Vertigo

Peripheral patterns *

Burst of upbeat-torsional nystagmus, lasting < 30 seconds, triggered by the Dix-Hallpike test to one side.

Unidirectional spontaneous (i.e., primary gaze) nystagmus, with ↑ in velocity in the direction of the nystagmus fast phase and ↓ velocity in the opposite direction. E.g. left beating nystagmus in primary gaze, with an increase in velocity with left gaze, and a decrease (but not reversal) with right gaze.

BPPV

Vestibular neuronitis (labyrinthitis)

Central Patterns

Spontaneous vertical nystagmus (upbeat or downbeat).

Gaze-evoked direction changing nystagmus (i.e., persistent left beating on left gaze and then persistent right beating on right gaze).

Persistent downbeating nystagmus triggered by a positional test such as the Dix-Hallpike test. §

Stroke, multiple sclerosis

Chiari malformation

Meds (e.g., antiepileptics) stroke, multiple sclerosis, cerebellar degenerative disorder

Physiological patterns

Persistent downbeating nystagmus triggered by a positional test such as the Dix-Hallpike test.

BPPV = benign paroxysmal positional vertigo.

*For peripheral vestibular nystagmus, the velocity of nystagmus typically increases by inhibiting visual fixation and decreases by encouraging visual fixation. However, the effect of visual fixation does not discriminate one peripheral vestibular disorder from another.

§ The Dix-Hallpike test is a specific positional test to asses for positional nystagmus. The patient sits upright and the head is turned about 45⁰ to one side. The patient is then quickly guided by the physician down to a supine position with the head extended over the end of the examining table. In this position, the eyes are observed for nystagmus triggered by the test. The patient is then brought back to the sitting position and the test is then repeated with the head turned to the opposite side.