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