Term
| How does reduced vestibular function relate to reactions? |
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Definition
| Decreased sensitivity of receptor to stimuli. The info processed may be accurate, but insufficient, or not getting through. Can be B or U, and can be complete or incomplete. |
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Term
| What are some causes of reduced vestibular function? (9) |
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Definition
| 1. Head injury 2. CN VIII Dmg 3. Labyrinthitis 4. Ideopathic degeneration 5. Vascular Occlusions 6. Acoustic neuroma 7. Central problems (stroke, tbi, cerebellar dysfunction) 8. Autoimmune disease 9. Antibiotics |
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Term
| How can head injury result in reduced vestibular function? |
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Definition
| May lead to inner ear contusion and scarring of hair cells. It can affect central or peripheral apparati. |
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Term
| What is Ideopathic Degeneraion? |
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Definition
| Degenration of the vestib system that is more accelerated than the normal aging process. |
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Term
| What problem with CN VIII can lead to reduced vestibular function? |
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Definition
| Inflammation (neuronitis) usually is unilateral, and causes degneration. |
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Term
| What areas of vestib system can be affected by vascular occlusions? |
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Definition
| The ear, the midbrain and the cerebellum. |
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Term
| What is Acoustic Neuroma? What is the Tx for this condition? |
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Definition
| A benign tumor of the vestibular nerve. Tx = resection. |
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Term
| What are the risks of acoustic neuroma tx? |
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Definition
| The resection usually results in some inner ear damage which can result in hearing and balance deficits. It can also result in facial nerve damage, because CN 7&8 travel together. |
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Term
| What is an example of an autoimmune disease that can result in decreased vestibular function? |
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Definition
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Term
| How do some antibiotics reduce vestibular function? |
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Definition
| Some, such as gentomycin are ototoxic to the hair cells, and this causes irreversable damage. |
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Term
| What does asymmetric vestibular loss produce for Sx? |
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Definition
| Vertigo, Gaze stability problems for the first few months, and Imbalance. |
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Term
| Define Vertigo. What is it usually caused by? |
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Definition
| Spinning sense. Usu. caused by a vestibulo-ocular problem. |
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Term
| Define Imbalance. How is it different from vertigo? |
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Definition
| Imbalance is ataxia as a result of decreased vestib function. Vertigo is a spinning sense. You can have each of these without the other. |
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Term
| What does bilateral vestibular loss result in for Sx? |
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Definition
| Usually no vertigo, There is: Imbalance (ataxia), movement w/ head fixed to the trunk - walk stiffly, Oscillopsia, No gaze stability if there is a loss of VOR w/ lost of function. |
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Term
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Definition
| The world seems like its always moving. |
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Term
| Why is there usually no vertigo w/ bilateral vestibular loss? |
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Definition
| because there is no mismatch between information from the ears. |
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Term
| What's the difference between reduced and distorted vestibular function? |
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Definition
| Reduced means there is less info getting through, distorted means there is something wrong with the information getting through, the information isn't decreased. |
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Term
| Give an example of distorted vestibular function. |
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Definition
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Term
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Definition
| brief episodes of vertigo and nystagmus produced by changes of head position relative to gravity. |
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Term
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Definition
| The inner ear system is intact, but the stimulus is transduced inaccurately because otoconia get clumped together, bump into the cupula, keep the hairs bent even after the head has stopped moving. This causes compensatory nystagmus when the VOR kicks in. All of these things together result in a feeling of vertigo. |
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Term
| What provokes vertigo in BPPV? |
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Definition
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Term
| What is fluctuating vestibular function? what are the Sx? |
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Definition
| All of a sudden you have severe dizzyness and loss of balance. Can last minutes to days. Sx= vertigo unrelated to position, hearing loss, tinnitis, imbalance. |
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Term
| What are some causes of fluctuating vestibular function? |
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Definition
| Maniers Disease (endoplymphatic hydrops), perilymph fistula. |
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Term
| What is the cause of manier's disease? |
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Definition
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Term
| What are endolymphatic hydrops? |
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Definition
| fluctuating pressure of endolymph. They are unpredictable and associated w/ higher pressures; not necessarily associated w/ movement. |
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Term
| What is perilymph fistula? |
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Definition
| It's an opening in the canal which results in fluid leaking out. It's associated w/ lower pressures. |
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