Microsoft Office Pro 2007 acoustic neuroma.html

[uioovcfghh]

acoustic neuromas, often known as vestibular schwannomas, are non-malignant tumors of the 8th cranial nerve. most generally they occur through the covering cells (schwann cells) with the inferior vestibular nerve (komatsuzaki and tsunoda, 2001). they comprise about 6 percent of all intracranial tumors, about 30% of brainstem tumors, and about 85% of tumors in the region with the cerebellopontine angle -- another 10% are meningiomas. only about 10 tumors are newly diagnosed each year per million persons in the united states,Microsoft Office Pro 2007, corresponding to between 2000 and 3000 new cases each year. in patients with hearing asymmetry, it is believed that only about 1 in 1000 has acoustic neuroma (source: nih).

acoustic neuroma occurs in two forms: a sporadic form and a form associated with an inherited syndrome called neurofibromatosis type ii (nf2). about 95 percent of all cases are sporadic. nf2 is rare; there are only several thousand affected individuals in the entire united states, corresponding to about 1 in 40,000 individuals. roughly 5% of patients with acoustic neuroma have type ii neurofibromatosis. there is presently no evidence that radiation from cellular phones causes acoustic neuroma (muscat et al, 2002).
signs and symptoms:
hearing loss is the most frequent symptom,Windows 7 Ultimate Key, occurring in more than 95 percent of patients. about 90 percent present with a one-sided, slowly progressive hearing impairment. an example is shown below. a high-frequency sensorineural pattern is the most common type, occurring in approximately two-thirds of patients. in the remaining third the next most common observation is hearing loss at low frequency (which would be more typical of meniere's disease). even less frequently, some have the "cookie bite" pattern (suggestive of congenital hearing loss). a sudden hearing loss occurs in about 25 percent of patients with acoustic neuroma. however, because acoustic neuroma is a rare condition, sudden hearing loss attributable to an acoustic tumor occurs in only 1-5 percent of patients with sudden hearing loss as there are many more common causes (daniels et al, 2000). hearing can be completely normal in about 11% of patients (morrison and sterkers, 1996). tinnitus is very common in acoustic neuroma,Office 2010 Download, is usually unilateral and confined to the affected ear.
in spite from the origin of acoustics in the inferior vestibular nerve (komatsuzaki and tsunoda, 2001),Office 2007 Download, vertigo (spinning) is not common, occurring in only about 20 percent of persons with acoustic neuroma. vertigo is more common with smaller tumors. unsteadiness is much more prevalent than vertigo,Office Pro 2007, and approximately 70 percent of patients with large tumors have this symptom. cerebellar symptoms (i.e. poor coordination with the arms) are unusual.

facial sensory disturbances occurs only in large tumors (about 50 percent of those greater than 2 cm in size). the facial sensory disturbance may respond to carbamazepine medication for neuralgia. facial weakness is uncommon. facial twitching, also referred to as facial synkinesis or hemifacial spasm, occurs in about 10 percent of patients. headache prior to surgery occurs in roughly 40 percent of those with large tumors.
diagnosis of acoustic neuroma: