1/
@US_FDA approved the #Qcollar jugular compression device to "protect athletes' brains during head impacts."
This decision was based on VERY FLAWED DATA and does NOT demonstrate the safety or effectiveness of the Q-collar.
Read detailed thread⬇️
bit.ly/3q9ZZJL
@US_FDA approved the #Qcollar jugular compression device to "protect athletes' brains during head impacts."
This decision was based on VERY FLAWED DATA and does NOT demonstrate the safety or effectiveness of the Q-collar.
Read detailed thread⬇️
bit.ly/3q9ZZJL
2/
Here is the text from the @FDADeviceInfo press release.
If you don't understand the highly nuanced #MRI technique known as DTI, these results sound straightforward and convincing.
THEY ARE NOT. Don't be fooled by these numbers!🤔
I will dissect these in the thread below.
Here is the text from the @FDADeviceInfo press release.
If you don't understand the highly nuanced #MRI technique known as DTI, these results sound straightforward and convincing.
THEY ARE NOT. Don't be fooled by these numbers!🤔
I will dissect these in the thread below.
3a/
"No significant changes" is based AVERAGE response, not individual.
First, an easy-to-understand analogy below.
If half the sample experiences an increase and half experiences a decrease, they can cancel each other out to falsely suggest "no change" when one does exists!
"No significant changes" is based AVERAGE response, not individual.
First, an easy-to-understand analogy below.
If half the sample experiences an increase and half experiences a decrease, they can cancel each other out to falsely suggest "no change" when one does exists!
3b/
This is what we see with DTI data in Qcollar.
Below, I labeled Fig. 8 from Myer et al (BJSM, 2016).
It's not that the group wearing Qcollar had no change. Rather, 9 decreased a DTI parameter, 8 increased it, 2 stayed unchanged.
Is that really "no significant change?"
This is what we see with DTI data in Qcollar.
Below, I labeled Fig. 8 from Myer et al (BJSM, 2016).
It's not that the group wearing Qcollar had no change. Rather, 9 decreased a DTI parameter, 8 increased it, 2 stayed unchanged.
Is that really "no significant change?"
4a/
Next issue. Is "no change" in DTI a good thing which suggests a protective effect?
Keep in mind, this data was collected in HIGH SCHOOL players. Adolescents.
Should DTI parameters be unchanged in healthy growing brains? The answer is no - it SHOULD be changing!
Read on...
Next issue. Is "no change" in DTI a good thing which suggests a protective effect?
Keep in mind, this data was collected in HIGH SCHOOL players. Adolescents.
Should DTI parameters be unchanged in healthy growing brains? The answer is no - it SHOULD be changing!
Read on...
4b/
Many studies demonstrate age-related change in DTI.
One example below from Ghosh et al in Developmental Neuroscience 2017.
Rows are different DTI parameters.
Columns are white matter in different brain regions.
X-axis is age.
Some values increase with age, some decrease.
Many studies demonstrate age-related change in DTI.
One example below from Ghosh et al in Developmental Neuroscience 2017.
Rows are different DTI parameters.
Columns are white matter in different brain regions.
X-axis is age.
Some values increase with age, some decrease.
4c/
Again, plenty of research demonstrates changes in DTI are a normal part of development in adolescents.
Likewise, training effect can also influence DTI. For example, dance training has different effects on DTI than music training.
bit.ly/3sC8NtJ
Again, plenty of research demonstrates changes in DTI are a normal part of development in adolescents.
Likewise, training effect can also influence DTI. For example, dance training has different effects on DTI than music training.
bit.ly/3sC8NtJ
4d/
If changes in DTI are a normal part of age-related development and training, how can we interpret "no significant change" as a good thing?
Unchanged DTI in high school football players wearing Qcollar (or any other young athlete) is potentially ABNORMAL, not protective!
If changes in DTI are a normal part of age-related development and training, how can we interpret "no significant change" as a good thing?
Unchanged DTI in high school football players wearing Qcollar (or any other young athlete) is potentially ABNORMAL, not protective!
5a/
We also need to consider the MAGNITUDE of DTI change.
Again, easy analogy to start. If a study shows that a new drug causes a 300 pound person to lose 0.08 pounds of body fat over 12 months, does that matter clinically?
Now, lets consider magnitude change in terms of DTI
We also need to consider the MAGNITUDE of DTI change.
Again, easy analogy to start. If a study shows that a new drug causes a 300 pound person to lose 0.08 pounds of body fat over 12 months, does that matter clinically?
Now, lets consider magnitude change in terms of DTI
5b/
DTI data (Axial Diffusivity, AD) from Henry et al (J Neurotrauma 2011) below.
Control group's AD is ~0.8.
Chronic concussion group AD ~0.93. (6 months post-injury).
That's about a 16% INCREASE in AD in athletes w/ TBI vs those without.
How's that compare to Qcollar data?
DTI data (Axial Diffusivity, AD) from Henry et al (J Neurotrauma 2011) below.
Control group's AD is ~0.8.
Chronic concussion group AD ~0.93. (6 months post-injury).
That's about a 16% INCREASE in AD in athletes w/ TBI vs those without.
How's that compare to Qcollar data?
5c/
Again, let's look at Myer et al 2016, this time the group that did NOT wear the Qcollar.
Greatest change was in Subject 1.
Pre-season AD ~0.001193
Post-season AD ~0.001141
That's only ~4.3% change in AD in the MAXIMAL "responder!" Meaningful?
Don't #ThinkBeyondTheHelmet
Again, let's look at Myer et al 2016, this time the group that did NOT wear the Qcollar.
Greatest change was in Subject 1.
Pre-season AD ~0.001193
Post-season AD ~0.001141
That's only ~4.3% change in AD in the MAXIMAL "responder!" Meaningful?
Don't #ThinkBeyondTheHelmet
5d/
In 5b, we saw ~16% INCREASE in AD weeks after concussion. The Qcollar group (see 3b) had 8 players INCREASE AD over the season.
In 5c, we saw ALL these players without Qcollar had a DECREASE in AD over the season - that's is NORMAL (see 4b, Ghosh).
Which is healthier? 🤔
In 5b, we saw ~16% INCREASE in AD weeks after concussion. The Qcollar group (see 3b) had 8 players INCREASE AD over the season.
In 5c, we saw ALL these players without Qcollar had a DECREASE in AD over the season - that's is NORMAL (see 4b, Ghosh).
Which is healthier? 🤔
6a/
Does DTI data, as used in the FDA approval of Qcollar actually tell us the status of #brain health?
No!
We can look to animal studies examining response to #concussion to understand this better. #braininjury #CTE
Example study ⬇️
jneurosci.org/content/27/44/…
Does DTI data, as used in the FDA approval of Qcollar actually tell us the status of #brain health?
No!
We can look to animal studies examining response to #concussion to understand this better. #braininjury #CTE
Example study ⬇️
jneurosci.org/content/27/44/…
6b/
In that study, mice were experimentally given a traumatic brain injury. #TBI
DTI data were examined at multiple time points afterward.
We see AD decreased immediately after TBI. But after just 1 week, it was back to normal!
Does this mean mice's brains had recovered?
In that study, mice were experimentally given a traumatic brain injury. #TBI
DTI data were examined at multiple time points afterward.
We see AD decreased immediately after TBI. But after just 1 week, it was back to normal!
Does this mean mice's brains had recovered?
6c/
The mice's brains were also examined under the microscope at the same timepoints later.
After a week or a month, they still had lots of microscopic pathology!
So, "unchanged" DTI data (as the Qcollar claims is evidence of protection), does not reflect a healed brain!
The mice's brains were also examined under the microscope at the same timepoints later.
After a week or a month, they still had lots of microscopic pathology!
So, "unchanged" DTI data (as the Qcollar claims is evidence of protection), does not reflect a healed brain!
7a/
Is it possible that only the seemingly "good" results were reported and used to conclude the Qcollar protects the brain?
Indeed, selection bias is very possible. I would argue it is likely... VERY likely.
#Statistics
#epitwitter
#research
#Epidemiology
🤥🤥🤥🤥🤥🤥🤥
Is it possible that only the seemingly "good" results were reported and used to conclude the Qcollar protects the brain?
Indeed, selection bias is very possible. I would argue it is likely... VERY likely.
#Statistics
#epitwitter
#research
#Epidemiology
🤥🤥🤥🤥🤥🤥🤥
7b/
There are multiple DTI parameters. Above, I mentioned axial diffusivity (AD), but there are others like MD, RD, and FA.
Also, MULTIPLE regions of the brain are examined.
Combine many brain regions & parameters and you have hundreds of analyses to search for #significance.
There are multiple DTI parameters. Above, I mentioned axial diffusivity (AD), but there are others like MD, RD, and FA.
Also, MULTIPLE regions of the brain are examined.
Combine many brain regions & parameters and you have hundreds of analyses to search for #significance.
7c/
Myer 2018 (BJSM) reports DTI data in anterior thalamus, not posterior thalamus
Yuan 2018 (Hum Brain Mapp) reports DTI data in posterior thalamus, not anterior thalamus
Myer 2017 (Front Neurol) doesn't report data on anterior or posterior thalamus.
Why the inconsistency?
Myer 2018 (BJSM) reports DTI data in anterior thalamus, not posterior thalamus
Yuan 2018 (Hum Brain Mapp) reports DTI data in posterior thalamus, not anterior thalamus
Myer 2017 (Front Neurol) doesn't report data on anterior or posterior thalamus.
Why the inconsistency?
7d/
Ideally, one should account for multiple comparisons with some sort of #statistical adjustment to reduce the risk of false positive findings.
In other words, MORE stringent statistical analysis is needed.
Instead, they did LESS stringent analyses w/ p<0.10 in Yuan 2018!
Ideally, one should account for multiple comparisons with some sort of #statistical adjustment to reduce the risk of false positive findings.
In other words, MORE stringent statistical analysis is needed.
Instead, they did LESS stringent analyses w/ p<0.10 in Yuan 2018!
7e/
If DTI data are useful to demonstrate #Qcollar "protects the brain," then athletes with more severe head impacts exposure should CONSISTENTLY have a greater change in their DTI data.
Spoiler alert - this isn't the case!
Screencap from my @JAMANeuro paper on this ⬇️
If DTI data are useful to demonstrate #Qcollar "protects the brain," then athletes with more severe head impacts exposure should CONSISTENTLY have a greater change in their DTI data.
Spoiler alert - this isn't the case!
Screencap from my @JAMANeuro paper on this ⬇️
7f/
The concerning thing here is that all of these studies are coming from the same research group.
Why are there so many inconsistencies in reporting?
My guess is that only the data that seemingly validates effectiveness is reported, and data which contradict it are not. 🤥
The concerning thing here is that all of these studies are coming from the same research group.
Why are there so many inconsistencies in reporting?
My guess is that only the data that seemingly validates effectiveness is reported, and data which contradict it are not. 🤥
8a/
There's even more to it than all of that in this thread.
Bottom line is this - the data used to claim the Qcollar is safe or effective is not valid to do so
It's plagued by mathematical misrepresentation, inappropriate assumptions, and even suspicious (unethical?) issues.
There's even more to it than all of that in this thread.
Bottom line is this - the data used to claim the Qcollar is safe or effective is not valid to do so
It's plagued by mathematical misrepresentation, inappropriate assumptions, and even suspicious (unethical?) issues.
8b/
And this thread only discusses the problems w/ DTI data!
Please see my other thread regarding various other issues related why the entire physiologic basis for the Qcollar is scientifically unsound (and why their woodpecker-inspiration is a fable).
And this thread only discusses the problems w/ DTI data!
Please see my other thread regarding various other issues related why the entire physiologic basis for the Qcollar is scientifically unsound (and why their woodpecker-inspiration is a fable).
https://twitter.com/jsmoliga/status/1160225974136557568
8c/
My goal is to help athletes, coaches, parents, and sports organizations understand this complex topic so they can make informed decisions and not be fooled by scientific-sounding #pseudoscience.
If you liked this thread, please RETWEEET it! 🙏
My goal is to help athletes, coaches, parents, and sports organizations understand this complex topic so they can make informed decisions and not be fooled by scientific-sounding #pseudoscience.
If you liked this thread, please RETWEEET it! 🙏
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