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King-Devick Concussion Screening Test (K-D Test)
Please visit this website for more information about the instrument: King Devick Test for Concussion.
Supplemental: Sport-Related Concussion (SRC)
Short Description of Instrument
The King Devick Test for Concussion is a screening tool used to determine neurological functionality. The test measures planning and execution of saccades and rapid number naming to detect the presence of functional neurological deficits. It has proven to be an accurate method of measuring concussions in athletes and it is frequently used in this capacity.
Participants are required to read a series of single digit numbers displayed on 3 test cards on an i-Pad device. The time required to complete each card is recorded in seconds and a cumulative score is established.
Sport-Related Concussion (SRC) Related: Population of interest: Adolescents and adults with SRC.
Advantages: The KD test has been shown to be responsive to the effects of SRC (medically confirmed or otherwise) and is easy to use and interpret.  Many notable studies in the acute phase of concussion assessment have used assessment. Four clilnically-relevant studies in the subacute/chronic phase.  
Limitations: It is not as easy as it used to be. The cards are no longer being sold. The program is available only as a licensed IPad-based product and thus not readily available to the full spectrum of potential users. It is well-validated for the diagnosis of concussion at the time of or within hours of injury but less so for the subacute (>72 hours) phase and for concussion recovery.
Timeframe best used: within minutes to hours of concussion. Therefore, it is most useful in the acute phase of concussion. It has been used in 4 other clinically-relevant studies from 1 day post concussion to > 30 days post concussion.  In 2 of the 4 studies, K-D performance returned to baseline within 14–21 days of injury. In one study (Tjarks BJ et al. Journal of the Neurological Sciences  2013) K-D performance (without a baseline comparison), along with cognitive and visual memeory scores and symptoms on the ImPact test, tracked recovery over 30 (or more) days after injury, suggesting that the K-D test may also be useful to track concussion recovery.
Galetta KM, Barrett J, Allen M, Madda F, Delicata D, Tennant AT, Branas CC, Maguire MG, Messner LV, Devick S, Galetta SL, Balcer LJ. The King-Devick test as a determinant of head trauma and concussion in boxers and MMA fighters. Neurology. 2011;76(17):1456–1462.  
King D, Gissane C, Hume PA, Flaws M. The King-Devick test was useful in management of concussion in amateur rugby union and rugby league in New Zealand. J Neurol Sci. 2015;351(1-2):58–64.  
King D, Brughelli M, Hume P, et al. Concussions in amateur rugby union identified with the use of a rapid visual screening tool. J Neurol Sci. 2013;326(1-2):59–63.
Benedict PA, Baner NV, Harrold GK, Moehringer N, Hasanaj L, Serrano LP, Sproul M, Pagnotta G, Cardone DA, Flanagan SR, Rucker J, Galetta SL, Balcer LJ. Gender and age predict outcomes of cognitive, balance and vision testing in a multidisciplinary concussion center. J Neurol Sci. 2015;353(1-2):111–115.
Tjarks BJ, Dorman JC, Valentine VD, Munce TA, Thompson PA, Kindt SL, Bergeron MF. Comparison and utility of King-Devick and ImPACT® composite scores inadolescent concussion patients. J Neurol Sci. 2013;334(1-2):148–153.
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