Pain
HEALTH INFORMATION
Understanding how pain is processed in the brain
WHAT WE KNOW
The International Association for the Study of Pain (IASP) defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage”. Acute pain is the pain that says you’ve been hurt. It is often temporary and begins suddenly, often as a result of injury or inflammation. Sensory inputs from damaged tissue project via specific nerve fibres (nociceptors) to the brain, which generates a perception of pain – the quality of which depends on the tissue of origin. Reflex responses to a painful stimulus serve to protect the body from further damage: superficial pain – that originating in the skin – leads to withdrawal of the body part from the stimulus, whereas deep pain – that originating in muscle, for example – leads to protective responses that limit further damage to the injured body part.
Pain might be mild and last just a moment, or it might be severe and last for weeks or months. As the body repairs the damage the nociceptive messages cease, encouraging use of the injured or inflamed body part once again. It is important to get moving again as over-protection of an injury or under-use of a limb may lead to further complications.
Things that will help pain to feel better include making changes to exercise, where appropriate – so if running has caused an injury, switch to cycling or swimming; treat the injury with therapy, such as physical therapy, occupational therapy or massage therapy; or try meditation or deep relaxation techniques that aim to relax each part of your body or help manage pain.
In most cases, pain does not last longer than three months, and it disappears when the underlying cause of pain has been treated or has healed. Unrelieved pain, however, might lead to chronic pain. Chronic pain is considered to be pain that lasts for three months past the point of injury, and it is now generally accepted that changes in the brain are responsible for maintaining the pain long after the nociceptive signals of tissue damage have stopped.
OUR LATEST RESEARCH
DISCOVER-pain: Discovery of a cortical biomarker signature for pain
Low back pain (LBP) is ranked as the top single cause of disability worldwide. Costs have risen faster than for any other health condition and LBP is now equal to ischemic heart disease, and second only to cancer, as the costliest health condition. Approximately 40% of people who experience acute LBP develop chronic pain. These individuals are unresponsive to treatment, experience high levels of pain, struggle to perform daily tasks and frequently develop psychosocial comorbidities. The enormous scale of the problem is matched only by the mystery that accompanies it: despite decades of research, why some people develop chronic LBP while others do not, remains unknown.
The identification of biomarkers that can predict who will develop chronic LBP is a holy grail of pain research. Our new research has uncovered evidence for a unique biomarker signature that appears to predict i) an individual’s susceptibility to high pain severity, even before pain begins and ii) an individual’s susceptibility to developing chronic LBP following an acute episode. These biomarkers are now undergoing detailed investigation in on-going studies.
UNmaPPed: Understanding the physiology of persistent pain
People in pain move differently. Yet, the biological basis for altered movement in pain is poorly understood. This lack of understanding has led to treatments for persistent pain that target generic symptoms with limited effect. This NHMRC-funded trial is the first to examine how different aspects of the nervous system are altered in pain and how this relates to movement. This information will guide the development of new treatment strategies for persistent pain in future.
UPWaRD: Understanding persistent pain where it resides – in the brain.
Persistent musculoskeletal pain is one of the most significant health issues in the developed world. Termed a ‘Western epidemic’, low back pain is the most common form of persistent musculoskeletal pain and a leading cause of suffering and disability. Despite the enormity of the problem, many current therapies target generic symptoms, not underlying mechanisms, with limited effect. In 2010, the Australian National Pain Summit concluded ‘the management of pain is shockingly inadequate’. This assessment is not surprising given that critical information on the biological changes that underpin persistent low back pain is lacking. The UPWaRD study is a 5-year NHMRC-funded trial that investigates the role of brain plasticity, along with biological changes in the spinal cord, hormonal changes, genetics and stress, in the development of persistent low back pain.
https://www.upwardbackpainstudy.com
Medicines for Back Pain
The effects of tonic muscle pain on the sympathetic and somatic motor systems
Chronic pain, defined as pain lasting for >3 months, typically develops from injuries to deep tissues such as muscle, yet little is known about how long-lasting pain affects a person’s blood pressure or capacity to control their muscles. This project assesses the effects of tonic muscle pain on sympathetic nerve activity and stretch sensitivity of muscle spindles.
