Effects of Freezing of Gait and Visual Information on the Static Postural Control Ability in Patients with Parkinson`s Disease

Objective: The purpose of this study was to analyze the effects of freezing of gait and visual information on the static postural control ability in patients with Parkinson ' s Disease (PD) during the bipedal stance with feet together. Method: This study included a total of 36 patients with PD; the freezer group included 17 PD patients (age: 69.3 ± 6.2 yrs, height: 159.6 ± 9.0 cm, weight: 63.4 ± 9.78 kg) and the nonfreezer group included 19 PD patients (age: 71.4 ± 5.6 yrs, height: 155.8 ± 7.1 cm, weight: 57.7 ± 8.6 kg). Static postural control ability was analyzed using variables of center of pressure (COP) and dividing by mediolateral, anteroposterior, and integration factors during a bipedal stance with the eyes open and closed. Results: Freezers and nonfreezers showed increases in anteroposterior velocity, mediolateral velocity, averaged velocity, and mediolateral 95% edge frequency when visual information was blocked. Additionally, freezers had greater anteroposterior range, 95% confidence ellipse area, and COP anteroposterior mean position than nonfreezers. Conclusion: Freezers and nonfreezers showed a reduction in static postural control ability when visual information was blocked. Additionally, the results of this study found a significant difference in static postural control ability between freezers and nonfreezers with PD. In particular, anteroposterior range, 95% confidence ellipse area, and COP anteroposterior mean position might be used to distinguish between freezers and nonfreezers with PD.