The blink reflex has been shown to be sensitive to a number of neurological insults, including traumatic brain injury, Parkinson's disease and Huntington's disease, suggesting that it could be a useful tool for neurological assessment. Although electromyography (EMG)-derived time metrics were used to analyze the blink reflex as early as the 1950s, quantitative assessment of the blink response was never adopted widely in clinical practice, in part because existing technology was somewhat cumbersome and uncomfortable. Moreover, EMG is a highly sensitive technology requiring strict ambient parameters and was not easily performed outside the health care setting, limiting the applications of the blink reflex as a diagnostic indicator of neurological health. Advances in video and computer technology -- including improved digital image capture, higher frame speeds and higher processing speeds -- have now put portable, noninvasive, quantitative assessment of the blink within reach.
The Blink Reflexometer, a portable device developed by the Zucker Institute for Applied Neurosciences at the Medical University of South Carolina that has since been licensed to BLINKtbi (Charleston, SC), uses high-speed video to capture and quantitatively analyze a series of blinks that it stimulates with puffs of air. The device analyzes the recorded blinks based on data acquired from decades of blink reflex research to determine if the patient has experienced neurological insult.
In a validation study in ten healthy college students, the results of which were reported in an article published online December 12, 2017 by the IEEE Journal of Translational Engineering in Health and Medicine, a team of investigators at the Medical University of South Carolina and The Citadel obtained blink measurements for ten healthy college students using the Blink Reflexometer and compared them to published measurements obtained with EMG. Three parameters were measured: latency (time between stimulus to first eyelid movement), differential latency (difference in start time between eyelids) and duration (time from start of eyelid movement to eyelid open). Latency and duration measurements obtained with the Blink Reflexometer were in line with published results; only differential latency fell outside of published ranges. These findings suggest that the Blink Reflexometer can provide quantitative measurements of the blink that are on par with those obtained via EMG.
"We are excited to be able to take something that had been qualitative and make it quantitative and objective," says lead author Nancey Trevanian Tsai, M.D. "We talk about metrics all the time in medicine but when you are actually able to provide quantitative, objective data, it's a game changer. It's analogous to the difference between saying someone is feverish to measuring the patient's temperature, an objective measurement, with a thermometer."
This study was based on a small number of young, healthy patients, so larger studies in participants that better represent the general populace will be required. More studies will also be required to verify the usefulness of the blink reflex and of this novel device for neurological assessment in each area of clinical need. Although the Blink Reflexometer can measure changes in the blink reflex, it does not provide information on the underlying causes of those changes.
If the findings of those studies are promising, the device could make it possible to include the blink reflex as a metric or vital sign in medical examination. Because it is portable, it could be taken into the field for on-site neurological assessments. Potential uses are field-side assessment of athletes for concussion or field sobriety tests for marijuana intoxication.
The Blink Relexometer is patent pending and available for investigational use only. The Medical University of South Carolina, the Zucker Institute for Applied Neurosciences and authors Tsai, Semler and Kothera have financial interest in the technology.
Founded in 1824 in Charleston, The Medical University of South Carolina is the oldest medical school in the South. Today, MUSC continues the tradition of excellence in education, research, and patient care. MUSC educates and trains more than 3,000 students and residents in six colleges (Dental Medicine, Graduate Studies, Health Professions, Medicine, Nursing, and Pharmacy), and has nearly 13,000 employees, including approximately 1,500 faculty members. As the largest non-federal employer in Charleston, the university and its affiliates have collective annual budgets in excess of $2.2 billion, with an annual economic impact of more than $3.8 billion and annual research funding in excess of $250 million. MUSC operates a 700-bed medical center, which includes a nationally recognized children's hospital, the Ashley River Tower (cardiovascular, digestive disease, and surgical oncology), Hollings Cancer Center (a National Cancer Institute-designated center), Level I trauma center, Institute of Psychiatry, and the state's only transplant center. In 2016, U.S. News & World Report named MUSC Health the number one hospital in South Carolina. For more information on academic programs or clinical services, visit musc.edu. For more information on hospital patient services, visit muschealth.org.
About the Zucker Institute for Applied Neurosciences
The Zucker Institute for Applied Neurosciences (ZIAN) is a non-profit technology accelerator embedded within the Medical University of South Carolina (MUSC) Department of Neurosurgery in Charleston, S.C. Established in 2013, ZIAN's mission is to "apply scientific and clinical discovery to concrete neuroscience problems and develop technological advancements that will make a difference in patients' lives." ZIAN's management and development team includes a renowned faculty of neuroscience clinicians and scientists, along with talented engineers and business development experts. The team collaborates with industry partners to swiftly and efficiently meet the increasing patient and practitioner demand for breakthroughs in treatment across the spectrum of neurologic disorders. ZIAN is currently developing technologies in the areas of neurological assessment, spine surgery, imaging, neurovascular interventions and treatments for brain tumors and spinal cord injury. To learn more about ZIAN, call 843- 792-5406 or visit ianeuro.org.