A patient experiences dizziness with head movement. What supports a diagnosis of BPPV?

Benign Paroxysmal Positional Vertigo (BPPV) is characterized by brief episodes of dizziness triggered by changes in head position. The presence of horizontal nystagmus is a key diagnostic feature for BPPV. Nystagmus refers to involuntary eye movements, and in the case of BPPV, it typically occurs when the patient is positioned in a way that activates the affected semicircular canals. Horizontal nystagmus specifically indicates that the dizziness is likely caused by positional changes, consistent with the diagnosis of BPPV.

Other factors, such as tinnitus or new-onset hearing loss, can suggest alternative vestibular disorders, which are not characteristic of BPPV. Additionally, a duration longer than two years would suggest a chronic condition rather than the episodic nature typical of BPPV. In summary, the observation of horizontal nystagmus during head movements supports the diagnosis of BPPV effectively because it directly relates to the pathological mechanism behind the disorder.