Quiz-395-Section Two

The paramedic is performing a Dix-Hallpike manoeuvre on a patient with suspected posterior canal BPPV. Which head positioning sequence correctly aligns the posterior semicircular canal for maximal provocation?

Dix-Hallpike Technique and Interpretation

Rotate head 45° toward the ear being tested, then rapidly supinate with 20–30° head extension below horizontal

Rotate head 90° to each side sequentially while supine with neutral head elevation of 30°

Extend neck 45° below horizontal in the midline with no lateral rotation

Keep head upright at 45° flexion while tilting the patient laterally toward the affected ear

This field is required.

Press Enter ⏎

During positional testing, which nystagmus characteristic most strongly indicates a central etiology rather than benign paroxysmal positional vertigo?

Peripheral Versus Central Nystagmus Differentiation

Upbeat-torsional nystagmus with 5-second latency resolving within 45 seconds

Horizontal nystagmus with direction-changing pattern regardless of gaze fixation

Transient horizontal geotropic nystagmus fatiguing with repeated supine roll testing

Reversal of nystagmus direction upon return to upright sitting position

This field is required.

Press Enter ⏎

A patient demonstrates horizontal nystagmus during the supine roll test that beats toward the ground on both sides but is more intense when the right ear is down. What finding identifies the affected labyrinth?

Differential Canal BPPV Diagnosis

Left ear based on weaker nystagmus intensity during left lateral positioning

Right ear based on stronger geotropic nystagmus when that ear is dependent

Both ears based on bilateral nystagmus presence without lateralising asymmetry

Anterior canal based on absence of torsional component during testing

This field is required.

Press Enter ⏎

When applying the HINTS battery framework to a patient with acute prolonged vertigo, which combination of findings suggests posterior fossa stroke despite otherwise reassuring history?

HINTS Examination Framework

Positive head impulse test, unidirectional nystagmus, absent skew deviation

Negative head impulse test, direction-changing nystagmus, positive vertical skew deviation

Positive head impulse test, gaze-evoked nystagmus, absent vertical drift on cover-uncover

Negative head impulse test, unidirectional nystagmus, absent skew deviation with preserved fixation suppression

This field is required.

Press Enter ⏎

Why is bilateral sequential testing mandatory during BPPV diagnostic evaluation rather than unilateral testing of the clinically suspected ear alone?

Bilateral Testing Rationale and Safety

Bilateral BPPV occurs in approximately 10–17% of population cohorts, risking residual symptoms with unilateral treatment

Contralateral testing eliminates false-positive results caused by cervical spine artifacts during positioning

Repeated testing on one side produces cumulative fatigue confirming peripheral rather than central etiology

Ipsilateral dominance allows faster protocol completion with equivalent diagnostic accuracy in experienced clinicians

This field is required.