Nystagmus

o Slow < 40 jerks / mino Fast > 100 jer / min

So κ.φ= 40 – 100 jerks /min

Amplitude

o Fine < 1mmo Coarse > 3mm

Involvement

o Bilateral eyeso Unilateral eye

ABSENT NYSTAGMUS IN ACUTE SEVERE VERTIGO IS UNUSUAL

Normal findings

o Lateral gaze nystagmus

Ubnormal findings

o Spontaneous or front gaze nystagmuso Horizontal = peripheral disease = unilateral

vestibular pathology

o Vertical = CNS = brain stem lesion

Causes in infants and children

o Albinismo Bilateral optic nerve hypoplasia = morsier’s

syndromeo Bilateral media opacitieso Achromatopsiao Retinitis pigmentosA = USHER’S SYNDROME