Postural Sway Characteristics in Patients With Persistent Postural-Perceptual Dizziness: A Comparative Study Between Psychogenic Vertigo Patients and Healthy Controls

This study aimed to compare postural sway characteristics and evaluate postural sway as a potential biomarker for persistent postural-perceptual dizziness (PPPD) to clarify diagnostic boundaries. A total of 36 participants were enrolled, including 26 (72.2%) with PPPD, five (13.9%) with psychogenic vertigo, and five (13.9%) healthy controls. Postural sway tests were conducted on all participants, measuring the center of pressure (CoP) area, CoP length, and Romberg ratio. A subgroup analysis was also performed based on the presence of preceding organic diseases. The postural sway tests were conducted using a force platform under standardized conditions. Each participant stood barefoot on a stable surface for 60 seconds with eyes open and then with eyes closed, while data were sampled at 100 Hz. The results showed that both the PPPD and psychogenic vertigo groups exhibited significantly larger CoP areas compared to healthy controls, indicating increased postural instability. However, no significant difference was found between the PPPD and psychogenic vertigo groups. While CoP length in the PPPD group was similar to that of healthy controls, the psychogenic vertigo group showed a significantly greater CoP length with eyes closed. These findings suggest that patients with PPPD maintain fine postural control despite increased sway, indicating preserved central nervous system adaptation. No differences were observed between primary and secondary PPPD (s-PPPD). Overall, the postural sway characteristics of PPPD closely resembled those of psychogenic vertigo, supporting the notion that both conditions share features of functional dizziness disorders. Future research should include larger, age- and sex-matched cohorts, along with advanced posturography methods and detailed symptom assessments, to refine diagnostic criteria.