PAIN THRESHOLD

Pain threshold is a concept that has arisen from experimental work on animals. Nerves usually have to be stimulated above a certain intensity or frequency to signal pain. It is everyone’s experience that the severity of a pain depends on morale and behavior. Pain may not be felt in the heat of a battle, whereas pain seems worse if we are already frightened or anxious.

One physiological basis for a pain threshold is the endogenous opioid system (encephalins, endorphins and other molecules) which is activated by the descending pathways from the mid-brain. Pain activates the system. In experiments, rats can raise their pain threshold to an expected pain by behavioral conditioning. In humans, explanation and preparation for a painful procedure probably does the same thing. The endogenous opioid system is not active all the time. (Intravenous naloxone which inhibits the system does not cause pain in normal subjects.) (see Pain Pathways)

Pain threshold cannot be measured. It is best to assume that the complaint of pain means the person is experiencing pain. It is inaccurate and unhelpful to say that a person has a “low pain threshold”. This is a value judgment which really means “This person complains a lot about pain.”

Pain behavior differs from pain threshold. A person may exhibit pain behavior one moment and then (unaware of observers) may appear free of pain (as judged by activity levels, facial expressions, sleep, or behavior such as not needing analgesics). The question then is not “What is this patient’s pain threshold?” but “What does this person gain by behaving as if he had severe pain?”

«  The concept of pain threshold is clinically useful because it helps with pain control.

The problem of pain control is seen as having two components:

• Reducing pain

• Raising the pain threshold

The pain threshold is raised by:

• Reducing physical discomfort (sore mouth, nausea, etc.)

• Ensuring adequate sleep

• Discussing worries and fears

• Resolving emotional problems

• Maintaining contact with family and friends

• Developing a feeling of security

• Relaxation

• Diversional activities

«  “I could stand the pain so long as I knew that progress was being made.” (Norman Cousins, Anatomy of an Illness)

The author and publisher have taken precautions to ensure that the information in this book is error-free. However, readers must be guided by their own personal and professional standards of good practice in evaluating and applying recommendations made herein. The contents of this book represent the views and experience of the author, and not necessarily those of the publisher.