Antonenko Daria, Thams Friederike, Grittner Ulrike, Uhrich Jessica, Glöckner Franka, Li Shu-Chen, Flöel Agnes
Department of Neurology Universitätsmedizin Greifswald Greifswald Germany.
Berlin Institute of Health (BIH) Berlin Germany.
Alzheimers Dement (N Y). 2022 Feb 23;8(1):e12262. doi: 10.1002/trc2.12262. eCollection 2022.
Given rapid global population aging, developing interventions against age-associated cognitive decline is an important medical and societal goal. We evaluated a cognitive training protocol combined with transcranial direct current stimulation (tDCS) on trained and non-trained functions in non-demented older adults.
Fifty-six older adults (65-80 years) were randomly assigned to one of two interventional groups, using age and baseline performance as strata. Both groups performed a nine-session cognitive training over 3 weeks with either concurrent anodal tDCS (atDCS, 1 mA, 20 minutes) over the left dorsolateral prefrontal cortex (target intervention) or sham stimulation (control intervention). Primary outcome was performance on the trained letter updating task immediately after training. Secondary outcomes included performance on other executive and memory (near and far transfer) tasks. All tasks were administered at baseline, post-intervention, and at 1- and 7-month follow-up assessments. Prespecified analyses to investigate treatment effects were conducted using mixed-model analyses.
No between-group differences emerged in the trained letter updating and Markov decision-making tasks at post-intervention and at follow-up timepoints. Secondary analyses revealed group differences in one near-transfer task: Superior n-back task performance was observed in the tDCS group at post-intervention and at follow-up. No such effects were observed for the other transfer tasks. Improvements in working memory were associated with individually induced electric field strengths.
Cognitive training with atDCS did not lead to superior improvement in trained task performance compared to cognitive training with sham stimulation. Thus, our results do not support the immediate benefit of tDCS-assisted multi-session cognitive training on the trained function. As the intervention enhanced performance in a near-transfer working memory task, we provide exploratory evidence for effects on non-trained working memory functions in non-demented older adults that persist over a period of 1 month.
鉴于全球人口迅速老龄化，开发针对与年龄相关的认知衰退的干预措施是一项重要的医学和社会目标。我们评估了一种认知训练方案与经颅直流电刺激（tDCS）相结合对非痴呆老年人训练和未训练功能的影响。
56名老年人（65 - 80岁）以年龄和基线表现作为分层因素，随机分配到两个干预组之一。两组均在3周内进行为期九节的认知训练，同时一组在左侧背外侧前额叶皮层进行阳极tDCS（atDCS，1毫安，20分钟）（目标干预），另一组进行假刺激（对照干预）。主要结局是训练后立即在训练的字母更新任务上的表现。次要结局包括在其他执行和记忆（近迁移和远迁移）任务上的表现。所有任务在基线、干预后以及1个月和7个月的随访评估时进行。使用混合模型分析进行预定的分析以研究治疗效果。
在干预后和随访时间点，训练的字母更新和马尔可夫决策任务中未出现组间差异。二次分析显示在一项近迁移任务中存在组间差异：在干预后和随访时，tDCS组的高级n-back任务表现更优。其他迁移任务未观察到此类效果。工作记忆的改善与个体诱导电场强度相关。
与假刺激的认知训练相比，atDCS认知训练在训练任务表现上并未带来更优的改善。因此，我们的结果不支持tDCS辅助的多节认知训练对训练功能的即时益处。由于该干预增强了近迁移工作记忆任务的表现，我们为非痴呆老年人未训练的工作记忆功能在长达1个月的时间内持续存在的影响提供了探索性证据。
