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