Tracking the Source of “Selective Attention” Problems in Brain-injured Vets

An estimated 15 to 20 percent of U.S. troops returning from Iraq and Afghanistan suffer from some form of traumatic brain injury (TBI) sustained during their deployment, with most injuries caused by blast waves from exploded military ordnance. While obvious cognitive symptoms of minor TBI can dissipate within just a few days, blast-exposed veterans may continue to have problems performing simple auditory tasks that require them to focus attention on one sound source and ignore others, an ability known as “selective auditory attention.” According to a new study by a team of Boston University neuroscientists, such apparent “hearing” problems actually may be caused by diffuse injury to the brain’s prefrontal lobe. For their study, researchers presented a selective auditory attention task to 10 vets with mild TBI and to 17 control subjects without brain injuries. The researchers found that blast-exposed veterans with TBI performed worse on the task — that is, they had difficulty controlling auditory attention — “and in all of the TBI veterans who performed well enough for us to measure their neural activity, 6 out of our 10 initial subjects, the brain response showed weak or no attention-related modulation of auditory responses,” said computational neuroscientist Scott Bressler “Our hope is that some of our findings can be used to develop methods to assess and quantify TBI, identifying specific factors that contribute to difficulties communicating in everyday settings,” he noted. To learn more about the study, click here.