Eighth Nerve Dysfunction Research Articles

Patient-reported involvement of the eighth cranial nerve in giant cell arteritis

IntroductionThe frequency of eighth nerve lesions in patients with giant cell arteritis (GCA) has rarely been examined. However, sudden onset deafness has been recorded as a presenting feature of GCA on several occasions. This study sought to establish how common this and other symptoms of eighth nerve involvement are in a large retrospective survey.MethodsWe contacted 170 patients with GCA and 250 matched PMR patients, inviting them to participate in a questionnaire survey of symptoms of eighth nerve dysfunction. We compared the presence of deafness, tinnitus, loss of balance and vertigo in both groups and examined the relationship between the onset of these symptoms and other features of GCA.ResultsA total of 317 patients were recruited. The percentage of patients with symptoms of possible vestibulocochlear disease prior to commencement of steroid therapy was significantly greater among GCA patients than PMR patients for all domains. Hearing loss which was twice as common in GCA as in PMR (53% vs 26%) [p = 0.001]. Deafness was concurrent in 35% of GCA patients with other symptoms and 45% reported colocation with headache. Recovery with steroids occurred in 56% of these.ConclusionSymptoms of eighth nerve dysfunction are present in over half of patients with GCA. Recovery with steroids was predicted by concurrence with headache in terms of both timing and location. It appears that eighth nerve involvement, especially acute hearing loss, is a not infrequent feature of GCA and often responds well to steroid therapy. Clinicians should enquire about these symptoms when evaluating a patient for possible GCA.Key Points• Deafness is a frequent presenting feature of giant cell arteritis.• Vertigo, tinnitus and loss of balance are also often reported by GCA sufferers.• Steroid therapy is more likely to relieve these symptoms if they are ipsilateral and concurrent with headache.

Eighth Nerve Dysfunction in Type 2 Diabetes Mellitus

Introduction: Hearing impairment is one of the under-recognized complications of diabetes that affects the cognitive performance and quality of life. The study was conducted to estimate the prevalence of hearing impairment and analyze the type, degree and pattern of hearing impairment in diabetic population. Materials and Methods: The study was conducted as a case-control study including 50 diabetic patients and 20 healthy individuals after exclusion of confounding factors. Hearing assessment was done using pure tone audiometry. Results: The prevalence of hearing impairment in diabetics of age 35-65 years was 74% compared to normal population (15%). 7 out of 13 diabetic patients in the age group of 35-45, 19 out of 37 diabetics in the age group of 45-55 & 11 out of 13 diabetics in the age group of 55-65 had hearing impairment. 9 out of 12 diabetic patients having HbA1c of 7 had hearing impairment. 21 out of 27 patients with diabetes duration of 5years had hearing impairment. Out of 37 diabetic patients who had hearing impairment, 24 (64%) had diabetic neuropathy. Conclusion: Eighth nerve dysfunction is common among diabetics. Its prevalence among the diabetics increases with age and positively correlates with the duration of diabetes and presence of diabetic peripheral neuropathy. However, its prevalence did not show positive correlation with the HbA1c levels.

Multiple Ipsilateral Lower Extremity Masses in a 46-year-old Man

Multiple Ipsilateral Lower Extremity Masses in a 46-year-old Man

Café au lait spots: the pediatrician's perspective.

1. Mustafa Tekin, MD* 2. Joann N. Bodurtha, MD, MPH† 3. Vincent M. Riccardi, MD‡ 1. 2. *Clinical Genetics Fellow. 3. 4. †Associate Professor of Human Genetics, Pediatrics, Obstetrics and Gynecology, Virginia Commonwealth University/Medical College of Virginia Hospitals, Richmond, VA. 5. ‡President, The Neurofibromatosis Institute, La Crescenta, CA. Objectives After completing this article, readers should be able to: 1. Define cafe au lait spots typical of neurofibromatosis type 1 (NF1) and describe their frequency and variability in the normal population. 2. List three or more genetic disorders other than NF1 that are associated with cafe au lait spots. 3. Summarize three or more clinical manifestations and molecular bases of NF1 and NF2. 4. List the diagnostic criteria for NF1. 5. Summarize clinical findings of genetic disorders other than NF1 associated with cafe au lait spots. Every pediatrician faces the challenge of deciding if a patient who has cafe au lait (CAL) spots has an underlying genetic condition. CAL spots typical of neurofibromatosis type 1 (NF1) are discrete, round or oval, uniformly hyperpigmented skin patches. Their color varies from light to dark brown, and the border may be smooth or irregular. They usually are smaller in newborns, enlarge as children get older, and are less prominent in adults. The histologic basis of CAL spots is increased melanin content, with the presence of giant melanosomes in both melanocytes and basal keratinocytes and no melanocytic proliferation. The giant melanosomes in CAL spots are not unique to NF1; they can be seen in unaffected skin of adults who have NF1 and occasionally in normal skin of healthy individuals. Therefore, the presence of giant melanosomes is not helpful for diagnosing NF1. The frequency and number of CAL spots vary in the general population according to ethnic background and age. Sometimes otherwise healthy children who have red hair and often are of Irish or Welsh background have multiple areas of patchy hyperpigmentation. Similarly, multiple patchy areas of hyperpigmentation can occur in healthy children who have mixed ethnic backgrounds in which two parents have very different skin colors. CAL spots were noted in 0.3% of Caucasians and 18% of African-Americans …

Morphological evidence that impaired intraneural microcirculation is a possible mechanism of eighth nerve conduction block in acoustic neuromas.

In an attempt to better understand the mechanism of eighth nerve dysfunction in acoustic neuromas (vestibular schwannomas), we have morphologically examined microvessels and nerve fibers in the intracanalicular portion of eighth nerve specimens attached to these tumors. At the light microscopic level, microvessels were well preserved in all the specimens, even in the extremely flattened or markedly small nerve fascicles. However, the density of microvessels was quite variable in the different specimens, presumably as the result of different levels of compression by the tumors and the subsequent formation of a collateral microcirculation in each nerve. Focal areas of mild endoneurial fibrosis were found in 9 out of 22 specimens examined, but severe and widespread degeneration or demyelination was not found in any of the specimens. Ultrastructural studies frequently revealed mild to moderate abnormalities in myelin sheaths, and occasionally showed endothelial hyperplasia and hypertrophy in all the specimens. These findings are consistent with the slight to moderate reduction of endoneurial blood flow in the eighth nerves. The resultant ischemic condition in the eighth nerve may account for the eighth nerve conduction block in acoustic neuromas.

The diagnosis and management of neurofibromatosis 2 in childhood

Neurofibromatosis 2 (NF2) is an autosomal-dominant condition that causes multiple benign nervous system tumors, especially vestibular schwannoma. Although frequently confused with the more common neurofibromatosis 1, NF2 presents a distinct set of diagnostic, genetic, and management issues. The presentation and natural history of NF2 differs in children and adults, with eighth nerve dysfunction often overshadowed by the effects of other tumors on the nervous system. Molecular diagnostics is an important tool for early recognition of NF2, and when performed in the context of appropriate counseling and follow-up, may lead to a better final outcome of the disease. Further research into the molecular genetic etiology of NF2 promises to broaden the possibilities of therapy for this devastating disorder.

Molecular Genetic Screening for Children at Risk of Neurofibromatosis 2

The diagnosis and treatment of vestibular schwannoma (formerly known as acoustic neuroma) in patients with neurofibromatosis 2 (NF2) has been improved in recent years by advances in several clinical and scientific areas. Advances in imaging techniques have allowed high-resolution preoperative assessment of size, shape, and anatomic relationships of vestibular schwannomas. Advances in surgical techniques have decreased the risks of postoperative complications especially seventh and eighth nerve dysfunction. 1 Finally, advances in molecular biological techniques have made possible the presymptomatic diagnosis of affected individuals in approximately two-thirds of affected families. 2 The last development raises the issue of whether children with vestibular schwannomas should be identified before they develop symptoms from their tumors. If no treatment exists for a genetic disease that primarily presents in adulthood, there is little rationale for testing children for that disease. In the case of NF2, however, not only does an effective therapy exist, but also

Auditory brain-stem response audiometry in patients with Bell's palsy.

To evaluate the hypothesis of central nervous system involvement in Bell's palsy, the auditory brain-stem responses (ABR) of 32 patients were studied. In 14 (43.7%) of these patients ABR abnormalities were found. In each case the ABR deviation suggested prolonged brain-stem conduction time, independent of the side or severity of the paralysis. Site of lesion tests in this sample failed to demonstrate eighth nerve dysfunction and, thus, does not support a theory of a polyneuropathy that involves the auditory nerve.

Abducent nerve palsy following transverse fracture of the middle cranial fossa

Transverse sphenoidal fractures may be associated with a variety of skull base injuries and neural deficits. Among those nerve injuries, oculomotor palsies and particularly sixth cranial nerve palsy, are quite common. Blows on the side of the head in the squamous temporal region may run across the floor of the middle cranial fossa through the greater wing of the sphenoid in the transverse cranial axis. We report three cases of patients who had sustained craniofacial injury which included a transverse fracture of the middle cranial fossa through the sphenoid sinus, extending to the petrous apex and producing abducent, facial, and eighth nerve dysfunction. Spontaneous recovery from diplopia occurred in all cases within 4 months. The management of the patients and the patterns of transverse cranial base fractures and their associated clinical features are discussed.

The small acoustic tumour; a chance to preserve hearing.

The authors report their experience in the surgical management of small (less than 1.5 cm diameter) acoustic neuromas. Twenty-nine patients were treated. They had suffered symptoms of unilateral eighth nerve dysfunction on average for 37 months. High resolution CT with iv contrast was the primary investigation. In equivocal cases, air meatography was performed. All operations were performed by the senior author (LS). All tumours were totally removed, there were no deaths and all patients had an excellent result. There were 6 complications (CSF leak 3; meningitis 2; deep venous thrombosis 1). The facial nerve was preserved in 26 cases (and functioned adequately in all) and the cochlear nerve in 62%. In 4 cases with hearing pre-operatively, the decibel loss was the same or less post operatively. In 8 cases speech discrimination remained above 35%.

Psychoacoustic and electrophysiologic effects of partial eighth nerve damage

The authors present psychoacoustic and electrophysiologic data concerning a patient with partial damage to the auditory nerve, presumably from a dilated arterial vessel. The lesion was described and documented during neurosurgery for vestibular nerve decompression. Pure tone thresholds, psychoacoustical tuning curves, speech reception ability for spondaic words, maximum word recognition performance for monosyllabic NU-6 word lists, and performance on the synthetic sentence identification test in the ipsilateral and contralateral competing message modalities were normal. Findings consistent with eighth nerve dysfunction, absent contralateral acoustic reflexes, absent or unrecognizable early evoked potentials occurring in the first 10 msec, brainstem auditory evoked potentials (BAEPs), and slight rollover of the performance intensity function for monosyllabic words were obtained on the involved side. In spite of the grossly abnormal BAEPs, two late, presumably cortical, auditory evoked potential components, which occur in the 60 to 250-msec range--vertex potential and T complex--were present and normal. The findings indicate that the perceptual processes needed for speech reception and recognition and for the appearance of later, presumably cortical-evoked potentials can be preserved despite partial damage to the auditory nerve.

Auditory Dysfunction With Facial Paralysis

A series of 58 patients with idiopathic facial paralysis were studied to determine if a concomitant cochlear or eight nerve auditory dysfunction could be identified with traditional audiologic tests. Results indicated that only those patients with a facial nerve lesion, proximal to the stapedius branch, experienced reduced tolerance for loud sounds, reduction of speech discrimination at high-intensity levels, and abnormal loudness growth. Such findings suggest that changes in auditory function, accompanying facial nerve paralysis, are a mechanical effect due to absence of stapedial action. Site of lesion tests in this sample failed to demonstrate eighth nerve dysfunction and, thus, does not support a theory of polyneuropathy that involves the auditory nerve.