tDCS combined with kinesthetic motor imagery-based brain computer interface training promotes upper limb function in subacute stroke: A randomized controlled study

Abstract

Background Most stroke survivors have upper extremity dysfunction. According to neuroplasticity theory, transcranial direct current stimulation (tDCS) and kinesthetic motor imagery-based brain computer interface (KI-BCI) have the potential to improve the upper extremity function of participants with subacute stroke. However, the efficacy of tDCS combined with KI-BCI in participants with subacute stroke is unknown. Objective To investigate whether the combined effect of tDCS and KI-BCI on upper limb function in participants with subacute stroke is more effective than the effects of tDCS or KI-BCI alone. Methods We randomized 48 participants into a tDCS group (n = 16), a KI-BCI group (n = 16), and a tDCS-BCI group (n = 16). Participants in the tDCS group received 30 min of tDCS with the anode over M1. The KI-BCI group performed 30 min of KI-BCI training. Participants in the tDCS-BCI group received 15 min of tDCS and 15 min of KI-BCI. All participants received conventional intervention. The treatment cycle consisted of a 1 session each day, 5 days per week for 4 weeks. The Fugl–Meyer Assessment of Upper Extremity (FMA-UE) subscale, Motor Status Scale (MSS), Action Research Arm Test (ARAT), and Modified Barthel Index (MBI) were used to assess upper limb function, and activities of daily living (ADL) before and after the 4-week treatment period. In addition, electroencephalography (EEG) was used to explore potential clinical brain mechanisms. Results After four weeks of intervention, the tDCS-BCI group was superior to the tDCS group in terms of the MSS. The FMA-UE, MSS, and MBI scores of the KI-BCI group were superior to those of the tDCS group. There was no difference in the number of quantitative EEGs among the three groups, while the number of quantitative EEGs was greater than before. Conclusion TDCS combined with KI-CI training can improve upper extremity function. However, KI-BCI training alone can improve upper limb function and ADL simultaneously. TDCS could alter the electrical excitatory levels of the cerebral hemispheres. Trial registry number: ChiCTR2000034730