A traumatic brain injury – or TBI – is the disruption of normal brain function caused by an external force, including a jolt or blow to the head. Not all blows or jolts to the head cause a TBI. A TBI may be classified as:

• Mild (most common, also called a concussion)
• Moderate
• Severe
• Penetrating

Possible Symptoms

• Headaches
• Dizziness or balance problems
• Fatigue
• Feeling depressed, anxious or irritable
• Nausea
• Sensitivity to light and sound
• Sleep problems
• Trouble with memory and attention
• Vision changes
• Impulsivity

For more information, download the What You Should Know About Concussions and Concussion Signs and Symptoms fact sheets.