When blood carrying oxygen cannot properly get to the brain, it’s called a stroke. It is the fourth most common cause of death in the United States. People who lead sedentary lifestyles, are overweight, or have high cholesterol are likely to get strokes. Stroke often affects people with type 2 diabetes, obstructive sleep apnea, or cardiovascular disease. Tobacco smoke constricts the blood vessels and makes stroke more likely. Other risk factors are not about lifestyle in the same way. These fixed factors include being male, being over 55, being black, and having a family history of stroke or heart attack. People who have had a stroke already are more likely to have another, and should be especially careful.
Stroke, naturally, affects brain functioning. In particular, a stroke means a small portion of the brain is destroyed—how small a portion depends in part on how quickly someone with a stroke is able to get treatment. Often—though not always—stroke survivors experience some cognitive deficit after the incident. Now scientists have found that the reverse is also true: people with dementia or cognitive impairment may be at higher risk of stroke. The exact reason for this is unclear. It may be that both cognitive impairment and stroke are the result of cardiovascular problems. It is known that Alzheimer’s disease is associated with the same risk factors as type 2 diabetes, both of which have been linked with obesity.
Another thing stroke has been shown to effect is moral judgment. This has long been suspected—the stereotype of the elderly person who shows no signs of dementia but has no filter and is uninhibited—but actual evidence has been scant. now a study has quantified that. The researchers found that people who have survived strokes are less likely to punish people for bad intentions, provided those intentions were not realized, than people who have not had strokes. Study subjects were asked to evaluate the behavior of the protagonist in each of four scenarios: not causing harm, accidentally causing harm, a failed attempt to cause harm, and intentionally causing harm. The stroke patients were more forgiving in the third scenario than patients with no damage to the brain.