Many of the most common causes of an abnormal brain stem from problems that occur during fetal or early childhood brain development. In some cases, these problems have genetic causes. In other cases, issues with brain development result from environmental factors, including exposure to toxic substances or environmental stresses. Physical injuries can also result in the development of an abnormal brain. Some brain abnormalities appear gradually over the course of a lifetime.
The human brain is an extraordinarily complex structure. The sheer complexity of the human brain means that there are many different ways in which its development can go awry. The most severe genetic problems are typically fatal. Less serious problems in the development of a fetal brain often produce abnormal brain structures.
Cerebral palsy is one common condition that often results from abnormal brain development. It results from genetic issues. Typically this is linked to development problems in utero. This condition can manifest in many different forms but most commonly impacts the ability of the brain and nervous system to effectively control the body's musculature. Brain trauma may also cause cerebral palsy to appear later in life.
Epilepsy, like cerebral palsy, is often the result of structural abnormalities in the brain. It may be caused by genetic or environmental factors. Epilepsy produces bouts of unusual neural activity in the brain which may cause seizures or other symptoms.
Many substances found in the environment can hinder brain development or cause brain damage. Lead, most often in the form of lead paint, is one well-known example of this problem. Lead causes damage to many areas of brain tissue, and significant childhood exposure will limit the development of the brain.
Physical trauma to the head can cause brain abnormalities to appear. A single, mild incident of head trauma, such as a concussion, is unlikely to cause permanent changes to the structure of the brain. More serious or repeated traumatic brain injury, however, can cause swelling, tissue death, and bruising of brain tissues. This condition may produce any number of symptoms as any part of the brain can be impacted.
Brain tumors and aneurisms can both cause abnormal brains. A tumor will often displace or destroy healthy brain tissue as it grows. Aneurisms, swollen blood vessels in the brain, can also place pressure on nearby tissue, causing neurological symptoms.
Degenerative brain disorders stem from the gradual breakdown of normal brain structures and functions. These disorders often have multiple contributing causes. Genetics typically plays a large role, as do lifestyle and nutrition.
Alzheimer's disease is one of the most common degenerative diseases that can produce an abnormal brain. It stems from the gradual accumulation of damage to the brain in the form of plaques that impede normal brain function, tangles of non-functional support tissue, and lost connections between neurons. The end result of this condition is a brain that functions more slowly and erratically with memory loss and loss of emotional control as common symptoms. This disease is very common among the elderly.
Multiple sclerosis is much less common but has broadly similar effects on the brain. This disease, which is generally believed to be an auto-immune condition, causes the breakdown of the protective coating around nerve fibers. The loss of this coating makes nerves less able to transmit information. The disease typically progresses and then relapses, but the overall course of the disease produces brain degeneration.