In a spontaneous peripheral vestibular lesion, what is the typical nystagmus pattern?

• A. No nystagmus
• B. Pure vertical nystagmus
• C. Multidirectional nystagmus that persists
• D. Unidirectional horizontal-torsional nystagmus that is fatigable and suppressed by fixation

Answer: (D)

Spontaneous peripheral vestibular lesions create an imbalance between the two labyrinths, so the eyes drift slowly toward the affected side with a quick corrective saccade in the opposite direction. This produces a unidirectional horizontal-torsional nystagmus that beats away from the lesioned side. It's fatigable, meaning the nystagmus weakens with time or repeated testing, and it is suppressed by visual fixation because fixing the gaze helps stabilize the abnormal drift.

This pattern helps distinguish peripheral from central causes: central lesions can produce vertical or multidirectional nystagmus that is not consistently fatigable or suppressed by fixation.