King-Devick Test
The King-Devick Test (K-D Test) is defined by Mosby’s Medical Dictionary as a tool for evaluation of saccade, consisting of a series of charts of numbers. The charts become progressively more difficult to read in a flowing manner because of increasing space between the numbers. Both errors in reading and speed of reading are included in deriving a score. Saccades are quick, simultaneous movements of both eyes.
The King-Devick Test was developed in 1976 by Alan King, O.D. and Steven Devick, O.D. as an indicator of saccadic performance as it relates to reading ability. In 1983, a sample of 1202 children ages six to fourteen was screened using the K-D Test. The study done by the State University of New York (SUNY) concluded that the test was quick and easy to score and could be administered by non eye care practitioners. For more than 25 years, the King-Devick Test has been a proven indicator of oculomotor inefficiencies regarding eye movements during reading. The King-Devick Test (K-D Test) is utilized as a tool in schools, eye care and psychologist offices to help detect learning disabilities, including dyslexia.
The King-Devick Test (K-D Test) is an objective, physical test based on the measurement of the speed of Rapid Number Naming (reading aloud single digit numbers from three test cards), and captures impairment of eye movements, attention language and other correlates of suboptimal brain function. The sum of the three test card time scores constitutes the summary score for the entire test. The test can be administered in two minutes or less. In 2011, researchers discovered a link between King-Devick Test and sideline remove-from-play concussion screening.
Formats
Concussion
In 2010, researchers from the University of Pennsylvania Perelman School of Medicine investigated the King-Devick Test as a potential rapid sideline screening test for concussion in a cohort of 39 boxers and mixed martial arts (MMA) fighters. The K-D Test was administered pre-fight and post-fight. Post-fight K-D time scores were significantly higher (worse) for participants who had head trauma during the match compared to their pre-fight scores. The researchers concluded that the King-Devick Test is an accurate and reliable method for identifying athletes with head trauma, and is a strong candidate rapid sideline screening test for concussion.
In 2010, a longitudinal study was conducted involving 219 athletes from the University of Pennsylvania varsity football, sprint football, women’s and men’s soccer and basketball teams. Each subject underwent baseline King-Devick (K-D testing) prior to the start of the 2010-11 playing season. For athletes who had concussions during the season, K-D testing was administered immediately on the sidelines and changes in score from their baseline were determined. For the 10 athletes who had concussions, K-D testing showed worsening from their baseline score/time. This study of collegiate athletes provided further evidence in support of the K-D Test as a strong candidate rapid sideline visual screening tool for concussion.
In August 2011, Ralph Nader publicly called for the mandatory implementation of the King-Devick Concussion test in high school and youth sports. “Too many sports organizations, from little leagues to the professional level, continue to have their heads in the sand when it comes to concussion safety and prevention measures, said Nader. “The growing mound of research showing the often devastating long-term effects of sports-related brain trauma demands that we take proactive measures to protect our young athletes’ brains. The King-Devick test is a simple and objective sideline screening test that can be administered by coaches, trainers and parents.” Some sports medicine doctors and trainers have called the King-Devick test the “missing link” for practical sideline management of concussions due to its simplicity, objectivity and effectiveness.
In 2012, the K-D test was studied in the setting of amateur rugby athletes over the course of one competitive season in New Zealand. In this pilot study of 50 rugby athletes (mean age 19.3 years ± 4.0 standard deviation), the K-D test was able to accurately identify three players with witnessed head trauma who were subsequently diagnosed with concussion. By testing all athletes post-match, the K-D test was able to identify two players that had sustained a concussive injury that was neither reported nor witnessed. This pilot study revealed that the K-D test detected un-witnessed concussions by simply testing players after contact play. Additional larger scale studies are on-going to confirm the results found in this pilot study.
In 2012, the K-D test was included in a comprehensive review comparing sports-concussion testing tools. The review proposed that the K-D test has the potential to capture brain impairment not observed in standard neurocognitive testing. It reported that the K-D test is administrable in the quickest amount of time (less than 2 minutes as compared to others requiring upwards of 20 minutes for test administration). The K-D test does not require a medical professional to administer, assesses more the 50% of the brain’s pathways and gives a definite, and gives an objective outcome measure making it practical for sideline use at all levels of sports.
Before the fall football season of 2012, 80 King-Devick test kits were donated to the Chicago Public Schools (CPS) high school football programs by the Dave Duerson Foundation to ensure that every CPS football team had an effective sideline remove-from-play concussion screening tool. The donation was made in an effort to Contribute to a safer game of football in the memory of Dave Duerson who was a former Chicago Bears football player.
The King-Devick Test for remove-from-play concussion screening is a two-minute test that requires an athlete to read single digit numbers displayed on test cards, a computer, or an iPad and can be administered by coaches, athletic trainers, medical professionals and parents. Athletes must create a preseason or pregame baseline. A baseline is the cumulative amount of time it takes to read the three test cards aloud. For baseline testing, the entire test should be administered twice. The fastest cumulative time of the two attempts with no errors is considered to be the baseline. Immediately or soon after a suspected head trauma, the athlete is given the King-Devick Test once and if the time needed to complete the test is any longer than the athlete’s baseline test time and/or if there are errors, the athlete should be removed-from-play and should be evaluated by a licensed professional. The test has relevance to sports such as: football, hockey, soccer, basketball, lacrosse, rugby, and all other contact or collision activities. The King-Devick Test (K-D Test) is used in many school athletic programs. The test is also used at the professional level in the National Hockey League (NHL), Major League Soccer (MLS), and professional arena football.
Reading
The King-Devick saccadic eye movement test is an acceptable test instrument for eye movement dysfunctions. The test is easy to administer and has been incorporated in many visual screening protocol used by non-professionals. The test is also used in formal investigation into understanding learning related visual problems. Children attending New York Public schools were screened using the King-Devick Test (K-D Test) and there was a significant correlation with their citywide achievement test scores and was significant for predicting those students in the lower 25% of the class for all grades.
The more educators can be educated in accurate detection of vision problems; more can be done in helping children achieve academically as well. Saccadic eye movement deficiencies can be improved with training and correspondingly reading performance can be improved. Performance on the King-Devick Test is related to reading performance as young as 5 and 6 year olds in kindergarten. In addition, the King-Devick Test has shown to be statistically and practically significant in the reading development in adults.
The King-Devick Test is a readily available and useful tool for assessing residual oculomotor functions, and its components can also be used for in-school eye-movement training purposes. The King-Devick Test comprises one demonstration card and three test cards, which contain several rows of random numbers that become progressively more difficult to follow with either spotting or tracking skills. The test is scored based on age, speed and accuracy. Participants are asked to read the numbers on the three test cards from left to right as quickly as possible without making any errors. The sum of the three test card times, along with number of errors reading the test cards are recorded. The score is compared to pass/fail normative data for subjects from 6 years old through adulthood.
In addition to detecting learning disabilities, the King-Devick Test (K-D Test) has been studied as an in-school remediation tool to improve reading fluency. Students in grades 2-4 were screened for reading inefficiency using the King-Devick Test (K-D Test). Subjects who failed the test were entered into the study. A verbalized reading evaluation was administered to all subjects to serve as a measure of baseline and post-treatment reading performance. The treatment consisted of Rapid Number Naming therapy using proprietary King-Devick Test LLC software. The results of the study showed a statistically significant improvement in reading fluency among individuals who underwent Rapid Number Naming therapy in school for three 20 minute sessions (one hour total) per week for just six weeks.
Severe Sleep Deprivation Functionality Prediction
In April 2012, a study was published investigating the effect of severe sleep deprivation on the speed and accuracy of eye movements as measured by the King-Devick (K-D) test. Neurology residents and staff from the University of Pennsylvania Health System underwent baseline K-D testing followed by post call K-D testing. The conclusion of the study supported that the K-D test is sensitive to the effects of severe sleep deprivation on cognitive functioning, including rapid eye movements, concentration, and language function. Severe fatigue appears to reduce the degree of improvement typically observed in K-D test.
Multiple Sclerosis Quality of Life Measure
The King-Devick (K-D) Test of Rapid Eye Movements: A Bedside Correlate of Disability and Quality of Life in Multiple Sclerosis was a distinguished poster during poster presentations at the 38th Annual North American Neuro-Ophthalmology Society Meeting linking the King-Devick Test to multiple sclerosis.