Diffuse axonal injury (DAI) is a brain injury in which scattered lesions occur over a widespread area in white matter tracts as well as grey matter.[1][2][3][4][5][6][7] DAI is one of the most common and devastating types of traumatic brain injury[8] and is a major cause of unconsciousness and persistent vegetative state after severe head trauma.[9] It occurs in about half of all cases of severe head trauma and may be the primary damage that occurs in concussion. The outcome is frequently coma, with over 90% of patients with severe DAI never regaining consciousness.[9] Those who do wake up often remain significantly impaired.[10]