Learn About Concussion Symptoms and Warning Signs

What is a Concussion and How It Happens

A concussion is a type of brain injury caused by a bump, blow, or jolt to the head that changes how the brain normally works. It can also happen from hits to the body that are so powerful they cause the head and brain to move rapidly back and forth. When this happens, the brain essentially bounces or twists within the skull, creating chemical changes and sometimes stretching and damaging brain cells.

Concussions are also called traumatic brain injuries or TBIs. They're more common than many people realize. According to the Centers for Disease Control and Prevention (CDC), approximately 1.6 to 3.8 million sports and recreation-related concussions occur in the United States each year. However, many concussions go undiagnosed because people don't realize they've had one or don't seek medical attention.

Common situations where concussions occur include falls (the leading cause for older adults and young children), motor vehicle accidents, sports injuries, and assaults. Falls account for about 48% of all concussions treated in emergency departments. In sports, activities like football, ice hockey, soccer, and lacrosse have higher concussion rates. However, concussions can happen in any sport or recreational activity, including cheerleading, gymnastics, and cycling.

The key thing to understand is that you don't need to lose consciousness or be knocked out to have a concussion. In fact, most people who experience a concussion never lose consciousness. A person can seem fine on the outside but still have a serious brain injury that needs medical evaluation.

Practical Takeaway: Concussions result from head impacts or violent body movements that shake the brain. They're common in sports, falls, and accidents, and you don't need to be knocked unconscious to have one. If someone experiences a head injury, medical evaluation is important even if they seem okay.

Immediate Symptoms That Appear Right After a Head Injury

Some concussion symptoms show up immediately or within the first few hours after a head injury. Recognizing these early warning signs can help ensure the person gets medical attention quickly. The most common immediate symptom is headache or head pressure, reported by about 70% of people with concussions. The headache may feel like a dull ache, throbbing, or pressure inside the head.

Confusion is another frequent immediate symptom. A person with a concussion might seem disoriented, not understand where they are, or have trouble following what's being said to them. They might repeat the same question multiple times or seem "out of it." Some people describe feeling dazed or stunned, like they're in a fog and can't think clearly.

Dizziness and balance problems often appear right away. A person might feel like the room is spinning, feel unsteady when standing or walking, or have difficulty with coordination. They might stumble, bump into things, or feel lightheaded. Some people experience nausea or vomiting, especially in the first few minutes to hours after the injury.

Vision and hearing problems can also occur immediately. A person might report blurred or double vision, sensitivity to light, difficulty focusing on objects, or ringing in the ears. Speech problems are another sign—someone might slur their words, speak slowly, or have trouble finding the right words.

Memory loss related to the injury itself is important to note. A person might not remember what happened right before, during, or after the injury (called amnesia). This is different from general forgetfulness. There may also be changes in consciousness, such as appearing dazed, seeming unusually irritable, or not responding normally to questions.

Practical Takeaway: Immediate concussion symptoms include headache, confusion, dizziness, nausea, vision or hearing changes, and memory loss. Watch for these signs in the first hours after a head injury, and seek medical evaluation if any appear.

Delayed Symptoms That Develop Over Hours or Days

Not all concussion symptoms appear right away. Some emerge hours or even days after the injury. This is why observation after a head injury is so important. A person might feel fine initially but develop symptoms later. This delayed pattern happens because the brain's chemical and physical changes take time to develop.

Sleep disturbances are common delayed symptoms. A person might have trouble falling asleep, experience excessive drowsiness, or have unusual sleep patterns. Some people need significantly more sleep than usual to feel rested. Others have restless sleep or vivid, disturbing dreams. These sleep changes can persist for weeks after a concussion.

Cognitive difficulties often develop or become more noticeable over the first few days. Problems with concentration and attention are very common—a person might struggle to focus on reading, conversations, or work tasks. Memory problems beyond the initial amnesia can appear, such as difficulty remembering new information or following complex instructions. A person might feel mentally "foggy" or slow to process information. Some people describe it as feeling like their brain isn't working at full capacity.

Mood and personality changes can emerge several hours to days after injury. A person might become unusually irritable, anxious, sad, or emotional. They might have mood swings or seem withdrawn. Some people become more nervous or worried than usual. These mood changes can be surprising to family and friends and may be one of the more noticeable signs that something is wrong.

Sensitivity to light and noise often develops or intensifies over the first 24-48 hours. A person might request that lights be dimmed or want to avoid busy, noisy environments. They might find normal conversation volumes too loud or find it painful to be in bright rooms. This sensitivity can trigger or worsen headaches.

Neck pain, joint or muscle aches, and balance problems that weren't immediately obvious can also develop over the first few days. Some people develop sensitivity to motion or experience worsening dizziness when moving around.

Practical Takeaway: Delayed symptoms like sleep problems, difficulty concentrating, mood changes, and sensitivity to light or noise can appear hours to days after a head injury. Continue monitoring someone after an injury even if they seem fine initially.

Symptoms in Children and Adolescents

Concussion symptoms in children and teens can look different than in adults and may be harder to recognize. Young children especially may not be able to describe what they're feeling or may not realize something is wrong. Parents, teachers, and coaches need to watch for behavioral and physical changes.

Young children (ages 5-12) with concussions might not complain of headache at all, even though they have one. Instead, they might hold their head, rub their eyes, or complain about feeling "ouchies" without pointing to a specific location. They might cry more easily, seem unusually tired, or become clingy or fearful. Behavioral changes like becoming unusually quiet or withdrawn, or conversely becoming hyperactive or silly, can signal a concussion.

Adolescents (ages 13-18) often report similar symptoms to adults but may downplay their severity, especially if they want to return to sports. Teens might not mention headaches or dizziness because they're worried about being removed from activity. They might become quieter or seem emotionally withdrawn. Academic performance often drops—a teen who normally makes good grades might suddenly have trouble with schoolwork, forget homework, or have difficulty taking tests.

Sleep changes in children and teens are particularly notable. Young children might resist naps or bedtime or sleep much longer than usual. Teens might sleep excessively or have disrupted sleep. Both age groups might become unusually emotional or irritable, which can look like typical adolescent moodiness but is actually more pronounced than normal.

Children are at higher risk for concussions than adults in similar activities because their brains are still developing and their neck muscles are weaker, providing less support to the head. Research shows that young people may take longer to recover from concussions than adults. The CDC notes that children ages 0-17 have higher rates of emergency department visits for non-fatal traumatic brain injuries than any other age group.

Communication is key—adults caring for children after head injuries should ask specific questions: "Does your head feel different?" "Are lights bothering your eyes?" "Is it hard to think about what I'm saying?" Children may not volunteer information but will answer direct questions about their symptoms.

Practical Takeaway: Children and teens may not report concussion symptoms clearly