Asthma is an inflammatory disease that affects the airways. During an asthma attack, muscles that are around the airways tighten, which causes swelling of the the airways' linings. The swelling allows less oxygen to be taken in by the body and used by vital organs. When treated quickly, the effects of less oxygen intake are almost nothing, however, a long period of time without enough oxygen can affect the normal function of the brain.

The inflammation of the air passages can be triggered by allergy-causing substances. Examples include pet hair or dander, pollen, dust, stress, tobacco smoke, changes in weather and dust. Many people who have asthma have a family history of allergies or eczema, though not everyone does have a history. Exercise can also be a trigger for an asthma attack.

The most common symptoms of asthma are wheezing, shortness of breath, chest tightness and coughing. However, there are more severe symptoms of asthma that indicate an effect on the brain. Some patients experience severe anxiety because of the shortness of breath. Others may have a decreased level of alertness, such as severe drowsiness and confusion. The drowsiness and confusion can indicate that the level of oxygen in the brain is lower than normal.

Oxygen is vital to keeping the human body alive. When there is not enough oxygen, cell function is affected and can also lead to death. A reduction of oxygen in one or more areas of the body is known as hypoxia. A total lack of oxygen is known as anoxia. When there is any lack of oxygen, the brain is affected the most: the brain uses 20 percent of the body's oxygen. After four to six minutes without oxygen, brain cells begin to die.

The hippocampus, located in the medial temporal lobe of the brain, is responsible for converting short-term memories to long-term memories. When there is any damage to the hippocampus, memory function is disrupted. The hippocampus is very susceptible to hypoxia, though memory loss can only occur in a severe asthma attack where breathing is even more restricted than in a normal asthma attack. The amount of oxygen being taken in is less than 50 percent of normal capacity.

Asthma patients are given two types of medication: long-acting medications to prevent attacks and quick-relief medications that are used during an attack. The long-acting medications do not treat asthma, but rather prevent attacks through suppressing inflammation and opening airways. The combination of medications can prevent a serious enough asthma attack that would have an impact on the brain.