Persistent postural-perceptual dizziness

Expected SVV signature

The Bárány Society criteria for PPPD^[10] require persistent symptoms (≥ 3 months) without an active structural vestibular disorder. The vestibular work-up — caloric, VEMP, head impulse, SVV — is by definition normal. Persistent abnormality of any of these tests indicates a different (or additional) diagnosis.

Why SVV is useful even when it’s normal

PPPD is a diagnosis of inclusion: positive criteria for the symptom pattern (unsteadiness or non-spinning vertigo, exacerbated by upright posture, active or passive motion, and visual stimuli) plus exclusion of an active structural cause. A normal SVV is part of that exclusion. It tells the patient and the clinician that the graviceptive system is intact — a powerful piece of reassurance and a useful starting point for vestibular rehabilitation.

PPPD frequently arises after a precipitating vestibular event (an episode of vestibular neuritis, BPPV, or vestibular migraine). The original event may have produced an SVV tilt that has since normalised; the persistent symptoms are functional, not structural.

When PPPD plus a structural lesion coexist

A patient may have residual peripheral vestibular asymmetry (small SVV tilt of 2–3°) plus a functional PPPD overlay. The vestibular asymmetry will not explain the full symptom burden — but neither should it be dismissed. Both diagnoses can be made, and both treatment arms (vestibular rehabilitation for the periphery; cognitive-behavioural strategies and SSRI consideration for PPPD) can run in parallel.

Companion findings

• Symptoms persistent for ≥ 3 months, more days than not
• Exacerbation by upright posture, active or passive motion, and complex visual environments
• Normal head impulse, caloric, VEMP, and audiogram (after the precipitating event has resolved)
• Often a history of anxiety, panic, or depression — comorbid but not causal