1/56. Cutaneous-evoked tinnitus. I. Phenomenology, psychophysics and functional imaging.DC00166e and acute unilateral deafferentation of the auditory periphery (auditory and vestibular afferents) can induce changes in the central nervous system that may result in unique forms of tinnitus. These tinnitus perceptions can be controlled (turned on and off) or modulated (changed in pitch or loudness) by performing certain overt behaviors in other sensory/motor systems. Clinical reports from our laboratory and several other independent sources indicate that static change in eye gaze, from a neutral head-referenced position, is one such behavior that can evoke, modulate and/or suppress these phantom auditory events. This report deals with a new clinical entity and a form of tinnitus that can be evoked directly by cutaneous stimulation of the upper hand and fingertip regions. In 2 adults, cutaneous-evoked tinnitus was reported following neurosurgery for space-occupying lesions at the base of the skull and posterior craniofossa, where hearing and vestibular functions were lost completely and acutely in one ear (unilateral deafferentation) and facial nerve paralysis (unilateral deefferentation) was present either immediately following neurosurgery or had occurred as a delayed-onset event. Herein, we focus on the phenomenology of this discovery, provide perceptual correlates using contemporary psychophysical methods and document in one individual cutaneous-evoked tinnitus-related neural activity using functional magnetic resonance imaging. In a companion paper, neuroanatomical and physiological interactions between auditory and somatosensory systems, possible mechanistic accounts and relevant functional neuroimaging studies are reviewed.- - - - - - - - - - ranking = 1keywords = nerve (Clic here for more details about this article) |
2/56. Isolated metastases of adenocarcinoma in the bilateral internal auditory meatuses mimicking neurofibromatosis type 2--case report.A 56-year-old male with a history of lung cancer presented with isolated metastases of adenocarcinoma in the bilateral internal auditory meatuses (IAMs), mimicking the bilateral acoustic schwannomas of neurofibromatosis type 2, and manifesting as rapidly worsening tinnitus and bilateral hearing loss. magnetic resonance imaging showed small tumors in both IAMs with no sign of leptomeningeal metastasis. The preoperative diagnosis was neurofibromatosis type 2. Both tumors were removed and the histological diagnoses were adenocarcinoma. Neuroimaging differentiation of a solitary metastatic IAM tumor from a benign tumor is difficult, although rapidly progressive eighth cranial nerve dysfunction suggests a malignant process. Metastases should be considered as a rare diagnostic possibility in a patient with small tumors in both IAMs.- - - - - - - - - - ranking = 1keywords = nerve (Clic here for more details about this article) |
3/56. Somatic (craniocervical) tinnitus and the dorsal cochlear nucleus hypothesis.PURPOSE: Of all nonauditory sensory systems, only the somatosensory system seems to be related to tinnitus (eg, temporomandibular joint syndrome and whiplash). The purpose of this study is to describe the distinguishing characteristics of tinnitus associated with somatic events and to use these characteristics to develop a neurological model of somatic tinnitus. MATERIALS AND methods: Case series. RESULTS: Some patients with tinnitus, but no other hearing complaints, share several clinical features including (1) an associated somatic disorder of the head or upper neck, (2) localization of the tinnitus to the ear ipsilateral to the somatic disorder, (3) no vestibular complaints, and (4) no abnormalities on neurological examination. Pure tone and speech audiometry of the 2 ears is always symmetric and usually within normal limits. Based on these clinical features, it is proposed that somatic (craniocervical) tinnitus, like otic tinnitus, is caused by disinhibition of the ipsilateral dorsal cochlear nucleus. nerve fibers whose cell bodies lie in the ipsilateral medullary somatosensory nuclei mediate this effect. These neurons receive inputs from nearby spinal trigeminal tract, fasciculus cuneatus, and facial, vagal, and glossopharyngeal nerve fibers innervating the middle and external ear. CONCLUSIONS: Somatic (craniocervical) modulation of the dorsal cochlear nucleus may account for many previously poorly understood aspects of tinnitus and suggests novel tinnitus treatments.- - - - - - - - - - ranking = 1keywords = nerve (Clic here for more details about this article) |
4/56. Prolonged suppression of tinnitus after peripheral nerve block using bupivacaine and lidocaine.OBJECTIVE: The local anesthetic lidocaine has been shown to suppress tinnitus, albeit very temporarily, when administered intravenously. Long-term suppression by local anesthetics has not been reported. bupivacaine has not been studied. Here we report a case of prolonged (1-month) suppression of tinnitus following a peripheral nerve block performed with lidocaine and bupivacaine. CASE REPORT: A 57-year-old man undergoing facet and sacroiliac infiltration with lidocaine and bupivacaine experienced symptoms of systemic local anesthetic toxicity. He described significant perioral numbness. Shortly after this the patient noted that his long-standing and severe tinnitus was completely gone. Follow-up 1 month later revealed the tinnitus had not returned. Longer-term follow-up was not possible because the patient died. CONCLUSIONS: There are no reports regarding the use of bupivacaine for suppression of tinnitus. Although previous reports studying lidocaine for this purpose have shown only a brief effect, the use of bupivacaine or a combination of lidocaine and bupivacaine, as in this case, may represent a treatment for tinnitus that is worth further investigation. There currently is no effective long-term therapy for this debilitating problem.- - - - - - - - - - ranking = 5keywords = nerve (Clic here for more details about this article) |
5/56. A case of endolymphatic sac tumor with long-term survival.A 72-year-old man developed left facial palsy at age 14 and left-sided hearing loss at age 20. At the age of 59, he presented with gait disturbance, and a large left cerebellopontine angle tumor was detected, which had markedly destroyed the pyramidal bone. The tumor was subtotally resected, but he required two more operations at the ages of 64 and 69 because of tumor regrowth. At the present time, recurrent tumor has destroyed the occipital bone and is invading the scalp. However, even though he has several cranial nerve palsies and cerebellar ataxia, he remains in stable condition and demonstrates long-term survival. The patient's surgical specimens revealed a papillary adenoma, which was recently thought to be of endolymphatic sac origin, although the origin of this kind of tumor, whether arising from the middle ear or from the endolymphatic sac, has not been established with certainty so far. In this paper, we provide further evidence that this tumor originates from the endolymphatic sac, based on anatomical, histopathological, and embryological evidence.- - - - - - - - - - ranking = 1keywords = nerve (Clic here for more details about this article) |
6/56. radiosurgery for bilateral neurinomas associated with neurofibromatosis type 2.OBJECTIVE: The clinical course of bilateral acoustic tumors associated with neurofibromatosis (NF2) is generally troublesome, and no definite treatment strategy has been established. Follow-up results of bilateral acoustic tumors after radiosurgery are reported herein. methods: The current indications for radiosurgery are 1) a growing tumor less than 30 mm in mean diameter, 2) the ipsilateral ear has no serviceable hearing, and 3) there is risk of brain stem compression or brain stem dysfunction. Twenty cases of bilateral acoustic tumors were treated with the gamma knife, including 7 males and 13 females. The mean age was 38.2 years and the mean tumor size 24.4 mm. The tumors were treated with mean maximum and marginal doses of 26.8 Gy and 13.0 Gy, respectively. Among them, 12 patients had profound hearing loss in the ipsilateral (treated) ear, but the other 8 had serviceable hearing.RESULTS: Tumors treated with radiosurgery showed central necrosis in 60% of the cases at 6 months and in 70% at 9 months after radiosurgery. Thereafter, the tumors often demonstrated slow regression. The rate of tumor shrinkage was 20% at 12 months, 35% at 24 months, and almost 60% at 36 months. At the last follow-up (mean 33.6 months), the tumors demonstrated shrinkage in 50% and tumor control in 100%. The contralateral tumors were stable in 12 (60%) and enlarged in 8 (40%). Preservation of serviceable hearing ipsilaterally was obtained in 33.3%. Deterioration of ipsilateral facial nerve function, either in the natural course or as a complication, occurred in 10%. CONCLUSIONS: Because of good tumor control and tumor shrinkage as well as an acceptable complication rate, radiosurgery should be incorporated in the treatment strategy for bilateral acoustic tumors associated with NF2.- - - - - - - - - - ranking = 1keywords = nerve (Clic here for more details about this article) |
7/56. Sudden unilateral hearing loss with simultaneous ipsilateral posterior semicircular canal benign paroxysmal positional vertigo: a variant of vestibulo-cochlear neurolabyrinthitis?We describe 4 patients who all simultaneously developed a sudden total or partial unilateral sensorineural hearing loss and an unusual acute peripheral vestibulopathy in the same ear characterized by posterior semicircular canal benign paroxysmal positional vertigo with intact lateral semicircular canal function. Two patients also had ipsilateral loss of otolith function. The vertigo resolved in all 4 patients after particle-repositioning maneuvers. The findings of audiometry and vestibular tests indicated that the lesion responsible for this syndrome was probably located within the labyrinth itself rather than within the vestibulocochlear nerve and that it was more likely a viral vestibulocochlear neurolabyrinthitis than a labyrinthine infarction.- - - - - - - - - - ranking = 1keywords = nerve (Clic here for more details about this article) |
8/56. Immediate neurological deterioration after gamma knife radiosurgery for acoustic neuroma. Case report.The authors describe acute deterioration in facial and acoustic neuropathies following radiosurgery for acoustic neuromas. In May 1995, a 26-year-old man, who had no evidence of neurofibromatosis Type 2, was treated with gamma knife radiosurgery (GKS; maximum dose 20 Gy and margin dose 14 Gy) for a right-sided intracanalicular acoustic tumor. Two days after the treatment, he developed headache, vomiting, right-sided facial weakness, tinnitus, and right hearing loss. There was a deterioration of facial nerve function and hearing function from pretreatment values. The facial function worsened from House-Brackmann Grade 1 to 3. Hearing deteriorated from Grade 1 to 5. Magnetic resonance (MR) images, obtained at the same time revealed an obvious decrease in contrast enhancement of the tumor without any change in tumor size or peritumoral edema. facial nerve function improved gradually and increased to House-Brackmann Grade 2 by 8 months post-GKS. The tumor has been unchanged in size for 5 years, and facial nerve function has also been maintained at Grade 2 with unchanged deafness. This is the first detailed report of immediate facial neuropathy after GKS for acoustic neuroma and MR imaging revealing early possibly toxic changes. Potential explanations for this phenomenon are presented.- - - - - - - - - - ranking = 3keywords = nerve (Clic here for more details about this article) |
9/56. Vagal schwannoma of the cerebello-medullary cistern presenting with hoarseness and intractable tinnitus: a rare case of intra-operative bradycardia and cardiac asystole.Schwannomas arising from the lower cranial nerves (IX-XI) are rare, constituting only 3% of all intracranial schwannomas unassociated with neurofibromatosis. A great majority of these tumours present as jugular foramen lesions and less commonly they occur along the extracranial course of these nerves. An intracisternal location is extremely rare. We report a case of vagal schwannoma purely in the cerebello-medullary cistern causing distortion of the medulla oblongata. Total microsurgical excision of this tumor, arising from one of the rootlets of the vagus nerve, was achieved with preservation of the 9th, 10th and 11th cranial nerves.The intraoperative course was complicated by two episodes of complete cardiac asystole, each lasting for 4(s), and six episodes of severe bradycardia. The patient was relieved of his intractable tinnitus but continued to have a hoarse voice due to an ipsilateral partial vocal cord palsy.- - - - - - - - - - ranking = 4keywords = nerve (Clic here for more details about this article) |
10/56. cerebellopontine angle epidermoid tumor presenting with 'tic convulsif' and tinnitus--case report.A 22-year-old female presented with a cerebellopontine angle epidermoid tumor manifesting as a rare combination of hemifacial spasm, trigeminal neuralgia, and tinnitus. magnetic resonance imaging demonstrated the tumor distorting the brainstem and the fourth ventricle. The tumor was almost completely resected and the seventh-eighth cranial nerve complex was decompressed by mobilizing the anterior inferior cerebellar artery loop. No arterial loop was related to the trigeminal nerve. The patient was completely relieved of the "tic convulsif" and tinnitus after the surgery. The inflammatory nature of epidermoid tumor may be involved in the etiology of the syndrome. Microvascular decompression may be needed in addition to tumor removal in such cases.- - - - - - - - - - ranking = 2keywords = nerve (Clic here for more details about this article) |
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