Introduction

Changes in visual attention have been argued to influence freezing of gait (FOG) in people with Parkinson’s Disease (PD). However, the specific visual search patterns of people with FOG pathology (PD + FOG) and potential underlying mechanisms are not well understood. The current study explored visual search behavior in PD + FOG while walking on a pathway featuring environmental features known to exacerbate FOG (e.g., narrow doorway and tripping hazards). Potential underpinning attentional mechanisms were also assessed, such as conscious movement processing.

Methods

Visual search behavior of twelve people with PD + FOG tested in ON-state (M_age = 74.3) and twelve age-matched healthy controls (M_age = 72.5) were analyzed during a complex walking task. The task required participants to step over an obstacle and navigate through a narrow doorway, surrounded by clutter.

Results

People with PD + FOG more frequently directed visual attention to ongoing and imminent steps compared to healthy controls (Mdn = 26% vs Mdn = 14%, respectively; p = 0.042). Self-reported conscious movement processing was also significantly higher in people with PD + FOG. The one participant who froze during the walking task fixated the future trip hazard (obstacle, approximately 6 steps ahead) almost exclusively during freezing trials (i.e., 60-100% of the trial). In contrast, during ‘non-freeze’ trials, this participant increased the duration of fixations towards ongoing and imminent steps.

Conclusion

Results suggest that people with PD + FOG strongly monitor/control ongoing and immediately upcoming stepping movements. However, prolonged fixations towards threats to future movements might prevent people with PD + FOG from processing the visual information needed to do this, thereby provoke freezing episodes.

中文翻译：

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帕金森病步行的视觉运动控制：探索有意识的运动处理和步态冻结之间的可能联系。

介绍

有人认为视觉注意力的变化会影响帕金森病 (PD) 患者的步态冻结 (FOG)。然而，FOG 病理（PD + FOG）患者的特定视觉搜索模式和潜在的潜在机制尚不清楚。当前的研究探索了在 PD + FOG 中行走时的视觉搜索行为，该路径具有已知会加剧 FOG 的环境特征（例如，狭窄的门口和绊倒危险）。还评估了潜在的支持注意力机制，例如有意识的运动处理。

方法

在复杂的步行任务中分析了 12 名 PD + FOG 在 ON 状态（M_年龄= 74.3）和 12 名年龄匹配的健康对照（M_年龄= 72.5）中测试的视觉搜索行为。该任务要求参与者跨过障碍物并穿过一个狭窄的门口，周围杂乱无章。

结果

与健康对照组相比，PD + FOG 患者更频繁地将视觉注意力集中在正在进行和即将发生的步骤上（分别为Mdn = 26% 与Mdn = 14%；p = 0.042）。PD + FOG 患者自我报告的有意识运动处理也显着更高。在步行任务期间冻结的一名参与者几乎完全在冻结试验期间（即试验的 60-100%）注视着未来的旅行危险（障碍物，大约提前 6 步）。相比之下，在“非冻结”试验期间，该参与者增加了对正在进行和即将进行的步骤的注视时间。

结论

结果表明患有 PD + FOG 的人强烈监控/控制正在进行和即将到来的踏步运动。然而，长期关注对未来运动的威胁可能会阻止 PD + FOG 患者处理执行此操作所需的视觉信息，从而引发冻结发作。