In the article “A Prospective Diffusion Tensor Imaging Study in Mild Traumatic Brain Injury” ( Neurology ® 2010;74:643–650), Andrew Mayer and colleagues studied the effects of mild brain injury using a special kind of magnetic resonance image (MRI). The new MRI sequence is called diffusion tensor imaging (DTI). DTI is useful because it assesses the white matter of the brain in a very specific way. In a sense, the white matter of the brain is where the “wiring” of the brain is located. Like a computer, the brain is made up of many parts, each with a specific role. Although each part is important, how the parts are wired together is essential to the complete function. Dr. Mayer wanted to look at the “wiring” of the brain, after head injury, to understand better how this part of the brain is affected by an injury. Although a standard MRI is often used when a person has a brain injury, this type of MRI is not very good at showing smaller kinds of changes that occur after a mild brain trauma. Dr. Mayer and his group thought that even though a “standard” MRI cannot “see” the injury, the “wires” of the brain are injured in mild traumatic brain injury (mTBI). For this reason, the authors felt that DTI might be a more sensitive marker of brain injury. If the wiring is important to the complete brain function, then an injury to the white matter would lead to problems with how the computer works. This would cause difficulties with complex brain functions like attention, decision-making, and memory. In his study, Dr. Mayer directly compared people who had mild brain trauma to those without a known brain injury. In order to be thorough, he evaluated people with mTBI at 2 time points: both near the …