Gate Control Theory

Introductionwww.currentnursing.com

Gate control theory was described by Melzack and Wall in 1965.
This theory explains about a pain-modulating system in which a neural gate present in the spinal cord can open and close thereby modulating the perception of pain.
The gate control theory suggested that psychological factors play a role in the perception of pain.

Terms

Pain - an unpleasant sensory and emotional experience associated with actual or potential tissue damage.
Analgesia - the selective suppression of pain without effects on consciousness or other sensations.
Nociceptors - sensory receptor whose stimulation causes pain
Pain threshold: the point at which a stimulus is perceived as painful.
Phantom limb pain – feelings of pain in a limb that is no longer there and has no functioning nerves.
Sensation – the process of receiving, converting, and transmitting information from the external and internal world to the brain.

Major Concepts www.currentnursing.com

The three systems located in the spinal cord act to influence perception of pain, viz;
the substantia gelatinosa in the dorsal horn,
the dorsal column fibers, and
the central transmission cells.
The noxious impulses are influenced by a “gating mechanism.”
Stimulation of the large-diameter fibers inhibits the transmission of pain, thus “closing the gate.” Whereas, when smaller fibers are stimulated, the gate is opened.
When the gate is closed signals from small diameter pain fibres do not excite the dorsal horn transmission neurons.
When the gate is open pain signals excite dorsal horn transmission cells.
The gating mechanism is influenced by nerve impulses that descend from the brain.
Factors which influence opening and closing the gate are:
The amount of activity in the pain fibers.
The amount of activity in other peripheral fibers
Messages that descend from the brain.
A specialized system of large-diameter fibers that activate selective cognitive processes via the modulating properties of the spinal gate.

Gate Control theory

Gate is opened by
Physical Factors - Bodily injury
Emotional Factors - Anxiety & Depression
Behavioural Factors - Attending to the injury and concentrating on the pain
Gate may be closed by:
Physical Pain - Analgesic Remedies
Emotional Pain - Being in a ‘good’ mood
Behavioural Factors - Concentrating on things other than the injury

Conclusion

The theory guided research toward the cognitivebehavioral approaches to pain management.
This theory helps to explain how interventions based on somatosensory (auditory, visual and tactile) stimulation such as friction,music therapy and distraction provide pain relief.
Melzack (1996) extended the gate control theory explaining phantom limb pain.

References www.currentnursing.com

Dickenson AH, (2002). Gate Control Theory of pain stands the test of time. Br. J. Anaesth., 88 (6):755-757.
Smeltzer SC, & Bare BG. [Edrs] (2004) . Brunner and Suddarth's Textbook of Medical-Surgical Nursing. 10th edition. Philadelphia: Lippincott Williams & Wilkins.
Melzack, R. (1996). Gate control theory: On the evolution of pain concepts. Pain Forum, 5(1), 128–138.
Melzack R, & Wall PD. ( 1965). Pain mechanisms: a new theory. Science, 150: 971–9 (Free access)