Matar E, Shine J M, Naismith S L, Lewis S J G
Parkinson's Disease Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
Parkinson's Disease Clinic, Brain and Mind Research Institute, The University of Sydney, NSW, Australia.
J Neurol Sci. 2014 Sep 15;344(1-2):182-5. doi: 10.1016/j.jns.2014.06.054. Epub 2014 Jul 1.
Freezing of gait (FOG) is a disabling form of gait disturbance that is common in the advanced stages of Parkinson's disease (PD). Despite its prevalence, methods of studying and assessing FOG are limited. We have previously shown that a virtual reality paradigm was able to distinguish between those who report FOG ("freezers") and those who do not report FOG ("non-freezers"). In this paradigm, 'freezers' were found to have prolonged footstep latency in response to known triggers of FOG including doorways, sliding doors and dual-tasking. In this study, we employed the same paradigm to assess performance of 27 freezers and 14 non-freezers in their clinical 'on' and 'off' medication states. In this study, only participants in the freezing group demonstrated statistically significant increases in latencies experienced in the 'off' state compared to the 'on' state in response to wide and narrow doorways and the opening of a sliding door. By contrast, these behavioral differences were not apparent in non-freezers. Furthermore the delay was specific to environmental cues and was not due to generalized slowing in the 'off' state. The findings suggest that this motor delay when processing environmentally salient cues is specific to freezers and is partially mediated by dopamine-dependent neurocircuitry.
冻结步态（FOG）是一种致残性步态障碍，在帕金森病（PD）晚期较为常见。尽管其普遍存在，但研究和评估冻结步态的方法有限。我们之前已经表明，虚拟现实范式能够区分报告有冻结步态的人（“冻结者”）和未报告有冻结步态的人（“非冻结者”）。在这个范式中，发现“冻结者”在面对包括门口、滑动门和双重任务等已知的冻结步态触发因素时，脚步延迟时间延长。在本研究中，我们采用相同的范式来评估27名冻结者和14名非冻结者在临床“开”药和“关”药状态下的表现。在本研究中，只有冻结组的参与者在“关”药状态下，相比于“开”药状态，在面对宽门和窄门以及滑动门打开时，所经历的延迟时间有统计学上的显著增加。相比之下，这些行为差异在非冻结者中并不明显。此外，这种延迟是特定于环境线索的，并非由于“关”药状态下的普遍动作迟缓。研究结果表明，处理环境显著线索时的这种运动延迟是冻结者特有的，并且部分由多巴胺依赖的神经回路介导。
