Why biofeedback would help this problem: There are several different underlying problems which cause abnormal levels of anxiety. Biofeedback helps each for different reasons.
a.) Breathing problems which cause anxiety: Half or more of people who habitually breathe too rapidly with shallow breaths are anxious because of the effects of their breathing on their brains' chemistry. Most of these people are not aware they have incorrect breathing patterns. These incorrect patterns are easily detected using psychophysiological assessments and are corrected using several types of biofeedback related to helping people normalize their breathing patterns. When the breathing is normalized, the anxiety goes away.
b.) When a person experiences greater levels of anxiety or the anxiety lingers far longer than it should, the body's normal responses to an emergency situation don't shut down. This can cause the body to wear out while thinking and memory patterns change. The physiological reactions to anxiety are accurately assessed using psychophysiological recording techniques so both the patient and therapist always know when any therapy is helping and how much. Biofeedback treatments show the patient the abnormal physiological response levels. Patients use this knowledge to recognize when they are becoming abnormally anxious (so they learn to identify when is actually causing the anxiety) and to control their anxiety.
Children who are successfully trained to increase SMR show decreased activity levels. Successful neurofeedback training to decrease Theta while increasing Beta results in increased attention span and increased ability to learn math.
The training almost always takes place in a therapist's office. Sensors are pasted onto the scalp over the parts of the child's brain, which are to be trained. The sensors are connected to a computer, which runs a special training program. The program usually appears in the guise of a videogame. The videogame's progress or simply continuation is dependent upon the child producing the desired proportion of brain waves. The treatment may take 30 to 50 or more sessions for effects to be apparent and lasting.