28 April 2009, Magazine issue 2705
CONCUSSION involves a bang on the head followed by unconsciousness or giddiness then a few days of headache and nausea. At least that is the usual understanding.
But on the battlefield it has come to mean something altogether more sinister: a blast-induced brain injury with a catalogue of symptoms such as fatigue, irritability and insomnia (see “Brain shock”).
The US military claims 1 in 5 of its soldiers are returning from Iraq and Afghanistan debilitated by such symptoms, which it claims are due to mild traumatic brain injury (mTBI), as concussion is also known, and has launched screening programmes. Veterans groups have even warned of an epidemic.
It seems plausible that mTBI is responsible for this apparent surge in battlefield illness: homemade roadside bombs are one of the greatest dangers coalition troops face in Iraq and Afghanistan, and most soldiers now survive such explosions thanks to their modern body armour.
Yet recent studies into the epidemiology of mTBI suggest that the symptoms soldiers are reporting derive not from head injury but mostly from psychological illness such as post-traumatic stress disorder (PTSD). In other words, they are triggered largely by the ghastly experience of being on a battlefield.
The distinction is important. Physicians can provide soldiers with more effective treatment if they know what caused their symptoms. And a false diagnosis could well exacerbate the problem: telling patients what is wrong with them can influence how they respond to treatment. That means if soldiers think their distress is due to an enduring brain injury they are likely to take longer to recover.