Abstract
<jats:p>Background/Objectives: Patients with persistent postural perceptual dizziness (PPPD) have a balance discrepancy between their perceived and actual body movements. Quantifying this discrepancy would enable effective treatment of PPPD aimed at reducing perceived and actual body sway, and monitoring treatment improvement. Methods: 14 PPPD patients and 12 age-matched (age range 29 to 67) healthy controls (HCs) participated in this study. A SwayStarTM system measured, at lumbar 3, trunk pitch and roll sway, during 14 stance and gait tasks. For 3 stance tasks and 2 gait tasks subjects were asked to replicate the peak-to-peak roll and pitch trunk sway that they thought had occurred during the previous trial. The resulting amplitudes of peak-to-peak trunk sway were used to represent “measured” and “perceived” sway, respectively. To help improve balance control, PPPD patients received vibro-tactile balance-feedback of trunk sway (VT-fb) training 2 times a week for 2 weeks. Results: Linear regression slopes between mean peak-to-peak measured and perceived sway amplitudes were approximately 0.55 for HCs and 0.15 for PPPD patients, and similar in the pitch and roll directions for both HC and PPPD subjects. However, the intercept values were significantly larger for pitch (5x) and roll (6.7x) for PPPD subjects compared to HCs. At onset of VT-fb training, most (14 out 20) sway variables of PPPD patients had mean “measured” and, more significantly, “perceived” amplitudes which were greater than those of HCs. After 2 weeks of VT-fb training, PPPD patients had decreased mean sway amplitudes only greater than those of HCs for only 7 out of 20 variables, again with greater significance for perceived variables. amplitudes decreased by 35%. Conclusions: Comparisons with pitch intercept values for the linear regression between measured and perceived trunk sway indicated that these intercepts provide both a marker for PPPD as well as a measure of its improvement with training. Further, these results indicate that measured and perceived trunk sway of PPPD patients during stance and gait is greater than HCs but can be reduced with VT-fb training. The greatest difference with respect to that of HCs occurs for pitch sway standing eyes closed on foam and walking tandem steps, suggesting that pitch measures from these tests may also serve as markers for PPPD. The relationship between measured and perceived sway is dominated by large pitch and roll offsets in PPPD patients.</jats:p>