclusions needs continuations of the investigations and increasing number of patients. These researches are in progress.

Aged↗
PubMed2005

[The analysis of brainstem acoustic evoked potentials in diphtheritic polyneuropathy].

The possibility of central and peripheral impairment of the acoustic analyser was studied in 18 patients with severe diphtheritic polyneuropathy (DP) using brainstem acoustic evoked potentials (BAEPs). The acoustic nerve impairment was found in 27.8%, the central abnormalities--in 44.4%. All the patients with CNS impairment suffered from chronic alcoholism. The data obtained have been compared to those of 26 patients with chronic alcoholism. In this group, peripheral polyneuropathy was confirmed in 76.9% cases; BAEPs revealed isolated involvement of the peripheral part of the acoustic nerve in 7.7% and CNS impairment was found in 84.6% patients. The results of the study suggest that diphtheritic toxin is not implicated in CNS lesions. Central changes found in the BAEPs analysis were related to chronic alcohol intake and did not aggravate diphtheria course.

Adult↗
PubMed1998

Quality of life following acoustic neuroma surgery.

In the treatment of acoustic neuroma, operative results have improved greatly during recent years, with high rates of functional cranial nerve preservation. Because of this, it has become more important to consider issues of patient satisfaction and quality of life (QOL) following treatment for these lesions. The authors have developed a novel questionnaire designed to measure QOL in patients with acoustic neuromas, and they administered it to 50 consecutive patients at least 6 months after acoustic neuroma surgery. Overall QOL was judged to be good but with definite minor difficulties, including some problems with hearing, facial nerve function, headache, tinnitus, dizziness, activity level, enjoyment of life, and emotional well-being. No significant differences were found between age groups and different operative approaches, and only minor differences were found in relation to tumor size. Patients with intracanalicular tumors fared no better than those with cerebellopontine angle tumors. Analysis of the data suggests an overall good outcome from acoustic neuroma surgery; however, when discussing the possible effects on postoperative QOL, even the potential minor problems should not be minimized, especially in patients undergoing operation for small or intracanalicular tumors.

Journal Article↗
PubMed1991

[Structure and dynamics of photo-acoustic shock-waves in 193 nm excimer laser photo-ablation of the cornea].

The structure and dynamics of acoustic shock waves generated with a 193-nm ArF-excimer laser pulse (20 ns) in corneal photoablation were investigated using piezoelectric transducers (PVDF foily). The shock waves passed through the cornea at the speed of sound (1630 +/- 120 m/s). The duration of the acoustic half-value thickness was approximately 60 ns. At clinically relevant laser energy densities (200 mJ/cm2) the amplitude of the shock-waves was 80 bar. At higher energy densities (500 mJ/cm2) the amplitude reaches 150 bar. When laser pulses were applied with a spot size of 100 microns the amplitude of the acoustic transient decreased inversely with the distance to the interaction zone. At large beam diameters (4 mm), however, even at a distance of 3 mm from the interaction zone no significant decrease of the shock-wave amplitude could be found. It is assumed that the mechanical stress involved in laser-induced acoustic shock-waves may be the cause of cellular alterations and the structural damage to adjacent collagen layers leading to the onset of postoperative scar formation.

Animals↗
PubMed1994

[Vasoactivity of human nasal mucosa in response to sensory neurotransmitters (a study of nasal geometrical change with acoustic rhinometry)].

Intranasal blood flow is regulated not only by autonomic but also by sensory nervous systems. Sensory neurotransmitters are reported to control resistance vessels. Our investigation of intranasal vasoactivity before and after applying sensory neurotransmitters was conducted using acoustic rhinometry. Acoustic rhinometry is a modern method of evaluating the cross-sectional area and volume of the nasal cavity. Its characteristics are that it is a non-traumatic procedure, minimal time is required for measurements and reliability is high. In the present experiment, calcitonin gene-related peptide (CGRP) and substance P (SP) were used as the sensory neurotransmitters. Six males (26-39 years old), without nasal abnormalities, were examined for one hour with acoustic rhinometry before and after administration of these transmitters. Nose drops of these preparations were introduced into one nasal cavity of each candidates, while in the head tilt position. After application of nose drops, both sides were evaluated with acoustic rhinometry in regard to minimal cross sectional area (MCSA) and nasal volume. Both CGRP and SP decreased the MCSA and volume on the applied side within ten minutes, which was followed by a plateau level for 1 hour. The opposite sides showed no significant change in either MCSA or volume. Changes in the MCSA ratio increased dose-dependently as the concentration of CGRP or SP increased. Changes in the volume ratio decreased when the concentration of SP was increased from 10(-8) to 10(-7) M, while it converted and then rose at 10(-6) M. CGRP has a potent vasodilator effect on vascular smooth muscles. SP also induces relaxation of vascular tone via endothelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Echocardiographic on-line volumetry using acoustic quantification--comparison with manual echocardiographic analysis and cineventriculography].

Acoustic quantification (AQ) represents an ultrasound imaging system which provides detection and tracking of endocardial blood boundaries based on quantitative assessment of acoustic properties of tissue in real time. To assess on-line quantitation of left ventricular enddiastolic (EDV), endsystolic (ESV) volumes and ejection fractions (EF) AQ measurements were compared with off-line measurements obtained by manual analysis of video-taped images (MAN) and with cineventriculographic data (CV). Calculations by the AQ system were based on an algorithm using the monoplane disc method. One day before undergoing CV, 88 unselected patients were studied with echocardiography in the apical four-chamber view. Seventy (79.5%) patients could be studied by AQ. The regression equations for determination of EDV were y = 0.7x + 25.2; r = 0.87 (AQ vs. MAN) and y = 0.5x + 22.8; r = 0.80 (AQ vs. CV), for determination of ESV they were y = 0.8x + 11.4; r = 0.78 (AQ vs. MAN) and y = 0.7x + 6.9; r = 0.71 (AQ vs. CV), and for determination of EF they were y = 0.7x + 9.5; r = 0.77 (AQ vs. MAN) and y = 0.6x + 15.0; r = 0.71 (AQ vs. CV). Calculations of left ventricular volumes by AQ or MAN led to a systematic underestimation, compared to CV. EF was also underestimated by AQ, whereas no significant difference between the mean values of MAN and CV exists. In a heterogenous population, acoustic quantification based on quantitative assessment of tissue acoustic properties mostly permits on-line quantitation of left ventricular volumes and ejection fractions in real-time.

Adult↗
PubMed1996

Myocardial acoustics in pediatric allograft rejection.

BACKGROUND: Ultrasonographic tissue characterization is the assessment of physical properties of biologic tissue on the basis of quantitative analysis of its acoustic characteristics. Abnormalities in microscopic structure that occur with cardiac allograft rejection may result in characteristic alterations in myocardial acoustics. Ultrasonographic tissue characterization may allow noninvasive detection of rejection. METHODS: Findings in 22 pediatric heart transplant patients undergoing routine surveillance for rejection by endomyocardial biopsy were prospectively evaluated. Off-line ultrasonographic tissue characterization analysis was done on transthoracic echocardiograms obtained at each biopsy. Within patients, tissue characterization texture measures derived from the ultrasonographic image data were compared with histologic findings. Univariate multiple regression analysis was used to identify texture measures associated with acute allograft rejection in a subgroup (n = 8) with at least one biopsy-proven episode of moderate rejection. RESULTS: Measures of homogeneity (co-occurrence matrix correlation and heterogeneity (run-length nonuniformity) decreased with moderate rejection (p < 0.03). Homogeneity measures decreased if the patient had a previous episode of rejection. Several measures of heterogeneity (gray level difference and run-length statistics) were affected by the presence of edema. Run-length nonuniformity was the only measure that differentiated moderate rejection from edema. Discriminant analysis on all 22 patients correctly identified 96% of first rejection episodes (sensitivity 80%, specificity 64%), 93% of moderate and severe rejection episodes (sensitivity 71%; specificity 62%), and 69% of all rejection episodes (sensitivity 51%, specificity 91%). CONCLUSIONS: Histologic changes associated with moderate and severe pediatric allograft rejection as reflected by characteristic alterations in myocardial acoustics can be assessed with ultrasonographic tissue characterization. Histologic changes associated with transplantation itself (resolution of rejection and edema) also affect myocardial acoustics and must be taken into account in rejection surveillance.

Acute Disease↗
PubMed1996

Measurement of acoustic backscatter and attenuation in the liver of dogs with experimentally induced steroid hepatopathy.

OBJECTIVE: To determine the usefulness of a new method of measuring acoustic backscatter and attenuation in the liver of dogs with experimental steroid-induced hepatopathy. ANIMALS: 10 clinically normal dogs. PROCEDURE: Steroid hepatopathy was induced by daily injections of prednisone (2 mg/kg of body weight, IM). Dogs were evaluated histologically and were sonographically imaged on days 0, 3, 7, 10, and 14. Acoustic backscatter and attenuation were measured from in vivo images of dogs, using a video signal method, and compared with results obtained from analysis of the unprocessed radio frequency signal. RESULTS: Histologic evaluation revealed midzonal, predominantly water-filled vacuoles in hepatocytes by day 7, which persisted for the remainder of the study and significantly (P = 0.0001) increased liver weight on day 14. Attenuation and backscatter increased during the experimental period. Mean effective attenuation difference was higher (P = 0.015) in the liver imaged through a left paraxyphoid window in experimental dogs by day 3. Significantly (P < 0.05) greater attenuation persisted in the liver of experimental dogs throughout the experimental period. Mean backscatter ratio was significantly increased (P = 0.02) by day 10. Uncorrected pixel intensity of the liver in 2 experimental dogs was approximately equal to that of the spleen on day 10 and greater than that of the spleen on day 14. CONCLUSION: Administration of prednisone to dogs results in increased acoustic backscatter and attenuation in the liver. CLINICAL RELEVANCE: The video signal method is a sensitive technique for detecting subtle acoustic changes in the liver of dogs.

Animals↗