Reinhardt Julia, Rus-Oswald Oana G, Bürki Céline N, Bridenbaugh Stephanie A, Krumm Sabine, Michels Lars, Stippich Christoph, Kressig Reto W, Blatow Maria
Department of Neuroradiology, Clinical Neuroscience Center, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Department of Radiology, Division of Diagnostic and Interventional Neuroradiology, University Hospital of Basel, University of Basel, Basel, Switzerland.
Front Hum Neurosci. 2020 Sep 29;14:566735. doi: 10.3389/fnhum.2020.566735. eCollection 2020.
Gait analysis involving cognitive-motor dual task (DT) is a diagnostic tool in geriatrics. Cognitive-motor interference effects during DT, such as decreased walking speed and increased step-to-step variability, have a high predictive value for fall risk and cognitive decline. Previously we showed the feasibility of DT during functional magnetic resonance imaging (fMRI) using an MRI-compatible stepping device. Here, we improved the DT-fMRI protocol with respect to task difficulty and signal robustness, making it more suitable for individualized analysis to better understand the neuronal substrates of cognitive-motor interference effects. Thirty healthy elderly subjects performed cognitive and motor single tasks (ST; stepping or finger tapping), as well as combined cognitive-motor DT during fMRI. After whole brain group level analysis, a region-of-interest (ROI) analysis and the computation of dual task costs (DTC = activation difference ratio ST/DT) at individual level were performed. Activations in the primary (M1) and secondary motor as well as in parietal and prefrontal cortex were measured at the group level during DT. Motor areas showed decreased activation whereas parietal and prefrontal areas showed increased activation in DT vs. ST. Stepping yielded more distinctive activations in DT vs. ST than finger tapping. At the individual level, the most robust activations (based on occurrence probability and signal strength) were measured in the stepping condition, in M1, supplementary motor area (SMA) and superior parietal lobule/intraparietal sulcus (SPL/IPS). The distribution of individual DTC in SPL/IPS during stepping suggested a separation of subjects in groups with high vs. low DTC. This study proposes an improved cognitive-motor DT-fMRI protocol and a standardized analysis routine of functional neuronal markers for cognitive-motor interference at the individual level.
涉及认知 - 运动双重任务（DT）的步态分析是老年医学中的一种诊断工具。双重任务期间的认知 - 运动干扰效应，如步行速度降低和步幅变异性增加，对跌倒风险和认知衰退具有较高的预测价值。此前我们展示了使用MRI兼容的步进装置在功能磁共振成像（fMRI）期间进行双重任务的可行性。在此，我们在任务难度和信号稳健性方面改进了双重任务fMRI协议，使其更适合个体化分析，以更好地理解认知 - 运动干扰效应的神经基质。30名健康老年受试者在fMRI期间执行认知和运动单一任务（ST；步进或手指敲击）以及认知 - 运动双重任务。在全脑组水平分析之后，进行了感兴趣区域（ROI）分析以及个体水平的双重任务成本计算（DTC = 单一任务激活差异率/双重任务激活差异率）。在双重任务期间，在组水平上测量了初级运动皮层（M1）、次级运动皮层以及顶叶和前额叶皮层的激活情况。与单一任务相比，运动区域的激活减少，而顶叶和前额叶区域在双重任务中激活增加。与手指敲击相比，步进在双重任务与单一任务中产生了更明显的激活。在个体水平上，在步进条件下，在M1、辅助运动区（SMA）和顶上小叶/顶内沟（SPL/IPS）测量到了最稳健的激活（基于出现概率和信号强度）。步进期间SPL/IPS中个体DTC的分布表明，受试者可分为高DTC组和低DTC组。本研究提出了一种改进的认知 - 运动双重任务fMRI协议以及个体水平上用于认知 - 运动干扰的功能性神经标记物的标准化分析程序。
