The prevalence of Parkinson's disease (PD) increases with aging and both processes share similar cellular mechanisms and alterations in the dopaminergic system. Yet it remains to be investigated whether aging can also demonstrate electrophysiological neuronal signatures typically associated with PD. Previous work has shown that phase-amplitude coupling (PAC) between the phase of beta oscillations and the amplitude of gamma oscillations as well as beta bursts features can serve as electrophysiological biomarkers for PD. Here we hypothesize that these metrics are also present in apparently healthy elderly subjects. Using resting state multichannel EEG measurements, we show that PAC between beta oscillation and broadband gamma activity (50–150 Hz) is elevated in a group of elderly (59–77 years) compared to young volunteers (20–35 years) without PD. Importantly, the increase of PAC is statistically significant even after ruling out confounds relating to changes in spectral power and non-sinusoidal shape of beta oscillation. Moreover, a trend for a higher percentage of longer beta bursts (> 0.2 s) along with the increase in their incidence rate is also observed for elderly subjects. Using inverse modeling, we further show that elevated PAC and longer beta bursts are most pronounced in the sensorimotor areas. Moreover, we show that PAC and longer beta bursts might reflect distinct mechanisms, since their spatial patterns only partially overlap and the correlation between them is weak. Taken together, our findings provide novel evidence that electrophysiological biomarkers of PD may already occur in apparently healthy elderly subjects. We hypothesize that PAC and beta bursts characteristics in aging might reflect a pre-clinical state of PD and suggest their predictive value to be tested in prospective longitudinal studies.

帕金森病 (PD) 的患病率随着年龄的增长而增加，并且这两个过程具有相似的细胞机制和多巴胺能系统的变化。然而，衰老是否也可以表现出通常与 PD 相关的电生理神经元特征仍有待研究。以前的工作表明，β 振荡的相位和 γ 振荡的幅度以及 β 爆发特征之间的相位幅度耦合 (PAC) 可以作为 PD 的电生理生物标志物。在这里，我们假设这些指标也存在于明显健康的老年受试者中。使用静息状态多通道脑电图测量，我们表明，与没有 PD 的年轻志愿者（20-35 岁）相比，一组老年人（59-77 岁）的 β 振荡和宽带伽马活动（50-150 Hz）之间的 PAC 升高。重要的是，即使在排除了与光谱功率变化和 β 振荡的非正弦形状相关的混淆因素后，PAC 的增加仍具有统计学意义。此外，在老年受试者中也观察到更长的β爆发（> 0.2 s）的百分比随着其发病率的增加而增加的趋势。使用逆向建模，我们进一步表明升高的 PAC 和更长的 β 爆发在感觉运动区域最为明显。此外，我们表明 PAC 和更长的 beta 爆发可能反映了不同的机制，因为它们的空间模式仅部分重叠并且它们之间的相关性很弱。综合起来，我们的研究结果提供了新的证据，表明 PD 的电生理生物标志物可能已经出现在明显健康的老年受试者中。我们假设衰老中的 PAC 和 β 爆发特征可能反映了 PD 的临床前状态，并建议在前瞻性纵向研究中测试它们的预测价值。