International Congress of Parkinsons Disease and Movement Disorders edition:13 location:Paris, France date:June 07-11, 2009
Objective: To evaluate 1) the difference in turning behavior between freezers (FRs) and non-freezers (n-FRs) and 2) to explore possible predictors of turning behavior.
Background: Turning is the most important trigger for Freezing Of Gait (FOG) in Parkinson Disease (PD) but why this is so, is presently unknown.
Methods: 16 patients with PD (7 FRs and 9 n-FRs) during the off-period of the medication cycle and 10 age-matched controls were asked to walk straight ahead and to make a right 180° turn at an infrared reflective marker placed on the floor. An 8 camera VICON 3D motion analysis system was used to determine the amount of steps, turn duration and frequency of freezing episodes. The FOG questionnaire, UPDRSIII, Timed UP and Go test (with and without dual task) and the SCOPA-test of cognition were administered in the on-period.
Results: No significant differences were found between FRs and n-FRs for age, Hoehn &Yahr stage and UPDRSIII scores. Freezing was provoked in 4 out of 7 FRs during turning and only in one FR when walking straight. FRs needed significantly more steps than controls and n-FRs to complete the turn (15.5 vs. 5.6 and 6.1 steps respectively, p<0.05) and tended to have a longer turn duration (12.4 vs. 3.2 and 3.7 seconds respectively, p=0.085). However, similar results were found for walking straight (average number of steps was 10.1 vs. 5.8 and 6.8 steps respectively, p<0.05 and average turn duration 5.1 vs. 2.6 and 3.3 seconds, p<0.05). Turn duration was significantly correlated with number of steps and duration to walk 3m in a straight line, and the FOG questionnaire (R=.96, .97 and .75 respectively). Similar correlations were found for the amount of steps during turning (R= .96, .93 and .82, respectively). No correlations were found between turning behavior and UPDRSIII, SCOPA-COG and differences between the TUG with and without a dual task.
Conclusions: Turning behavior in FRs shows an abnormally high number of steps, FOG episodes and increased duration. However, turning seems highly dependent on patient’s performance during straight-line walking and patient’s reported freezing severity, but can not be explained by disease severity or mental function. Further research on turning and freezing should control for parameters of normal walking performance.