What side of the body does a stroke affect
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Understanding the Side of the Body Affected by Stroke
Stroke and Hemiparesis: Affected Side
A stroke typically results in hemiparesis, which is the weakness or partial paralysis on one side of the body. The side of the body that is affected by a stroke is usually opposite to the side of the brain where the stroke occurred. For instance, a stroke in the left hemisphere of the brain will generally affect the right side of the body, and vice versa .
Motor Impairment and Recovery
Ipsilesional and Contralesional Effects
Post-stroke, the severity of motor impairment can vary between the ipsilesional (same side as the brain lesion) and contralesional (opposite side) sides of the body. Studies have shown that the less-affected side (ipsilesional) can still exhibit motor impairments, although they are generally less severe compared to the contralesional side . Motor training involving the less-affected side (MTLA) has been shown to improve muscle strength, dexterity, and coordination on both sides of the body.
Functional MRI Insights
Functional MRI studies have revealed that the organization of the motor cortex after a stroke is influenced by the side of the stroke and the level of recovery. Patients with right arm involvement (left hemisphere stroke) show different patterns of brain activation compared to those with left arm involvement (right hemisphere stroke). These differences in brain activation are associated with the degree of motor recovery.
Body Composition and Temperature Changes
Segmental Body Composition
Stroke can lead to significant changes in body composition, particularly in the extremities. Patients often experience a decrease in bone and lean mass on the affected side, regardless of whether they have hemiplegia. Additionally, stroke patients tend to have an increase in trunk fat mass, which is not observed in the extremities.
Thermal Sensitivity
Stroke can also affect thermal sensitivity, leading to lower temperatures on the affected side of the body. This is particularly noticeable in the feet of hemiparetic individuals, where the temperature is significantly lower compared to healthy individuals.
Gait and Movement Variability
Center of Mass Trajectory
The movement disorders caused by stroke can alter the trajectory of the Center of Mass (CoM) during gait. Hemiparetic patients show significant deviations in CoM trajectory during both the stance and swing phases of the gait cycle, with more pronounced alterations on the affected side.
Motor Variability
Stroke survivors exhibit higher movement variability in the affected arm. However, they can modulate this variability depending on the task, which suggests potential for rehabilitation through task-specific training.
Implications for Rehabilitation
Understanding the side of the body affected by a stroke and the associated motor and sensory impairments is crucial for developing effective rehabilitation strategies. Tailored interventions that consider the specific side of the brain lesion and the resulting motor cortex organization can lead to better recovery outcomes. Additionally, addressing changes in body composition and thermal sensitivity can further enhance rehabilitation efforts .
Conclusion
In summary, a stroke typically affects the side of the body opposite to the side of the brain where the stroke occurred. This results in various motor and sensory impairments, including changes in muscle strength, body composition, and thermal sensitivity. Understanding these effects is essential for developing effective rehabilitation strategies that can improve patient outcomes and quality of life.
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