A stroke occurs when the blood supply to a part of the brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients. Brain cells can begin to die within minutes, making prompt medical attention important. While many types of strokes exist, this article focuses on subcortical strokes, a category affecting deeper brain regions.
Understanding Subcortical Stroke
The term “subcortical” refers to areas of the brain located beneath the cerebral cortex, the outer layer responsible for higher cognitive functions. Subcortical structures include regions like the basal ganglia, thalamus, internal capsule, brainstem, and white matter pathways. These areas control bodily functions such as movement, sensation, balance, and emotion.
Subcortical strokes are distinct from cortical strokes, which affect the brain’s outer surface. While cortical strokes often impact higher-level functions like language or spatial awareness, subcortical strokes primarily affect motor and sensory pathways. Approximately 30% of all ischemic strokes, caused by blockages, are subcortical.
Identifying Causes and Risk Factors
Most subcortical strokes are ischemic, resulting from a blocked blood vessel. These strokes often arise from small vessel disease, known as lacunar strokes. Lacunar strokes occur when small arteries deep within the brain become blocked, causing small, “pea-sized” areas of damage.
Several factors can damage these small blood vessels and increase the risk of subcortical stroke. Uncontrolled high blood pressure (hypertension) is a major risk factor, as it narrows and hardens arteries. Other factors include diabetes, high cholesterol, and smoking, leading to plaque buildup and blockages in small arteries. Advanced age also increases the risk of lacunar stroke.
Recognizing the Signs
The symptoms of a subcortical stroke can vary depending on the specific brain region affected, but they often involve motor and sensory changes. Common signs include weakness on one side of the body, affecting the face, arm, and leg. People may also experience sensory disturbances such as numbness or tingling.
Speech difficulties, slurred speech (dysarthria), and problems with balance or coordination can occur. While symptoms can be subtle, they may develop suddenly. Recognizing the signs of stroke, summarized by F.A.S.T. (Face drooping, Arm weakness, Speech difficulty, Time to call emergency services), is important. Prompt medical attention is important, even if signs appear subtle, to minimize potential brain damage.
Diagnosis and Initial Care
Diagnosing a subcortical stroke involves a thorough neurological examination and medical imaging. Computed tomography (CT) scans and magnetic resonance imaging (MRI) are tools used to confirm diagnosis and rule out other conditions. Diffusion-weighted MRI is effective for detecting acute strokes. Medical professionals also review the patient’s medical history for potential risk factors.
Upon arrival at the hospital, initial care focuses on stabilizing the patient and determining the type of stroke. For ischemic strokes, the goal is to restore blood flow to the affected brain area. While intravenous thrombolysis (like tPA) is a general stroke treatment, it may be less frequently indicated for small lacunar strokes. Managing blood pressure and preventing early complications are important aspects of acute care.
Path to Recovery
Recovery following a subcortical stroke is a process that varies significantly among individuals. Rehabilitation is a key part of this process and involves a multidisciplinary team. This team may include physical therapists improving movement and strength, occupational therapists assisting with daily activities, and speech therapists addressing communication and swallowing difficulties.
Early and consistent rehabilitation is important, as the brain has a capacity for reorganization, known as plasticity. Through repetitive, focused exercises, healthy parts of the brain can learn to take over functions from damaged areas. Patients may encounter challenges such as fatigue, mood changes like depression, or persistent motor and sensory deficits. Managing underlying risk factors is important to prevent future strokes and support long-term well-being.