Motor network reorganization after motor imagery training in stroke patients with moderate to severe upper limb impairment

Abstract

Background: Motor imagery training (MIT) has been widely used to improve hemiplegic upper limb function in stroke rehabilitation. The effectiveness of MIT is associated with the functional neuroplasticity of the motor network. Currently, brain activation and connectivity changes related to the motor recovery process after MIT are not well understood.Aim: We aimed to investigate the neural mechanisms of MIT in stroke rehabilitation through a longitudinal intervention study design with task-based functional magnetic resonance imaging (fMRI) analysis. Methods:We recruited 39 stroke patients with moderate to severe upper limb motor impairment and randomly assigned them to either the MIT or control groups. Patients in the MIT group received 4 weeks of MIT therapy plus conventional rehabilitation, while the control group only received conventional rehabilitation. The assessment of Fugl-Meyer Upper Limb Scale (FM-UL) and Barthel Index (BI), and fMRI scanning using a passive hand movement task were conducted on all patients before and after treatment. The changes in brain activation and functional connectivity (FC) were analyzed. Pearson's correlation analysis was conducted to evaluate the association between neural functional changes and motor improvement. Results:The MIT group achieved higher improvements in FM-UL and BI relative to the control group after the treatment. Passive movement of the affected hand evoked an abnormal bilateral activation pattern in both groups before intervention. A significant Group × Time interaction was found in the contralesional S1 and ipsilesional M1, showing a decrease of activation after intervention specifically in the MIT group, which was negatively correlated with the FM-UL improvement. FC analysis of the ipsilesional M1 displayed the motor network reorganization within the ipsilesional hemisphere, which correlated with the motor score changes.Conclusions: MIT could help decrease the compensatory activation at both hemispheres and reshape the FC within the ipsilesional hemisphere along with functional recovery in stroke patients.

The effects of visual skills training on cognitive and executive functions in stroke patients: a systematic review with meta-analysis

“…All participants had a history of diagnosed stroke and were aged between 30 and 77 years. One study examined participants with a mean age of 30.9–39.8 years [ 56 ], 14 studies of 52.5–62.6 years [ 55 , 58 , 59 , 76 , 78 , 80 , 82 – 84 , 87 , 88 , 90 , 92 , 94 ], six of 64.0–67.6 years [ 57 , 77 , 81 , 85 , 86 , 91 ], and three of 70.7–77.7 years [ 79 , 89 , 93 ]. A total of 357 women and 532 men were studied.…”

“…A total of 357 women and 532 men were studied. One study considered one woman and 28 men [ 92 ] and another five women and 25 men [ 76 ]. All other studies had a more balanced female-to-male ratio.…”

“…The localisation was indicated by five studies with right hemisphere [ 58 , 78 , 81 , 86 , 94 ], six with various [ 55 , 57 , 59 , 77 , 87 , 90 ], while all others did not provide any information. The main symptoms of the participants indicated eleven studies with cognitive dysfunction [ 55 – 57 , 59 , 78 , 79 , 82 , 83 , 86 – 88 ], five with motor dysfunction [ 58 , 77 , 90 , 92 , 94 ], three with visual disorders [ 80 , 81 , 89 ], and five did not provide any information [ 76 , 84 , 85 , 91 , 93 ]. For the time since stroke event, one study gave no indication [ 89 ], two generally less than 3 months [ 55 , 90 ], two from 3 to 6 months [ 56 , 80 ], three less than 6 months [ 57 , 59 , 87 ], two 0.5–0.6 months [ 58 , 86 ], seven 1.0–3.2 months [ 77 , 81 , 85 , 88 , 91 , 93 , 94 ], two 4.0–4.9 months [ 79 , 92 ], one more than 6 months [ 84 ], and four 8.3–20.8 months [ 76 , 78 , 82 , 83 ].…”

Effectiveness and brain mechanism of 40 Hz multitarget transcranial alternating current stimulation (tACS) on motor learning in stroke patients: Study protocol for a randomized controlled trial

“…Many clinical studies have con rmed the functional connectivity between the primary motor cortex (M1), primary sensory cortex (S1) and dorsolateral prefrontal cortex (DLPFC). The coactivation of M1 and S1 and DLPFC in planning, execution and control of movement has been well established [22][23][24]. In addition to the three brain regions mentioned above, recent studies have shown that cerebellar (CB) tACS can lead to improved cortical excitability and motor behavior [25], which affects balance and gait, limb movement, oculomotor control, and cognition.…”

Brain Activation Evoked by Motor Imagery in Pediatric Patients with Complete Spinal Cord Injury

“…At present, there is no effective treatment for pediatric CSCI. Currently, motor imagery (MI) is being studied as a potential treatment for the functional recovery of motor dysfunction diseases 5,6 because it can activate sensorimotor networks and can be performed by injured patients who are unable to move voluntarily. [7][8][9] MI is the mental simulation of a movement in the absence of obvious motor output.…”