Eye tracking detects high pressure inside the skull

Contact: Christine Hill 612.873.5719

Doctors Can Detect Pressure Increases Inside the Skull By Tracking Eye Movements During Watching of Music Videos

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Dr. Uzma Samadani

Eye movement tracking while watching a music video for 220 seconds can reveal whether there is increased pressure inside the skull.  The technology works by measuring the function of the nerves that rotate the eyeball.  “Doctors have known for more than 3000 years that high pressure inside the skull impairs the function of these delicate nerves, and that the first to be affected is usually the nerve that rotates the eye laterally” said neurosurgeon Dr. Uzma Samadani, the lead study investigator.

Participants in the National Space and Biomedical Research Institute (NSBRI) funded study were 23 patients in the neurosurgical intensive care unit who were awake but had brain problems such as bleeding, trauma, stroke or tumors requiring intracranial pressure monitoring with a drainage catheter.  On 55 occasions the patients watched music videos and Disney film clips while an eye tracking camera measured vertical and horizontal eye movements for 220 seconds.   There was a correlation between increased intracranial pressure and decreased function

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During a recent visit NASA astronaut Kjell Lindgren, MD (who received his medical training at HCMC), was given a demonstration of the eye-tracking technology.

 of the nerves moving the eye as detected with eye tracking.  Decreased lateral eye movements showed the strongest correlation with elevated intracranial pressure, consistent with what has long been known about nerve function.  Individual patients had normal tracking at lower pressures and decreased eye movement at higher pressures regardless of whether the high or low pressure occurred first.

Dr. Samadani, who is the Rockswold Kaplan Endowed Chair for Brain Injury Research at Hennepin County Medical Center as well as an Associate Professor at the University of Minnesota Medical School, noted that concussion and elevated intracranial pressure impact many of the same eye tracking metrics, suggesting that similar pathways may be impaired.

Study results were presented at a joint NASA/NSBRI research group meeting and are now published in the Journal of Neurosurgery.  The company Oculogica Inc has licensed exclusive world-wide rights for commercialization of the technology, for which a patent was issued earlier this month.

NSBRI funded the eye tracking research as a grant to the company Oculogica Inc through the SMARTCAP program which supports commercialization of technologies that will have utility both in space and on earth.  Eye tracking for detection of elevated intracranial pressure could potentially benefit 7 million Americans with hydrocephalus as well as have utility for concussion and other types of brain injury.  One potential indication for eye tracking would be identification of concussed subjects at high risk for second impact syndrome, which is thought to occur after, and further contribute to high intracranial pressure, which can be fatal.

NSBRI has a program investigating technologies for non-invasive monitoring of intracranial pressure which can potentially be elevated during space travel.  Astronauts who experience reduced gravity for prolonged periods of time are at risk for developing headaches and visual problems.  It is thought that without gravity, there is increased pooling of blood in the brain and elevated pressures inside the skull and eye structures.  This risk for elevated intracranial pressure impacts NASA’s plan for prolonged space travel.  Untreated elevated intracranial pressure can lead to cognitive difficulty and vision problems including blindness.  On earth, doctors currently drill holes into the skull to place monitors to measure this pressure in patients with trauma, bleeding in the brain, or certain tumors.  In space, such a measurement is not feasible, necessitating non-invasive measurement.

Dr. Samadani is a founder of the company Oculogica Inc., which is currently applying for FDA clearance for the eye tracking technology, called EyeBox.  She disclosed that she, New York University, the Department of Veterans Affairs and Hennepin County Medical Center all had equity interests in the company.

HCMC launches clinical trial to treat brain injury using vagus nerve stimulation

“Electroceutical” Treatment Hopes to Stimulate Brain Healing Without Medications

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Dr. Molly Hubbard, lead investigator of the VANISH TBI study examines a 3D hologram of the injured patient’s brain. The image was generated by Dr. Abdullah Bin Zahid in the HCMC Brain Injury Research Laboratory.

A simple slip on the ice while crossing a parking lot in downtown Minneapolis triggered the problem for 47-year-old John Doe (not his real name). By the time emergency medical personnel arrived he knew his own name, but did not remember falling, the date, or even where he was.  “I didn’t even know what had happened until I had been in the hospital for three days,” he said.

Brought into Hennepin County Medical Center (HCMC), John had classic brain injury, with tiny amounts of blood on the surface of his brain and interspersed into its folds. Radiology studies were consistent with brain trauma, but the injury was not severe enough to require surgery. Several days after the accident he moved into the brain injury rehabilitation unit at HCMC.

“I’m still trying to figure out how to get back to my normal life. It’s … hard to believe that this is my life. A lot of symptoms are starting to get better but they’re still there. I have problems remembering words,” said John, who works as a professional writer.

Luckily for John, HCMC, in conjunction with the University of Minnesota, has just launched a new clinical trial to treat brain injury, and he was the second patient to be enrolled.  He remarked, “I really like the idea of being able to help others with brain injury; maybe even help people who have it worse off than me.” Continue reading “HCMC launches clinical trial to treat brain injury using vagus nerve stimulation”

Visit HCMC at the Fair for hands-on health activities, eye-opening research

cropped more state farijpgHennepin County Medical Center (HCMC), Minnesota’s first Level I Adult and Pediatric Trauma Center is at the Minnesota State Fair during the best days of summer with hands-on health activities in the Health Fair 11 Building, located at the corner of Dan Patch Avenue and Cooper Street.

The fun begins on the first day of the Fair when kids are invited to try hands-on medical play activities including finger casting, play stitching, ultrasounds and more. Daily attractions include Bernie the Rescue Dog, HCMC’s mascot, who will be at the booth from 10am to 2pm as well as MVNA nurses who will offer flu shots and free blood pressure checks.

One of the unique daily features taking place at HCMC’s booth is the opportunity to participate in the Minnesota Healthy Brain Initiative research study. Participants complete a questionnaire, then watch a music video while their eyes movements are watched and measured using a tracking camera.

“Data have shown a connection between brain injury and abnormal eye movements,” explains neurosurgeon Uzma Samadani, M.D., Ph.D., the Rockswold Kaplan Endowed Chair for TBI Research at HCMC, who is also an associate professor at the University of Minnesota. “We’re so excited to have Fairgoers help with this research that will eventually be used to develop life-changing diagnostic and treatment methods.”

Dr. David Hilden, host of the Healthy Matters radio program heard every Sunday morning
on WCCO Radio will answer health questions from a live audience at the WCCO Radio booth on August 28 and September 4 from 7:30 to 8:30am. On August 28, Dr. Samadani will join Dr. Hilden on his show to briefly discuss the eye-tracking research.

For a full list of the exciting activities HCMC is offering at the 2016 Minnesota State Fair, go to hcmc.org/statefair.

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Abbott, Hennepin County Medical Center and University of Minnesota Collaborate to Launch the Nation’s Largest, Single-Center Prospective Study on Concussion and Traumatic Brain Injury

Researchers aim to develop a standard approach for evaluating and diagnosing traumatic brain injury, including concussion

  • Study will include various evaluation methods, including analysis of blood-based biomarkers, eye tracking and imaging to help classify severity of head injury

According to the Centers for Disease Control and Prevention (CDC), every year, there are an estimated 2.2 million emergency department visits for traumatic brain injuries (TBI).[i] For people with head injuries, quick evaluation and treatment are critical.

That’s why researchers at Hennepin County Medical Center (Minneapolis, Minn.) and the University of Minnesota are launching an innovative, comprehensive study in collaboration with Abbott to better identify the range of brain injuries among patients. Using multiple evaluation tools, including eye tracking, blood-based biomarkers, imaging and cognitive measures, scientists hope to develop a new standard approach to help classify brain injuries, including concussions, and provide the information needed to guide doctors’ treatment decisions.

“We know that there are different types of brain damage that can occur after trauma, whether it’s a mild concussion or a severe injury,” said neurosurgeon Uzma Samadani, M.D., Ph.D., Rockswold Kaplan Endowed Chair for TBI Research at Hennepin County Medical Center (HCMC), associate professor at the University of Minnesota and one of the lead investigators of the study. “Our goal with this study is to combine multiple assessment techniques to quickly assess the severity of brain injuries and enable clinicians to provide appropriate treatments.” Continue reading “Abbott, Hennepin County Medical Center and University of Minnesota Collaborate to Launch the Nation’s Largest, Single-Center Prospective Study on Concussion and Traumatic Brain Injury”

Eye Tracking Has High Sensitivity as a Biomarker for Concussion

Dr. Uzma Samadani
Dr. Uzma Samadani

Eye Tracking Detects Concussion with Sensitivity Comparable to that of Blood Tests for Heart Attack

New technology that tracks the eye movements of patients may be a more accurate measure of brain injury than any other diagnostic measurements currently in use, according to a study published in the journal Concussion. Dr. Uzma Samadani, who recently joined Hennepin County Medical Center, in collaboration with researchers at the Steven and Alexandra Cohen Veterans Center at NYU Langone Medical Center, developed the technology that can serve as a biomarker for concussion by tracking patients’ eye movements as they watch music videos.  

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Subject participating in eye tracking study

The eye tracking technology works by having patients watch a music video for 220 seconds while eye movements are measured using a tracking camera.  Videos used in the study ranged from Disney’s Puss in Boots to Wavin Flag by K’Naan.  Multiple measures of each eye’s movement, followed by comparisons of their positions over time are used to distinguish between normal subjects and those with concussion.

In the work, led by Uzma Samadani, MD PhD, Charles Marmar, MD, and Eugene Laska PhD, the investigators built a classifier based on 34 emergency room patients with brain injury and 34 uninjured healthy control subjects of similar age. A classifier is a mathematical model that converts a patient’s eye movement measures into a prediction of the concussive status of the individual. They then tested the models on a dataset of 255 subjects, of whom 8 had concussions, and found that the eye tracking test had an optimal sensitivity of 88% and specificity of 87%.

Typically, a classifier produces a score and a subject is classified as having a concussion if the score exceeds a predefined threshold value. The accuracy of a biomarker is measured by plotting the probability of a true versus false positivity at each possible threshold value and the Area Under the Curve (AUC) is computed. A perfect biomarker has an AUC of 1.00, while a worthless marker – no better than the chance toss of a coin – has an AUC of 0.50.  Most tests used clinically have AUC’s greater than 0.80.  For example, serum troponin, the most commonly performed blood test for heart attacks has an AUC ranging in various studies from 0.76 to 0.96.  In this study, the eye tracking based classifier had an AUC of 0.88, and a cross-validated AUC of 0.85.

According to Dr. Samadani, the major challenge for any technology proposed as a biomarker for concussion is first defining concussion.  “When doctors look for a biomarker for heart attack, it is relatively easy to check the accuracy of a potential candidate because they can perform a cardiac catheterization and confirm that the heart vessel is blocked and an attack has occurred.  There is no analogous capability with brain injury – there is no gold standard diagnostic, no blood test, and no imaging study for definitively concluding that a patient has experienced a concussion.  We use symptom severity scales and standardized cognitive examination assessments but the imperfect nature of these may result in incorrect subject classification. Potentially, eye tracking may be more accurate than it appears, because of its objective appraisal of a complicated process of coordination that may be impaired.”

The investigators defined concussion as (1) trauma to the head with a normal CT (computed tomography) scan of the brain, (2) symptom severity score of 40 or greater on SCAT3 testing and (3) standardized assessment of concussion (SAC) score less than 24.  The symptom severity score measures the self-reported severity of 22 concussion symptoms ranging from headache to dizziness and irritability.  The SAC measures orientation, memory, and concentration – capabilities which have some variability even among uninjured healthy control subjects.

In an accompanying editorial that also appears in the journal, Dr. Samadani proposes that eye tracking will help diagnose and classify brain injury and concussion, particularly in patients with elevated pressure inside their skulls and disruption of pathways in the brain that control eye movements.

“The ultimate goal for brain injury” said Dr. Samadani, “is to achieve the same level of diagnostic capability and care as currently exists for other medical conditions.  Right now when someone comes in to the emergency room with chest pain, doctors perform an EKG, blood test, imaging, and treatment.  With brain injury we need to be able to achieve the same level of care – to assess all aspects of the problem rigorously, classify, and treat accordingly.  We already know that there is much more to brain injury than what is seen on a CT scan.  Eye tracking tells us how well the brain is working regardless of how it looks, and represents the beginning of a solution to this problem.  It is non-invasive, inexpensive and extremely quick.  Testing does not require reading nor language skills which makes it useful for multiple patient populations.”

Commenting further on the study was Dr. David Cifu, the Herman J. Flax, M.D. Professor and Chair of Rehabilitation at Virginia Commonwealth University, Senior TBI Specialist with the U.S. Department of Veterans Affairs and Principal Investigator of the VA/Department of Defense Chronic Effects of NeuroTrauma Consortium.

“This innovative research by Samadani and colleagues highlights a novel approach to objectively and rapidly support the diagnosis of acute concussion using a novel technique of assessing eye tracking. This publication may represent the first step in the development of a more exacting method of diagnosing and monitoring recovery from traumatic brain injury. Computerized assessment of eye tracking may represent the first truly useful biomarker of TBI.”

Brain injury is the number one cause of death and disability in Americans under age 35, according to the U.S. Centers for Disease Control and Prevention. Every year, 1.4 million people suffer from a traumatic brain injury in the United States. Of those, 50,000 die and 235,000 require hospital admission.  Internationally it is a leading cause of death in India and China where access to radiographic diagnostics is also limited.

Dr. Samadani is the Rockswold Kaplan endowed chair for traumatic brain injury at Hennepin County Medical Center and an Associate Professor of Neurosurgery at the University of Minnesota.  Dr. Marmar is the Lucius N. Littauer Professor and Chair of the Department of Psychiatry at NYU Langone Medical Center and Director of its Cohen Veterans Center. Dr. Laska is a statistician at the Nathan Kline Institute for Psychiatric Research and a Research Professor of Psychiatry at the NYU School of Medicine.  Other co-authors of this study include Meng Li MA, Meng Qian PhD, Robert Ritlop M Eng, Radek Kolecki MS, Marleen Reyes BA, Lindsey Altomare BA, Je Yeong Sone, Aylin Adem, Paul Huang MD, Douglas Kondziolka MD, Stephen Wall MD, and Spiros Frangos MD. Technology described in this paper has been licensed to Oculogica Inc., a neurodiagnostic startup company in which NYU, Dr. Samadani and Robert Ritlop have an equity interest.

The work was supported in part by the Steven & Alexandra Cohen Veterans Center for the Study of Post-Traumatic Stress and Traumatic Brain Injury at NYU Langone.