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At least 1,225 records · Page 68Linked to original sources
PubMed2002

[Neuropathy in nearby cranial nerves after acoustic schwannoma gamma knife radiosurgery, a follow-up study].

OBJECTIVE: To investigate the risks of facial, trigeminal and acoustic neuropathies after acoustic schwannoma gamma knife radiosurgery. METHODS: The clinical data of forty-three patients with 46 masses of acoustic schwannoma who underwent gamma knife radiosurgery with the dose of 12 approximately 15 Gy to the tumor margin between January 1997 and October 2000 and were followed up for 6 approximately 24 months (on average 16.9 months) were studied. The tumor diameter was 10 approximately 20 mm in 12 cases, 21 approximately 30 mm in 23 cases, >/= 31 mm in 11 cases, with the average value of 28 mm. RESULTS: The general tumor control rate was 91.3%. The useful hearing preservation rate was 100% immediately after radiosurgery, 87% 6 months later and 78% 2 years later. The hearing preservation rate was high for small tumors. The facial and trigeminal neuropathies began to appear after 6 months. The incidence rates of facial neuropathy was 15.3%, 7.6%, and 3.8% 6 months, 1 year and 2 years after radiosurgery respectively. The incidence rates of trigeminal neuropathy was 11.4%, 3.8%, and 3.8% respectively 6 months, 1 year, and 2 years after radiosurgery. The incidence of neuropathy was 3.8% for tumors with a diameter < 30 mm for both facial and trigeminal nerves. The hearing in 2 out of 15 cases with dysaudia began to improve 6 months after radiosurgery. The incidence of neuropathy for tumors with the diameter > 30 mm was 3.8% for both nerves 2 years after raadiosurgery. The preservation rate of useful hearing for tumors with the diameter < 20 mm was 100% after radiosurgery. CONCLUSION: Stereotactic radiosurgery using gamma knife with a dose of 12 approximately 15 Gy to the tumor margin succeeds in controlling acoustic schwannoma and preserving useful hearing. The incidence of facial and trigeminal neuropathies are low. The neuropathy caused by gamma knife radiosurgery is sub-lethal and can be recovered gradually.

Adolescent↗
PubMed2002

Hypervascular intracisternal acoustic neuroma.

The diagnosis of acoustic neuroma is usually evoked in a patient presenting with a long history of hearing disturbance in whom an enhancing lesion within the internal auditory canal and/or the cerebellopontine angle is found on MRI. Hypervascularity with arteriovenous shunting and early filling of enlarged veins is a common feature of malignancy and has been reported very rarely in benign acoustic neuroma. We present the case of a patient without hearing disturbance, who showed a highly vascular lesion with no component in the internal auditory canal, making the preoperative diagnosis of acoustic neuroma very challenging. We discuss here the intracisternal site of origin and hypervascularity of acoustic neuroma, and also the differential diagnoses and management of such tumors.

Adult↗
PubMed2002

[Keyhole microsurgery for acoustic neurinomas through suboccipital retrosigmoid sinus approach].

BACKGROUND AND OBJECTIVE: Acoustic neurinomas is one of the most common benign tumor in central nervous system, the main treatment is surgical resection. This study is to explore keyhole surgery with suboccipital retrosigmoid sinus approach for acoustic tumor resection and discuss how to improve the surgical skill and effect. METHODS: Thirteen cases of acoustic neurinomas from Sept. 2000 to Dec. 2001 in our department were operated using keyhole craniotomy technique through unilateral modified suboccipital retrosigmoid approach with "[symbol: see text]" incision. All patient underwent suboccipital craniotomy in order to maintain anatomical replacement, and the tumors (2.0-4.4 cm in diameter) were removed under microscope. RESULTS: Tumors were completed resected in 11 cases, subtotally removed in 2 cases. Eleven patients had obtained anatomic preservation of the facial nerves. Complete follow-up information was obtained in all patients for a period of 3-15 months after operation. House-Brackmann Score in 8 case were Grade I-II, 4 cases Grade III-IV, one case Grade V. Grades I and II facial nerve function were maintained in 61.5% of cases, measurable hearing was preserved in 53.8% of cases(7 cases), and 38.5% of cases maintained serviceable hearing. No severe permanent operative complications were found and no surgical mortality occurred. CONCLUSIONS: Microsurgery with keyhole craniotomy is a safe and effective method for treatment of patients with small and medium-size acoustic neuromas. The advantages of keyhole suboccipital craniotomy are anatomical replacement, less postoperative complications, and beneficial to patient's mental health.

Adult↗
PubMed2001

[The relationship between acoustic analysis and auditory assessment].

OBJECTIVE: To investigate the relationship between acoustic analysis and auditory assessment of hoarseness. METHOD: 24 normal and 154 cases of pathological voice were included in this research. They were divided into 4 groups with different hoarseness and were accepted acoustic analysis. The parameters were analyzed by SPSS statistical software. RESULT: There were significant difference on acoustical parameters among each group excluding no difference of the jitter between normal and light hoarseness. NNE and SNR were the major parameters in descriptive of hoarseness. There were good correlation between 5 parameters and hoarseness assessment. CONCLUSION: Acoustic analysis is a useful method in clinical application to assess hoarseness with objective and simple advantage.

Adolescent↗
PubMed1999

[The influences of vowel ae and a: on acoustic measures].

OBJECTIVE: To study the influences of vowel ae and a: on acoustics measures. METHOD: Fifty-three cases of laryngeal diseases were measured acoustically. The acoustic sampling were vowels ae and a:. RESULT: The results showed that Fo, Jitter and Shimmer were similar between two groups, and NNE of vowel a: was much lower than that of ae, indicating larger glottal closure in vowel a:. CONCLUSION: Vowels have something to do with glottal closure, therefore influencs acoustical measures.

Acoustics↗
PubMed2000

[Acoustic analysis and characteristics of vocal range in Beijing Opera actors].

OBJECTIVE: To get the objective acoustic parameters of the voice of Beijing Opera actors and set a foundation for the training and protection of the special professional voice. METHODS: Seventy-three (age 16-57 years) professional actors and students were asked to produce sustained comfortable vowels /a/ and /i/, and to sing two pieces of songs which were in the category of Xipi and Erhuang respectively. Dr. Speech for windows version 3.0 was used to get the acoustic parameters of the vowels and the songs. RESULTS: F0 of the vowels /a/ and /i/ of different Hangdangs were Chou (272.6 +/- 42.0) Hz (mean +/- s), (304.2 +/- 22.1) Hz; Xiaosheng (499.3 +/- 34.0) Hz, (485.4 +/- 18.7) Hz; Laosheng (335.6 +/- 60.0) Hz, (317.9 +/- 45.1) Hz; Hualian (319.0 +/- 61.3) Hz, (340.1 +/- 68.8) Hz; Laodan (427.6 +/- 47.2) Hz, (437.7 +/- 45.8) Hz; Huadan (535.8 +/- 48.8) Hz, (561.6 +/- 29.2) Hz; Qingyi (548.0 +/- 69.5) Hz, (543.5 +/- 79.3) Hz; these and other acoustic parameters of vowels such as Jitter, Shimmer and NNE were all within the normal range given by the software. The vocal range of Beijing Opera actors was from 1.7 to 2.8 oct, and most of the highest and the lowest pitches were higher than that of tenor or soprano. CONCLUSIONS: These findings may help to provide insight regarding the acoustic characteristics of the voice of Beijing Opera actors.

Adolescent↗
PubMed2003

The laryngectomee substitute voice: image processing of endoscopic recordings by fusion with acoustic signals.

OBJECTIVES: The most radical cancer therapy of the throat is the total excision of the larynx which post-operatively results in the loss of voice. A widely-used method of voice rehabilitation is the insertion of a silicone valve, which establishes an unidirectional connection between trachea and esophagus. Thus, during exhalation, air can be directed from the trachea into the esophagus. This air stream excites tissue vibrations of the esophagus and the hypo-pharynx which act as a substitute voice generator. Purpose of the current study is to present a technique for visualizing the dynamics of the substitute voice generating element. METHODS: Digital high speed videos of the vibrating tissue are simultaneously recorded with the emitted acoustic signal. The high speed sequences are directly evaluated by a three-step knowledge based algorithm. It considers correlation between image and acoustic data, information about the gray value of each pixel, and continuity of tissue vibration. The temporal properties of an image series are investigated by evaluating the time dependent gray value at each pixel position. RESULTS: The applicability of the algorithm is exemplarily demonstrated using the data of one male patient. It enables the identification of the regions within an image series which are mainly responsible for the acoustic signal. Additionally, the dynamics of tissue vibrations are visualized. The main propagation direction can be clearly identified. CONCLUSIONS: The new methodology summarizes the information about endoscopic and acoustic recordings of substitute voice into a single image. The results allow a first estimation of tissue velocity and elastic properties of oscillating tissue.

Algorithms↗
PubMed2003

[A quantitative evaluation of spinocerebellar degeneration by an acoustic analysis--the effect of taltirelin hydrate on patients with Machado-Joseph disease].

A clinical evaluation of 10 patients with Machado-Joseph disease (MJD) was performed by using an acoustic analysis soft (SoundScope, GW Instruments Inc) before and on 4 weeks of treatment of taltirelin hydrate (TH). A rapid repetitive monosyllable/ka/was recorded as the samples were analyzed in a computer. The repetition period (ms) and the maximum intensity (volt) was measured from the sound spectrogram and the amplitude envelope for each speech wave. Three acoustic parameters, which were mean of period (ms) (m-P), coefficient of variation of period (%) (CV-P), and coefficient of variation of amplitude (%) (CV-A), were calculated according to Ishida's acoustic analysis method. The average age in this study group was 52.4 +/- 11.4 years (32-73 years), the mean scores of International Cooperative Ataxia Rating Scale (ICARS) was 35.0 +/- 18.6. Significant correlation was shown between CV-A and ICARS scores before therapy (p < 0.05). CV-P was decreased significantly (p < 0.05) from 10.9 +/- 0.12% to 9.2 +/- 0.26% after TH, and its degree of decrement correlated with ICARS scores (p < 0.05), which means a greater effect of TH is expected in patients with milder symptoms. ICARS scores did not change with a statistical significance. TH was shown to be effective on the ataxic speech of patients with MJD by quantitative methods. The acoustic analysis used in this study is a sensitive and objective evaluation method for following up the clinical severity of MJD and judging effectiveness of a drug.

Adult↗
PubMed2003

[Prevention and therapy of cerebrospinal fluid leakage after translabyrinthine acoustic neuroma removal].

OBJECTIVE: To evaluate the modified wound closure technique and other methods for preventing and treating the cerebrospinal fluid (CSF) leakage after removal of acoustic neuroma by translabyrinthine approach. METHODS: In a series of 85 cases of acoustic neuroma surgery, two kinds of technique of wound closure, the traditional (as first group) and the modified (as second group), have been subsequently used to prevent CSF leakage. The incidences of CSF leak were analyzed respectively. Conservative and surgical treatments were applied to treatment the CSF leak. RESULTS: In the first group, the CSF leak was 19.5% (8/41), and that of second group was 2.3% (1/44). There was significant difference between them (P = 0.013). The CSF leak mainly occurred in large acoustic neuromas surgery with traditional wound closure technique. Among 9 cases of CSF leaks, 3 were controlled by conservative method, 5 by one single revision surgery and one by two revisions. CONCLUSIONS: The revision technique of wound closure could significantly reduce the incidence of CSF leakage after acoustic neuroma removal by translabyrinthine approach. The revision surgery is an effective method for stopping the CSF leak.

Adult↗
PubMed2003

A peptide inhibitor of c-Jun N-terminal kinase protects against both aminoglycoside and acoustic trauma-induced auditory hair cell death and hearing loss.

Hearing loss can be caused by a variety of insults, including acoustic trauma and exposure to ototoxins, that principally effect the viability of sensory hair cells via the MAP kinase (MAPK) cell death signaling pathway that incorporates c-Jun N-terminal kinase (JNK). We evaluated the otoprotective efficacy of D-JNKI-1, a cell permeable peptide that blocks the MAPK-JNK signal pathway. The experimental studies included organ cultures of neonatal mouse cochlea exposed to an ototoxic drug and cochleae of adult guinea pigs that were exposed to either an ototoxic drug or acoustic trauma. Results obtained from the organ of Corti explants demonstrated that the MAPK-JNK signal pathway is associated with injury and that blocking of this signal pathway prevented apoptosis in areas of aminoglycoside damage. Treatment of the neomycin-exposed organ of Corti explants with D-JNKI-1 completely prevented hair cell death initiated by this ototoxin. Results from in vivo studies showed that direct application of D-JNKI-1 into the scala tympani of the guinea pig cochlea prevented nearly all hair cell death and permanent hearing loss induced by neomycin ototoxicity. Local delivery of D-JNKI-1 also prevented acoustic trauma-induced permanent hearing loss in a dose-dependent manner. These results indicate that the MAPK-JNK signal pathway is involved in both ototoxicity and acoustic trauma-induced hair cell loss and permanent hearing loss. Blocking this signal pathway with D-JNKI-1 is of potential therapeutic value for long-term protection of both the morphological integrity and physiological function of the organ of Corti during times of oxidative stress.

Acoustic Stimulation↗
PubMed2003

Acoustic analysis of speech through a hearing aid: perceptual effects of changes with two-channel compression.

Compression amplification significantly alters the acoustic speech signal in comparison to linear amplification. The central hypothesis of the present study was that the compression settings of a two-channel aid that best preserved the acoustic properties of speech compared to linear amplification would yield the best perceptual results, and that the compression settings that most altered the acoustic properties of speech compared to linear would yield significantly poorer speech perception. On the basis of initial acoustic analysis of the test stimuli recorded through a hearing aid, two different compression amplification settings were chosen for the perceptual study. Participants were 74 adults with mild to moderate sensorineural hearing impairment. Overall, the speech perception results supported the hypothesis. A further aim of the study was to determine if variation in participants' speech perception with compression amplification (compared to linear amplification) could be explained by the individual characteristics of age, degree of loss, dynamic range, temporal resolution, and frequency selectivity; however, no significant relationships were found.

Aged↗
PubMed2004

Voice acoustic analysis of normal Taiwanese adults.

BACKGROUND: Because of advances in voice research, voice acoustic analysis including fundamental frequency (F0), sound pressure level (SPL), jitter, shimmer, harmonics-to-noise ratio (H/N ratio), and maximum phonation time (MPT) can now be easily recorded and analyzed with a computer. Because these systems are widely used in clinical practice, this study was designed to establish the normal acoustic analysis parameters in normal Taiwanese adults. METHODS: From Mar. 2002 to Dec. 2002, 45 Taiwanese women and 45 Taiwanese men younger than 50 years old were recruited as subjects for this study. The commercially available Computer Speech Lab and Aerophone II system manufactured by Kay Elemetrics Corp. were used to record the aforementioned acoustic data under comfortable phonation. Each gender was separated equally into 3 age subgroups. Then differences between gender and age subgroups were investigated by statistics software SPSS 10.0. Our results were compared with data from previous reports. RESULTS: The value of F0 (counting; vowel /a/) was greater for females (203.2 +/- 21.7; 213.4 +/- 25.4 Hz) than for males (118.3 +/- 17.3; 121.3 +/- 16.4 Hz). Conversely, the value of MPT was greater for males (28.0 +/- 9.4 sec) than for females (22.6 +/- 7.6 sec). There were no significant differences in average SPL and jitter between female (77.8 +/- 5.5 dB; 0.66 +/- 0.27%) and male (77.5 +/- 5.5 dB; 0.56 +/- 0.23%) subgroups. Except for shimmer and H/N ratio in the male subgroup, there were no differences in parameters within both gender subgroups with respect to age. CONCLUSIONS: We have developed a body of normal data for various parameters of acoustic analysis in different age groups and genders. It seems that the majority of voice characteristics of adults were relatively stable and did not change with aging between 20 and 49. But the shimmer and H/N ratio were variable in different genders and age groups. However, the voice characteristics of adults older than 50 years old were not recorded in this study and therefore require further investigation.

Adult↗
PubMed2002

[The study of MRI examination of acoustic neuromas].

OBJECTIVE: To discuss the examination parameters of acoustic neuromas. METHOD: The MRI features of 20 lesions 20 patients with acoustic neuroma had been analyzed retrospectively. The examinations were performed by a 1.5 Tesla superconducting magnet system transaxial T1. T2-weighted imagines and coronal or sagittal T1. T2-weighted imagines were obtained in each cases. 20 patients were examined with Gd-DTPA. RESULT: 20 cases of acoustic neuroma were divided into three groups according to the tumor size: 1.1 approximately 2 cm (4 lesion) ;2. 2 approximately 4 cm (14 lesion); 3. over 4 cm (2 lesion). T1 weighted imagines shovos the equal or low signal;T2 weighted imagines shows the high signal. Low and high mixture signal will be shown when being hemorrhage or necrosis. CONCLUSION: Combining thin slice and Gd-DTPA in MRI examination was the best method to find acoustic neuroma. MRI not only can find small intracanalicular tumors, but also has advantages in demonstrating the formation of cyst and hemorrhage, the compression of adjacent anatomical structures and the tumor vessels.

Adult↗
PubMed2004

The acoustic attenuation and hydraulic roughness in a large section sewer pipe with periodical obstacles.

The acoustic attenuation, relative sound pressure levels and the equivalent Nikuradse wall roughness under variable flow conditions in a 600 mm concrete sewer pipe are experimentally investigated. The values of the acoustic attenuation are obtained in the case of airborne sound propagation in the dry pipe. A range of values of the equivalent wall roughness is artificially generated by deploying a periodical array of engineering bricks. A novel method of rapid evaluation of the acoustic attenuation is proposed. The method relies upon sound reflections from the adjacent manholes. The results demonstrate that the acoustic attenuation depends strongly on the value of the equivalent wall roughness. This work can pave the way to the efficient methodology for the in-situ, physical evaluation of the equivalent hydraulic roughness of new and existing sewer networks.

Acoustics↗
PubMed1992

Electrical evaluation of the facial nerve in acoustic neuroma patients: preliminary comparison between transcranial magnetic coil stimulation and electroneurography.

Subclinical involvement of the facial nerve by acoustic neuromas may be identified preoperatively using conventional electroneurography (ENoG). The clinical application of extratemporal stimulation distal to the stylomastoid foramen is limited in these cases by the more proximal site of the lesion. Transcranial magnetic coil stimulation (MCS) is a noninvasive means by which the facial nerve is stimulated at the level of the motor cortex or the brain stem, before it enters the internal auditory canal. Topographically such an assessment may have more diagnostic relevance than other forms of electrical stimulation in acoustic neuroma patients. To test this theory the facial nerves of 20 patients with acoustic neuromas were stimulated using ENoG and MCS preoperatively and 1 week postoperatively. Stimulation parameters were comparable and included threshold and suprathreshold levels of stimulation while compound action potential amplitudes and early and late response latencies were monitored. Facial nerve function was assessed clinically using the Stennert grading system. All the patients had clinically normal facial nerve function preoperatively. Normative data suggested a close correlation between threshold and suprathreshold amplitudes generated by both ENoG and MCS. To the contrary, in the pathologic ears there was a higher incidence of stimulus response abnormality determined by MCS than by ENoG. A comparison of these data, tumor size, and postoperative results promotes further evaluation of MCS as a prognostic index in acoustic neuroma patients.

Action Potentials↗
PubMed1992

Epidemiology, pathogenesis, and genetics of acoustic tumors.

This article reviews the epidemiology of both unilateral and bilateral (NF-2) acoustic tumors. The growth rate of acoustic tumors is examined from a clinical, radiographic, and laboratory perspective. The anatomic, histologic, and biochemical considerations as well as the influences of sex hormones on acoustic tumor formation are reviewed. Also presented are an update on the laboratory search for the NF-2 gene on chromosome 22 and recently identified DNA markers. Predictions are made concerning the potential future applications of genetic testing for prenatal or presymptomatic diagnosis of the disease that causes bilateral acoustic tumors.

Female↗
PubMed2005

Ultra-high-frequency ultrasonic external acoustic stimulation for tinnitus relief: a method for patient selection.

We proposed a method for patient selection and application of criteria for predicting success with bone-conduction external acoustic stimulation using high-audio-frequency sound in the ranges of 10-20 kHz and 20-26 kHz for individuals with subjective idiopathic tinnitus (SIT) of the severe disabling type. Ultra-high-frequency (UHF) stimulation for tinnitus relief has been found to be most effective when residual neuronal function exists in the acoustic ranges of 10-14 kHz, with thresholds no greater than 40-50 dB sound pressure level (SPL). Ultrasonic (US) acoustic stimulation is recommended for patients with audiometric thresholds greater than 50-60 dB SPL for frequencies of 10-14 kHz. Fifty-two consecutive patients seen for the primary complaint of SIT of the severe disabling type received a trial of either UHF or US bone-conduction acoustic stimulation. Tinnitus relief was reported in 22 of the 52 patients. The application of criteria for patient selection predicted tinnitus relief in 20 of the 22.

Acoustic Stimulation↗
PubMed2006

[Preliminary study of intraoperative auditory monitoring techniques in acoustic neuroma surgery].

OBJECTIVE: To investigate the value of intraoperative auditory monitoring techniques in acoustic neuroma surgery. METHODS: Ten cases with acoustic neuroma were resected with retrosigmoid approach. Continuous hearing monitoring of auditory brainstem responses (ABR) and transtympanic electrocochleography (ECochG) was performed during operation. RESULTS: Before surgery, 3 patients had class A hearing, 4 had class B hearing, and 3 had class C hearing. With ABR monitoring, 5 patients had waves I , III and V, 5 had only waves I preoperation. After anesthesia,only 2 cases had waves I, III and V, 6 had wave I (Compound action potential, CAP N1 is equivalent to wave I of ABR) and 2 had no waves. The hearing was preserved in 2 cases, which had class A hearing post operation with tumor size <2 cm. With continuous hearing monitoring, the waves of I , III and V could be evoked in one case. In another case, the waves of I, III could be evoked after the tumor resection with the disappearance of wave V. The hearing was not preserved in 8 cases. The 6 out of 8 cases showed up CAP (waves I ) waveform. The CAP amplitudes decreased significantly in 4 cases and even dropped to zero while dissecting the tumor at the lateral end of the internal auditory canal (IAC) or clamping the internal auditory artery (IAA) during operation. After surgery, the CAP amplitudes were recovered to 50%-60% of normal level or normal. In one case, although the cochlear nerve was cut down, the CAP could still be recorded after the tumor resection. However, the CAP amplitudes was dropped to zero while pressurized and pulled cochlea nerve of brainstem lateral and the wave disappeared post-operation in another cases. The waves had not been recorded in two cases after anesthesia. One of them showed low amplitude of CAP wave when the tumor partially removed. The others had no wave all the time. CONCLUSIONS: In combination with ABR monitoring, ECochG proved to be a useful supplementary tool for hearing preservation in acoustic neurinoma surgery. Drilling of the IAC and tumor removal at the lateral end of the IAC were the most critical steps for achieving hearing preservation. The surgeon's experience are the most significant factors influencing the hearing outcome after removal of acoustic neuroma.

Adolescent↗