Mackenzie Vestibular flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Ampullopetal flow

Endolymph flow toward the ampulla, which excites horizontal canal hair cells and increases afferent firing; in vertical canals the polarity is reversed.

Ewald's second law

For the horizontal canal, excitation produces a stronger response than inhibition, which explains the direction of nystagmus in caloric and rotational testing.

Utricle function

The utricle lies roughly horizontal and senses horizontal linear acceleration and head tilt; its signals contribute to ocular counter-roll and postural tone.

VOR latency

The vestibulo-ocular reflex acts within about 5 to 7 milliseconds through a three-neuron arc, stabilizing gaze during high-velocity head movement.

Velocity storage

A central mechanism that prolongs the horizontal VOR time constant to roughly 15 to 20 seconds, sustaining the slow phase of caloric nystagmus.

Duration triage rule

Vertigo lasting seconds suggests BPPV, minutes to hours suggests migraine or Meniere disease, and days suggests neuritis, stroke, or concussion.

Meniere disease features

Recurrent spontaneous vertigo lasting 20 minutes to 12 hours plus fluctuating low-frequency hearing loss, tinnitus, and aural fullness; low-frequency SNHL supports the diagnosis.

Vestibular neuritis pattern

Acute prolonged vertigo with a positive head impulse test and no new hearing loss or focal neurologic signs; the superior vestibular division is most often involved.

HINTS exam logic

Normal head impulse, direction-changing nystagmus, and skew deviation suggest a central lesion; all three peripheral-pattern findings favor a peripheral cause.

Central red flags

New headache, diplopia, dysarthria, dysphagia, hemianesthesia, truncal ataxia, vertical or direction-changing nystagmus, and inability to stand warrant urgent evaluation.

Head impulse technique

With fixation on a target, deliver quick 10 to 20 degree unpredictable head thrusts; a corrective saccade indicates reduced VOR gain on that side.

Dix-Hallpike maneuver

Head turned 45 degrees toward the tested ear, then rapid move from sitting to supine with neck extended 20 degrees; upbeating torsional nystagmus with latency indicates posterior canal BPPV.

Supine roll test

With the patient supine, turn the head 90 degrees to each side; geotropic nystagmus is stronger on the affected side and apogeotropic on the unaffected side.

Skew deviation test

Alternate cover testing in primary gaze; a vertical corrective movement indicates skew deviation, which suggests a central rather than peripheral vestibular lesion.

Head-shaking nystagmus

After 20 seconds of horizontal head shaking at about 2 Hz, a single direction of nystagmus suggests peripheral asymmetry, while reversal suggests central disease.

Jongkees formula

Unilateral weakness equals right warm plus right cool minus left warm plus left cool, divided by the total of all four responses, times 100.

vHIT gain

Video head impulse testing measures VOR gain at high head velocities; gain below about 0.8 with corrective saccades suggests hypofunction, though partial deficits can be missed.

cVEMP

Cervical VEMP uses loud clicks or 500 Hz tone bursts recorded from the sternocleidomastoid; it tests the saccule and inferior vestibular nerve.

oVEMP

Ocular VEMP is recorded below the eyes with upward gaze; it tests the utricle and superior vestibular nerve and is absent in superior division involvement.

Rotary chair testing

Sinusoidal rotation quantifies VOR gain, phase, and symmetry at low frequencies; it is useful in bilateral vestibulopathy and suspected central disease.

Epley maneuver sequence

From Dix-Hallpike position, rotate the head 90 degrees to the opposite side, roll the patient to side and prone, then sit up, holding each position until nystagmus settles.

Semont maneuver

A rapid swing from the affected side to the opposite side through sitting; it is an alternative liberatory maneuver for posterior canal BPPV.

Geotropic nystagmus

Horizontal nystagmus beating toward the ground on both sides in supine roll testing; it indicates horizontal canal BPPV and is treated with a 360-degree roll.

Canal conversion

After repositioning, debris can move into another canal, most often the horizontal canal; new rotational vertigo should prompt repeat supine roll testing.

Gaze stabilization exercise

Small-amplitude head rotations while fixating a target; these drive VOR adaptation and are dosed according to symptom provocation and duration.

Bilateral vestibulopathy rehab

Rehabilitation emphasizes substitution with visual and somatosensory cues, balance training, and fall prevention, because VOR adaptation cannot restore bilateral loss.

Dizziness Handicap Inventory

A 25-item self-report measure of self-perceived handicap from dizziness, scored 0 to 100, used to track rehabilitation progress.

Downbeat nystagmus

Nystagmus beating downward in primary gaze, often associated with cerebellar or cervicomedullary lesions; it is a central finding that warrants neuroimaging.

VOMS assessment

A concussion screening battery including smooth pursuit, saccades, convergence, VOR, and visual motion sensitivity; provocation of 2 or more points is considered positive.

Cervicogenic dizziness

Dizziness associated with neck pain and altered cervical proprioception, diagnosed clinically after other causes are excluded; it improves with cervical proprioceptive training.

PPPD criteria

Persistent postural-perceptual dizziness involves unsteadiness and visual motion sensitivity lasting 3 months or more; treatment includes rehabilitation and cognitive behavioral therapy.

Fall precautions

During caloric, rotary chair, and repositioning procedures, maintain a clear path, allow seated recovery, and assist patients with balance deficits to reduce fall risk.