The presently-disclosed subject matter includes methods and devices for diagnosing, prognosing, and treating brain damage in a subject, including brain damage caused by stroke or a traumatic brain injury (TBI). The methods can comprise providing a sample obtained from the subject, exposing the sample to an antibody selective for a visinin-like protein, detecting the presence of a complex that includes the antibody and the visinin-like protein, and diagnosing and/or prognosing the subject as having brain damage if there is the presence of the complex. Embodied methods can also comprise administering a treatment for brain damage if the subject includes the presence of the visinin-like protein.