what are VEMPs?
- vestibular evoked myogenic potentials
- small-twitch muscular response (i.e. SCM, IR, soleus)
what are peripheral vestibular lesions?
damage to labyrinths or vestibulo-cochlear nerve (CN VII)
what are central vestibular lesions?
damage to vestibular nuclei or pathways projecting to brainstem, thalamus, or cerebellum
what are common symptoms of unilateral vestibular lesions?
- vertigo
- nausea
- postural instability
what causes vertigo?
spontaneous nystagmus
what causes nausea?
- sensory mis-match or conflict
- vestibular-autonomic connections
how do we test for postural instability?
- Rhomberg test (feet together, eyes closed)
- Fukuda test (marching in place)
- Dynamic posturography
when testing postural instability, which way do patients with lesions sway/fall?
they turn or fall to the side of the lesion
when we lose vestibular nuclei, where do we see symptoms?
- contralateral eye
- ipsilateral tonically active muscles
what are causes of uni-lateral vestibular lesions?
- tumours
- vestibular neuritis
- surgery
- Meniere’s disease
- perilymph fistula
- benign paroxysmal peripheral nystagmus (BPPN)
what surgical procedures would impact the vestibular system?
- labyrinthectomy (chemical or surgical damage to labyrinth)
- vestibular nerve section (tumour removal)
describe Meniere’s disease
- episodic: starts with fullness in ear, hearing loss, tinnitus, moves to vertigo, nausea, imbalances, and drop attacks
- mechanism: increased endolymph volume and pressure, small ruptures of membranous labyrinth
- causes: viral/autoimmune/genetic/?
- treatment: lifestyle change, surgery
what causes a perilymph fistula?
- traumatic injury or severe pressure damage
- round/oval window ruptures, perilymph leaks out
- abnormal nystagmus triggered with pressure (flying, coughing)
describe BPPN
benign paroxysmal peripheral nystagmus
- cause: trauma or age
- how: otoconia dislodge
- diagnosed: with Dix-Hallpike Maneuver
- treated: Epley Maneuver
causes of bilateral vestibular loss
- ototoxic medication
- meningitis
- bilateral Meniere’s disease
common symptoms of bilateral vestibular loss
- postural instability (without vision)
- blurry vision (when moving and fixating)
when do we see issues with the opto-kinetic reflex?
when we have a central vestibular lesion
