Effects of Mental Imagery Training Combined With Task Oriented Training by EMG-Driven Soft Robotic Hand Stroke in Stroke

The World Health Organization (WHO) defines stroke as a condition marked by the sudden onset of clinical symptoms reflecting a focal or global disturbance in brain function, lasting more than 24 hours or leading to death, with no apparent cause other than a vascular origin. WHO estimates that approximately 15 million people worldwide experience a stroke each year. It continues term disability .Stroke remains a widespread concern in developing nations, but it continues to be largely overlooked. One of the most affected areas following stroke is the impairment of motor skill.

Motor deficits, especially hemiparesis, are frequently seen in stroke survivors and greatly hinder their ability to carry out daily activities, which in turn negatively influences their overall quality of life. Upper limb motor deficits are frequently seen in stroke survivors, with nearly 78% affected. Approximately 50% of them struggle particularly with hand function needed for daily living activities. Compensatory movements are frequently seen during upper extremity tasks, often involving proximal joints compensating for limited distal joint function. Most notable improvements in upper extremity motor function usually take place within the first six months after stroke onset. However, around 65% of stroke survivors continue to experience difficulty using their affected hand during the chronic stage. As a result, restoring upper extremity function especially hand function is crucial for chronic stroke survivors to achieve independence in daily activities.

Previous research has shown that task-oriented training can greatly improve upper extremity motor function, even in individuals with chronic stroke. The task- oriented approach is a functional activity-based method that emphasizes practicing specific tasks repeatedly to improve performance. The task-oriented approach incorporates such functional tasks, making it a practical intervention for patients. This treatment focuses on enhancing motor function by encouraging active use of the affected upper limb because patients use the unaffected side more during arm action, it is necessary to apply therapy to the affected arm.

Another technique used with stroke patients is Mental imagery(MI) /Mental Practice(MP) technique does not require great economic investments and can be performed anywhere, because no special equipment is needed. It is safe, given that the technique can be repeated many times without great physical effort. MI is a technique in which individuals imagine themselves performing physical tasks without any actual movement. Theory suggests that Mental rehearsal of a task activates the similar regions of the brain as activated by physical performance of the same task. Recent research indicates that when MI is combined with physical practice, it can significantly improve the recovery of motor functions. In MI, reactivation occurs when a movement is mentally simulated rather than physically executed, reflecting a voluntary effort. This allows individuals to develop and refine motor skills without actual movement.

Recently, wearable robotic hands have attracted considerable interest as rehabilitation tools in hospitals and therapy centers. These robotic devices help stroke patients perform repetitive hand functions such as opening and grasping. Research has demonstrated that rehabilitation using wearable robotic hands or gloves, which are activated by surface electromyography signals, combining with TOT can improve motor performance and reduce abnormal muscle tone patterns.

This study proposes integrating MI with TOT using soft robotic hand to potentially enhance motor learning and functional recovery by simultaneously engaging both cognitive and sensorimotor pathways. The combination could provide a synergistic effect, maximizing cortical activation and functional gains in stroke survivors with upper limb deficits. By investigating this approach, the study aims to contribute to more effective rehabilitation protocols for improving UL function post-stroke. This combination may lead to faster recovery and better motor performance without extra financial burden. This information can help rehabilitation professionals assess upper limb motor recovery, monitor progress, and develop targeted interventions.

Inclusion criteria

• Participants clinically diagnosed with stroke in chronic stage (6 months after the onset of stroke) with a pure unilateral motor paresis after stroke.
• 18-70 years of age.
• Sufficient cognition to follow simple instructions and understand the content and purpose of study (MMSE score 28)
• Able to sit up for at least 45 minutes.
• Detectable residual signals from the affected side's Flexor digitorum (FD) and Extensor Digitorum (ED) muscles.
• Modified Ashworth Scale (MAS) score of finger extensor less than or to 3
• Ability to provide informed consent

Exclusion criteria

• Patients with severe dysphasia with inadequate communication.
• Any additional medical or psychological condition affecting their ability to comply with the study protocol.
• History of other neurological disease or psychiatric disorders, including alcoholism and substance abuse