Diagnosis Of Acoustic Tumors Research Articles

Auditory brainstem response testing in acoustic neuroma diagnosis

In the past year, there was a lack of published papers on using auditory brainstem responses for acoustic tumor diagnosis. This lack is probably caused by the large number of published studies demonstrating that standard auditory brainstem response measures frequently fail to detect small (≤ 1 cm) a

Resolved sudden hearing loss as a presenting symptom of retrocochlear lesion.

To determine whether acoustic neuroma-induced sudden hearing loss is associated with hearing recovery and, if so, to characterize its clinical, audiometric and imaging manifestations. The files of 72 patients with sudden hearing loss evaluated between 1989 to 2001 were reviewed. All patients underwent pure tone audiometry, acoustic reflex and auditory brain revoked response (ABR) test. Magnetic resonance imaging (MRI) was performed followed by a second hearing test after one month. The findings were compared between patients with and without evidence of tumors on imaging, and between patients with tumors with and without recovery. Twenty-five patients (35%) had a diagnosis of acoustic tumor. Of these, six (24%) recovered hearing after one month. Five of them had small intracanicular tumors and one had a small extracanicular tumor. There was variability in the hearing loss. Five had a pathological ABR and one had normal ABR. We conclude that recovery from hearing loss does not exclude acoustic tumors and these patients therefore require full evaluation including MRI.

Diagnosis of acoustic tumors

Diagnosis of acoustic tumors

Diagnosis of acoustic tumors

Diagnosis of acoustic tumors

Expert Opinion on the Diagnosis of Acoustic Tumors

Ideally, clinicians recommend diagnostic tests when the patient's risk of disease is sufficient to justify putting numerous similar patients through the morbidity required to diagnose disease in one patient. In the case of acoustic tumor diagnosis, there are few published data available to the clinician to help assess risk in an individual patient. The purpose of this study was to obtain information by an opinion poll of a group of experts. We used the Delphi method to poll clinicians trained at the House Ear Clinic. We asked these experts 20 questions related to acoustic tumor diagnosis. Some of the expert opinion presented herein is the only data related to acoustic tumor diagnosis available to clinicians. These data are a first step in elevation of decision-making for tumor diagnosis above the level of speculation. However, the experts, responses displayed a pattern of inaccuracy that limits the clinical application of their opinion. Exposing this pattern was instructive for identifying desirable features of protocols for diagnosing tumors. We recommend that protocols not depend on clinicians estimating probability of tumor. Instead, protocols may list specific findings, such as unilateral distortion on the telephone, to indicate, when present, that the risk of tumor is sufficient to order a diagnostic test.

Expert opinion on the diagnosis of acoustic tumors

Ideally, clinicians recommend diagnostic tests when the patient’s risk of disease is sufficient to justify putting numerous similar patients through the morbidity required to diagnose disease in one patient. In the case of acoustic tumor diagnosis, there are few published data available to the clinician to help assess risk in an individual patient. The purpose of this study was to obtain information by an opinion poll of a group of experts. We used the Delphi method to poll clinicians trained at the House Ear Clinic. We asked these experts 20 questions related to acoustic tumor diagnosis. Some of the expert opinion presented herein is the only data related to acoustic tumor diagnosis available to clinicians. These data are a first step in elevation of decision-making for tumor diagnosis above the level of speculation. However, the experts’ responses displayed a pattern of inaccuracy that limits the clinical application of their opinion. Exposing this pattern was instructive for identifying desirable features of protocols for diagnosing tumors. We recommend that protocols not depend on clinicians estimating probability of tumor. Instead, protocols may list specific findings, such as unilateral distortion on the telephone, to indicate, when present, that the risk of tumor is sufficient to order a diagnostic test. (Otolaryngol Head Neck Surg 1997;117:622-7.)

聴神経腫ようの診断

聴神経腫ようの診断

聴神経腫瘍の診断-ことに診断困難例,非,典型例の診断をめぐって

聴神経腫瘍の診断-ことに診断困難例,非,典型例の診断をめぐって

聴神経腫ようの早期診断

聴神経腫ようの早期診断

Magnetic Resonance Imaging in 38 Cases of Acoustic Tumors

The value of magnetic resonance imaging (MRI) in the diagnosis of acoustic tumors was retrospectively assessed in 38 cases. A 0.15 Tesla permanent magnet and a 1.5 Tesla superconducting magnet were employed in 24 and 14 cases, respectively. Gadolinium diethylene triamine pentaacetic acid (Gd-DTPA), a paramagnetic contrast agent, was used in 10 cases. Acoustic tumors were identified in all cases. Small, medium, and large tumors were depicted with equal clarity by MRI and computed tomography (CT). However, tumor contour and extension, accompanying cysts, and brainstem displacement were more clearly visualized on MRI. The use of Gd-DTPA improved the quality of the MR images by markedly enhancing the acoustic tumors in all cases. In particular, detection of small acoustic tumors and intra- or paratumoral cysts was facilitated by the use of Gd-DTPA. The possibility of a correlation between acoustic tumor histology and MRI features was studied by calculation of the contrast to noise (C/N) ratio in 10 cases of acoustic tumor and 7 cases of meningioma. No definite correlation was demonstrated, but there appeared to be some difference in the C/N ratio between acoustic tumors and meningiomas. In three volunteers, MRI demonstrated intracanalicular nerves, separately. Because of its higher resolution, MRI can be expected to replace CT and air CT in the diagnosis of acoustic tumors.

聴神経腫ようの診断

聴神経腫ようの診断

Clinico-Statistical Study on Acoustic Tumors with Sudden Hearing Loss

Acoustic tumors associated with sudden hearing loss were studied clinico-statistically to clarify the differential diagnosis between so-called sudden deafness and acoustic tumor of this type. A significant difference was found in the frequency of such abnormalities as gaze nystagmus, canal paresis in the caloric (nystagmus) test, inhibition of optokinetic nystagmus, dilatation of the internal auditory canal, and cranial nerve signs. However, there was no significant difference in such symptoms as preceding upper respiratory tract infection and rotatory vertigo at the onset of sudden deafness. In this study, most of the patients with sudden deafness had tumors of 2 cm or larger in diameter. Apart from the atypical feature of sudden onset, the acoustic tumors of this type have several characteristics. Therefore, the differential diagnosis of two diseases is not difficult if the possibility of acoustic tumor is taken into consideration and the above tests are performed for equivocal cases. The CT scan provides the most useful information for making a definite diagnosis of acoustic tumors in cases of this type.

Decision analysis of auditory brainstem responses and rotational vestibular tests in acoustic tumor diagnosis.

This study addresses the problem of the escalation of the costs of medical care which make diagnosis of acoustic tumor expensive. Specifically, we examined the hypothesis that a test protocol of the auditory brainstem response (ABR) in parallel with sinusoidal harmonic acceleration (SHA) is more cost-effective in identification of the risk of tumor than ABR alone. The subjects were 74 patients with acoustic tumors and 78 controls. ABR and SHA data from these subjects were submitted to decision analysis. ABR was more cost-effective than the protocol of ABR in parallel with SHA. Using these data, we outlined a "decision tree" for acoustic tumor diagnosis that fit the goals of high sensitivity when earlier probability of tumor was high, and high specificity when earlier probability of tumor was low.

Anatomic basis for labyrinthine preservation during posterior fossa acoustic tumor surgery

Earlier diagnosis of acoustic tumors promises to increase our opportunity to identify patients with serviceable hearing. Critical to a posterior fossa transmeatal approach for acoustic tumor resection is preservation of the underlying labyrinth. Although the labyrinth has been recognized as a limiting factor in exposure of tumor in the internal auditory canal, few reports have detailed the microscopic surgical anatomy posterior to the internal auditory canal. An anatomic study was undertaken to determine consistent relationships between critical structures within the temporal bone relevant to hearing preservation surgery. The results of this study indicate that, whereas topographic landmarks are helpful for orientation, the more consistent relationship of the labyrinth to the vestibular aqueduct and singular canal allows a more accurate localization of the underlying labyrinth. Although the vestibule frequently prevents direct visualization of the transverse crest, a dissection based upon the microsurgical anatomy will maximize visualization of the lateral fundus while preserving the integrity of the labyrinth.

聴神経しゅよう診断のためのＡＢＲモデルの検討

聴神経しゅよう診断のためのＡＢＲモデルの検討

Verhallter Freiburger Sprachtest

In 107 patients with different types of hearing loss (air conduction, sensorineural and combined) we ascertained the monaural discrimination loss of monosyllables with the help of the normal and distorted Freiburg speech test. It was evident that the quotient obtained from the measured discrimination is a very good and useful measure to characterise the ability to analyse the peripheral hearing system. Compared with normal hearing individuals and patients with air conduction hearing loss or combined loss of hearing, persons with perception hearing loss show a much greater and more divergent quotient. The discrimination of distorted speech depends more on age than that of normal speech; however, it is considerably reduced from the sixth decade of life onwards. The distortion test offers the expertising the possibility of improved assessment of speech discrimination by workers in a noisy environment in case of unfavourable hearing conditions, but it is also of considerable importance in fitting hearing aids and in the diagnosis of acoustic tumours.

Acoustic reflex testing in otoneurology.

Three parameters of the acoustic reflex have been used in otoneurologic diagnosis: threshold (ART), decay (ARD), and latency (ARL). Each test is defined, put in historical perspective, and discussed in relation to diagnostic implications. We recommend that these three tests - ART, ARD, and ARL - be used as a group and describe how they are implemented in the audiologic diagnosis of acoustic tumors and other lesions affecting the auditory system in the cerebellopontine angle and brain stem.

Diagnosis of acoustic tumors

Diagnosis of acoustic tumors

Comparison of results of auditory brain stem response and acoustic reflex latency in acoustic tumor diagnosis.

Persons with cerebellopontine angle tumors often have an increase in the latency of the acoustic reflex response that is comparable to the auditory brain stem response (ABR) in its sensitivity. However, reflex latency is less specific, since it may be prolonged in patients with Meniere's disease.

Diagnosis of Acoustic Tumor by CT-Scanning

Early diagnosis of acoustic tumors plays an important role in minimizing the disorder caused by operation and in the aspect of rehabilitation. It can be said that the otorhinolaryngologists' mission is to make an early diagnosis of acoustic tumors. A present, however, unfortunately, acoustic tumors are only rarely detected at the stage where the affected area is confined to the internal auditory meatus, i. e, so-called “ear tumor”. In many cases of early acoustic tumors, there are no abnormal objective findings except perceptive deafness and a reduced or extinct response on caloric nystagmus examination. On many occasions, neuro-otolbgical examination does not lead to a definite diagnosis of acoustic tumor but only suggests its presence. Therefore, we cannot but resort to diagnostic imaging in order to confirm the presence or absence of a tumor. As a next step, CT is performed following plain roentogenography, pluridirectional tomography, etc. Conventional CT where the limits of the detectable image in the diameter of the tumor have been considered to be 1.5-2cm is, however, not helpful for early diagnosis. For this reason, we have been troubled with a gap between what the functional test results indicate and CT-findings. We are now equipped with CT (from the Review of metrizamide cisternograms produced by GE CT/T) which seems to adequately fill such a gap and be useful for early diagnosis of acoustic tumors. We believe that CT-scan will reveal a greater number of cases of “ear tumor”.