Rhythmic laser cue is beneficial for improving gait performance and reducing freezing of turning in Parkinson's disease patients with freezing of gait

Background and aim: Gait time components in Parkinson's disease (PD) patients such as step time, gait rhythmicity, symmetry, and coordination are exacerbated during turning. Freezing of gait (FOG) can be triggered off when such gait-timing deficiency exceeds a certain threshold. Whether laser visual cue could improve the impairments of gait time components and reduce freezing episodes in turning remains unclear. Different from continuous laser (CL), rhythmic laser (RL) cue could provide rhythmic temporal information. The aim of this study was to investigate the effect of RL and CL cue to identify which one was better at modulating gait time components and improving gait performance in turning. Methods: Twenty-three patients on dopaminergic medication performed the "8-shaped" turning task. Test conditions included no laser (NL), CL and RL cues. Gait parameters such as numbers of freezing episodes, the turning time, step time, gait arrhythmicity, asymmetry, and discoordination were assessed. Results: The numbers of freezing episodes, the turning time, step time and the gait arrhythmicity were significantly improved in RL cue compared with both CL and NL conditions, whereas no significant difference was found between CL and NL conditions. Gait asymmetry and discoordination did not show significant difference between the three conditions. Conclusion: Compared with CL cue, it seems that synchronization in RL cue might be beneficial in improving the background gait performance and reducing freezing in turning. For PD patients with FOG, RL cue might be promising when applied as an optional technique in gait rehabilitation.