NCS Vestibular Rehabilitation 1 — Questions and Answers
Question 1: Which semicircular canal is most commonly affected in benign paroxysmal positional vertigo (BPPV)?
- Anterior semicircular canal
- Posterior semicircular canal (Correct answer)
- Horizontal semicircular canal
- Superior semicircular canal
Correct answer: Posterior semicircular canal
The posterior semicircular canal is affected in approximately 85–90% of BPPV cases due to its anatomical orientation making it most susceptible to canalith accumulation when upright.
Question 2: The Dix-Hallpike test is the gold standard for diagnosing BPPV affecting which canal?
- Horizontal semicircular canal
- Anterior semicircular canal
- Posterior semicircular canal (Correct answer)
- Cochlear duct
Correct answer: Posterior semicircular canal
The Dix-Hallpike maneuver positions the posterior semicircular canal in the plane of gravity, provoking characteristic upbeat-torsional nystagmus when canaliths are displaced into that canal.
Question 3: What type of nystagmus is characteristic of posterior canal BPPV when performing the Dix-Hallpike test?
- Pure horizontal, direction-changing nystagmus
- Upbeat-torsional nystagmus beating toward the affected ear (Correct answer)
- Downbeat-torsional nystagmus toward the unaffected ear
- Purely vertical downbeat nystagmus
Correct answer: Upbeat-torsional nystagmus beating toward the affected ear
Posterior canal BPPV produces upbeat-torsional nystagmus beating toward the affected (lowermost) ear due to ampullofugal deflection of the cupula by displaced canaliths.
Question 4: The Epley canalith repositioning maneuver for posterior canal BPPV guides canaliths from the posterior semicircular canal back into the:
- Endolymphatic sac
- Anterior semicircular canal
- Utricle (Correct answer)
- Cochlea
Correct answer: Utricle
The Epley maneuver uses four sequential head positions to move free-floating canaliths (otoconia) out of the posterior semicircular canal and back into the utricle where they cannot cause symptoms.
Question 5: The head impulse test (Halmagyi-Curthoys test) assesses the integrity of which reflex?
- Vestibulo-spinal reflex
- Optokinetic reflex
- Vestibulo-ocular reflex (Correct answer)
- Cervico-ocular reflex
Correct answer: Vestibulo-ocular reflex
The head impulse test detects VOR deficits by observing whether corrective catch-up saccades occur after a rapid, small-amplitude horizontal head thrust toward each side.
Question 6: A patient with acute unilateral vestibular neuritis would most likely demonstrate which finding on examination?
- Bilateral symmetric caloric weakness
- Spontaneous nystagmus beating toward the affected side
- Positive head impulse test when the head is thrust toward the affected side (Correct answer)
- Pure vertical downbeat nystagmus
Correct answer: Positive head impulse test when the head is thrust toward the affected side
Unilateral vestibular neuritis causes ipsilesional VOR deficit, resulting in a positive head impulse test (visible corrective saccade) when the head is rapidly thrust toward the lesioned side.
Question 7: Which characteristic distinguishes peripheral vestibular nystagmus from central vestibular nystagmus?
- It may be purely vertical
- It is direction-changing with lateral gaze
- It is direction-fixed and suppressed by visual fixation (Correct answer)
- It is not associated with any hearing symptoms
Correct answer: It is direction-fixed and suppressed by visual fixation
Peripheral vestibular nystagmus is direction-fixed (fast phase does not change direction with gaze) and is suppressed by visual fixation, distinguishing it from central causes.
NCS Vestibular Rehabilitation 1
Which semicircular canal is most commonly affected in benign paroxysmal positional vertigo (BPPV)?