Nystagmus is best described as which of the following?

• A. Loss of ability to coordinate muscles for complex movements
• B. Rhythmic, quick oscillations of the eyes
• C. Movement decomposition
• D. Decrease in muscle tone

Answer: (B)

Nystagmus is defined by rhythmic, quick oscillations of the eyes. You’ll often see the eye drift slowly in one direction and then quickly snap back with a fast corrective movement, or move in a pendular, smooth back-and-forth pattern. This eye-movement pattern reflects disruption in the neural systems that stabilize gaze, such as the vestibulo-ocular pathways and cerebellar circuits.

That’s why this description is the best choice: it directly captures the characteristic eye movements. The other ideas describe different neuromuscular phenomena—general limb coordination problems, movement decomposition (breaking a movement into parts), or decreased muscle tone (hypotonia)—which are not the defining features of nystagmus.