Vestibular Exam Flashcards
what lab tests may be used to evaluate vestibular function?
- audiogram
- ENG/VNG, caloric testing
- VEMP testing
what are the 3 things an audiogram will look at?
- Auditory asymmetry
- retrocochlear pathology
- ear canal and tympanic membrane integrity
what type of info does auditory asymmetry tell us during an audiogram?
= sig difference in threshold hearing levels between ears
- indicates the possibility of peripheral vestibular or auditory nerve pathology
- Meniere’s disease
- acoustic neuromas
- perilymph fistula
- labyrinthitis
what is retrocochlear pathology and what findings during an audiogram suggest it?
- refers to site of lesion at:
- CN VIII
- cerebellopontine angle
- CN VIII root
- unilateral sensorineural hearing loss, impaired speech recognition
what is an ENG?
electronystagmography
electrodes placed around the eye to measure the VOR via muscle activation
what is a VNG?
videonystagmography (VNG)
more commonly utilized than ENG
utilized video goggles to monitor eye movements and VOR
what is caloric testing?
a subtest to evalute integrity of unilateral vestibular apparatus
horizontal canal comparative exam
flushing cold/hot water into the ear
Caloric testing and COWS
- Cold irrigations generate nystagmus in the Opposite direction
- Warm irrigations in the Same direction function bilaterallyl
describe how caloric testing impacts a healthy ear
- Back of ear canal sits close to horizontal canal,
- The cold water brings the temp down of the endolymph and inhibits that canal causing the eyes to begin moving in that direction
- But this is auto corrected due to other input from other systems which causes the eyes to rapidly move back causing nystagmus
what is VEMP?
Vestibular Evoked Myogenic Potential
short-latency muscle reflexes typically recorded from the neck (cVEMP) or eye (oVEMP) muscles with surface electrodes
what is cVEMP?
Cervical Vestibular Evoked Myogenic Potential
measurement of saccule function via its inhibitory control of SCM
what would be considered abnormal functioning during cVEMP?
- abnormal saccule function
- no muscular response to sound
- asymmetrical response R vs L (due to lack of inhibition of SCM on one side)
- Structural abnormality
- evoked response from softer sound waves
what types of conditions should be ruled out during the system’s review
- Stroke
- Migrane
- Seizure
- Heart disease
- Head injury, temporal bone frx
- Cervical cord compression
- Arrhythmias
- Orthostatic hypotension
- HTN
- DM (retinopathy)
- Arthritis, spinal stenosis
- Ankylosis Spondylitis
- Anxiety, Panic
what is included in subjective history for “dizziness”?
- type of dizziness/description of symptoms
- triggers
- onset/duration
- frequency
describe the term “dizziness”
- non-specific term
- encompasses feeling of imbalance, spinning, and lightheadedness
- can have a multitude of vestibular and non-vestibular causes
describe the term vertigo
- false sense of self-motion
- rotational or linear
- due to imbalance of tonic neural activity to vestibular cortex
- caused by peripheral or central vestibular damage
describe the term oscillopsia
- gaze instability
- illusionary sensation that a stational visual world is moving
- can be seen with bilateral > unilateral vestibulopathy, central vestibular dysfunction
describe the term disequilibrium
- imbalance or unsteadiness while standing or walking
- common causes:
- visual changes
- vestibular dysfunction
- proprioception deficits
- Other causes:
- neuromuscular deficits
- joint pain
- psychological factors
describe the term lightheadedness
- also referred to as pre-syncope
- caused from brief decreases in blood flow to brain
describe the term motion sickness
- episodic dizziness, tiredness, pallor, diaphoresis, salivation, and N/V
- induced by passive locomotion (car) OR motion in visual surroundings while standing still
- caused by sensory mismatch between visual and vestibular systems
list some RED flags to screen out for during the subjective history
- severe HA
- rapid hearing decline
- dysarthria
- discoordination
- diplopia
- decreased mentation and urinary incontinence
- acute weakness
- decreased consciousness
- additional cranial nerve dysfunction
what should be included in the vestibular examination?
- Auditory screen
- gaze stability assessment
- cervical dizziness tests
- balance and postural control assessment
list gaze stability assessments
- spontaneous nystagmus
- evoked nystagmus
- smooth pursuit
- saccades
- optokinetics
- dynamic visual acuity
- head impulse test
- head shake test
- skew deviation
list types of eye movements that could be observed
- smooth pursuit
- saccades
- VOR
- optokinetic
- Nystagmus
T/F: Nystagmus can be a normal finding
FALSE
95% of the time it is abnormal
what is nystagmus?
repetitive, to-and-fro movement of the eye characterized by a fast and slow phase of movement
- caused by imbalance between vestibular apparatus signaling
- defined by the direction of the fast phase of movement
- upwards/downwards, horizontal, torsional
nystagmus presentation can range from ______________
spontaneous to responsive
to triggers
constant to intermittent
what are the 2 main ways to classify nystagmus?
- spontaneous
- evoked
list the types of spontaneous nystagmus
- peripheral vestibular imbalance nystagmus
- congenital nystagmus
- central nystagmus
list the types of evoked nystagmus
- gaze-evoked
- head shaking
- optokinetic
- positional
- caloric
- pressure-induced
- sound-induced
define spontaneous nystagmus
onset of nystagmus without any cognitive, visual or vestibular stimulus
occurs in the absence of any purposeful eye or head motion
Compare peripheral vs central spontaneous nystagmus
- Peripheral nystagmus
- mixed horizontal/torsional
- present with acute lesions, rarely with chronic stable lesions
- more prominent with fixation removed
- Central nystagmus
- vertical or torsional
- acute or chronic
- more prominent with fixation present
what are 2 options for visual fixation blockers?
- Frenzel lenses
- Video infrared googles
list 2 outcome measures that can be used in a vestibular examination
- Motion sensitivity quotient → obj measure
- dizziness handicap inventory → subj measure
describe the motion sensitivity quotient
- position-dependent clinical examination that evaluates symptom response
- excellent clinical utility, but psychometric data still in infancy
- Specificity → 80%
- Sensitivity → 100%
how is the motion sensitivity quotient scored?
- Mild vestibular dysfunction → 0-10
- Moderate vestibular dysfunction → 11-30
- Severe vestibular dysfunction → 31-100
describe the dizziness handicap inventory outcome measure
- 25-item self-assessment inventory designed to evaluate self-perceived handicap from dizziness
- 0-100 scale, higher scores = higher percieved handicap
- 3 subscales of questions:
- physical
- emotional
- functional
describe the metrics/cut-off scores for the dizziness handicap inventory questionnaire
- cut-off scores for disability:
- mild = 0-30
- moderate = 31-60
- severe = 61-100
- MCID = 18
