The mTBI Keystone Study is built to answer one question with enough rigor that medicine and policy cannot look away: do persistent post-concussive symptoms arise from the brain, from the craniocervical junction, or from both? Every design decision — the imaging, the arms, the outcome measures — serves that question.
Why the neck may hold the answer
The craniocervical junction is the small, mobile region where the skull meets the top two vertebrae of the spine. It is held together not by bone but by a network of delicate ligaments, and it is built for movement rather than for absorbing extreme force. A blast can transmit forces exceeding 150 times the pull of gravity through the head and neck. The rigid skull protects the brain; the junction beneath it has far less protection, and it is where much of that force is absorbed. When those ligaments stretch or tear, the top vertebrae can shift — and a cascade of consequences follows, each traceable to a specific piece of anatomy.
A drainage problem in the brain
The jugular veins carry blood and metabolic waste out of the brain, and they run directly past the upper cervical spine. A rotational shift of the top vertebra can pinch a jugular vein against the base of the skull, slowing outflow and allowing pressure and waste to build inside the head. The glymphatic system — the brain’s own waste-clearance network — depends on that same drainage path. This is the most likely source of the brain fog so many veterans describe: not vague or imagined, but a plumbing problem, and plumbing problems can be fixed.
A blood-flow problem and a brainstem under strain
The arteries that feed the back of the brain thread through channels in these same upper vertebrae before turning sharply to enter the skull. Misalignment can put tension on them and reduce oxygen-rich blood flow to the brainstem and cerebellum — the regions that govern balance, coordination, and basic regulation. The brainstem itself sits at this junction, and disruption there affects the nerves that control eye movement, balance, facial sensation, and the body’s stress response. This is why the symptoms cluster the way they do: dizziness, visual instability, headaches, and a nervous system locked in a state of alarm.
The connection that matters most
Among the structures affected is the trigeminal nucleus, the brain’s central processor for pain in the head, face, and neck. When the junction is misaligned, it can irritate this center and produce relentless, severe pain. If a meaningful share of the chronic suffering attributed to brain injury actually stems from a correctable structural problem, then identifying it is not an academic exercise — it is a matter of lives.
Design: three arms, one definitive comparison
The full randomized controlled trial enrolls 400 veterans across three arms — craniocervical care, brain-focused care, and both in coordinated sequence — so any measured improvement can be attributed, not assumed. Each participant moves through a comprehensive imaging battery (MRI, SPECT, qEEG, and cone beam CT) and objective testing at every stage, producing a detailed map of which specific symptoms trace to direct injury of the brain versus injury to the neck that disrupts the brain. That distinction — drawn from imaging and objective data rather than from stories — is what makes this work unique, and what could reshape how the Department of Defense and Veterans Affairs screen, diagnose, and treat one of the signature injuries of modern service.
Last updated August 15, 2026