Question

Understand and be able to describe why certain pain interventions work to control pain based on the type and physiology of pain. This should include non-pharm interventions related to the gate-control theory of pain.

Answer 1

Pain perception varies across different individuals according to their mood, emotional condition and prior experience, even if the pain is caused by similar physical stimuli and results in a similar degree of damage. If not for this theory, pain perception would be still associated with the intensity of the pain stimulus and the degree of damage caused to the affected tissue.

Chronic pain can be best understood from a biopsychosocial perspective through which pain is viewed as a complex, multifaceted experience emerging from the dynamic interplay of a patient’s physiological state, thoughts, emotions, behaviors, and sociocultural influences. A biopsychosocial perspective focuses on viewing chronic pain as an illness rather than disease, thus recognizing that it is a subjective experience and that treatment approaches are aimed at the management, rather than the cure, of chronic pain. Current psychological approaches to the management of chronic pain include interventions that aim to achieve increased self-management, behavioral change, and cognitive change rather than directly eliminate the locus of pain. Benefits of including psychological treatments in multidisciplinary approaches to the management of chronic pain include, but are not limited to, increased self-management of pain, improved pain-coping resources, reduced pain-related disability, and reduced emotional distress – improvements that are effected via a variety of effective self-regulatory, behavioral, and cognitive techniques. Through implementation of these changes, psychologists can effectively help patients feel more in command of their pain control and enable them to live as normal a life as possible despite pain. Moreover, the skills learned through psychological interventions empower and enable patients to become active participants in the management of their illness and instill valuable skills that patients can employ throughout their lives.

The Gate Control Theory of controlling pain signals through gates is a major advance in understanding pain. Under the theory, the more open the gates are, the more pain or suffering. Alternatively, the more the gates are closed, the less pain and suffering is experienced, as illustrated in the Gate Control Theory. Of course, the important issue is what factors tend to open and close the gates. These can be divided into sensory, cognitive and emotional influences.

Factors that open the pain gates and cause more suffering include sensory factors, including such things as injury, inactivity, long-term narcotic use, and poor body mechanics. Cognitive factors include focusing on the pain, a lack of outside or pleasurable interests, worrying about the pain, and focusing on bad things associated with the pain. Emotional factors include depression, anger, anxiety, stress, frustration, hopelessness, and helplessness.

Factors that close the pain gates and cause less suffering include sensory factors including increasing activity, short-term use of pain medication, relaxation training, meditation, and aerobic exercise. Cognitive factors include outside interests, pain coping thoughts, and distracting from the pain. Emotional factors include having a positive attitude, decreasing depression, being reassured that the pain is not harmful, taking control of the pain, taking control of non-pain aspects of life, and stress management.

A simple sensory example of the gate process occurs when a person bangs his or her head on a cabinet corner, or strikes the “funny bone” in the elbow. This results in a fast-moving and “sharp” pain. However, when the area is rubbed, in an attempt to ease the pain, the nerve signal produced by the rubbing overrides the sharp pain and closes the spine gate. This results in the experience of less sharp pain (which has been replaced by the rubbing sensation). The same principle for closing the gates can be applied in the cognitive and emotional realms (as will be seen subsequently).

Although the Gate Control Theory explains many complicated findings related to pain, just a few examples include:

• Pain responses vary widely with the meaning of the situation in which it is experienced. Someone who experiences an injury in a life-or-death situation may barely notice the pain at that time; however, in a different situation, the same pain experience would result in excruciating pain.
• If pain is required for a desired goal, such as winning a game, getting a tattoo, or child-birth, the pain is much more bearable than a similar pain due to a negative occurrence such as an injury due to an accident or a serious medical condition.
• Chronic pain begins with some type of injury, but may continue long after the actual tissue damage from the injury is healed.

Pain Signals Travel at Different Speeds
In considering the Gate Control Theory, it is helpful to review the way pain signals work in the body:

• Fast pain signals, those using A-delta fibers, are crucial to protecting the body from injury. These nerve fibers send a quick message if a person touches something sharp, for instance. This type of pain is sometimes called "warning pain." While A-delta signals are felt quickly, they generally don't last long.
• Chronic pain messages move more slowly along C-fibers and the pain lingers longer. It is often described as aching, dull, cramping, burning, or nagging pain. This type of pain—called “reminder pain” for its role in ensuring that the brain is aware of the injury—feels worse than warning pain. It is the type of pain that can continue after the injury heals.

Both fast and slower pain messages use the same routes through the spinal cord, but their paths diverge in the brain.

Faster pain messages are sent to the brain's cortex, which is responsible for higher level thinking. Slower messages go to the parts of the brain that release stress hormones and handle emotions, the hypothalamus and the limbic system. The pathway of these slower messages is one factor in the role of stress, depression, and anxiety in chronic pain.

Pain signals from throughout the body are sent along the peripheral nervous system, meeting in the spinal cord. According to the Gate Control Theory, a number of factors determine which pain messages are allowed to get through the gate and reach the brain, such as:

• Strength of the pain message
• Competing messages, such as touch or heat
• Brain signals giving high or low priority to the pain message

A key element of the theory is the concept of a gate that allows pain signals to reach the brain when it is open, and blocks the signals when it is closed. When a quick signal from a nerve fiber can close the gate, it can keep the slower messages from getting through, resulting in less pain. So, the first area where pain can be influenced is at the spinal gates. However, there is a second level at which pain perception can be influenced and that is in the brain itself. Once the pain signal is allowed through the spinal gate, the brain can amplify it, decrease it, or ignore it altogether.

Various cognitive (thoughts about the pain) and emotional (depression, anxiety, etc.) factors will determine what happens to the pain signal. Consider the example of having a stomachache. If the individual believes the stomachache is due to a spicy meal the night before, the pain will be experienced much differently than if he or she firmly believes it is due to stomach cancer (even if it is not).