Vestibular System Anatomy & Physiology Techniques Flashcards
7 cards from real CVT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Vestibular System Anatomy & Physiology Techniques flashcards as text
The gain of the VOR is defined as the ratio of:
Answer: Eye velocity to head velocity
VOR gain = eye velocity / head velocity; a healthy VOR has a gain near 1.0, meaning eye speed closely matches and opposes head speed to stabilize gaze.
Which pathway carries vestibular signals from the vestibular nuclei to the contralateral abducens nucleus to coordinate horizontal gaze?
Answer: Medial longitudinal fasciculus (MLF)
The MLF carries internuclear signals from the vestibular nuclei to the contralateral CN VI (abducens) nucleus to coordinate horizontal conjugate eye movements.
A patient with a unilateral left peripheral vestibular lesion at rest would be expected to show spontaneous nystagmus with fast phase beating:
Answer: To the right (contralesional)
A left peripheral lesion reduces left-side tonic input, so the right side dominates and drives the slow phase leftward, with fast-phase nystagmus beating to the right (contralesional).
Caloric testing assesses function of which semicircular canal?
Answer: Horizontal canal
Caloric testing uses warm or cool water/air to create convection currents affecting the horizontal (lateral) semicircular canal, since it is closest to the external auditory canal in the supine head-raised position.
The velocity storage mechanism in the vestibular system is primarily mediated by:
Answer: The vestibular commissure connecting bilateral vestibular nuclei
Velocity storage extends the time constant of the VOR beyond that of the semicircular canals via commissural connections between the bilateral vestibular nuclei.
During the Epley canalith repositioning maneuver for right posterior canal BPPV, the patient is moved through a series of positions designed to:
Answer: Move free-floating otoconia out of the posterior canal into the utricle
The Epley maneuver uses gravity and sequential head positions to guide free-floating canalith debris (otoconia) from the posterior canal back into the utricle.
Which reflex pathway helps maintain upright posture by inhibiting ipsilateral flexors and facilitating ipsilateral extensors in response to vestibular input?
Answer: Lateral vestibulospinal reflex
The lateral vestibulospinal reflex, via the lateral vestibulospinal tract from Deiters' nucleus, facilitates ipsilateral extensor muscles and inhibits flexors to support upright stance.