According to a new study, it is possible to predict which patient will develop chronic pain after whiplash just three days after the injury.
- Three days after a whiplash injury, scientists can predict which patients will develop chronic pain within a year.
- They noticed that there was increased activity between the hippocampus and cortex in injured people who developed chronic pain. They are also more anxious after the accident.
- Being able to identify people at risk of chronic pain early can improve their care according to researchers.
Whiplash is a very common injury from road accidents. The sudden movement of the head that occurs during the impact causes tears in the muscles, tendons or ligaments of the neck. Some patients have chronic pain from this injury and others do not.
Researchers at Northwestern University have found that it is possible to predict the risk of chronic pain within three days by observing brain activity. The study was published in the journal Nature Mental Health on October 24.
Chronic pain: increased activity between two areas of the brain and anxiety to blame?
Wishing to identify the first indicators of the transition from acute to chronic pain after whiplash, the team brought together more than 200 people treated for this type of injury. These patients underwent a functional MRI within three days of the cervical trauma. The researchers looked at their brain activity in regions involved in learning and memory at this critical time. Over the next 12 months, the volunteers were interviewed regularly about their suffering and underwent psychological and psychophysical tests.
The results show that the more the hippocampus (the memory center of the brain) communicated with the cortex (area involved in long-term memory storage), the more likely the patient was to develop chronic pain. Additionally, the higher the injured person’s anxiety immediately after the car accident, the easier it was to accurately predict chronic pain a year later.
Thus, the researchers assure that assessing the patient’s brain activity and anxiety level in the three days after a whiplash can help predict their risk of chronic pain afterwards.
Whiplash and pain: a discovery that can improve prevention
Paulo Branco, assistant professor of anesthesiology and pain medicine at Northwestern University Feinberg School of Medicine, offers a hypothesis to explain why this increased activity between the two areas of the brain is a risk factor for chronic pain.
“Communication between the hippocampus and cortex is thought to index the formation of new memories related to the accident and the subjects’ pain”explains the first author in a press release. For him, this leads patients’ brains to encode a strong memory associating a movement of the head and neck with pain. “It creates expectations and associations”adds Dr. Branco. “If the memory has great emotional meaning, then it causes these patients to associate this movement with pain. When the brain receives these signals, it pays more attention to them based on the painful memories that were formed by the accident .”
“Although we generally think of pain as only relating to injury, it is the brain that actually constitutes the experience of pain”he continues. “The brain decides whether a movement should be painful or not, and we think this may depend on previous experiences stored in memory.”
For the authors of the study, this discovery will help improve the management and prevention of chronic pain after cervical trauma. “Since anxiety plays an important role in brain changes, targeting anxiety immediately after injury may be able to stop these changes, perhaps through anti-anxiety medications or other medications “adds corresponding author Professor Apkarian. “Future novel treatments targeting hippocampal activity and connectivity through pharmacology or neuromodulation techniques are also possible.”
