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Gerontology Mod08
Vestibular System - Age and Pathologic Changes
| Question | Answer |
|---|---|
| What is vestibulopathy? | Pathology of the peripheral vestibular system, central vestibular system, or neural pathway connecting htem |
| Common symptoms of vestibulopathy | Vertigo Visual disturbances Oscillopsia Nausea and vomitting Imbalance Brain fog Fatigue |
| Signs of vestibulopathy | Nystagmus Gaze instability Coordination deficits Gait ataxia Impulsion Oscillopsia Disequilibrium |
| Age related changes affecting vestibular system | Vestibular hair cell degeneration Vestibulocular reflex deficits Peripheral neuropathy Otoconia displacement |
| Common causes of vertigo | Imbalance of tonic vestibular signals arising from: Inner ear Middle ear Brainstem Cerebellum |
| Signs of a central lesion | Impaired saccades Smooth pursuit Optokinetic nystagmus Usually seen with central lesions Diplopia Ataxia |
| Causes of central lesions | Ischemia of the brain stem Cerebellar infarts Medullary infarcts MS etc. |
| Signs of Peripheral Vesitbulopathy | Often involve hearing loss and tinnitus without neurologic signs Often develop acutely adn have intermittent and short lasting symptoms Tend to cause more severe vertigo with N&V |
| Benign Paroxysmal Positional Vertigo (BPPV) | Syndrome characterized by short-lived episodes of vertigo associated with rapid chaqnges in head position Associated nystagmus with a latency of a few seconds and fatigues after 30 seconds Nystagmus in "signature" patterns |
| Canalithiasis | Cause of BPPV Term used for loose otoconia flowing within the semicircular canals |
| Cupulolithiasis | Cause of BPPV Term used when otoconia attach to the cupula within the ampulla making it gravity sensitive |
| Vestibular Hypofunction | When the peripheral vestibular system is damaged unilaterally, neuronal activity reaching the ipsilateral vestibular nuclei is reduced compared to the contralateral vestibular nuclei |
| Signs of vestibular hypofunction | Spontaneous nystagmus - typically resolves within a couple of weeks Loss of visual acuity: gaze instability, oscillopsia Postural instability |
| Endolymphatic Hydrops | Abnormality in the quantity, composition, and/or pressure of the endolymph Primary - idiopathic = Meniere's disease Secondary - response to underlying condition (head trauma, ear surgery, inner ear disorders, allergies, systemic disorders) |
| What will visual acuity at a distance poorer than 20/50 affect? | Significant effect on postural stability |
| What modification can be made to the vision test to check for vestibular hypofunction? | With unilateral hypofunction there will be a doulbing of vision when turning the head to one side. |
| In a patient with vestibular hypofunction what is the result of the Head Impulse Test (Head Thrust Test)? | The pt's eyes will go to the side that is weak then saccade back to the other side. This occurs when their vision is on a fixed point and their head is moved. |
| Medical treatments for vertigo | Antihistamines - prevent motion sickness, nausea, vomitting, and vestibulopathy Phenothiazines - control severe N&V Anticholinergics - prevent N&V, and motion sickness Benzodiazepines - CNS depressant, used for anxiety - chronic problems |
| What medications should be discontinued if vertigo presents? | Ototoxic medications (i.e. ASA) |
| Modified Epley | Canalith repositioning maneuver for the posterior canal (BPPV) |
| Horizontal Roll | Canalith repositioning maneuver for the horizontal canal (BPPV) |
| Vestibular Rehabilitation Therapy (VRT) | Treatment for Hypofunction Relies on the plasticity of the CNS Does not regenerate or treat the damaged vestibular end-organ itself Allows CNS and brain to adapt to asymmetrical input from VOR and VSR |