Deiber Marie-Pierre, Meziane Hadj Boumediene, Hasler Roland, Rodriguez Cristelle, Toma Simona, Ackermann Marine, Herrmann François, Giannakopoulos Panteleimon
INSERM U1039, Faculty of Medicine, La Tronche, France.
Biomarkers of Vulnerability Unit, Department of Mental Health and Psychiatry, University Hospitals of Geneva, Geneva, Switzerland.
J Alzheimers Dis. 2015;47(2):335-49. doi: 10.3233/JAD-150111.
Future treatments of Alzheimer's disease need the identification of cases at high risk at the preclinical stage of the disease before the development of irreversible structural damage. We investigated here whether subtle cognitive deterioration in a population of healthy elderly individuals could be predicted by EEG signals at baseline under cognitive activation. Continuous EEG was recorded in 97 elderly control subjects and 45 age-matched mild cognitive impairment (MCI) cases during a simple attentional and a 2-back working memory task. Upon 18-month neuropsychological follow-up, the final sample included 55 stable (sCON) and 42 deteriorated (dCON) controls. We examined the P1, N1, P3, and PNwm event-related components as well as the oscillatory activities in the theta (4-7 Hz), alpha (8-13 Hz), and beta (14-25 Hz) frequency ranges (ERD/ERS: event-related desynchronization/synchronization, and ITC: inter-trial coherence). Behavioral performance, P1, and N1 components were comparable in all groups. The P3, PNwm, and all oscillatory activity indices were altered in MCI cases compared to controls. Only three EEG indices distinguished the two control groups: alpha and beta ERD (dCON > sCON) and beta ITC (dCON < sCON). These findings show that subtle cognitive deterioration has no impact on EEG indices associated with perception, discrimination, and working memory processes but mostly affects attention, resulting in an enhanced recruitment of attentional resources. In addition, cognitive decline alters neural firing synchronization at high frequencies (14-25 Hz) at early stages, and possibly affects lower frequencies (4-13 Hz) only at more severe stages.
阿尔茨海默病的未来治疗需要在疾病发展出不可逆的结构损伤之前，在临床前阶段识别出高风险病例。我们在此研究了在认知激活状态下，基线脑电图信号是否能够预测健康老年人群中的细微认知衰退。在97名老年对照受试者和45名年龄匹配的轻度认知障碍（MCI）患者执行简单注意力任务和2-back工作记忆任务期间，记录了连续脑电图。经过18个月的神经心理学随访，最终样本包括55名稳定（sCON）对照和42名衰退（dCON）对照。我们检查了P1、N1、P3和PNwm事件相关成分，以及theta（4 - 7Hz）、alpha（8 - 13Hz）和beta（14 - 25Hz）频率范围内的振荡活动（ERD/ERS：事件相关去同步化/同步化，以及ITC：试验间相干性）。所有组的行为表现、P1和N1成分相当。与对照组相比，MCI患者的P3、PNwm和所有振荡活动指标均发生了改变。只有三个脑电图指标区分了两个对照组：alpha和beta ERD（dCON > sCON）以及beta ITC（dCON < sCON）。这些发现表明，细微的认知衰退对与感知、辨别和工作记忆过程相关的脑电图指标没有影响，但主要影响注意力，导致注意力资源的募集增强。此外，认知衰退在早期会改变高频（14 - 25Hz）的神经放电同步，可能仅在更严重阶段影响低频（4 - 13Hz）。
