Pain research stems back to the earliest times of human enquiry, from the understanding of analgesia by the early Greeks, to Aristotle and Pluto who imagined pain to be more of an emotion than a sensation.
Centuries later, Meshack and Wall proposed the ‘gate control’ theory of pain (1965). This theory was about the psychological influence on pain perception. Before this theory, pain was associated with the degree of damage to tissues at site of injury. But we now know pain is a lot more complex than this.
Pain sensation does not reach the brain straight away. The Gate theory suggests that these pain signals enter “neurological gates” at the spinal cord level that can block or allow pain signals to travel to the brain. In basic terms, it does this by allowing small nerve fibres carrying pain signals to pass through and large nerve fibres to be blocked.
This occurs in the dorsal horn of the spinal cord. Small fibres (pain signals) and large fibres (normal fibres for touch, vibration and pressure) carry information to the dorsal horn with the pain information either being sent to the brain or diminished as a result of inhibitory neurons. The greater the larger fibre activity, the less pain people tend to experience. This may explain why we feel relief when we rub or massage the site of an injury, as it increases large fibre activity and thereby reduces pain sensation.
The gate control theory has paved the way for new ways to manage pain. The theory we may better manage pain by selecting larger fibres that carry non-pain stimuli. Relaxation, outside interests and good coping skills may also help close the pain gate.
The gate theory proposes that one’s state of mind influences the pain signals sent by the brain. The gate may stop, reduce or intensify these signals depending on one’s thoughts or mood. Some chronic pain sufferers may cope with pain better than others, depending on attitude and their ability to distract themselves. Anxiety and depression, it is now thought, become more pronounced as the brain rewires itself in anticipation of future episodes of pain.
Pain is extremely varied and at times complex. People’s pain threshold is the same, but our response varies greatly. Culture, attitude, behaviour and our earliest experience with pain affect how we respond to it.
The body of pain research is enormous and we have only presented a snapshot. We now know that the sooner we seek treatment for our aches and pains the better the prognosis. Multidisciplinary approaches, involving experts and treatment modalities from many disciplines of the physical and biopsychosocial are now seen as the gold standard.