I appreciate the concern. Blaming brain injuries on the HANS is not appropriate. The point can be made that brain injuries that would have been inconsequential without the HANS (because they would have been found on autopsy instead of in the ICU!) are now a problem. It is most likely impact with hard objects inside or outside the cockpit that is causing the head injuries. Attention to details like lateral head restraints, an appropriate seat, head nets on both sides, and SFI-approved rollbar padding are the best places to look to reduce these kinds of injuries. Remember, issues with seat belts/harnesses can result in head/brain injuries as the driver may have enough belt stretch to allow the helmeted head to hit the steering wheel or other items within the cockpit.

Knowing the exact location of the injury within the brain, the exact type of brain injury, the details of the car, and the crash would be helpful in pinpointing the cause of injury.