Frequent Concussion Often Results in Increased Trigeminal Pain
Mild traumatic brain injury (mTBI or concussion) is a widespread health concern, with an estimated 42 million sufferers worldwide each year. Most people who sustain mTBI/concussion report headaches that may persist long into the recovery period. Headaches are diagnosed as “chronic” when a person experiences a head pain on at least fifteen days of the month for three or more months in a row.
Current research suggests that the likelihood of developing chronic pain and headaches is influenced by repeat concussion and by the time interval between injuries. However, the exact effects of repeat concussion on the function of the trigeminal pain system, or the area of the brain responsible for facial pain and headaches, are unknown. A recent study used an animal model to examine the effects of single versus repeat head injury on the trigeminal pain system. They found that:
- Trigeminal sensitivity increased when head injury was more frequent and when the time between head injuries was reduced.
- Frequent mTBI/concussion induces the release of a pain-signaling chemical compound in the brain, called CGRP.
- Frequent mTBI/concussion causes astrocytosis, a neurological response to head injury that can cause scar formation and inhibit neurons’ ability to regenerate after damage.
Although even a single head injury is associated with negative health outcomes, repetitive concussion – especially in a small time frame – is responsible for serious damage to the physical structure of the trigeminal pain system, often leading to chronic facial pain headaches in the post-mTBI recovery period. For people at high risk for repeat concussion, such as soldiers and athletes, clinicians are advised to target and treat the trigeminal system directly to reduce the likelihood of chronic headaches.
Tybursky AL, Chen L, Assari S, et al. Frequent mild head injury promotes trigeminal sensitivity concomitant with microglial proliferation, astrocytosis, and increased neuropeptide levels in the trigeminal pain system. The Journal of Headache and Pain. (2017).