Introduction
A stroke, which is referred to as a cerebrovascular accident (CVA), occurs when the blood flow to the brain is either blocked or when a blood vessel is ruptured. A cardiovascular accident is reported to be one of the major causes of death and impairments. One of the main disabilities in patients post-stroke is an imbalance which occurs in almost 70 percent of stroke survivors. A cardiovascular accident often results in muscle spasticity, weakness, abnormal gait, and balance dysfunction. Fall is a common complication observed in patients with a stroke, which can result in life-threatening situations. Hence, improvement of balance is important in treating stroke patients.
What Are the Complications of a Cardiovascular Accident?
The cardiovascular accident results in cardiovascular disease that develops signs of brain function disorder that improves rapidly and continues for more than 24 hours.
-
Patients who suffer from stroke may result in disruption of the sensory system resulting in motor dysfunction of the hemiparetic limb.
-
Loss of sense of awareness in correcting movement errors and impaired tactile perception are other common complications of stroke resulting in impaired correction of limb motion.
-
Stroke survivors often present with gait abnormality having a decreased stance phase and prolonged swing phase of the paretic side.
These complications further increase the probability of a fall and loss of balance in stroke survivors. This results in disruption of the normal day-to-day activities of the patient.
How Does a Cerebrovascular Accident Affect the Postural Balance?
Postural orientation involves control of the positions of the body parts by skeletal muscles with respect to each other and gravity. Balance is a condition in which all the forces acting on the body are balanced such that the center of mass is within the stability limits and the boundaries of the base of the support. Balance emerges from a complex interaction of sensory systems responsible for the detection of body position and motion, the motor system responsible for the organization and execution of muscle movements, and the higher-level central nervous system responsible for integration and action plans.
Post-stroke patients carry complex combinations of sensory, motor, emotional, and cognitive deficiencies that affect the static and dynamic balance in stroke patients. After a stroke injury, the supraspinatus control over the spinal reflex activity is interrupted, resulting in impaired reflex adaptations and impaired stretch reflex pathways. The balance impairment increases the risk of falls and impacts the quality of life in stroke survivors.
What Is Vibration Stimulation Therapy?
Due to the complexity of a stroke injury, many treatment modalities have been used in managing the impaired balance of a stroke patient. The vibration manipulation technique is one of the effective modalities in treating loss of balance in stroke rehabilitation. This technique is a non-invasive treatment. Vibration therapy helps in increasing bone density, reducing muscle spasms, and increasing muscle tone. This therapy involves two delivery modes;
-
The whole-body vibration technique is used in a rehabilitation setting, which comprises specialized equipment.
-
Another delivery method is the local vibration technique. This technique involves the use of a handheld instrument focusing on individual muscles.
The stretch reflex, which is an automatic reflex present inside every muscle of the body, is constantly looking to be stimulated through movement. In paralytic patients, the stretch reflex exchanging messages to and from the brain gets impaired. The stretch reflex is waiting to be stimulated even when the muscles are not sending and receiving messages from the brain. An increase in muscle tone or stiffness is a complication resulting from the lack of communication between the brain and the desire for the muscles to move. This occurs when the muscles affected by the cardiovascular accident are unable to communicate with the central nervous system.
Thus, vibration therapy stimulates the stretch reflexes, thereby reestablishing the communication between the brain and the muscle, resulting in reduced muscle spasticity and increased muscle build-up.
What Is the Role of Plantar Vibration in Treating Stroke Patients With Impaired Balance?
The plantar surface of the foot is considered to be the sensory area for posture control, foot positions, and balance. Vibrations-sensitive receptors, especially the fast adapting receptors, are distributed randomly over the plantar surface. Impairment of the somatosensory system is common in people with chronic stroke. Recent studies have shown that sensory vibratory stimulation applied over the plantar surface in an adult stroke survivor showed improved plantar flexor spasticity and ankle-passive range of motion, which are important for balance and fall risks. Vibrations applied to the plantar surface might enhance the stimulation of stretch receptors responsible for communication with the central nervous system.
Is Plantar Vibration Effective in Stroke Patients?
The physical therapist provides the plantar vibration through a vibratory stimulation device. The stimulation can deliver vibration stimuli at frequencies ranging from 40 to 100 hertz (Hz). For the past ten years, many studies have been conducted to understand the effectiveness of plantar vibration in improving balance in stroke patients. A study conducted by the physical therapy and rehabilitation hospital of the Kirikkale University aimed to compare the effectiveness of local vibration in the plantar region of the foot with conventional physical therapy interventions in static and dynamic balance in stroke patients. 30 patients with stroke were included in this randomized control trial. Patients who received plantar vibrations showed greater improvements in static and dynamic balance assessment than compared to the control group receiving conventional physical therapy. Particularly the patients receiving the plantar vibrations showed improvement in postural stability, balance, fall, and walking speed. A small effectiveness of about ten percent in the TUG (timed up and go) test was identified after the plantar vibration therapy. The TUG test is a sensitive and specific test for measuring functional mobility and dynamic balance.
Conclusion
A cerebrovascular accident is a life-threatening condition that can cause balance impairment increasing the risk of falls in stroke survivors. It can negatively affect the quality of life and also restricts social participation in patients with stroke. Hence, it is important in stroke neurorehabilitation to improve balance and reduce fall risk. Vibration therapy at a frequency of 100 HZ in patients who suffered from stroke shows improvement in muscle spasticity. With recent studies and pieces of evidence, the plantar vibration technique is added to physical therapy interventions to improve functional mobility and dynamic balance.
