Our Blogs

What Are the Most Common Types of Concussions?

Written by Berkowitz

The word concussion with icons in the background

A concussion is a mild form of traumatic brain injury. Not all concussions are created equal, however. Some concussions are more severe than others; for example, concussions can be further classified according to which symptoms are the most prevalent. Classifying a concussion can be an essential step toward determining the value of any compensation that may be due.

Common Causes of Concussions

Most concussions are caused by road accidents, slip and fall accidents, contact sports, and criminal assaults. Think of falling down a flight of stairs, for example, or being injured in a bar fight. Boxing is particularly dangerous since the game’s very object is to give your opponent a concussion (a “knockout”). Road rage is also a common scenario that leads to concussions. Some concussion risks are hard to avoid—slipping on the soap in the shower, for example.

The “Eggshell Skull Plaintiff” Doctrine

One of the leading legal reasons for classifying concussions is to determine how damages are to be calculated. Two people with concussions derived from the same accident may suffer radically different symptoms. This is due to the differing effects of their concussions on their pre-existing state of health. For this reason, one party might be entitled to far more compensation than the other, despite suffering a similar injury.


Imagine that two people suffer precisely the same impact on their heads in a car accident. One of them suffers only a mild concussion. The other one, the “eggshell skull plaintiff,” suffers severe brain damage because their skull is naturally thin due to a congenital disability.

Under the “eggshell skull plaintiff” doctrine, the at-fault party would need to compensate both of them fully. They could not argue that they should be partially relieved from liability towards the eggshell skull plaintiff simply because the relative thinness of one of the victim’s skulls was not their fault. A defendant must take their victim as they find them.

Two Ways to Classify Concussions: By Severity and By Symptoms

Ultimately, how many different types of concussions exist depends on how you choose to classify them. For legal purposes, one of the classification goals is to make it easier to determine the amount of damages that the defendant must pay. Thus, the two most common ways of classifying concussions are (i) based on severity and (ii) based on types of symptoms.

Classification Based on Severity

The most common way of classifying a concussion is based on its severity. Traditionally, concussions have been classified as Grade 1, Grade 2, or Grade 3.

Grade 1 concussions

Grade 1 concussions are mild. The following typical symptoms last for anywhere from a few minutes to a few days:

  • Headaches,
  • Dizziness,
  • Nausea,
  • Memory loss, and
  • Difficulty concentrating.

Grade 1 concussions typically occur in minor traffic accidents and sports injuries, and they never result in unconsciousness.

Grade 2 concussions

A Grade 2 concussion is moderate, with symptoms that can include:

  • Tinnitus (ringing in the ears),
  • Short-term amnesia (for a few minutes), and

Someone suffering from a Grade 2 concussion may or may not lose consciousness. If they lose consciousness, the period of unconsciousness can last from a few seconds to a few minutes.

Grade 3 concussions

A Grade 3 concussion is the most severe type of concussion, and it always results in a loss of consciousness. Unconsciousness may last for longer than five minutes. Other symptoms include:

  • Amnesia for 24 hours or even longer,
  • “Seeing stars,” and
  • Nausea/vomiting.

Grade 3 concussions sometimes (but not always) result in long-term or even permanent brain damage. It can take weeks for the victim to reach maximum medical improvement (the point where the patient has improved as much as they are ever likely to).

Classification Based on Types of Symptoms

The Stanford University Brain Performance Center has classified concussions into five subtypes (cognitive, ocular-motor, headache/migraine, vestibular, and anxiety/mood) and two associated conditions (sleep disturbance and cervical strain). This relatively new classification system promises significant contributions to the treatment of concussions.

Cognitive concussions

The symptoms of a “cognitive” concussion involve impairment of specific cognitive abilities such as attention, reaction time, speed of mental processing time, memory storage and retrieval, learning, and executive-level organization of thoughts and behavior. Symptoms may include dazed or sluggish behavior, blurry vision, balance problems, trouble following directions, difficulty maintaining balance, and sensitivity to light or noise.

Ocular-motor concussions

“Ocular-motor” refers to the visual system—eyesight, focusing, depth perception, binocular vision, and visual perception, for example. Many concussion victims endure temporary and sometimes even permanent deficits to their ocular-motor system for some time after suffering a concussion. People with ocular-motor deficiencies have trouble collecting, interpreting, and processing visual stimuli.

Some ocular-motor dysfunction victims exhibit symptoms similar to those of cognitive dysfunction, even though ocular-motor disorder is not cognitive dysfunction. Ocular-motor deficits, however, could more accurately be classified as a learning disability because they can impair the victim’s ability to collect and process information without affecting intelligence.

The victim may have trouble reading, driving, or spending time in front of a screen. They may also have trouble focusing, resulting in impaired depth perception. They may suffer from “ice-cream headaches” (pain behind the eyes), sensitivity to light, double vision, and nausea. Because of deficits in information processing, they may have difficulty dealing with complex visual environments.

Headache/migraine concussions

Headaches are the most common post-concussion symptom. Migraine headaches are common, and they are often accompanied by nausea, vomiting, and sensitivity to sound, light, and smell. People who frequently suffer from headaches before their concussion are most at risk for even more severe headaches following a concussion.

Vestibular concussions

The vestibular system is responsible for balance. Disturbances to this system result in vertigo, dizziness, nausea, vomiting, lightheadedness, “brain fog,” and balance problems. Some victims find walking difficult due to balance problems. Anxiety and confusion are common side effects of these symptoms due to a feeling of disorientation.

Anxiety/mood concussions

Anxiety and mood disturbances are expected reactions to some of the disturbing symptoms of a concussion. However, in an anxiety/mood concussion, at least some of these symptoms are directly attributable to physical causes. Typical symptoms include nervousness, emotional sensitivity, hypervigilance, rumination and brooding, depression, anger, irritability, fatigue, insomnia, feeling overwhelmed, and hopelessness.

Patients with a history of depression and anxiety are particularly susceptible to this type of concussion. Symptoms can often be treated with exercise and other social and physical activity within any concussion limitations.

Sleep disturbance (concussion-related condition)

Sleep disturbance is considered a concussion-related condition rather than a concussion type because sleep disturbances are never the only symptom of a concussion. Symptoms include excessive sleepiness (especially in the daytime) and insomnia.

Although sleep disturbances can occur as a secondary result of other distressing symptoms of a concussion, the sleep disturbance at issue here is a direct result of brain injury. Sleep disturbances can also retard recovery from other concussion symptoms.

Cervical strain (concussion-related condition)

This concussion-associated condition refers to a sprain of the ligaments of the cervical spine. In common parlance, it refers to injuries such as whiplash. Symptoms include neck pain and stiffness, weakness in the neck or other upper extremity, headaches, pain/tenderness in the cervical spine (neck region), and muscle palpitations, among other symptoms.

Post-Concussion Syndrome

Symptoms of a concussion do not always disappear within a couple of weeks. About one in ten concussion victims suffer from persistent symptoms, sometimes lasting a year or even longer. This condition is known as post-concussion syndrome.

Unfortunately, post-concussion syndrome not only involves the continuation of existing concussion symptoms but, in many cases, also consists of the introduction of new symptoms such as:

  • Anxiety,
  • Behavioral changes,
  • Dizziness,
  • Emotional problems,
  • Fatigue,
  • Insomnia,
  • Intense headaches,
  • Irritability, and
  • Sensitivity to light and noise.

Doctors cannot predict who will and who will not develop post-concussion syndrome. Moreover, the exact physiology of this condition is still essentially a mystery.

A Word of Warning: Second Impact Syndrome

Second impact syndrome occurs when you suffer a second concussion before a previous concussion has fully healed. Strictly speaking, this does not count as a type of concussion. However, it is worth mentioning because of the uniqueness of one of its common symptoms—sudden death. If you have suffered a concussion, do NOT put yourself at risk of another one (by returning prematurely to the football field, for example) until your doctor tells you that it is safe to do so.

If your loved one died from second impact syndrome, you might need to investigate whether it resulted from negligence. A coach who sent your loved one back out onto the football field too soon after a head injury may have caused their death, for example.

If your loved one’s death was someone else’s fault, you might be able to recover damages in a wrongful death claim. Compensation in a wrongful death claim can be quite substantial.

Waste No Time

If you have suffered a concussion, you might have a personal injury claim against whoever caused it. You might even have a medical malpractice claim against your healthcare provider. Unless you have already begun investigating your claim, however, your situation is unstable. Evidence degrades over time, and witness memories fade. If you delay, then eventually, the statute of limitations will catch up to you.

The experienced Connecticut personal injury lawyers at Berkowitz Hanna are familiar with all types of concussion-related claims due to decades of combined experience. Call us today or contact us online for a free initial consultation. We serve clients throughout the state of Connecticut from our offices in Stamford, Bridgeport, Danbury, and Shelton. We work on a contingency basis, which means that you won’t owe us anything if we don’t win your case.