Manenti Rosa, Sandrini Marco, Gobbi Elena, Cobelli Chiara, Brambilla Michela, Binetti Giuliano, Cotelli Maria
Neuropsychology Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
Department of Neurorehabilitation Sciences, Casa di Cura Privata del Policlinico, Milan, Italy.
Front Aging Neurosci. 2017 Dec 5;9:401. doi: 10.3389/fnagi.2017.00401. eCollection 2017.
Episodic memory is critical to daily life functioning. This type of declarative memory declines with age and is the earliest cognitive function to be compromised in Alzheimer's disease (AD). Subjective memory complaints are commonly reported by older adults and have been considered a risk factor for developing AD. The possibilities for prevention of memory disorders in older adults have increased substantially in recent years. Previous studies have shown that anodal transcranial Direct Current Stimulation (tDCS) applied over the left lateral prefrontal cortex (PFC) after a contextual reminder strengthened existing verbal episodic memories, conceivably through reconsolidation, in elderly people. In this study, we hypothesized that anodal tDCS applied over the left lateral PFC after a contextual reminder would improve delayed memory retrieval relative to placebo (sham) stimulation in elderly individuals with SMC. Twenty-two subjects learned a list of words. Twenty-four hour later, tDCS (anodal or placebo) was applied over the left lateral PFC after a contextual reminder. Memory retrieval was tested 48h and 30 days later. These findings showed that anodal tDCS over the left lateral PFC strengthened existing episodic memories, a behavioral effect documented by improved recognition up to 30 days, relative to placebo stimulation. This study suggests that tDCS after a contextual reminder can induce long-lasting beneficial effects by facilitating the consolidation processes and opens up the possibility to design specific non-invasive interventions aimed at preventing memory decline in this at-risk population.
情景记忆对日常生活功能至关重要。这种陈述性记忆会随着年龄的增长而衰退，并且是阿尔茨海默病（AD）中最早受到损害的认知功能。老年人经常报告有主观记忆问题，并且这些问题被认为是患AD的一个风险因素。近年来，预防老年人记忆障碍的可能性大幅增加。先前的研究表明，在情境提示后，对左侧前额叶皮层（PFC）施加阳极经颅直流电刺激（tDCS）可以增强老年人现有的言语情景记忆，这可能是通过重新巩固实现的。在本研究中，我们假设，对于有主观记忆问题（SMC）的老年人，在情境提示后对左侧前额叶外侧施加阳极tDCS相对于安慰剂（假）刺激，将改善延迟记忆检索。22名受试者学习了一组单词。24小时后，在情境提示后对左侧前额叶外侧施加tDCS（阳极或安慰剂）。在48小时和30天后测试记忆检索。这些结果表明，相对于安慰剂刺激，左侧前额叶外侧的阳极tDCS增强了现有的情景记忆，这一行为效应通过长达30天的改善识别得到证明。本研究表明，情境提示后的tDCS可以通过促进巩固过程诱导长期有益效果，并为设计旨在预防这一高危人群记忆衰退的特定非侵入性干预措施开辟了可能性。
