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This page will provide you with a comprehensive overview on the pathophysiology of hemiparesis, the causes of hemiparesis, the symptoms of hemiparesis and the treatment of hemiparesis as it pertains to stroke. We sincerely hope that our website helps to further your understanding on the topic of both hemiparesis and stroke. If you have further questions, please contact a healthcare professional.
What is Hemiparesis?
Hemiparesis, weakness on one side of the body, is a common consequence of head trauma, cerebral palsy and stroke. The term hemiparesis comes from the words “hemi,” which means half, and “paresis,” which means partial paralysis. Importantly, this is significantly different from hemiplegia, which is paralysis of half of the body; a patient with hemiparesis can still move parts of the body on the side that is affected whereas a patient with hemiplegia cannot.
Connection Between Hemiparesis and Stroke
Hemiparesis and stroke are both well studied conditions because of their high prevalence and their irreversible nature. Stroke, also referred to as a brain attack, is when a patient has insufficient blood flow to the brain. The subsequent hypoxia associated with stroke may lead to brain injury, and consequently, other conditions that require brain injury, such as hemiparesis.
It is important to recognize that because both hemiparesis and stroke are associated with brain injury, they are conditions that are have irreversible consequences. Moreover, because about 80% of people who have a stroke have some form of one sided body weakness, hemiparesis and stroke have a strong correlation. It is essential to understand and be able to detect both hemiparesis and stroke because they have potential lifelong implications
Forms of Hemiparesis
Due to the fact that hemiparesis can be a result of injury in different parts of the brain, there are different forms of it that may exist. In general, the five forms of hemiparesis are:
Pure Motor Hemiparesis: This is the most common form of hemiparesis. It may affect one part of the body more than another and typically involves weakness in the leg, arm and face.
Ataxic Hemiparesis Syndrome: This is the second most frequent form. Like, pure motor hemiparesis, ataxic hemiparesis syndrome also typically involves weakness and clumsiness on one side. Importantly, the symptoms may take hours or day to develop.
Ataxia: When a person has injury in the lower portion of their brain, the person may have difficulties coordinating their movements. This form of hemiparesis is called ataxia. Notably, ataxia is also a condition that may occur without the presence of hemiparesis. It typically involves difficulties with walking, balance and posture.
Left Sided Hemiparesis: Contrary to what the name suggest, left sided hemiparesis involves injury to the right side of the brain. The right side is important in learning processes, behavior and non-verbal communication. Consequently, this form of hemiparesis may cause a patient to have short attention spans, talk excessively and have memory problems.
Right Sided Hemiparesis: Likewise, when a person has right sided hemiparesis, the person has injury on the left side of the brain. The left side is important in language, and thus, a person with this form may have difficulties with talking and comprehending what someone says.
Causes of Hemiparesis
The most important causes of hemiparesis are stroke, spinal cord injury and traumatic brain injury. This is simply all of these conditions are capable of causing brain injury in non-specific areas. For example, when a person has a stroke their lesions may occur anywhere in the brain where hypoxia is present. This is important because the pathophysiology of hemiparesis depends on the location of the brain injury.
The brain, a complex vital structure, has many different regions that are responsible for different actions. Specifically, one of the most important areas in hemiparesis is the corticospinal tract (a pathway of neurons beginning in motor areas of the brain). This area primarily controls body movement. The corticospinal tract begins in the motor areas of the brain and continues down the internal capsule and brainstem until it crosses lower medulla. Next, it continues down the spinal cord into motor neurons controlling each muscle. Any injuries that are above the medulla cause contralateral hemiparesis (opposite side) whereas any injuries below the medulla cause ipsilateral hemiparesis (same side).
The side that is affected is crucial in determining the problems the patient faces. For example, a patient with right sided hemiparesis has left side brain injury, and thus, may have difficulties with language. In contrast a patient with left sided hemiparesis has right side brain injury, and thus, may have difficulties with learning, non-verbal communication, and their attention span.
Symptoms of Hemiparesis
Both the causes of hemiparesis and the pathophysiology of hemiparesis helps determine symptoms of hemiparesis. For example, if a patient has brain injury in the rights side above the medulla, the left side is affected and the patient may present with difficulties in non- verbal communication.
Likewise, if a patient has brain injury in the right side below the medulla, the right side of the body is affected and the patient may present with difficulties in non-verbal communication. It is important to note that the causes of hemiparesis affect the severity of the symptoms of hemiparesis. For example, when a person has a stroke, they may have a minor stroke or a major stroke, and thus, the associated brain lesions may be minimal or severe, respectively. However, some general common symptoms of hemiparesis include:
• Loss of balance or loss of motor skills
• Pusher syndrome – when patients actively push their weight away from the nonhemiparetic (strong) side to the hemiparetic (weak) side. Notably, this is different than normal stroke patients who try to use their stronger side to accommodate.
• Impaired ability to grasp objects
• Decrease in movement precision
• Muscle fatigue
Diagnosis of Hemiparesis and Stroke
Although the timing of hemiparesis and stroke are different, the diagnosis of both hemiparesis and stroke typically involves clinical examination and various radiological scans. More specifically, when a patient first arrives to the hospital with a stroke, the doctor may observe symptoms such as: dizziness, loss of balance, loss of coordination, confusion and sudden weakness in the body.
If the doctor suspects stroke, they may investigate further through CT scans, MRI scans, heart studies, and blood tests. Importantly, the medical professional must act fast in both the diagnosis and treatment of stroke to minimize the amount of brain injury that occurs.
In contrast, because the diagnosis of hemiparesis occurs after stroke, the matter is less urgent and the medical professional may take more time considering the patient’s history and symptoms. This is important because hemiparesis and stroke are only one of the many pairs of related conditions after a stroke.
After considering the patient’s history, the medical professional will often confirm the presence of hemiparesis by using radiological studies, such as a CT scan or MRI scan, to confirm the presence of brain injury or spine injury and determine its location. Once they find the lesion location they can determine the type, the prognosis (based off the severity of the lesion) and the appropriate treatment of hemiparesis.
Treatment of Hemiparesis and Stroke
Due to the fact that brain injury is incurable, treatment of hemiparesis and stroke typically focuses on reducing symptoms and compensatory techniques. Simply put, the overall goal in the treatment of hemiparesis and stroke is to help the individual live a normal life. Two common therapies used include:
Physical therapy: This can help the patient regain some muscle strength while minimizing the disability and pain
Occupational Therapy: This form of therapy educates patients and families about compensatory techniques the individual can use to continue their daily living. Some techniques may involve environmental modification or adaptive equipment.
Alternatively, if the lesion is not severe, there are some forms of therapy that may be used to help the patient regain movement. This is partially because of neuroplasticity and the ability to strengthen muscles. Some common therapies include:
Electrical Stimulation: This therapy involves applying a small electrical shock via electrical pads on the weakened muscles to help the patient’s muscles contract. Overall, this helps strengthen the muscle and increase the range of motion.
Motor Imagery: One newer, but relevant, therapy involves the use of mental images. Specifically, a person is told to practice imagining moving a certain part of their body. It is relevant because it can activate important areas in the brain and muscle that would normally be activated if they were doing the activity.
Modified Constraint: Induced therapy (mCIT)- mCIT therapy involves forcing a patient to perform a certain activity by constraining other methods they may use. For example, if a patient with left sided hemiparesis was asked to pick up something, their right side may be constrained, so they have no choice but to push their left side. Notably, it can only be used in patients that have some level of movement remaining.
Living with Hemiparesis and Stroke
Hemiparesis is a serious condition that can negatively impact the quality of an individual’s life. Specifically, because it can cause trouble with moving limbs, it can also prevent an individual from performing simple activities, such as dressing oneself.
Ultimately, this may cause psychological and social distress. For this reason, it is essential to ensure the patient is receiving the help and support they need through various counsellors and medical professionals. More importantly, because hemiparesis is associated with increased safety risks, it is crucial to make accommodating changes to the environment. Some things that can be done to increase safety includes:
• Installing “grab bars” to assist the individual when moving around
• Installing ramps in place of stairs
• Ensuring there is a tub bench
• Placing plastic adhesive strips on the bottom of the bathtub to prevent the individual from slipping
• Buying electric toothbrushes and razors
In addition to making various changes in the environment, it is essential for the individual to make some simple lifestyle changes to promote a healthy recovery and avoid another stroke. Some examples include:
• being active
• performing various muscle strengthening exercises
• eating a healthy diet
• walking carefully to prevent falls
For any additional information on hemiparesis and stroke please contact your local healthcare professional.