Perceptual, Cognitive, and Motor Rigidity in Parkinson's Disease

运动僵硬是帕金森病（PD）的一个标志性症状，越来越多的证据表明，非运动领域如认知和人格的僵硬。问题是，这种刚性是否延伸到视觉感知，这是已知的PD异常。对健康成人感知的研究主要集中在感知可逆性上，即切换双稳态模糊图像的能力。知觉可逆性取决于PD典型影响的大脑区域，包括皮质-丘脑皮质回路。本研究旨在探讨PD患者的知觉刚性及其与运动、认知和人格刚性的关系。非痴呆PD患者和年龄匹配的正常对照参与者将呈现双稳态（可逆）图像，并评估他们从一种感知解释转换到另一种感知解释的自然能力。他们对双目竞争的交替率（一个图像对另一个图像的感知优势）将被评估。为了探索刚性的可能机制，将进行几个实验，包括检查意志控制，视觉空间注意，以及在刺激特征退化时参与自下而上处理的能力。参与者将被评估认知刚性（执行功能的神经心理学测试，包括毅力）、运动刚性（手臂和腿部运动之间以及骨盆和胸部旋转之间的相对相位的步态测量）和人格刚性（问卷调查）。据推测，与对照组相比，PD患者会表现出知觉可逆性的降低，因为他们有意“放弃”主导知觉的能力会降低，这是由于支持选择性注意和设定转移认知能力的额-纹状体-顶叶网络受损。其次，假设自下而上的信息对PD患者知觉优势的影响弱于对照组。第三，假设在PD组中，知觉刚性与认知、运动和人格刚性之间存在显著相关性，因为这些运动和非运动PD症状都源于功能失调的基底节区的直接和间接影响。了解PD患者知觉刚性的本质可以为知觉干预的发展提供信息，以提高PD患者的生活质量和独立性。

Motor rigidity is a hallmark symptom of Parkinson's disease (PD), and there is increasing evidence for rigidity in non-motor domains such as cognition and personality. The question is raised as to whether such rigidity extends to visual perception, which is known to be abnormal in PD. Research on perception with healthy adults has focused on perceptual reversibility, which is the ability to switch the image of a bistable ambiguous figure. Perceptual reversibility depends on brain areas that are typically affected by PD, including corticostriatal-thalamocortical circuitry. The proposed study aims to examine perceptual rigidity in PD, the mechanisms associated with this perceptual phenomenon, and its association with motor, cognitive and personality rigidity. Non-demented PD patients and age-matched normal control participants will be presented with bistable (reversible) figures and will be assessed for their natural ability to switch from one perceptual interpretation to the other. Their alternation rate for binocular rivalry (perceptual dominance of one image over the other one) will be assessed. In order to explore possible mechanisms underlying rigidity, several experiments will be conducted including examinations of volitional control, visuospatial attention, and the ability to engage in bottom-up processing when stimulus features are degraded. The participants will be assessed for cognitive rigidity (neuropsychological tests of executive function including perseveration), motor rigidity (gait measures of relative phase between arm and leg movements and between pelvic and thoracic rotation), and personality rigidity (questionnaire). It is hypothesized that relative to the control group, individuals with PD will show reductions in perceptual reversibility in that they will have a reduced ability to intentionally "let go" of the dominant percept due to compromised fronto-striatal-parietal networks that support the cognitive abilities of selective attention and set-shifting. Second, it is hypothesized that bottom-up information will have a weaker effect on perceptual dominance in PD patients than in control participants. Third, it is hypothesized that in the PD group, there will be significant correlations between perceptual rigidity and cognitive, motor, and personality rigidity as these motor and non-motor PD symptoms all emanate from the direct and indirect influence of the dysfunctional basal ganglia. Understanding the nature of perceptual rigidity in PD can inform the development of perceptual interventions to enhance PD patients' quality of life and independence.