Eye-tracking device measures severity of concussion and brain injury
12 February 2015
A novel eye-tracking device can effectively measure the severity
of concussion or brain injury in patients presenting to emergency
departments following head trauma. The simple and objective
diagnostic tool could also be developed for use on the sidelines at
It is a significant improvement on the only field 'tool'
available at the moment — a medic moving a finger in front of the
injured person's face. A better method to evaluate head injuries in
the field is badly needed as shown by discussions following many
sports events when injured players returned to the field of play
after head injuries.
A recent example is Welsh rugby player George North who was hit
on the head twice and appeared to be knocked out on the second
incident during the international against England on 6 February. He
was allowed to return to play because the team medics had not seen
that incident, but passed him as fit. Doctors say he has not
suffered any ill-effects since but he has not been picked for the
next game against Scotland on 15 February to give him an extended
period of recovery.
The eye-tracking technology used in this study was originally
developed by lead investigator Dr Uzma Samadani and colleagues at
the Cohen Veterans Center to assess eye movement in veterans of
Middle East conflicts suspected of suffering from traumatic brain
injury (TBI), concussion or other forms of brain injury.
In this new study, researchers studied trauma patients in the
emergency department at Bellevue Hospital Center in New York City.
The patients watched a 4-minute video playing inside of an aperture
moving around the perimetry of a video monitor while a camera
recorded eye movements.
A patient watches a video while eye movements are
tracked by a camera
The study showed that 13 trauma patients who had hit their heads
and had CT scans showing new brain damage, as well as 39 trauma
patients who had hit their heads and had normal CT scans, had
significantly less ability to coordinate their eye movements than
normal, uninjured control subjects. Twenty-three trauma subjects who
had bodily or extremity injuries but did not require head CT scans
had similar abilities to coordinate eye movements as normal
Among patients who had hit their heads and had normal CT scans,
most were slightly worse at 1-2 weeks after the injury, and
subsequently recovered about one month after the injury. Among all
trauma patients, the severity of concussive symptoms correlated with
severity of disconjugacy. The study has been published online in the
Journal of Neurotrauma.
"Concussion is a condition that has been plagued by the lack of
an objective diagnostic tool which, in turn, has helped drive
confusion and fears among those affected and their families," says
Dr Samadani, who is also assistant professor in the Departments of
Neurosurgery, Psychiatry, Neuroscience and Physiology at NYU Langone.
"Our new eye-tracking methodology may be the missing piece to help
better diagnose concussion severity, enable testing of diagnostics
and therapeutics, and help assess recovery, such as when a patient
can safely return to work following a head injury."
The eyes have served as a window into the brain, with
disconjugate eye movements — eyes rotating in opposite directions —
considered a principal marker for head trauma as early as 3,500
years ago. Current estimates by optometrists suggest that up to 90%
of patients with concussions or blast injuries exhibit dysfunction
in their eye movements.
Unfortunately, the "state-of-the-art" tool to detect eye
conjugacy is asking a patient to follow along with a physician’s
finger, according to Dr Samadani, who also serves as co-director of
the Steven & Alexandra Cohen Veterans Center for the Study of
Post-Traumatic Stress and Traumatic Brain Injury at NYU Langone.
"Traumatic brain injury is one of the most common causes of
neurologic morbidity in the world today," says Dr Richard Ellenbogen,
the Theodore S Roberts Endowed Chair and professor and chairman of
the Department of Neurological Surgery at University of Washington
Medicine and co-chair of the Head, Neck and Spine Committee of the
National Football League. "Sports concussion, on the mild end of the
spectrum of TBI, has captured the fascination of both the public and
media. Since concussion affects all ages, both genders and occurs in
all sports, being able to make the diagnosis quickly and accurately
is essential. The challenge physicians have in identifying
concussion is that the diagnosis is often based on self-reported
"Dr Samadani and her colleagues have come up with a novel and
objective manner of assessing patients with a suspected TBI," he
added. "The beauty to their method is that it is non-invasive,
reproducible and easy to perform on the sidelines or in the field.
It provides a simple and elegant method of being able to assess the
functional deficits that occur with TBI, and thus help the physician
make a rapid and accurate diagnosis.
"By tracking eye movements, they have been able to quantitatively
assess the function of the brain. Their new approach will hopefully
identify those patients who may be missed by basing the evaluation
simply on subjective complaints. This work adds an important
dimension to our ability to provide safe, rapid and accurate care to
those who suffer TBI in sports or with daily life activities."
This new study of non-military, civilian trauma patients visiting
the emergency department builds on recent research conducted by Dr.
Samadani, supported through the Cohen Veterans Center, which found
that the use of this novel eye-tracking technology could reveal
oedema, or swelling, in the brain as a potential biomarker for
assessing brain function and monitoring recovery in people with head
That study, published Dec. 16 in Journal of Neurosurgery, looked
exclusively at military veterans. Dr Samadani’s future work aims
to replicate eye-tracking’s diagnostic potential for head injuries
on a larger scale in Iraq and Afghanistan veterans with
post-concussive syndrome and post-blast military brain injury.
Estimates from the Centers for Disease Control and Prevention
state about 2.5 million US emergency department visits were
associated with traumatic brain injury in 2010, with rates
increasing by about 70% over the previous decade. Currently
there is no tool seen as a gold standard for diagnosing concussions,
and imaging tests like CT-scans and MRIs are ineffective in the
absence of structural damage to the brain.
"Two patients who suffer a head injury and present with
virtually-identical CT-scans might have completely different
symptoms," Dr. Samadani points out. "That’s where eye-tracking can
help objectively reveal when one patient may be much more affected
by a concussion than another."
Also lending third-party support for Dr. Samadani’s research is
Dr Sean Grady, the Charles Harrison Frazier Professor and
Chairman of the Department of Neurosurgery at the Perelman School of
Medicine at the University of Pennsylvania, commented, "The importance of this study is that it establishes a reliable
test and a 'biological' marker for detecting concussion. Since concussion can occur without loss of consciousness,
this can be particularly important in sideline evaluations in
athletics or in military settings where individuals are highly
motivated to return to activity and may minimize their symptoms.
More work is needed to establish its sensitivity and specificity,
but it is very promising."
Dr Samadani has submitted patents describing the technology
utilized in this paper. These patents are owned by NYU and the VA
and licensed to Oculogica Inc., a company co-founded by Dr. Samadani
and co-investigator Robert Ritlop.