LAB - Vest. Exam Flashcards
What should you expect to find with the Weber and Rinne test if vestibular-related
auditory loss is present?
Weber: louder in unaffected ear
Rinne: no BC or AC
Why does it matter whether your patient has taken anti-vertigo medications prior to your session?
Difficult to evaluate nystagmus
What are the two ways that we will observe nystagmus during a clinical examination?
Spontaneous or gaze evoked
Peripheral Vestibular Nystagmus:
- Effect of fixation
- Direction of fast phase
- Effect of gaze
Unidirectional nystagmus
Fixation: nystagmus decreases
Fast Phase: Mixed (horizontal + torsional)
Gaze: increased toward gaze direction of quick phase (away from involved ear)
Acute > chronic
Central Vestibular Nystagmus:
- Effect of fixation
- Direction of fast phase
- Effect of gaze
Multidirection nystagmus
Fixation: nystagmus increases or stays the same
Fast Phase: Single-plane (torsional or vertical)
Gaze: does not change or reverses direction
Acute or chronic
Explain Alexander’s Law and its clinical relevance.
Describes how to classify peripheral vestibular nystagmus.
1st degree nystagmus
only present when gaze directed towards fast phase
2nd degree nystagmus
present in primary gaze < directed toward fast phase (strongest)
3rd degree nystagmus
present in all 3 gazes, strongest when gaze directed towards fast phase
What is the purpose of visual fixation blockers?
Take away the ability to fixate
In which of the following scenarios could you NOT use visual fixation blockers?
- Assessing for spontaneous nystagmus
- Assessing VOR with a head impulse test
- Assessing VOR with the head-shaking test
- Assessing eye movements elicited during BPPV maneuvers
- Assessing VOR with a head impulse test
What is an abnormal responses for the Head Impulse Test?
- Corrective saccade +/- post-thrust nystagmus (PNS)
- Normal w/vertigo (CNS)
How can sensitivity be improved with the Head Impulse Test?
- Unpredicted Head Thrusts
- Frequency (2Hz) and velocity >180 deg/sec
- Maintaining appropriate head positioning (30º below neutral)
What is an abnormal responses for the Head Shake Test?
PVD: >3 beats nystagmus
CVD: vertical nystagmus
What does the Dynamic Visual Acuity test investigate?
functional challenge to VOR, better for subacute/chronic cases
What is the abnormal response to the Dynamic Visual Acuity Test?
3 or more line degradation
What is the functional relevance of optokinetic nystagmus?
Works synergistically with VOR to maintain gaze stability
What is an abnormal response during optokinetic testing?
Asymmetrical response
What do smooth pursuit and saccades test for?
Central vestibular disorders
What would be an abnormal response to smooth pursuit and saccades tests?
Slow, inaccruate, hypo/hypermetric
What does Skew Deviation test for?
Central vestibular involvement
What is an abnormal response to the Skew Deviation test?
Deviation of one eye while the other is being covered, followed refixation after uncovering it.
What does VOR Cancellation test for?
cerebellar control with regards to modulation of VOR
What is an abnormal response to the VOR Cancellation test?
corrective saccades ipsilaeral to cerebellar lesion