Strokes are a significant health concern worldwide. According to the World Health Organization (WHO), stroke is the second leading cause of death and the third leading cause of disability worldwide. Every year, over 15 million people worldwide suffer a stroke. A stroke can have a significant impact on the central nervous system function. When a stroke occurs, blood flow to a part of the brain is disrupted, causing that part of the brain to become damaged or die.
The specific effects of a stroke depend on where in the brain the damage occurs, but common symptoms, all of which have a large detrimental effect on the ability to perform activities of daily living, include:
Weakness or paralysis on one side of the body: If the damage is on one side of the brain, it can affect the opposite side of the body. This can make it difficult to move or control certain muscles.
Sensory disturbances: A stroke can cause numbness, tingling, or loss of sensation in parts of the body. This can affect the ability to feel touch or temperature.
Speech and language difficulties: Damage to the areas of the brain that control speech and language can make it difficult to communicate or understand language.
Cognitive changes: A stroke can cause changes in memory, thinking, and overall cognitive function.
After suffering a cerebral stroke, it can disrupt descending commands from motor cortical areas to the spinal cord, which can result in permanent motor deficits of the arm and hand. However, below the lesion, the spinal circuits that control movement remain intact and could be targeted by neurotechnologies to restore movement.