OBJECTIVE Parkinson's Disease (PD) is a neurodegenerative disease caused by the loss of dopaminergic neurons. Cognitive impairments have been reported using the event-related potential (ERP) technique. Patients show reduced novelty P3 (nP3) amplitudes in oddball experiments, a response to infrequent, surprising stimuli, linked to the orienting response of the brain. The nP3 is thought to depend on dopaminergic neuronal pathways though the effect of dopaminergic medication in PD has not yet been investigated. METHODS Twenty-two patients with PD were examined "on" and "off" their regular dopaminergic medication in a novelty 3-stimulus-oddball task. Thirty-four healthy controls were also examined over two sessions, but received no medication. P3 amplitudes were compared throughout experimental conditions. RESULTS All participants showed sizeable novelty difference ERP effects, i.e. ndP3 amplitudes, during both testing sessions. An interaction of diagnosis, medication and testing order was also found, indicating that dopaminergic medication modulated ndP3 in patients with PD across the two testing sessions: We observed enhanced ndP3 amplitudes from PD patients who were off medication on the second testing session. CONCLUSION Patients with PD 'off' medication showed ERP evidence for repetition-related enhancement of novelty responses. Dopamine depletion in neuronal pathways that are affected by mid-stage PD possibly accounts for this modulation of novelty processing. SIGNIFICANCE The data in this study potentially suggest that repetition effects on novelty processing in patients with PD are enhanced by dopaminergic depletion.

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帕金森病新奇重复的多巴胺能调节：P3 事件相关脑电位的研究

目的 帕金森病 (PD) 是一种由多巴胺能神经元丢失引起的神经退行性疾病。使用事件相关电位 (ERP) 技术报告了认知障碍。患者在古怪实验中表现出降低的新颖性 P3 (nP3) 幅度，这是对罕见的、令人惊讶的刺激的反应，与大脑的定向反应有关。尽管尚未研究多巴胺能药物对 PD 的影响，但认为 nP3 依赖于多巴胺能神经元通路。方法 在一项新颖的 3 刺激奇数任务中，对 22 名 PD 患者进行了“开”和“关”常规多巴胺能药物的检查。34 名健康对照者也接受了两个疗程的检查，但没有接受药物治疗。在整个实验条件下比较了 P3 振幅。结果 所有参与者在两个测试阶段都表现出相当大的新奇差异 ERP 效应，即 ndP3 振幅。还发现了诊断、药物治疗和测试顺序的相互作用，表明多巴胺能药物在两个测试阶段调节了 PD 患者的 ndP3：我们观察到在第二个测试阶段停止用药的 PD 患者的 ndP3 振幅增强。结论 PD“关闭”药物的患者显示出 ERP 证据，证明重复相关的新奇反应增强。受中期 PD 影响的神经元通路中的多巴胺耗竭可能是这种新奇处理调节的原因。意义 本研究中的数据可能表明，多巴胺能耗竭增强了重复对 PD 患者新奇处理的影响。