A mild concussion is a brain trauma that causes a change in mental functioning, states Brain Injury Association of America. Grade 1 concussions are the mildest type of concussion. After the injury, individuals maintain consciousness, but experience confusion for up to 15 minutes.
Symptoms of a grade 1 concussion include being dazed and an inability to follow directions or think clearly, states Brain Injury Association of America. With a grade 2 concussion, the individual experiences similar symptoms that last longer and may also suffer amnesia. With a grade 3 concussion, the person losses consciousness and experiences more serious symptoms such as a noticeable change in brain function, behavior and cognition.
In addition to the cognitive symptoms, concussions may also cause a person to feel nauseous, dizzy or tired, notes WebMD. People with concussions may experience blurred vision, difficulty balancing and sensitivity to light. Changes in sleeping patterns or mood may also occur.
Most people fully recover from a mild concussion with rest, according to WebMD. Even if symptoms disappear quickly after a mild concussion, the brain is still healing and is more prone to injury. Repeated concussions may cause permanent damage and inhibit a person's ability to learn, speak or move. Concussions are common after car and bike accidents, fights and falls.