Does the Pisa syndrome affect postural control, balance, and gait in patients with Parkinson's disease? An observational cross-sectional study.

Introduction: An altered sense of verticality, associated with impaired proprioception and somatosensory integration deficits, has been reported in patients with Parkinson's disease (PD) but it has not been characterized in patients with Pisa syndrome (PS). Therefore, we investigated postural control, balance, and gait disturbances in patients with PD and PS, patients with PD but without PS, and aged-matched normal controls. Methods: This observational cross-sectional study involved patients with PD and PS (n = 10, Hoehn & Yahr score <4), patients with PD but without PS (n = 10), and age-matched healthy controls (n = 10). The primary outcome measure was the velocity of CoP displacement (VEL_MED_AP/ML) assessed by static stabilometry in eyes open (EO) and eyes closed (EC) conditions. The secondary outcomes were other stabilometric parameters, the Sensory Organization Balance Test (SOT), and gait analysis (GA). Results: There were no significant differences in demographic and clinical data and Berg Balance Scale scores between the groups. There was a significant main effect in the VEL_MED_AP/ML between the groups and eye conditions (p = .016). A significant main effect was found in the EO (p = .01) and EC (p = .04) conditions. Post-hoc comparisons showed a significant increase in VEL_CoP in both the EO and EC conditions only in the patients with PD and PS. No significant main effects on SOT and GA were found. Conclusion: Patients with PD and PS had more difficulty achieving good postural alignment with gravity and greater velocity of body sway than the other groups. Rehabilitation programs for patients with PD and PS should include spine alignment and dynamic postural training.