Rapid Eye Test May Hold Key to Youth Concussion Diagnosis, Study Shows

A new study conducted by the Children's Hospital of Philadelphia (CHOP) has shown that an existing handheld device may provide objective measures to diagnose concussion in adolescents. Currently accepted diagnostic protocols are often subjective, and can be influenced by pre-existing medical conditions and personal bias.

This can lead to athletes returning to play too soon or stop them from being pulled from a game in the first place. A second injury, before the initial concussion has healed, can have lasting impacts on brain development and function.

What the Study Shows

Published in the September issue of JAMA Opthalmology, the study has determined that adolescents with a concussion have a different pupillary light reflex (PLR) of the eye than their non-concussed peers.^

In this original study, researchers used a handheld dynamic infrared pupillometer (DIP) to measure the pupil’s reaction to light. This device can record images and videos of the pupils under different conditions and provide objective measurements and data about the pupillary reaction.

The study looked at high school athletes aged 12-18 years. It compared PLR measurements between athletes with a known concussion and their non-concussed peers. It found a statistically significant difference in 8 of the 9 measurements taken. From this, they were able to ascertain that concussion does cause a physical difference in the pupil's reaction to light.

The researchers from CHOP are particularly interested in using the data to develop an objective diagnostic tool for concussion. Because the pupils of the human eye are under the influence of the autonomic nervous system, the results cannot be altered by the conscious effort of a participant.

How Is Concussion Diagnosed Now? 

“Currently the diagnosis of a sports-related concussion is a clinical one.” Reports Melissa Biscardi, RN, MSc, clinical researcher and concussion clinician at RehabLab in Toronto, Ontario. “The diagnosis is made by a medical professional such as a neurologist, physician, or a nurse practitioner."

Current concussion diagnoses are subjective in nature and can be influenced by pre-existing conditions in some individuals. Pediatric concussion assessments predominantly look at the visio-vestibular system. That means that it assesses vision, balance, movement and the relationships between these functions.

During a concussion assessment, a patient may be asked to follow a moving object with their eyes only. A concussed person may find that this task causes fatigue, headaches, or nausea. Likewise, when they are asked to walk in a heel-toe fashion both forwards, backwards, with their eyes open, and closed, their ability in performing these tasks may indicate a concussion due to a disturbance in the visio-vestibular systems.

Lead researcher and sports medicine pediatrician Christina Master, MD, FAAP, CAQSM, FACSM, explains that pre-existing conditions that affect the visual systems (e.g. the need for glasses or “lazy-eye” conditions) or vestibular system (e.g. motion sickness) need to be considered as part of the overall assessment.

Additionally, personal or family history of conditions such as ADHD, dyslexia, or learning difficulties must be considered. Biscardi explains that “ADHD and learning disabilities are thought to complicate recovery of sports-related concussion.” Although further research in this area is required, these conditions must be factored into an assessment to provide an appropriate recovery plan.

Why Objective Diagnoses Are Needed

Objective tests will still need to be used in combination with current testing due to such variety in the human condition. However, adding a rapid objective measure into the assessment can strengthen and support findings. It may help add a layer of security to assessment, particularly if a patient's injury recall information is vague or inconsistent.

Master hopes that this new test will be seen on sidelines at youth sporting events within the next few years. "We hope that this will be something that in the future could be developed into an easy-to-use sideline instrument to prevent premature return to the playing field".

Although each state has implemented laws surrounding concussion in youth sport, Nationwide Children’s Hospital report that implementation of these laws could be improved.

For example, the Centers for Disease Control and Prevention (CDC) notes one existing policy that requires any player to be removed from play if they have a suspected concussion. But if a player does not want to be removed from play, they may try to mask symptoms like confusion or simply not admit to symptoms such as pain or nausea.

Similarly, another law requires a player with a suspected concussion to obtain medical clearance and wait for a minimum of 24 hours after the injury before returning to play. Symptoms of a concussion can sometimes be delayed by several days, which means if clearance is obtained within 24 hours of the injury, symptoms may not yet be obvious and thus the diagnosis could be missed.

Biscardi says that a missed diagnosis can put a player at risk of further injury that can lead to second impact syndrome, "when the brain swells rapidly shortly after a person suffers a second concussion before symptoms from an earlier concussion have subsided."

When we consider how much a person's balance and coordination can be affected by concussion, then the risk of a second injury is very real.

With these issues in mind, the ability to assess concussion with objective measures is a much-needed tool.

Where to Go From Here

Further study is needed to determine how accurate the PLR measure is when used close to the time of injury. The current study looked at patients with a confirmed concussion using current diagnosis methods. These patients were an average of 12 days post-injury. To ensure this tool can be used at sporting sidelines, further testing will need to be performed closer to the time of injury.

Master explains that "Even though pupillary light reflex metrics are not quite ready for game time clinical use just yet, it does reinforce what we have observed clinically, that concussion often affects your vision after concussion. It is important to be aware of that when trying to figure out if you or your child has one and how to get better and back to school and activities afterwards."