Lecture 5 Vestibular System


PT546 Neuropathology Flashcards on Lecture 5 Vestibular System, created by Mia Li on 02/08/2018.
Mia Li
Flashcards by Mia Li, updated more than 1 year ago
Mia Li
Created by Mia Li almost 5 years ago

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Question Answer
Most common vestibular disorder in the elderly? Benign Paroxysmal Positional Vertigo
Label the following on a picture: 1. endolymph 2. ampulla 3. cupula 4. cilia 5. crista ampullaris 6. axons of vestibular ganglion 7. otoliths 8. gelatinous layer 9. hair cells 10. macula
Resting output of the vestibular nerve is _______. About 6o mV.
In an intact system, eye movement in VOR is a result of _______ in signal sent from vestbular nerve on each side. Difference
Key subjective questions regarding onset of dizziness? 1. sudden or insidious onset? 2. is it episodic? 3. how long does it last? 4. any association with postural/ head position changes?
What are the characteristics of vertigo? 1. sensation of movement in the absence of stimuli 2. spinning, rocking, tilting
Specific follow-up questions regarding vertigo 1. episodic? 2. duration? 3. changes with the head position? 4. nausea and vomiting? 5. constant- associated disequilibrium
Disequilibrium is the sense of unsteadiness or _______. It occurs mainly during ________ or _______ and gets better when _______ or ________. Disequilibrium is the sense of unsteadiness or [imbalance]. It occurs mainly during [walking] or [standing] and gets better when [sitting] or [lying down].
What are some key follow-up questions for disequilibrium? 1. associated neurological symptoms 2. difficulty ambulating in the dark 3. other types of vestibular symptoms
What are some common symptoms of hypotension-related dizziness? 1. presyncope 2. light-headedness 3. foggy head 4. spatial disorientation
What are some follow-up questions if patient has hypotention-related dizziness? 1. associated heart disease 2. posture-related dizziness 3. palpitation 4. medication 5. anxiety 6. hyperventilation
Name some associated symptoms with vestibular problems. Ear-related: tinnitus, hearing loss, phonophobia Eye-related: visual changes, aural fullness, photophobia Others: nausea, vomiting, headache 4Ds
Name the 4 Ds Diplopia Dysarthria Dysphagia Dysmetria
What some special tests for vestibular disorders? 1. MRI 2. CT 3. Audiometric exam
Rationale for MRI? 1. Brain and internal auditory canals (with or without gadolinium) 2. Identification of infarction, tumor
Rationale for CT? 1. Have a good visual of the temporal bones, brain, internal auditory canals 2. assist in identification of hemorrhage, infarction, tumor
What is auditormetric exam trying to differentiate? 1. distinction between conductive or sensorineural loss 2. see if there is word distinction (ability to understand speech)
T/F: Unilateral hearing loss is a sign of aging. F. Need further evaluation.
What is ENG/ VNG? ENG: electronystagmography (electrodes around eye muscles) VNG: videonystagmography
Name the tests that can assess inner ear responses. 1. vestibular evoked myogenic potentials (VEMP) 2. Spontaneous eye movement 3. position testing 4. visual tracking 5. vestibular testing (caloric or rotary chair testing)
Nystagmus is a (reflexive/voluntary) oscillation of the eyes. Reflexive
The fast beat is in the direction of the ear with (increased/decreased) neural activity. Increased.
T/F: Nystagmus at visual end range and during optokinetic stimulation is normal. T.
T/F: Nystagmus suggests central dysfunction. F. Can be either central or peripheral.
Direction fixed nystagmus is (peripheral/central) Peripheral. (horizontal nystagmus)
If the lesion is peripheral, nystagmus (increases/decreases) with visual fixation. Decreases.
If the patient has peripheral vestibular problem and is experiencing left-beating nystagmus, having him/her looking to the left will (increase/decrease) the nystagmus. Increase.
General direction of nystagmus caused by central vestibular dysfunction: direction-changing. pure vertical or pure torsional.
Nystagmus caused by peripheral vestibular dysfunction is (pure/mixed) in direction. mixed pattern with torsion and vertically.
What are some non-vestibular causes of dizziness? 1. multi-factorial 2. panic attack 3. anxiety 4. orthostatic hypotension 5. arrhythmia 6. diabetes 7. hypoglycemia 8. infection 9. medications
match the following with peripheral/ central vestibular dysfunctions. 1. BPPV 2. Cerebellar disorders 3. acoustic neuroma 4. tumors 5. Migraines 6. vestibular neuritis/ labrynthitis 7. MS 8. TBI/ Concussion 9. Meniere disease 10. TIA/ stroke 11. ototoxicity Peripheral: BPPV, Meniere disease, vestibular neuritis/ labyrinthitis, ototoxicity, acoustic neuroma Central: TBI/ concussion, TIA/ stroke, cerebellar disorders, tumors, MS, migraines
What is the pathology of BPPV? The crystals on saccule and utricle break off and interfere with endolymph signals. (when brain is stopped, crystals keep moving)
Other than idiopathic BPPV, what are some etiologies? 1. post-traumatic 2. viral neurolabyrinthitis 3. vertebrobasilar ischemia 4. Meniere's
What are the two forms of BPPV? 1. Canalithiasis 2. Cupulolithiasis
Mechanism of canalithiasis Calcium carbonate crystals (otoliths) in canal
Mechanism of cupulolisthiasis The otoliths are stuck on the cupula (sail-like membrane)
If BPPV lasts for <60sec, it is more likely ____________ while if it lasts more than 60 sec, it is more likely _________. < 60 sec: canalithiasis > 60 sec: cupulolithiasis
Briefly describe the timeline of BPPV. 1. sudden onset of vertigo with nystagmus upon positional changes 2. lasts seconds to minutes 3. episodic
If you suspect BPPV involving anterior and posterior canals, what test should you do? Dix Hallpike
If you suspect BPPV involving horizontal/lateral canals, what test should you do? Roll test
T/F: BPPV symptoms remain the same intensity with repeated testing. F. The symptoms will likely fatigue.
BPPV is central or peripheral? Peripheral
BPPV involves labyrinth or nerve? Labyrinth
Age of population commonly affected by vestibular neuritis/ labyrinthitis 30 - 60
Women are usually affected by vestibular neuritis/ labyrinthitisin their _____s while men are usually affected in their ____s. women 40s. Men 60s.
Possible causes of vestibular neuritis and labyrinthitis? 1. viral infection of upper respiratory tract 2. viral infection of GI tract 3. Autoimmune 4. vascular 5. bacterial infection
T/F: neuritis and labyrinthitis are usually bilateral. F. Unilateral.
How may the symptoms of unlateral vestibular dysfunction be exacerbated? head movement due to inaccurate VOR.
Outline the general timeline of vestibular neuritis/ labyrinthitis. 1. sudden onset of vertigo. may experience nausea/vomiting/nystagmus. 2. Lasts 1-3 days (think acute infection) 3. Vertigo decreases after 3 days, but dizziness and disequilibrium continue. 4. Symptoms will be improving, but still remain worse with quick movements.
T/F: There is no change in hearing due to vestibular neuritis/labyrinthitis. F. May have sensory neural hearing loss.
How is VOR affected by neuritis/labyrinthitis? unilateral VOR with a positive HIT test. (remains after 3 days)
Diagnostic test to confirm/rule out vestibular neuritis/ labyrinthitis: VNG/ENG Reduced unilateral response to caloric stimulation. Ipsilateral hypo- or non-responsive.
Short-term treatment for vestibular neuritis. Vestibular suppressants (to reduce symptoms.
Long-term treatment for neuritis/ labyrinthitis. Vestibular rehabilitation (good prognosis).
Is vestibular neuritis/ labyrinthitis central or peripheral? Peripheral.
T/F: Meniere's disease is usually inulateral. F. Can be either unilateral or bilateral.
The onset of Meniere's disease is usually ____ years old. 40 - 60 years old.
Pathogenesis fo Meniere's disease: 1. trauma 2. infection 3. immunie-mediated 4. genetic predisposition
When patients have Meniere's disease, they are likely experiencing _________________, increased pressure and volume causing abdominal firing of hair cells. malabsorption or endolympe.
Is Meniere's disease episodic? How long can it last? Episodic. Lasts hours to days.
Is prognosis better for acute or chronic Meniere? Acute. (higher risk of permanent damage to vestibular and cochlear organs.
What is the general timeline like for Meniere's Disease? 1. sudden onset of vertigo (> 20min, <24 hours), tinnitus, fullness, hearing loss 2. lasts for minutes to hours 3. resolution of symptom followed by sudden again. 4. fluctuating and progressive 5. Eventual permanent hearing loss and disequilibrium.
Spectrum of hearing loss. Low frequency
Diagnostic tests for Meniere's disease Audiogram (low frequency hearing loss) VNG/ENG (loss of vestibular function)
Treatment options for Meniere's disease. 1. diet (low sodium, alcohol, nicotine, caffeine) 2. Diuretics 3. Suppressive medications 4. Surgery (vestibular nerve section/ labyrinthectomy) 5. Gentamicin perfusion 6. Psychological support 7. Vestibular rehabilitation
What is the 3rd most common intracranial tumor? Acoustic neuroma
Which part of the vestibular system is mostly affected by ototoxicity? Hair cells in vestibular system
Which part of CN VIII is affected by acoustic neuroma? Schwann cells
What are some common locations of tumors for acoustic neuroma? 1. vestibular portion of CN VIII 2. Labyrinth 3. Brainstem 4. Cerebellum
T/F: Symptoms of acoustic neuroma is usually bilateral. F. Usually inilateral.
General timeline of acoustic neuroma 1. insidious onset 2. unilateral hearing loss, may have tinnitus 3. may experience dizziness, and/or disequilibrium 4. gradual worsening 5. central involvement if left untreated
Gold standard to dx acoustic neuroma MRI with gadolinium of internal auditory canals
What are the top 3 medications that cause ototoxicity? Gentamicin Tobramycin Vancomycin
Is ototoxicity usually unilateral or bilateral? Bilateral.
T/F: HIT is positive in ototoxicity. T. (bilaterally positive!)
What are some signature symptoms of ototoxicity? 1. severe disequilibrium 2. oscillopsia 3. falls
Diagnostic test for ototoxicity: ENG/VNG Rotary chair
T/F: Ototoxicity has a faster and better prognosis compared to unilateral vestibular hypofunction. F. Slower and worse prognosis
T/F: With good PT, pt. with ototoxicity can regain previous balance. F. (postural control will NEVER return to normal)
Which situations should your patient avoid if they are diagnosed with ototoxicity? 1. low light situations 2. uneven terrain 3. fatigue
What are some possible reasons that may trigger central vestibular dysfunction? 1. vestibular migraine 2. multiple sclerosis 3. TIA/stroke 4. TBI/ concussion 5. Vertebrobasilar ischemia 6. cerebellar disorders 7. tumors 8. drug intoxication
What is oscillopsia? objects in visual field seem to be oscilating
What are some symptoms of central vestibular dysfunction? 1. disequilibrium 2. nausea 3. lightheadedmess 4. headache 5. falls 6. oscillopsia 7. occasionally vertigo
What are some signs of central vestibular dysfunction? 1. incoordination 2. ataxia 3. disequilibrium 4. abnormal convergence 4. nystagmus (vertical/directional changing) 5. impaired VOR cancellation 6. saccadic smooth pursuit 7. abnormal saccades 8. 4Ds (diplopia, dysphagia, dysarthria, dysmetria)
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