What distinguishes peripheral nystagmus from central nystagmus?

Peripheral nystagmus is characterized by the phenomenon that visual fixation can inhibit its occurrence. This means that when a person with peripheral nystagmus tries to focus their gaze on a specific point, the nystagmus may diminish or stop altogether. This is typically associated with disorders of the inner ear or vestibular pathways, such as vestibular neuritis or benign paroxysmal positional vertigo (BPPV), where external stimuli can help stabilize the system.

In contrast, central nystagmus, which often stems from conditions affecting the central nervous system, does not typically respond to visual fixation. This distinction is critical for diagnosis, as it aids clinicians in identifying the underlying cause of nystagmus based on whether it can be inhibited by visual attention.

The other options provide important clinical insights but do not directly address the specific distinguishing feature of peripheral versus central nystagmus. For example, while hearing loss is commonly associated with peripheral causes, it is not a definitive criterion for differentiating them. Similarly, the duration of episodes can vary widely in both types and does not provide a clear differentiation. Finally, response to medication can vary depending on the specific underlying condition and is not a reliable marker for distinguishing between peripheral and central n