auditory function and balance Flashcards
clinical vestibular disturbance: define dizziness, vertigo and oscillopsia; recognise how these conditions differ; explain the consequences of uni- and bilateral loss of vestibular function
effect of unilateral lesion in vestibular system
could be organ or nerve, so no resting discharge from one side of vestibular system, so interprets as movement in direction of no resting discharge, so eyes move to left; vision recorrects -> constant cycle of slow brainstem movement and fast central compensation
8 methods of diagnosing unilateral lesion in vestibular system
anamnesis, cranial nerves, balance and gait assessment, cerebellum, gaze assessment (eye movements), vestibular tests, imaging, subjective assessment (questionnaires)
4 vestibular tests in vestibular diagnosis
caloric test, vHIT, VEMP, rotational test
2 imaging techniques in vestibular diagnosis
CT scan, MRI
symptoms of vestibular lesion
vertigo, dizziness and giddiness, unsteadiness, self-motion perception
define vertigo
illusion of movement (usually rotational or ‘true vertigo’, whereas dizziness and giddiness are more vague)
define unsteady
off balance (bilateral vestibulopathy)
2 locations of peripheral vestibular disorders
labyrinth, vestibulocochlear nerve
4 examples of peripheral vestibular disorders
vestibular neuritis, BPPV, Meniere’s disease BVF, UVF
location of central vestibular disorders
CNS (brainstem/cerebellum)
3 examples of central vestibular disorders
stroke, MS, tumours
evolution of vestibular disorders
acute -> intermittent -> recurrent -> progressive
2 examples of acute vestibular disorders
vestibular neuritis (‘labyrinthitis’), stroke
example of intermittent vestibular disorder
benign paroxysmal positional vertigo (BPPV)
2 examples of recurrent vestibular disorders
Meniere’s disease (rare), migraine (common)
example of progressive vestibular disorder
acoustic neuroma on vestibulocochlear nerve, causing degeneration
7 differential diagnoses to vestibular disorders which present with similar dizzy symptoms
heart disorders, presyncopal episodes, orthostatic hypotension, anaemia, hypoglycaemia, psychological, gait disorders
parts of vestibular system (pyramidal)
spinal cord -> ponto-medullary junction (where nerve to peripheral vestibular organ) -> vestibular cerebellum -> thalamus -> cerebral cortex
what is vestibular-motion perception
sensation of motion (self or environment)
what is oscillopsia
defect in seeing environmental motion (indicates nystagmus)
define nystagmus
seeing visual world move (slow phase, fast phase repeated)
dizziness or vertigo
describe symptoms in words: self or environmental motion (eyes shut), seeing room move; origin may come from ear or brain
illusory self-motion: low current
feeling of gentle rocking of self
illusory self-motion: high current
feeling of violent spinning of self and room
most common emergency room vertigo diagnoses, which history and examination are aimed at
benign paroxysmal positional vertigo (BPPV) - always look for, vestibular neuritis (bipalsy), migrainous vertigo, stroke, mixed (Meniere’s <1% - disorder of inner ear)
3 simple measurements to take when acute vertigo suspected
postural blood pressure, arterial saturation, ECG
what 3 things are ruled out when diagnosing acute vertigo
presyncope, pulmonary embolism, cardiac dysrhythmia
3 core examination areas for acute vertigo
eyes, ears, legs
4 investigations of core eye examination for acute vertigo
gaze, vestibulo-ocular reflex, hallpike, fundoscopy
investigation of core ear examination for acute vertigo
otoscopy
investigation of core legs examination for acute vertigo
gait (and tandem)
gaze in patients with peripheral nystagmus
nystagmus suppressed with vision, so without visual fixation, nystagmus increases intensity so is peripheral (affecting ear)
vestibulo-ochlear reflex in patients with nystagmus
doll’s eyes and head impulse test - tell which way nystagmus is as eyes taken off target when head moved - can tell peripheral
fundoscopy in patients with acute vertigo
retina, spontaneous nystagmus, effect of visual fixation on nystagmus
otoscopy in patients with acute vertigo, and impact on antibiotic admission
rarely informative except for unilateral peripheral vestibular loss (e.g. Herpes) or suppurative infection in meningitis, so oral antibiotics never indicated
gait and tandem walking in patients with acute vertigo
narrow gait?, count how many mistakes out of 10 tandem steps, see if eye closure affects balance, and can maintain balance for >20s without vision
investigating BPPV (benign paroxysmal positional vertigo): position and duration
lying back in bed, with very brief duration (seconds as beware prolonged malaise)
investigating BPPV (benign paroxysmal positional vertigo): red flags
headache, atypical nystagmus
investigating BPPV (benign paroxysmal positional vertigo): typical vs atypical vs complex
typical: latency of 10 seconds before see nystagmus when tilt head back due to crystal movement (localise canal), atypical and complex: down-beating nystagmus is central); adaptability, fatiguability
treating posterior canal BPPV (benign paroxysmal positional vertigo)
epley, semont (right hallpike and semont) to remove crystal debris from semicircular canal
define vestibular agnosia in acute traumatic brain injury
lack of sensation of dizziness despite a peripheral vestibular activation (evoked nystagmus) indicates a loss of vestibular sensation; nystagmus but don’t see world spin
vestibular neuritis: onset
subacute (minutes -> hours) continuous vertigo
vestibular neuritis: symptoms
obvious “vestibular” nystagmus, positive head impulse test, normal gait
vestibular neuritis: treatment
vestibular sedatives (24-36 hours), mobilise at day 3, treat any BPPV or migraine
vestibular neuritis: 5 red flags
headache, gait ataxia, hyperacute onset, vertigo and hearing loss, polonged symptoms (>4 days)
vestibular neuritis red flags: cause of 40% headaches
posterior circulation stroke
vestibular neuritis red flags: cause of gait ataxia
may be only non-vertiginous manifestation of cerebellar stroke
vestibular neuritis red flags: what does hyperacute onset suggest is origin
vascular
vestibular neuritis red flags: what does vertigo and hearing loss indicate
AICA or ugent ENT problem
vestibular neuritis red flags: what do prolonged symptoms indicate
floor of 4th ventricle problem
acute vestibular migraine: history, symptoms and diagnosis
history of migraine, acute vertigo with/out headache and recurrent episodes, diagnosis of exclusion
acute vestibular migraine: main differential diagnosis
cerebellar stroke
acute vestibular migraine: 5 red flags (same for cerebellar stroke)
headache, gait problems, hyperacute onset, hearing loss, prolonged symptoms (>4 days)
cerebellar stroke: symptoms
thunderclap onset vertigo, difficulty walking, headache
