The brain is the most important part of the body. It controls every part of daily living. Some of the functions it controls are breathing, walking, balance, movement, seeing, hearing, feeling, and speaking. It also controls concentration, judgment, personality, behavior, and memory.
Normally, the brain is very well protected by a hard, bony skull, and spinal fluid, which surround it. The skull is a closed structure; therefore the brain has a limit on how much it can expand within the skull. Brain tissue, spinal fluid, and blood must stay constant in the brain at all times in order for us to function normally. Damage to the brain occurs when there are injuries causing bleeding, bruising, or tearing of the brain, tumors, an increase in spinal fluid within the brain, decreased oxygen to the brain, or internal bleeding due to a ruptured blood vessel. This damage or injury causes changes to how the brain normally functions.
Brain cells cannot be replaced. If certain brain cells are destroyed, their function is lost forever. However, certain injured brain cells may regain their function and in some cases, recovery may occur when other cells of the brain take over the functions of the destroyed cells.
Brain injury can cause problems with concentration, forgetfulness, confusion, and poor judgment. These symptoms are distressing to the patient, family, and friends. Patients frequently recognize that they are confused and inappropriate, but have limited ability to control it. Excitement, fear, agitation, and hyperactivity are frequent responses. This phase is often followed by emotional and physical fatigue. There may also be a period of emotional depression of variable length in many brain-injured patients.
A patient may be paralyzed on one or both sides of his body. This paralysis will usually be noted on the opposite side of the body from the actual site of the brain injury since regions of the brain controlling these functions are on the opposite side. A similar pattern of sensory problems may be seen as well. Problems may also be experienced with control of bowel and bladder function. A combination of impairment in one or more of those functions can cause much difficulty in basic everyday tasks.