Characterization of Postural Sway in Patients With Persistent Postural-Perceptual Dizziness (PPPD) Using Wearable Motion Sensors

Objective: To extend previous investigations of postural control in patients with persistent-postural perceptual dizziness (PPPD). Study Design: Case-controlled, cross-sectional, observational investigation. Setting: Tertiary care center. Patients: Fifteen patients with PPPD, 15 control volunteers. Interventions: Measurement of anterior-posterior (AP) and medial-lateral (ML) sway at the waist using wearable accelerometers during posturography; assessment of reach and gait. Main Outcome Measures: Peak-to-peak AP and ML sway displacement on the six conditions of the Sensory Organization Test (SOT); Scores on the SOT, Functional Reach Test (FRT), and Dynamic Gait Index (DGI). Results: Compared to control volunteers, patients with PPPD had significantly greater sway displacement at the waist in the AP direction in SOT conditions 3, 5, and 6 and in the ML direction in SOT conditions 2 and 4, resulting in significantly lower median equilibrium scores on the composite index and all six SOT conditions. Patients with PPPD had significantly lower scores on the FRT and DGI that were not correlated with SOT performance. AP sway in conditions 3 and 6 differentiated patients with PPPD from controls with high sensitivity (≥0.87) and specificity (≥0.87). Conclusions: This study replicated previous work showing poor SOT performance by patients with PPPD who had greater AP sway associated with visual dependence and greater ML sway in low demand conditions than controls. Patients with PPPD also performed poorer on the FRT and DGI, but lack of correlation with SOT scores suggested different mechanisms of impairment in postural control, reach, and ambulation. AP sway demonstrated potential as a diagnostic marker.