Reviewer: Queenie Lee
I work at Sick Kids.
So why am I here speaking to you about soldiers with PTSD?
I was asked a question by Defense Canada.
It was a question I really didn't want to answer.
As a scientist, I answer questions all the time,
questions posed ages ago, or questions my team and I identify,
as we discover new information in our research.
This is the nature of being a scientist,
always asking why, trying to understand more and more,
pushing the frontiers, trying to uncover underlying causes.
But what about a question that you think doesn't have an answer?
This was a dilemma my team and I faced a while ago.
Let me give you a little bit of background.
In my work at Sick Kids,
I'm focusing on children with autism, and infants children born very pre-term.
Using specialized imaging equipment,
we look at the brain structure and function in these children
compared to children that don't have these challenges.
This research allows us
to determine differences in the brain and their behaviors
between these groups of children,
and this provides a basis for understanding the disorders,
and future treatments.
To do this, we have specialized imaging technology.
You'll all have heard of an MRI: magnetic resonance imaging,
and it essentially takes a picture of their brain.
So if I was to show you this picture,
your brain would respond immediately.
You'd have activity in the visual cortices,
maybe some in the frontal lobes as well.
If you were in an MRI, I would see your brain anatomy,
and if I looked at blood flow measures,
I would also get an indication of brain function.
But MRI is very slow.
It doesn't show us real time activity in the brain.
EEG, electroencephalography,
does give us a real-time measure of the electrical activity of the brain.
We can see when things are happening in the brain,
but it isn't as accurate in telling us where things are happening.
So with these two technologies,
we could see brain function,
either where it happens or when it happens.
So let me go back to my question.
The Canadian Armed Forces asked me if I could diagnose a brain dysfunction:
post-traumatic stress disorder, PTSD.
Now, I've been studying brain functions since my first year of university.
I love working in this field.
But this was not an expected question.
PTSD is a terrible and significant problem,
unfortunately common in soldiers returning from a war zone.
They haven't been physically injured usually,
but they have been traumatized,
and this produces disordered thinking.
It's an invisible injury.
It is not something that can be diagnosed easily.
Sure, there are signs and symptoms, unusual behaviors,
but it basically needs to be self-reported.
And often, soldiers remain silent with a sense of shame or anxiety,
you know, that they should just be able to get over it.
If, to have a proven diagnostic test of PTSD,
would allow the Armed Forces to help these soldiers,
they'd be able to detect it, help, and monitor recovery.
But we - and when I say "we,"
this is my good colleague, Dr. Liz Pang, and our teams at Sick Kids -
we weren't sure we wanted to answer this question.
This wasn't anything that we were currently studying.
And sure, we knew with our expertise,
that we could understand more about the brain function or dysfunction,
but not necessarily diagnose.
However, we had the knowledge and the tools to do the work.
After all, we're looking at subtle changes
in the brains of children with cognitive difficulties.
And we also felt a strong sense of moral and social obligation
to help these soldiers
who'd put themselves at great risk, and been injured.
So we agreed to try to answer the question:
can we find brain measures
that reliably differentiate soldiers with and without PTSD?
This is rather like trying to find a virus on your computer.
It's not broken, you haven't dropped it, all the peripherals are working,
but it's doing some strange or unusual things.
And unlike a computer, we can't take the brain apart.
We can't just reinstall the software or replace the motherboard.
And keep in mind
that the brains of soldiers with PTSD don't look particularly differently.
It isn't like somebody with Alzheimer's or a brain tumor.
It's just the function that has changed.
And looking at brain function,
we need to have specialized equipment to see the activity and the timing.
And as I mentioned, this is a challenge.
However, we had at our disposal
a front-line, incredibly sensitive and accurate imaging technology
that was not being used very widely
in clinical populations other than epilepsy:
magnetoencephalography, MEG.
MEG has the spatial resolution of MRI,
along with the temporal capabilities of EEG.
The Armed Forces heard that we were using this advanced imaging technology
to study cognitive and psychiatric disorders,
and that was why they came to us.
MEG is smaller than an MRI, and totally silent.
With it, we see the magnetic fields of the brain,
and we can see them in real time.
So we can see what is happening in the brain, where and when,
to the thousandths of a second.
This is not possible with MRI.
With MRI, it can take up to six seconds to see a response.
So, to go back to how we answered this question,
we included four groups in our research study.
We had two groups from the military:
soldiers who were known to have PTSD via psychiatric diagnosis,
and soldiers who didn't,
who had been deployed in the same war zone,
had the same combat experience,
but who hadn't developed PTSD.
We also included two civilian groups:
a group who had suffered mild traumatic brain injury, MTBI,
and a group that hadn't.
And we included the MTBI group
because PTSD and MTBI are often associated in returning soldiers.
So, what did we do?
We recorded the magnetic fields of the brain in our participants
before, during, and after they completed a number of different tasks in the MEG.
And these are tasks that tapped the abilities
that are often reported to be problematic in PTSD and MTBI,
abilities such as attention, memory,
emotional processing, mental flexibility.
And during the tasks,
we included images and words from the Afghan war.
We found, using these tasks in MEG,
that soldiers with PTSD had brain patterns
that were remarkably different from those other groups.
For example, in the soldiers with PTSD,
we saw patterns of hyperactivity in the high-frequency bands
in this network,
as if they were overconnected in the high frequencies.
And if you look at this network,
it involves frontal areas, hippocampal areas, temporal lobe,
areas that are involved in memory and in attention.
When we looked at the MEG before and after they saw combat-related stimuli,
the MTBI and their control group showed no differences.
But the soldiers reacted.
And the soldiers without PTSD reacted more,
and their brains became hyper-aroused
and looked like this, like the soldiers with PTSD.
In contrast,
the soldiers with PTSD were already on high arousal in this network.
They couldn't get any more wound up.
So the difference between these two groups
was that the soldiers with PTSD are staying in high arousal.
And importantly, this level of high arousal correlated positively
with the psychiatric symptoms and their severity that we also measured.
We also found
that when we showed the soldiers pictures that they had seen before,
and we asked them to recognize them, and these are combat-related pictures,
those with PTSD showed a very rapid, double activation
in a quarter of a second in the amygdala.
The amygdala is associated with emotional processing in the brain.
As if they're spinning their wheels with strongly emotional stimuli.
This was not seen in the other soldiers.
Those with MTBI had different patterns on the various tasks,
but they were also atypical.
So in this study,
we found that we had an objective means
to determine the presence of PTSD, as well as its severity.
These studies used extensive high-level analyses,
that included measures of brain connectivity and complexity,
to accurately classify PTSD and MTBI.
And very importantly,
the measures of brain function with PTSD and MTBI
were different from those without the disorders,
but they were also different from each other.
So physical trauma and psychological trauma
had distinct effects on the brain,
even though the behavioral symptoms are overlapping.
Given this better understanding,
we should be able to diagnose PTSD earlier,
they can get help earlier,
this should reduce the duration of the illness,
and have a significant impact on their lives and that of their families.
With the ability to diagnose,
this PTSD can be validated as a very real injury,
and the stigma associated with it should begin to fall away.
And imagine what we can do with this approach
with other mental illnesses.
This is a breakthrough in our current models,
and it can change the whole optics of mental health diagnosis.
I didn't want to answer this question
when I was first posed by Defense Research Canada,
largely because we didn't think it could be answered.
But we tried, and the results were surprising.
Not only did we answer this question,
we also provided the basis to answer many other questions
on which we're currently working.
So good questions can motivate us to act.
But it is easy to shy away from difficult questions.
I almost did.
So I'm asking you:
what questions are you being asked that you don't want to answer?
What breakthroughs are you walking away from
because the questions are putting you outside your comfort zone?
Outside my comfort zone
was a discovery that I believe will change the lives of thousands.
Thank you.
(Applause)