Injuries, diseases, and infections can damage brain cells and cause atrophy.
- Stroke happens when blood flow to part of the brain is interrupted. Without a supply of oxygen-rich blood, neurons in the area die. Functions controlled by those brain areas — including movement and speech — are lost.
- Traumatic brain injury is damage to the brain that may be caused by a fall, motor vehicle accident, or another hit to the head.
Diseases and disorders
- Alzheimer’s disease and other forms of dementia are conditions in which brain cells become progressively damaged and lose the ability to communicate with one another. It causes a loss of memory and thinking ability severe enough to be life-altering. Alzheimer’s disease, typically beginning after age 60, is the leading cause of dementia. It’s responsible for 60 to 80 percent of all cases.
- Cerebral palsy is a movement disorder caused by abnormal brain development in the womb. It causes a lack of muscle coordination, difficulty with walking, and other movement disorders.
- Huntington’s disease is an inherited condition that progressively damages neurons. It usually begins in mid-life. Over time, it affects a person’s mental and physical abilities to include severe depression and chorea (involuntary, dance-like movements throughout the body).
- Leukodystrophies are a group of rare, inherited disorders that damage the myelin sheath — a protective coating that surrounds nerve cells. Usually beginning in childhood, it can cause problems with memory, movement, behavior, vision, and hearing.
- Multiple sclerosis, which usually begins in young adulthood and affects women more often than men, is an autoimmune disease in which the immune system attacks the protective coating around nerve cells. Over time, the nerve cells become damaged. As a result, problems in sensation, movement, and coordination can occur. However, like other diseases noted, it can also lead to dementia and brain atrophy.
- AIDS is a disease caused by the HIV virus, which attacks the body’s immune system. Although the virus doesn’t directly attack neurons, it does damage the connections between them via proteins and other substances it releases. Toxoplasmosis associated with AIDS can also damage brain neurons.
- Encephalitis refers to an inflammation of the brain. It’s most often caused by herpes simplex (HSV), but other viruses such as West Nile or Zika can also cause it. The viruses injure neurons and cause symptoms such as confusion, seizures, and paralysis. An autoimmune condition can also cause encephalitis.
- Neurosyphilis is a disease that damages the brain and its protective covering. It can occur in people with the sexually transmitted disease syphilis who don’t get fully treated.
Some of these conditions — like neurosyphilis, AIDS, and traumatic brain injury — may be preventable. Practicing safe sex by wearing condoms can prevent syphilis and HIV infections. Wearing your seat belt in the car and putting on a helmet when you ride a bicycle or motorcycle can help prevent brain injuries.
Other conditions, like Huntington’s disease, the leukodystrophies, and multiple sclerosis, are not preventable.