Personalized brain activity modulation to improve balance and cognition in elderly fallers

站立和行走几乎总是与说话、阅读等其他脑力活动同时完成 或者解决问题。能否安全地完成这类重要的“双重任务”取决于一个人的 有效激活涉及运动和认知功能的适当大脑网络的能力。在……里面 最近遭受其他原因不明跌倒的老年人，这种双重任务会显著干扰 可以控制站立或行走。因此，我们认为，旨在促进大脑激活的策略 在认知-运动大脑网络中，拥有巨大的潜力来降低双重任务成本，增强许多其他 身体和认知功能的各个方面，最终减少老年人的跌倒。经颅直视 电流刺激(TDC)是一种安全、非侵入性的技术，它可以选择性地增强大脑的兴奋性(即， 激活的可能性)通过在放置在头皮上的电极之间传递低电平电流。我们有 在一系列开创性的研究中证明了tDCs靶向左侧背外侧前额叶皮质 (DLPFC)--参与认知“执行”功能的主要大脑区域--包括在 老年人的双重任务表现和活动能力。尽管如此，tDCs的最佳脑区(S)，以及 多期tdcs干预所带来的益处持续时间尚不清楚。此外，到目前为止，tdcs Delivery曾试图基于对“典型”大脑的建模来优化电流流动，因此还没有 根据老化大脑的解剖结构中的个体差异进行个性化。 我们将进行一项随机、假对照、双盲试验，随访期为6个月 比较4种不同个性化、多时段tdcs干预对双重任务成本的影响 站立和行走(目标1)，以及其他身体(目标2)和认知(目标3)因素对 对于有过跌倒经历的老年人来说，跌倒的原因路径对日常功能很重要。我们 将招募120名年龄在65-85岁之间、跌倒两次或以上的男性和女性(每支干预臂30名) 在过去的一年里，他们害怕再次摔倒，但没有重大的神经或肌肉骨骼疾病。Tdcs 干预将包括为期四周的20次会议，目标1)仅针对左侧dlPFC；2)双边 仅初级运动皮质(M1，腿部区域)；3)这两个区域同时存在；或4)两者都不存在 区域(即，伪装)。我们将利用基线结构磁共振成像的当前流程建模来定制tDC 电极放置和刺激参数，以优化每个电极内流向所需目标(S)的电流 参与者的大脑。我们假设多焦点tdcs旨在同时增加功能 激活运动和认知网络将在双重任务和其他重要任务上获得最大好处 在这一脆弱的老年人群体中，导致跌倒的因果路径上的身体和认知结果。 这项试验的结果还将为未来使用tdcs进行预防跌倒试验奠定基础。

Standing and walking are almost always completed in unison with other mental tasks such as talking, reading or problem solving. The ability to safely perform this important type of “dual tasking” is dependent upon one's capacity to effectively activate the appropriate brain networks involved in both motor and cognitive function. In older adults who have suffered recent, otherwise unexplained falls, such dual tasking significantly interferes with the control of standing or walking. We thus contend that strategies designed to facilitate brain activation within cognitive-motor brain networks hold great potential to reduce dual task costs, enhance numerous other aspects of physical and cognitive function, and ultimately, reduced falls in older adults. Transcranial direct current stimulation (tDCS) is a safe, noninvasive technology that can selectively enhance brain excitability (i.e., the likelihood of activation) by passing low-level currents between electrodes placed upon the scalp. We have demonstrated in a series of ground-breaking studies that tDCS targeting the left dorsolateral prefrontal cortex (dlPFC)—a primary brain region involved in cognitive “executive” function—incudes lasting improvements in dual task performance and mobility in older adults. Still, the optimal brain region(s) to target with tDCS, and the duration of benefits induced by multi-session tDCS interventions, are unknown. Moreover, to date, tDCS delivery has attempted to optimize current flow based on modeling of a “typical” brain and has thus not been personalized to individual differences in the anatomy of the aging brain. We will conduct a randomized, sham-controlled, double-blinded trial with a 6-month follow-up period to compare the effects of 4 different personalized, multisession tDCS interventions on the dual task costs to standing and walking (Aim 1), as well as other physical (Aim 2) and cognitive (Aim 3) factors on the causal pathway to falls that are important to everyday function, in older adults with previous falls. We will recruit 120 men and women (30 per intervention arm) aged 65-85 years with two or more falls within the past year, who are fearful of falling again, yet have no major neural or musculoskeletal disorders. tDCS interventions will entail 20 sessions over a four-week period targeting 1) the left dlPFC only; 2) the bilateral primary motor cortex (M1, leg regions) only; 3) both of these regions simultaneously; or 4) neither of these regions (i.e., sham). We will utilize current flow modeling of baseline structural MRIs to customize tDCS electrode placement and stimulation parameters to optimize current flow to the desired target(s) within each participant's brain. We hypothesize that multi-focal tDCS designed to simultaneously increase functional activation of motor and cognitive networks will have the greatest benefits on dual tasking and other important physical and cognitive outcomes on the causal pathway to falls in this vulnerable population of older adults. The outcomes of this trial will also set the stage for future falls prevention trials using tDCS.