Introduction

Concussions remain a significant concern for healthcare providers due to their high incidence rates and variable recovery times influenced by numerous risk factors. The absence of valid biomarkers makes the diagnosis and assessment of concussions particularly challenging.¹

The exact number of concussions each year is hard to determine as many go undetected or unreported. According to the Centers for Disease Control and Prevention (CDC), mild traumatic brain injury (mTBI) constitutes at least 75 percent of all traumatic brain injuries in the United States. Each year, approximately 3 million people seek medical attention for TBI in the U.S., with most cases classified as mild TBI or concussions.

Concussions can affect anyone, but young children, teenagers, and individuals aged 65 and older are at greater risk. Males generally face a higher risk compared to females across most age groups, and people in the military and athletes in contact sports are particularly prone to repeated concussions.²

What is a concussion?

A concussion is referred to as a mild form of traumatic brain injury. It occurs when an external impact to the head or body causes the brain to shift inside the skull, such as from a fall against a hard surface or a hit that makes the head and brain move rapidly back and forth. This sudden movement can stretch and damage brain cells, cause chemical changes, and temporarily disrupt normal brain function, particularly in areas related to memory and orientation. Even mild traumatic brain injuries like concussions are considered brain disorders and can potentially lead to long-lasting or permanent effects, including chronic traumatic encephalopathy (CTE), a fatal brain disease linked to repeated traumatic brain injuries.

Diagnosis

Initial assessment

Clinical history

• A healthcare professional can assess the severity of a concussion and determine if treatment is necessary
• They will inquire about the incident that caused your head injury, review your symptoms, and conduct a neurological examination
• This exam will assess neurological function and reflexes (including vision, eye movement, and reaction to light), balance and coordination (including hearing, strength, and the motion and tenderness of neck muscles)
• Verbal, written, or computerized tests are used to examine your thinking power, memory, problem-solving skills and concentration
• Additionally, you will be asked about any mood changes, sleep disturbances, or behavioral changes³

Mechanism of injury

Falls are the leading cause of concussions in both adults and children, followed by being struck by or against an object and motor vehicle crashes. It is estimated that over 25% of concussions occur during sports activities. In athletic settings, females are more prone to concussions than males.  While males are more likely to be injured through player-to-player contact, females are more often injured through contact with the playing surface or equipment. Other risk factors for concussions include auto accidents, pedestrian or bicycle accidents, military combat, and physical abuse. A previous concussion history increases the risk of experiencing another.⁴

Assessment of symptoms reported by the patient

The symptoms of a concussion can be subtle and may not appear immediately, sometimes lasting for days, weeks, or even longer. Common symptoms following a mild traumatic brain injury include headache, confusion, and amnesia, typically involving memory loss of the event that caused the concussion. Physical symptoms may include headache, ringing in the ears, nausea, vomiting, fatigue or drowsiness, and blurry vision. Observers might notice signs such as temporary loss of consciousness, slurred speech, delayed responses to questions, a dazed appearance, and forgetfulness, such as repeatedly asking the same question.

Seek emergency care for any of these symptoms:

• Repeated vomiting or nausea
• Fluid or blood drainage from the ears or nose
• Loss of consciousness for more than 30 seconds
• Unbearable headache
• Vision or eye changes. For instance, the black parts of the eye, known as the pupils, may be bigger than usual or of unequal sizes
• Tinnitus (Ringing in the ears)
• Slurred speech
• Obvious changes to mental function, like behavioral changes 
• Confusion or disorientation and disturbance in physical coordination 
• Seizures or convulsions 
• Dizziness that does not go away or that goes away and comes back
• Weakness in arms and legs
• Significant bruises, including those behind the ears or around the eyes. It is especially important to seek emergency care if these symptoms appear in infants under 12 months of age

Differential diagnosis

The differential diagnosis immediately following a head injury should consider potentially severe conditions such as cervical spine injury, intracranial hemorrhage, or skull fracture.

Concussion symptoms can overlap with those of other pre-existing chronic conditions, including headache disorders or migraines, mental health conditions like anxiety, depression, or post-traumatic stress disorder, and attention-related issues such as attention deficit hyperactivity disorder. ⁵

Physical examination

Neurological assessment

Cases suspected of having a head injury are assessed using the Glasgow Coma Scale (GCS), which measures their level of consciousness based on neurological signs and responsiveness. The scale has a range from 3 to 15, with 3 indicating deep coma or death and 15 representing full consciousness without confusion. For a mild head injury, the initial GCS score will be between 13 and 15, and patients are not discharged until their GCS reaches 15. 

Cognitive assessment

Neuropsychological tests, such as the SCAT5 or Child SCAT5, are recommended to assess cognitive function. These tests are administered hours, days, or weeks after the injury or at multiple intervals to identify any trends. Some athletes also undergo pre-season baseline testing to establish a reference point for comparison in case of a future injury.

Diagnostic tools and tests

Various standardized diagnostic tools are used in pre-hospital settings to assess potential concussions following an acute head injury. One of the most widely used tools is the Sports Concussion Assessment Tool 6 (SCAT6), which is commonly employed by athletic trainers and sports medicine professionals to evaluate athletes immediately after a suspected head injury. For younger patients aged 5 to 12 years, the Child SCAT6 is available. These assessments are most effective when conducted in a quiet environment with minimal distractions.

Another essential tool in concussion management is the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT). This computerized test is specifically designed to evaluate student athletes by measuring cognitive functions such as visual and verbal memory, reaction time, and processing speed. Ideally, athletes take the 30-minute test before their sports season begins to establish a baseline. If a head injury occurs, follow-up tests are conducted at different intervals, allowing healthcare providers to compare results and track recovery. This approach helps determine when brain function has returned to normal, guiding decisions about when it is safe for an athlete to resume activity.⁶

Additionally, other assessment tools like the Vestibular/Ocular Motor Screening (VOMS), the Balance Error Scoring System (BESS), and positional tests such as the Dix-Hallpike and supine roll tests are used to evaluate vestibular system impairments, which are common in concussed patients. These tools aid in diagnosing and managing concussion-related balance and coordination issues.

Imaging techniques

A CT scan is typically considered if observation after discharge is uncertain, if intoxication is present, or if there is a suspected increased risk for bleeding, particularly in individuals over the age of 60 or under 16. However, it's important to note that most concussions without complications cannot be detected through MRI or CT scans. A blood test called the Brain Trauma Indicator was approved in the United States in 2018. This test may help rule out the risk of intracranial bleeding in adults, potentially eliminating the need for a CT scan.

Treatment

Immediate management

• If you suspect someone has a concussion following a head injury, follow the basic first aid steps  
• If a concussion has occurred during sports, stop playing immediately
• Apply a cold compress to the injury site to minimize swelling, but never place ice on the skin directly as it is too cold. Repeat the compress every 2 to 4 hours and leave it in place for 20 to 30 minutes.
• Seek medical help immediately if you experience any of the emergency symptoms
• Ensure someone stays with you for the first 24 hours after the injury in case more serious symptoms develop. 

Symptom management

There is limited treatment for symptoms such as dizziness, fatigue, or memory loss following a concussion. For headaches, over-the-counter pain relievers can be used, with paracetamol often recommended over NSAIDs like ibuprofen to minimize the risk of bleeding. Staying hydrated and eating foods that your stomach can tolerate are also important. If concussion symptoms persist and impact your quality of life, consulting a behavioral health therapist, physical therapist, or occupational therapist can help manage the physical, cognitive, and emotional side effects. 

The Concussion Recognition Tool 5 (CRT5) is also used to assist in identifying concussion symptoms in both children and adults and guide you on the appropriate next steps.

Rehabilitation strategies

Physical and cognitive rest is recommended for the first 24–48 hours following a concussion. After this period, individuals should gradually begin gentle, low-risk physical and cognitive activities that do not exacerbate current symptoms or trigger new ones. Patients should refrain from drinking alcohol or using recreational drugs. They should follow a step-by-step approach to returning to work, school, and sports. The steps include:

• Stage 1 (Immediately after injury): 24–48 hours (maximum) of relative physical and cognitive rest. This includes gentle daily activities such as walking around the house, light housework, and light schoolwork that do not worsen symptoms. No sports activities.
• Stage 2: Light aerobic exercise like walking or stationary cycling
• Stage 3: Moderate-intensity activities like running drills or skating drills
• Stage 4: Non-contact training sets (exercise, cognitive load and coordination)
• Stage 5: Full-contact practice sets (requires medical clearance)
• Stage 6: Return to full-contact sports or high-risk activities (requires medical clearance)⁷

Long-term management and follow-up

The most commonly encountered complication of a concussion is post-concussion syndrome (PCS), which is marked by persistent symptoms lasting weeks to months after the initial injury. In one study, the median duration of symptoms was seven months. PCS can involve any concussion symptoms, but it typically presents with a combination of somatic, emotional, and cognitive symptoms. ⁸

One of the most concerning and rare complications of a concussion is second-impact syndrome (SIS). This condition occurs when there is a repeat blow or injury to the head before the initial concussion has fully resolved, leading to rapid and severe swelling of the brain. SIS can result in dangerous neurological complications, such as brain herniation and death. However, existing research and data on this condition are unreliable.⁹

Research on the long-term effects of a concussion remains relatively limited. Of particular concern is the possibility of developing chronic traumatic encephalopathy (CTE), a condition marked by gradual neurodegeneration resulting from repetitive head injuries. Symptoms may manifest as memory disruptions, alterations in behavior or personality, and difficulties with speech or gait. The precise incidence and prevalence of CTE remain unclear, and currently, its definitive diagnosis requires neuropathological examination.

Summary: Diagnosis and treatment of concussion

Concussions are a significant health concern, particularly due to their high incidence and unpredictable recovery. They often result from external head or body impacts that cause the brain to move inside the skull, leading to temporary brain function disruptions. Concussions are common in sports, with athletes, military personnel, and certain age groups at higher risk.

Diagnosis involves a thorough clinical history, neurological examination, and cognitive tests. Tools like the SCAT6 and ImPACT test are often used to assess the severity and track recovery, while imaging techniques like CT scans may be employed when complications are suspected. The initial management includes rest, symptom monitoring, and seeking emergency care for severe symptoms like unconsciousness or vomiting.

Treatment mainly focuses on symptom management, including pain relief, hydration, and gradual return to activities. Rehabilitation involves a step-by-step process to ensure recovery without exacerbating symptoms. Long-term complications like post-concussion syndrome (PCS) and rare conditions like second-impact syndrome (SIS) can arise. Repeated concussions may lead to chronic traumatic encephalopathy (CTE), a degenerative brain disease. Continued research is necessary to fully understand the long-term effects of concussions.