Külzow Nadine, Cavalcanti de Sousa Angelica Vieira, Cesarz Magda, Hanke Julie-Marie, Günsberg Alida, Harder Solvejg, Koblitz Swantje, Grittner Ulrike, Flöel Agnes
Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Neurocure Cluster of Excellence, Berlin, Germany.
Clinical Research Unit, Berlin Institute of Health, Berlin, Germany.
Front Neurosci. 2018 Jan 10;11:746. doi: 10.3389/fnins.2017.00746. eCollection 2017.
Object-location memory (OLM) is known to decline with normal aging, a process accelerated in pathological conditions like mild cognitive impairment (MCI). In order to maintain cognitive health and to delay the transition from healthy to pathological conditions, novel strategies are being explored. Tentative evidence suggests that combining cognitive training and anodal transcranial direct current stimulation (atDCS), both reported to induce small and often inconsistent behavioral improvements, could generate larger or more consistent improvements or both, compared to each intervention alone. Here, we explored the combined efficacy of these techniques on OLM. In a subject-blind sham-controlled cross-over design 32 healthy older adults underwent a 3-day visuospatial training paired with either anodal (20 min) or sham (30 s) atDCS (1 mA, temporoparietal). Subjects were asked to learn the correct object-location pairings on a street map, shown over five learning blocks on each training day. Acquisition performance was assessed by accuracy on a given learning block in terms of percentage of correct responses. Training success (performance on last training day) and delayed memory after 1-month were analyzed by mixed model analysis and were controlled for gender, age, education, sequence of stimulation and baseline performance. Exploratory analysis of atDCS effects on within-session (online) and between-session (offline) memory performance were conducted. Moreover, transfer effects on similar trained (visuospatial) and less similar (visuo-constructive, verbal) untrained memory tasks were explored, both immediately after training, and on follow-up. We found that atDCS paired with OLM-training did not enhance success in training or performance in 1-month delayed memory or transfer tasks. In sum, this study did not support the notion that the combined atDCS-training approach improves immediate or delayed OLM in older adults. However, specifics of the experimental design, and a non-optimal timing of atDCS between sessions might have masked beneficial effects and should be more systematically addressed in future studies.
物体位置记忆（OLM）会随着正常衰老而衰退，在轻度认知障碍（MCI）等病理状况下，这一过程会加速。为了维持认知健康并延缓从健康状态向病理状态的转变，人们正在探索新的策略。初步证据表明，将认知训练与阳极经颅直流电刺激（atDCS）相结合，据报道这两种方法单独使用时都能带来微小且往往不一致的行为改善，与单独进行每种干预相比，二者结合可能会产生更大或更一致的改善效果，或者二者兼具。在此，我们探究了这些技术对OLM的联合疗效。在一项受试者盲法、假刺激对照的交叉设计中，32名健康老年人接受了为期3天的视觉空间训练，并同时接受阳极（20分钟）或假（30秒）atDCS（1毫安，颞顶叶）刺激。要求受试者在街道地图上学习正确的物体 - 位置配对，每个训练日通过五个学习块展示。通过给定学习块上正确反应的百分比来评估习得表现的准确性。通过混合模型分析来分析训练成功率（最后一个训练日的表现）和1个月后的延迟记忆，并对性别、年龄、教育程度、刺激顺序和基线表现进行控制。对atDCS对训练期间（在线）和训练之间（离线）记忆表现的影响进行了探索性分析。此外，还探究了训练后即刻以及随访时对相似训练（视觉空间）和不太相似（视觉构建、言语）的未训练记忆任务的迁移效应。我们发现，atDCS与OLM训练相结合并没有提高训练成功率或1个月延迟记忆及迁移任务中的表现。总之，本研究不支持atDCS训练相结合的方法能改善老年人即时或延迟OLM的观点。然而，实验设计的细节以及atDCS在各训练之间的时机选择不理想，可能掩盖了有益效果，未来研究应更系统地解决这些问题。
