Which of the following is NOT a sign of concussion?

The correct response identifies a condition that significantly contrasts with typical signs of concussion. Concussions, which result from a blow to the head or body that causes the brain to move rapidly within the skull, frequently manifest symptoms such as headaches, lack of coordination, and sensitivity to light.

The presence of clear thinking and sharp memory, however, does not align with the expected symptoms of a concussion. In fact, individuals who have sustained a concussion may experience confusion, impaired memory, and difficulty concentrating. The symptoms are typically associated with a disturbance in cognitive function, which is not represented by clarity of thinking and memory. Thus, having clear cognitive function would indicate the absence of a concussion rather than the presence of it. Understanding these distinctions is crucial in the assessment and management of head injuries.