Yesterday we posted the NOCSAE statement regarding the Virginia Tech Helmet Ratings, as with most things in life this is only one side of the story. NOCSAE is doing what they feel is in their best interest; likewise the rating system and its researchers – namely Stefan Duma – are doing what they thing is good work.
Fortunately for everyone out there this blog reaches far and wide and provides an outlet for openness and comments from all that choose to do so. As I have stated many times I try to bring a balanced source for information regarding concussions. With that being said, Stefan Duma reached out to us to clear up some of the information from NOCSAE, from his and the Virginia Tech Helmet Ratings. Below is the email I received from Stefan;
I wanted to clarify two parts of their release that are incorrect and misleading. I told them this before they released it, but they chose not to make the changes.
First, only one helmet, the Xenith X2 increased two stars, and most importantly it did have substantial design changes. The 2013 [version] added much more padding and it performed much better. I have no idea why NOCSAE is misleading the public about this.
Second, we did re-test all of the helmets. I have no idea why NOCSAE is implying that we did not. Each year we re-test samples from all makes and models. If the values are within the range of previous years we keep them the same. But, if the values are outside of the previous range, we use the new values. In this light, some helmets moved down. When you examine those, there are clear differences in the materials.
I relayed all of this to NOCSAE, and I am disappointed they made the statement so misleading and inaccurate.
You can share this if you like.
As you can see there is a problem here. First NOCSAE states “some helmets in the 2013 STAR rating, without a change in design or materials, were moved from a 3 STAR rating to a 5 STAR rating after being retested…” If by ‘some’ NOCSAE means one then they would be correct, but the use of the word ‘some’ implies there were more than one helmet. Duma clearly says in this open email that only one helmet made this jump (Xenith X2) and it was due to design change, in Duma’s opinion.
Second the assertion that VT did not retest all the helmets is in contention here as well, Duma says they did retest all the models while NOCSAE states, “but not all brands/models were retested.”
I clearly have no idea why we have such differing views on this, but I would trust Duma when he is saying what he said. I do wonder why NOCSAE would make this statement, after Duma broached their concerns, and bring it out for a press release.
Regardless I still stand by my opinions; find the best helmet that fits properly and will remain fit properly while playing – and people should not solely rely upon ratings that do fully mimic the possible mechanism of injury.
Wait there is more from Duma, regarding the last part of my opinion, Virginia Tech will be changing their testing protocol going forward and addressing another part of this complex puzzle of mechanism of injury – rotational force;
Also, I wanted to mention that everything we do moving forward will include both linear and rotational acceleration metrics.
This testing change is based on this PAPER/RESEARCH, the conclusions are as follows;
This study introduces a new method of assessing the overall risk of concussion from peak linear and rotational acceleration for a given impact. The combined probability of concussion is unique in that it determines the likelihood of sustaining a concussion for a given impact, regardless of whether the injury would be reported or not. Two separate datasets were used to assess the predictive capability of linear acceleration, rotational acceleration, and the combined probability of concussion method. ROC analyses suggested all parameters were good predictors of injury for the datasets analyzed, with the combined probability of concussion and linear acceleration being significantly better predictors than rotational acceleration. Of the parameters analyzed, the combined probability of concussion method produced the greatest AUC because it can account for more impact scenarios than linear or rotational acceleration alone. Future applications include assessing concussion risk in a laboratory setting for evaluating product safety, including head protection and automobile restraint design.
It is good to know that the rating system will now take the rotational component into consideration when determining ratings for helmets. I will be very interested to see if this changes any of the helmets, or more curious to me, a change in the rating system as a whole. Duma and his team deserve some credit for making necessary changes and encompassing more of the complex mechanism of injury.