True about central nystagmus ?
**Core Concept**
Central nystagmus is a type of nystagmus that originates from a problem in the central nervous system, specifically the brainstem or cerebellum. It is characterized by involuntary, rhythmic eye movements. The underlying cause can be related to **lesions** or **diseases** affecting these areas.
**Why the Correct Answer is Right**
Since the correct answer is not provided, let's discuss the general characteristics of central nystagmus. Central nystagmus can result from **vascular disorders**, **infections**, or **degenerative diseases** affecting the brainstem or cerebellum. The **vestibular nuclei** and **cerebellar flocculus** play crucial roles in the pathophysiology of central nystagmus.
**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific details of option A, we cannot determine why it is incorrect.
**Option B:** Similarly, without the details of option B, its incorrectness cannot be explained.
**Option C:** The same applies to option C.
**Option D:** And option D.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that central nystagmus often has a **rotatory component** and can be **purely vertical** or **purely torsional**, which helps differentiate it from peripheral nystagmus.
**Correct Answer:**