Upper limb dysfunction is a common functional Impairment after a stroke. Nearly 75% of acute stroke survivors experience upper limb symptoms while only 5% of adult stroke victims regain fully functional upper limb after completing their rehabilitation program. Chronic loss of sensation and muscle weakness enhance the degree of functional limitations caused by upper limb dysfunction.
Stroke-led upper limb dysfunction is a direct consequence of the lack of signal transmission from the motor cortex after stroke. This transmission generates the movement impulse to the spinal cord which executes the movement via signals to muscles. Such lack of transmission after stroke results in delayed initiation, delayed termination of muscle contraction and slowness in developing force. This is manifested as upper limb’s inability to move or move quickly.
Initially flaccid, the affected upper limb tends to develop increased resting tone, exaggerated stretch reflexes and spasticity (muscle control disorder, characterized by tight or stiff muscles and an inability to control those muscles) of varying degrees. The impairment causes the functional limitations in using the affected upper limb after stroke, eventually leading to learned nonuse. Initially, nonuse may occur because of muscle weakness or sensory loss, however, it may become habitual (a learned behavior) as time progresses even though the individual can move it.
The pattern of weakness should be examined immediately to rule out spinal cord injury or peripheral nerve injury. Early assessment of upper limb dysfunction and its recovery planning should be started as early as possible, taking each patient’s clinical status into consideration.
Options to treat stroke-led Upper limb dysfunction
Understanding the nature of upper limb impairment is essential to restore its function. However, functional rehabilitation of upper limb can be bit puzzling as the type and nature of the impairments may change with motor recovery. Therefore, the treatment needs to target the impairment at a given point in time, requiring approaches that avoid complications, promote recovery and provide compensatory strategies in varying combinations.
Research supports that approaches that enhance experience-dependent Neuroplasticity may be best-suited for stroke survivors with upper limb dysfunction. Using neuroplasticity-based interventions, impairment needs to be translated into functional improvements through everyday tasks, ongoing home based exercise or self-managed therapy programs.
During early inpatient rehabilitation, Upper Extremity Interventions such as Constraint Induced Therapy (CIT) are commonly used. Later on, mental imagery, bilateral movements and aerobic exercise might be used for repairing the motor cortex. Certain virtual-reality based rehabilitation can be used as adjunctive therapy. Robotic technology is often utilized to increase the number of repetitions in a motivating environment.