Which type of brain injury is not caused by physical impacts?

Acquired brain injury refers to damage to the brain that occurs after birth and is not the result of a physical impact. This type of injury can be caused by a variety of factors including strokes, infections, or exposure to toxic substances, among others. Unlike traumatic brain injuries, which are directly linked to external physical forces impacting the head, acquired brain injuries arise from internal physiological processes or other non-impact-related mechanisms.

In contrast, traumatic brain injury, contusive brain injury, and penetrating brain injury all involve some level of direct force or trauma that affects the skull or brain tissue. Traumatic brain injury typically encompasses all injuries resulting from external physical impacts, while contusive and penetrating injuries specifically refer to bruising of the brain and injuries that breach the skull, respectively. Thus, acquired brain injury is distinct because it can occur without any direct physical trauma to the head.