The annual Society for Neuroscience conference is currently underway in Washington DC and Technology Review has a couple of article that reports on some of the highlights.
One piece is particularly interesting as it focuses on the use diffusion tensor imaging (DTI), a type of MRI scan that identifies the white matter nerve pathways in the brain, to detect otherwise undetectable brain damage.
These white matter pathways are like cabling that runs through the brain and in some forms of head injury they can get twisted, pulled or suffer sheering injuries which may not be easily visible on standard MRI scans.
A minority of people who suffer head injury with no detectable injury on standard MRIs will suffer emotion and behaviour disturbance, memory difficulties, diffuse headaches and problems with concentration.
This is sometimes diagnosed as post concussion syndrome and the researchers hope that DTI scans will find that people with these sorts of complaints will be found to have clear white matter disturbance.
Actually, this is one of the oldest debates in head injury and stretches back to the time when soldiers were first returning from the First World War with ‘shell shock’.
One of the theories, largely championed by Maudsley psychiatrist Frederick Mott, was that the shock waves from the shells disturbed the brains of the individuals causing microscopic brain damage.
However, it soon became clear that some soldiers who had ‘shell shock’ had never been near a shell explosion, while others had genuine brain injury but had similar sorts of problems which weren’t easily explained by the physical damage they’d endured.
One of the key lessons from this time was that our expectations, beliefs, emotions and interpretation of experiences and injuries contributed as much to the actual symptoms and disability as the physical damage.
Interestingly, similar sorts of problems have been reported in soldiers returned from Iraq and, as echoed in the TechReview article, there is a big push to clearly separate cases of ‘genuine brain injury’ from ’emotional trauma’.
History tells us that attempting a clear separation is likely to be futile, because the same symptoms can be produced by either one, or a combination, and knowing that one definitely plays a part doesn’t rule out the other.
So it’s interesting to hear the people quoted in the article suggest that DTI imaging could help assess who is cognitively able or not, who has a ‘real injury or is faking’, or whether someone should be sent back to the battlefield, because it relies on a cut-and-dry distinction between ‘brain injury’ and ‘psychological problem’ which doesn’t exist in the real world.
As an aside, white matter isn’t invisible on MRI or CT scans, as suggested in the article, although some white matter injuries might be.
And if you’re still hungry for more SfN news, TechReview has another bulletin with several highlights.