bronchial dilation, gastrointestinal functioning, and brain wave activity. The con-
cept is simple: If individuals can develop sensory awareness of an involuntary
function, they can learn to sense it. For example, if skin temperature in the hands is
converted into an audible signal, the beeps give one’s ears and brain feedback. As
people learn to dilate the arteries in their hands, thus raising skin temperature, the
beeps speed up, providing instant feedback on what is occurring in the body.
Biofeedback teaches people what it feels like to be relaxed internally so they can re-
create the feeling whenever they choose.
The Tools of Biofeedback
Biofeedback instruments are highly sensitive electronic devices that monitor physio-
logical processes. Signals from the body are amplified by the instrument and con-
verted into usable information. The instruments may have meters, tones, or a
computer display that presents the information to the patient. Temperature or ther-
mal feedback is a primary tool for general relaxation training and treatment of spe-
cific vascular diseases. Blood flow in the hands responds to stress and relaxation,
and the client learns to relax by watching the rise and fall of finger temperature.
Electrodermal response (EDR) or galvanic skin response (GSR) feedback devices meas-
ure sweat gland activity of the fingertips or palm. This response is highly sensitive to
emotions and thoughts.
It is used in general relaxation training, helping people reduce the impact of signifi-
cant stressors, and in treating excessive sweating. Electromyography (EMG) feedback
measures muscle tension with sensors placed on the skin over appropriate muscles.
EMG feedback is used for general relaxation training and is the primary tool for the
treatment of tension headache, pain reduction, and muscle spasm or paralysis due
to injury or stroke. Sensors on the fingers provide pulse feedback, which is used for
people experiencing anxiety, hypertension, and some cardiac arrhythmias.
Respiratory resistance biofeedback measures the rate, volume, and rhythm of respi-
ration and is useful in both asthma and the hyperventilation of anxiety and panic
attacks. Electroencephalograph (EEG) records information about brainwave activity
from sensors placed on the scalp. Changes in brain waves reflect changes in atten-
tion as well as in states of arousal from sleep to alert wakefulness. This type of feed-
back is used for mind quieting, attention control, insomnia, pain control, and
substance abuse treatment. Cardiovascular (EKG) feedback is available through
portable heart-rate monitors to augment a person’s ability to control heart rate. In
addition to being used by persons with cardiac disease, many professional athletes
use this system to aid in their training. Sensors can now measure and report the
CHAPTER 19 BIOFEEDBACK 243
