4 Types of Brain Injuries and 3 Levels of Severity

Brain injuries come in many forms, and they can all profoundly impact your life. After an accident, a brain injury can have dramatic and life-changing consequences, potentially leaving you with permanent cognitive and motor impairment. 

Here are the most common types of traumatic brain injuries and how their severity is determined.

Levels of Traumatic Brain Injury Severity

A traumatic brain injury (TBI) is categorized as mild, moderate, or severe. The most common way to classify severity is using the Glasgow Coma Scale (GCS) as soon as possible after the injury.

The GCS measures the state of consciousness and motor, verbal, and eye response. TBI victims are scored on a 15-point scale. 

Mild TBI

A mild brain injury or concussion is the least severe form of TBI. However, it is still considered a serious injury and may have lasting effects. 

A mild TBI can cause symptoms such as: 

  • Brief loss of consciousness 
  • Trouble concentrating
  • Memory loss
  • Headache
  • Mood changes such as anger or sadness
  • Sensitivity to sound and light
  • Dizziness or balance issues
  • Blurred vision
  • Nausea
  • Trouble thinking or confusion

With a mild traumatic brain injury, the best GCS score is 13 to 15 within 24 hours of the injury. 

Moderate TBI

A moderate brain injury is much more serious than a mild TBI. This level of severity typically requires rehabilitation and intensive medical care. Even with prompt treatment and improvement, there may be permanent effects. 

The most common moderate TBI symptoms include: 

  • Loss of consciousness for up to 24 hours
  • Headache that persists or worsens
  • Recurring or persistent nausea or vomiting
  • Seizures
  • Inability to wake up
  • Uneven pupil dilation
  • Slurred speech
  • Poor coordination
  • Numbness or weakness in the legs, arms, hands, or feet
  • Amnesia
  • Impaired cognitive function

With a moderate TBI, the best GCS score is nine to 12 within 24 hours of the head injury.

Severe TBI

A severe brain injury may involve injury to multiple areas of the brain or widespread damage. A severe TBI usually results in permanent, profound consequences. 

A severe brain injury may cause many symptoms in addition to the above, including: 

  • Loss of consciousness longer than 24 hours
  • Extreme disorientation or confusion
  • Poor reflexes
  • Loss of muscle function
  • Profound impairment of speech and/or cognitive function

With a severe TBI, the best GCS score is eight or lower within 24 hours of the injury.

Categories of Brain Injuries

Brain injuries are not just classified by severity. They are also categorized based on the mechanism of injury. 

Open or Closed

Open head injuries involve a penetrating wound to the skull, such as a gunshot. Closed head injuries involve only internal injuries. Both are serious, but open head injuries are usually more severe. 

Primary or Secondary

A brain injury is primary if it happens at or very soon after the initial trauma. Secondary brain injuries are a complication of an initial injury. After an initial brain injury, a series of changes is triggered in the brain. The cascade of blood vessels, chemical, and cellular changes can trigger further damage. 

An accident can cause both a primary and secondary brain injury. Sometimes secondary brain damage is caused by infection, disease, or lack of oxygen without an initial brain injury. 

Traumatic or Acquired

A traumatic brain injury or TBI is caused by trauma. This may be rapid acceleration and deceleration or a blow to the head. An acquired brain injury or ABI is the result of infection, disease, inadequate oxygen, or other internal factors. 

Brain injuries caused by congenital conditions, genetic conditions, or birth injuries are usually not classified as either traumatic or acquired.

Four Common Types of Brain Injuries Caused By Accidents

There are more than 288,000 TBI-related hospitalizations every year. Most of these brain injuries are caused by sports incidents, slip and fall accidents, car accidents, and violence. The following are four of the most common types of TBIs victims suffer in accidents. 


Up to 3.8 million people sustain concussions every year. However, nearly half are believed to go undiagnosed and untreated. Concussions account for about 80% of traumatic brain injuries. 

A concussion can be the result of violent shaking, a blow to the head, or rapid acceleration and deceleration. Many concussions happen in sports, falls, traffic accidents, and workplace accidents.

Coup-Contrecoup Brain Injury

A coup-contrecoup injury refers to two separate brain injuries that happen at the time of an accident. A coup injury is damage below the site of an impact. A contrecoup injury is damage opposite the impact. A coup-contrecoup brain injury means both injuries have happened. 

Coup-contrecoup injuries are serious because they involve damage to two or more areas of the brain. It takes significant force to cause a coup-contrecoup injury. Most of these injuries are caused by traffic accidents.

Hypoxic or Anoxic Brain Injury

Hypoxic and anoxic injuries are similar types of acquired brain injury. In many cases, they are secondary to an initial injury sustained in a fall, swimming accident, boating accident, or car crash. 

Anoxic/hypoxic brain injuries are due to insufficient oxygen to the brain. An anoxic injury happens when oxygen is entirely cut off, while hypoxic injuries happen when at least some oxygen still reaches the brain.

Diffuse Axonal Injury (DAI)

DAI is one of the most severe forms of brain injury. It happens when nerve fibers are torn or sheared while the brain rotates and shifts. Diffuse axonal injuries result in widespread damage to multiple areas of the brain. DAI is the most common cause of coma and disability in TBI survivors.

Brain injuries are one of the most serious consequences of an accident. Even a mild TBI can be traumatic, with an average one-year cost of more than $13,500. A moderate to severe TBI may leave you unable to return to work and affect every aspect of your life.

If you or someone you love has suffered a brain injury, contact a skilled personal injury attorney to discuss your case. You may be entitled to compensation from the at-fault party for your medical bills, lost earnings, and more.

Contact an Orlando Personal Injury Lawyer from Norden Leacox Car Accident And Personal Injury Lawyers for Help Today

For more information, please contact Norden Leacox Car Accident And Personal Injury Lawyers to schedule a free consultation with a personal injury lawyer in Orlando today. We have five convenient locations in Florida, including Orlando, Melbourne, Cocoa, Titusville, and Palm Bay

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