Graduate School of Health Sciences, Hokkaido University, Sapporo, 060-0812, Japan.
Department of Rehabilitation Science, Faculty of Health Sciences, Hokkaido University, Sapporo, Hokkaido, 060-0812, Japan.
J Transl Med. 2023 Feb 24;21(1):143. doi: 10.1186/s12967-023-03989-9.
The left dorsolateral prefrontal cortex (DLPFC) is involved in early-phase manual dexterity skill acquisition when cognitive control processes, such as integration and complexity demands, are required. However, the effectiveness of left DLPFC transcranial direct current stimulation (tDCS) on early-phase motor learning and whether its effectiveness depends on the cognitive demand of the target task are unclear. This study aimed to investigate whether tDCS over the left DLPFC improves non-dominant hand dexterity performance and determine if its efficacy depends on the cognitive demand of the target task.
In this randomized, double-blind, sham-controlled trial, 70 healthy, right-handed, young adult participants were recruited. They were randomly allocated to the active tDCS (2 mA for 20 min) or sham groups and repeatedly performed the Purdue Pegboard Test (PPT) left-handed peg task and left-handed assembly task three times: pre-tDCS, during tDCS, and post tDCS.
The final sample comprised 66 healthy young adults (mean age, 22.73 ± 1.57 years). There were significant interactions between group and time in both PPT tasks, indicating significantly higher performance of those in the active tDCS group than those in the sham group post tDCS (p < 0.001). Moreover, a greater benefit was observed in the left-handed assembly task performance than in the peg task performance (p < 0.001). No significant correlation between baseline performance and benefits from tDCS was observed in either task.
These results demonstrated that prefrontal tDCS significantly improved early-phase manual dexterity skill acquisition, and its benefits were greater for the task with high cognitive demands. These findings contribute to a deeper understanding of the underlying neurophysiological mechanisms of the left DLPFC in the modulation of early-phase dexterity skill acquisition.
This study was registered in the University Hospital Medical Information Network Clinical Trial Registry in Japan (UMIN000046868), Registered February 8, 2022 https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000053467.
左侧背外侧前额叶皮层（DLPFC）参与需要认知控制过程（如整合和复杂性要求）的早期手动灵巧性技能获取。然而，左侧 DLPFC 的经颅直流电刺激（tDCS）对早期运动学习的有效性以及其有效性是否取决于目标任务的认知需求尚不清楚。本研究旨在探讨 tDCS 是否能提高非优势手的灵巧性表现，并确定其功效是否取决于目标任务的认知需求。
在这项随机、双盲、假对照试验中，招募了 70 名健康、右利手的年轻成年人参与者。他们被随机分配到主动 tDCS（2 mA 持续 20 分钟）或假刺激组，并反复进行三次左手 Purdue 钉板测试（PPT）左手钉任务和左手装配任务：tDCS 前、tDCS 期间和 tDCS 后。
最终样本包括 66 名健康的年轻成年人（平均年龄，22.73±1.57 岁）。在这两个 PPT 任务中，组间和时间间均存在显著的交互作用，表明 tDCS 后主动组的表现明显优于假刺激组（p<0.001）。此外，在左手装配任务的表现中观察到更大的益处，而在钉任务的表现中则没有（p<0.001）。在这两个任务中，都没有观察到基线表现与 tDCS 益处之间存在显著相关性。
这些结果表明，前额叶 tDCS 显著改善了早期手动灵巧性技能获取，并且对于认知要求较高的任务，其益处更大。这些发现有助于更深入地了解左侧 DLPFC 在调节早期灵巧性技能获取中的神经生理机制。
本研究在日本大学医院医疗信息网络临床试验注册中心（UMIN000046868）注册，注册日期为 2022 年 2 月 8 日https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000053467。
