Brain Dynamics Multidisciplinary Research Center, Dokuz Eylül University, Izmir, Turkey Department of Neurosciences, Dokuz Eylül University, Izmir, Turkey Department of Neurology, Dokuz Eylül University Medical School, Izmir, Turkey Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul Kültür University, Istanbul, Turkey.
J Alzheimers Dis. 2013;37(4):759-67. doi: 10.3233/JAD-130569.
Mild cognitive impairment (MCI) is considered as a prodromal stage for Alzheimer's disease (AD) in the majority of cases. Event-related oscillations might be used for detection of cognitive deficits. Our group's earlier results showed diminished delta visual and auditory target oscillatory responses in AD, and we investigated whether this prevails for MCI. Eighteen MCI subjects and 18 age-matched healthy elderly controls were investigated. The maximum peak-to-peak amplitudes of oscillatory responses for each subject's averaged oscillatory target responses in delta, theta, and alpha frequency bands upon application of visual oddball paradigm were measured. Repeated measures of ANOVA was used to analyze four locations (frontal, central, parietal, occipital), at three coronal (left, midline, right) sites. Independent t tests were applied for post-hoc analyses. The oddball target delta response (0.5-3.0 Hz) was 26-32% lower in MCI than healthy controls over fronto-central-parietal regions [F(1.34) = 4.562, p = 0.04]. Without a group effect, theta oscillatory responses (4-7 Hz) showed significant differences in coronal electrodes indicating highest values over mid-electrode sites, and a anteriorposterior x coronal effect, being maximum at mid-central. Alpha frequency band analyses indicated no statistical differences. Peak-to-peak amplitudes of visual target delta oscillatory responses were lower in fronto-central-parietal regions in MCI than in healthy controls. This supports our earlier findings in AD, showing hypoactive delta fronto-central-parietal regions during cognitive tasks. These results indicate that event-related oscillations may detect early changes of brain dynamics in MCI, and deserves to be investigated as a candidate biomarker in further studies using multimodal techniques.
轻度认知障碍 (MCI) 在大多数情况下被认为是阿尔茨海默病 (AD) 的前驱阶段。事件相关振荡可能用于检测认知缺陷。我们小组的早期结果表明，AD 患者的视觉和听觉目标振荡反应的 delta 波减弱，我们研究了 MCI 是否存在这种情况。我们调查了 18 名 MCI 患者和 18 名年龄匹配的健康老年人对照者。在应用视觉Oddball 范式时，测量每个受试者的平均振荡目标反应的 delta、theta 和 alpha 频带中的振荡反应的最大峰峰值振幅。使用重复测量的方差分析来分析四个位置（额部、中央、顶叶、枕部），在三个冠状（左、中线、右）部位。进行独立样本 t 检验进行事后分析。与健康对照组相比，MCI 患者的 Oddball 目标 delta 反应（0.5-3.0 Hz）在前额-中央-顶叶区域降低了 26-32%[F(1.34) = 4.562, p = 0.04]。没有组间效应，theta 振荡反应（4-7 Hz）在冠状电极上显示出显著差异，表明中电极部位的数值最高，以及前后 x 冠状效应，在中中央部位达到最大值。alpha 频带分析未显示出统计学差异。与健康对照组相比，MCI 患者的视觉目标 delta 振荡反应的峰峰值振幅在前额-中央-顶叶区域较低。这支持了我们在 AD 中的早期发现，表明在认知任务中，delta 波额-中央-顶叶区域的活动减少。这些结果表明，事件相关振荡可能检测到 MCI 中大脑动力学的早期变化，并且值得使用多模态技术进一步研究作为候选生物标志物进行研究。
