Description

Stroke is one of the leading causes of mortality and long-term disability, with millions of new cases each year and a large proportion of survivors living with lasting impairments in movement and function. After a stroke, damage to the motor areas and descending pathways of the brain frequently leads to spasticity, a condition in which muscles become abnormally tight and resist passive stretch; this increase in muscle tone is velocity-dependent and often accompanied by weakness and loss of selective control. Spasticity develops in a substantial proportion of stroke survivors and is especially disabling when it involves the upper limb, where it interferes with reaching, grasping, releasing, and the performance of essential activities of daily living such as dressing, feeding, and personal care.

Upper limb involvement is particularly common because most strokes affect the middle cerebral artery (MCA) territory, which supplies key regions of the motor cortex and internal capsule responsible for control of the face and arm more than the leg. As a result, many patients present with the characteristic pattern of flexor spasticity in the shoulder, elbow, wrist, and fingers, while the lower limb may show relatively better recovery or a different pattern of impairment. Recovery of upper limb function is also typically slower and less complete than that of the lower limb: walking often returns earlier, whereas fine hand and arm movements require more complex cortical processing and richer sensorimotor integration, which are more vulnerable to damage and harder to reorganize. This slower recovery reflects, in part, the lower effective neuroplasticity or more limited spontaneous re-organization in upper limb networks after stroke, meaning that more intensive, targeted, and often multimodal interventions are needed to restore arm and hand function.

Because of these factors, the upper limb frequently remains a limitation for independence even when a patient can walk, and persistent spasticity in the arm can further block functional gains by causing abnormal postures, contractures, and pain. Traditional approaches to spasticity management; such as oral antispastic medications and botulinum toxin injections can reduce muscle tone, but they often provide only temporary relief, may have systemic or local side effects, and do not always translate into meaningful functional improvements. These limitations have driven interest in innovative, non-invasive options that can modulate muscle tone and support neuroplasticity while fitting into comprehensive rehabilitation programs.

Extracorporeal shock wave therapy (ESWT) is one such emerging modality as it delivers controlled acoustic waves to targeted muscles and soft tissues and is thought to act through a combination of mechanical, vascular, and neuromodulator mechanisms. Experimental and clinical studies suggest that ESWT may reduce spasticity by altering reflex excitability, influencing neuromuscular junction function, and promoting tissue regeneration and remodeling, with reported side effects generally mild and transient. Early and mid-term clinical evidence indicates that ESWT can safely decrease spasticity and, in some trials, achieve functional gains comparable to more established treatments, but the exact mechanisms, optimal parameters (energy, frequency, number of shocks, treatment sites, and session frequency), and long-term functional impact are not yet fully defined.

This study focuses on the upper limb spasticity as it is the region where disability is often greatest, recovery is slowest, and current options are imperfect. By targeting key flexor muscle groups of the affected upper limb with ESWT, the aim is to reduce pathological muscle overactivity and spasticity, thereby creating a more favorable biomechanical and neurophysiological environment for active training and functional use. The study plan hypothesizes that systematically applied ESWT, integrated with structured rehabilitation, can meaningfully improve upper limb function in stroke, addressing a critical unmet need in post-stroke care and contributing evidence toward standardized, parameter-based ESWT protocols.