Clinical vestibular system Flashcards
State the two perceptual mechanisms that are the basis of symptoms
- Vestibular-motion perception. (sensation of motion)
- Seeing environmental motion… i.e. oscillopsia which indicates a nystagmus
This is like when sitting on the train and you think you’re moving because you see the other train next to you moving
i.e.
did they feel like they were moving (i.e. falling like a stone, going round a carousel) and did they see the world move
Commenest causes of emergency room vertigo
- BPPV – 35%
- Vestibular Neuritis – 15%
- Migrainous Vertigo – 15%
- Stroke – 5%
- Mixed (syncope, anxiety…) – 30%
Meniere’s is less than 1%
Possible causes of acute vertigo outside of neurological diagnosis
How to rule these out
PRESYNCOPE
PULMONARY EMBOLISM &; CARDIAC DYSRHYHMIA
do
postural blood pressure.
arterial saturation
ECG
Which system (visual or auditory) is better placed in spatial locatilsation and temporal differences
Auditory system is not so good at localising in space, but eyes are
Auditory system detects changes over time much quicker than the visual system
Which examinations can you do for vertigo
EYES: • Gaze • VOR • Hallpike • Fundoscopy
• EARS: • Otoscop
LEGS: – Gait (+ tandem)
Outline the two phases of a saccade
Fast and slow phase
Slow is due to the nystagmus and then the fast beating back because of the brainstem
T/F a vetibular problem relates to the inner eatr
F…. vestibular problem could involve anywhere in the system… brainstem, ear, cerebellum etc
How can the gaze test on a nystagmus patuent help distinguish between a central and pheripheral vision
This test involves blinding both eyes (by covering one and shining bright light in the other so you can see the nystagmus still)
If it is a peripheral systagmus problem (I.e. with the inner ear) then the nystagmus will be worsened when the patient is blinded. This is because visual system helps to suppress the nystagmus, so when this is removed it increases the nystagmus
If it is central then there will be no worsening when the blindness happens, because the visual input does not help to suppress anyway because of problem with CNS
How can the VOR be tested
doll’s head impulse test (eyes will not remained fixed on you when head turned to the lesioned side)
How can fundoscopy help in the vestibular diagnosis
- Retina 2. Spontaneous nystagmus? 3. Effect of visual fixation on nystagmus?
How can otoscopy help in vestibular diagnosis
Rarely informative in acute vertigo (except for looking for VZV vesicles in acute unilateral peripheral vestibular loss or suppurative infection in meningitis)
t/f/ oral antibiotics are never indicated for actue vertigo
T…. I think because usually viral (VZV/meningitis)
What is BPPV
Benign paroxysmal positional vertigo
What does paroxysmal mean
Sudden onset/attack
When does BPPV commonly occur
Positional – lying back in bed • Brief – seconds [beware prolonged malaise]
