A concussion is defined as a mild traumatic brain injury (mTBI) that occurs after a blow or jolt to the head or body, resulting in a temporary disruption of normal brain function. Diagnosis is a clinical determination made by a healthcare professional based on a series of assessments, not a single definitive test. The diagnostic process involves observing symptoms, comprehensive clinical evaluations, and using advanced imaging to rule out more serious injuries.
Recognizing Immediate Symptoms and Danger Signs
Identifying the initial signs of a concussion is the first step in diagnosis, usually performed by a bystander, coach, or parent. Observable signs of a possible concussion include a vacant stare, appearing dazed or stunned, confusion about the current game or event, a delayed or slowed response to questions, or unsteadiness while walking. These signs indicate that the brain’s normal processing speed and coordination have been temporarily affected.
It is important to distinguish typical concussion symptoms from “Red Flags,” which signal a medical emergency requiring immediate transport to the nearest hospital. These signs indicate a potentially severe structural injury, such as bleeding or swelling in the brain. Immediate emergency care is necessary if the person experiences a severe or worsening headache, repeated vomiting, slurred speech, seizures or convulsions, is unable to be awakened, or has one pupil that is noticeably larger than the other.
Clinical Evaluation Methods
Once a concussion is suspected, a healthcare professional conducts a clinical evaluation, which forms the foundation of the diagnosis. This evaluation begins with a medical history, where the provider gathers information about the injury mechanism, immediate signs observed, and the patient’s current symptoms (e.g., headache, dizziness, or fogginess). Since concussions are functionally based injuries, diagnosis relies heavily on these self-reported symptoms and observed deficits.
The physical examination assesses the functional areas of the brain most commonly affected by an mTBI. This includes a neurological exam that checks reflexes, sensation, and strength, alongside specific tests for balance and cognitive function. Balance is often assessed using standardized tools like the Balance Error Scoring System (BESS), which requires the patient to maintain various stances (double-leg, single-leg, and tandem) on firm and foam surfaces while counting the number of errors made.
Cognitive testing evaluates the patient’s memory, concentration, and orientation, often through standardized questions. For instance, the provider may ask a patient to recall a short list of words, repeat digits backward, or state the current date and location. These components are frequently combined into comprehensive tools like the Sport Concussion Assessment Tool (SCAT), a structured protocol used by medical professionals to systematically evaluate symptoms, cognition, and balance.
Advanced Imaging and Diagnostic Tools
While the diagnosis of a concussion is clinical, advanced imaging plays a role in ruling out more severe, life-threatening injuries. CT scans or Magnetic Resonance Imaging (MRI) are not used to diagnose the concussion itself, as the injury is a microscopic cellular event that typically does not show up on these scans. The purpose of these tools is to visualize the brain’s structure and check for complications that require immediate intervention.
A CT scan is the most common imaging tool used in an emergency setting because it is fast and effective at detecting acute structural problems. It uses a series of X-rays to generate cross-sectional images that can reveal skull fractures or visible bleeding in or around the brain, such as a hemorrhage. An MRI uses magnetic fields and radio waves to produce detailed images of soft tissues and may be used later to identify subtle changes or microbleeds if symptoms are persistent or worsening. If a patient exhibits any of the “Red Flags,” imaging is ordered to ensure a serious structural injury is not present.
Testing for Return to Activity
Testing does not end with the initial diagnosis; a comprehensive assessment is required to ensure the brain has fully recovered before a patient returns to high-risk activities. For athletes or individuals in certain professions, this process often involves comparing post-injury function to a pre-injury baseline test. A baseline test, ideally taken before the season begins, measures the individual’s normal cognitive function, reaction time, and balance.
Computerized neurocognitive tests, such as ImPACT or similar platforms, are used to quantify cognitive recovery by comparing post-injury scores to the individual’s baseline. Post-injury scores must return to or exceed the established baseline before medical clearance is considered. Even after symptoms resolve and cognitive test scores normalize, the final phase involves a graduated, stepwise exertion protocol.
This exertion protocol, often taking several days, begins with light aerobic activity and progresses through sport-specific drills. The patient must successfully complete each step, typically over a 24-hour period, without any return of symptoms before advancing to the next level. This final testing phase confirms the brain can tolerate the physical and mental stress of full activity before a healthcare provider grants final medical clearance.