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Abnormal noise/inner ear (tinnitus) is usually involvement of which brain structure?
Cochlea
Fluid that fills the canals
Endolymph
- Smaller than a spec of dust
- Age related changes - hypertrophy, variability in size, fragmentation, fissured, pitted, weaknening of links
- Worse with females / osteoporetic (older age; but starts worsening in middle age)
- Otoconia SHOULD BE in the otoliths
- Belong in wall of saccule and floor of utricle
Role of otoconia and dysfunction
- Maintains image of a small moving target on the fovea which is the center of the retina (region of highest visual acuity)
- This comes from the BRAIN, issue is CNS involvement
- Test of oculomotor movement via H-test: horizontal and vertical
- Abnormal or intact
If patient presents with abnormal saccades.. where is the issue?
Cerebellar or pons
Gel like bud, embedded with sensory hair cells, that sits within the ampullated (dilated) portion of each canal
Cupula
Signals travel from labyrinth to the brain via which nerve?
Vestibulocochlear N
What is the major artery supply to the inner ear?
Anterior inferior cerebral artery (AICA) off of the Basilar A
- Anxiety
- Fear avoidance
Psychological impact relating to vestibular issues
- VOR testing and visual acuity testing
- VOR and visual acuity testing can help rule in a PNS diagnosis
- VOR testing can help in an acute stroke
Other tools
- Not affected by gravity
- Sense rotation
- 3 in each ear, 6 total (horizontal, anterior, posterior)
- Parts of the canal: endolymph, ampulla, cupula
- Dysfunction of SCCs: "spinning" or vertigo
Semicircular canals
Dilated space/opening at the end of each canal; cilia/hair cells are located within ampulla, more specifically held in endolymph in a place called the cupula
Ampulla
- Are affected by gravity
- Detect forward/backward head tilts and translation of head; detect gravity and position in space
- Otolithic organs (2 in each ear) = utricle and saccule
- Otoconia are IN the otolith organs - should NOT be in the SCCs
- Canals originate from utricle
- Pulling/shifting = utricle dysfunction
Otoliths
- Observation
- Oculomotor testing
- Gaze stability assessment
- Findings
- Action
CNS screening components
- Looking for evoked nystagmus while patients gaze is sustained on an object
- CNS disorder if nystagmus is direction changing with gaze, wont change with PNS disorders
Gaze holding
- Concussion/brain injury
- MS, stroke, cerebellar degeneration (established CNS dysfunction)
- Dizziness of unknown origin: recent fall, missed stroke, undiagnosed tumor/aneurysm
Central vestibular disorders - CNS
What is the major recipient of outflow from vestibular nucleus complex, major source of input for vestibular reflexes
Cerebellum
- Benign paroxysmal positional vertigo
- Vestibular neuritis/labyrinthitis
- Acoustic neuroma
Peripheral vestibular disorders -- PNS
- Rapid eye movements that bring the object of interest onto the fovea, voluntary and conjugate
- Abnormal = cerebellar or pons issue
- Test of oculomotor movement: patients eyes move between two targets, horizontal and vertical
- Looking for symmetry, accuracy, speed
- Abnormal or intact
Saccades
- over/under shooting
- must use corrections
- nystagmus
Abnormal saccades
- Vestibular migraine
- Cervicogenic dizziness
- Disuse disequilibrium (deconditioning)
- Cardiac
- Psychological
- Chronic subjective dizziness
- Medication induced dizziness
- Persistent postural perceptual dizziness
- Visual vertigo
Non-otogenic dizziness
- Inability to maintain focus
- Lacks smoothness
- Nystagmus
Abnormal smooth pursuit
- resting eye position
- Spontaneous nystagmus
Smooth pursuit
Saccades
Gaze holding
Oculomotor testing and gaze stability assessment
What are the 5 D's?
1. Dysarthria
2. Dysphagia
3. Diplopia
4. Drop attacks
5. Dizziness ***
- With gaze holding, presence of nystagmus
- At rest, presence of nystagmus
Gaze evoked or spontaneous nystagmus