Abstract
Background
Post-stroke dysfunction in bimanual coordination causes decreased independence in activities of daily living. Past studies and reviews have reported the neural mechanisms underlying bilateral movements with an independent goal (BMIG) in healthy adults; however, those underlying bilateral movements with a common goal (BMCG) remain unclear. The purpose of this study is twofold: to review the neural mechanisms underlying upper-limb BMCG in healthy and stroke individuals, compared with BMIG and rest, and to determine the effects of non-invasive brain stimulation (NIBS) on improving BMCG in healthy and stroke individuals.
Methods
We conducted a literature search in the PubMed, Embase, Medline vis EBSCO, and Web of Science databases. Two authors independently screened the studies, extracted data, and qualitatively synthesized the studies.
Results
Fifteen studies were included. Of these studies, nine focused on brain activation underlying BMCG, and seven focused on the effects of NIBS on BMCG. In healthy individuals, three brain activation patterns underlying different BMCGs were identified. When healthy individuals performed BMCG and BMIG, the main differences observed were increased activation in the right superior temporal cortex and bilateral secondary somatosensory cortex. Compared with healthy controls, stroke patients demonstrated increased involvement of the unaffected cortical areas and decreased positive neural coupling between the primary motor cortex (M1) and supplementary motor area in the affected hemisphere during BMCG. Excitatory stimulation applied over the ipsilateral M1 and the contralateral dorsal premotor cortex may improve the performance of BMCG in stroke patients with mild and severe impairments, respectively.
Conclusion
Stroke patients may be compensatorily recruited with more brain areas to execute the BMCG tasks compared to healthy individuals. The improvement of BMCG in stroke is because of the improvement of general motor impairment rather than a specific effect on BMCG.
Systematic Review Registration
This review was registered on Inplasy.com (INPLASY202350080)