Reverse King-Devick Test and History of Multiple Concussions

Plain-language summary

The purpose of this study is to examine the effects of concussion history and reading direction on baseline King- Devick Test (KDT) performance, a common component of sideline concussion assessments. The KDT is a timed assessment of saccades, or quick movements of the eyes between two points. This test is a form of rapid automatized naming and involved subjects reading digits arranged on a tablet screen as quickly and accurately as possible. The test has three progressively more challenging test "cards," as the horizontal guidelines between digits disappear from test card 1 to 2, and the vertical spacing between the lines of digits decreases from test card 2 to 3. KDT performance is evaluated in terms of both speed (duration to all three test cards) and the number of errors (digits read incorrectly or omitted). Previous studies have identified several factors that affect KDT performance aside from head injury, including age, sex, sleep deprivation, learning disabilities, and first languages other than English. History of concussion has not been shown to influence KDT performance. The investigators hypothesize that since the left-to-right (L-R) reading direction of the KDT is the same way in which to read English, the long-term effects of prior concussions on saccadic eye movements may be masked. The investigators want to answer the following three research questions: 1) What is the effect of KDT reading direction on baseline KDT performance? If the test is performed by reading digits in a right-to-left (R-L) direction, will KDT times be slower and the number of errors increase relative to a typical L-R KDT? 2) What is the effect of a history of multiple concussions on KDT performance relative to no history of concussion? 3) Is the R-L KDT more sensitive to a history of multiple concussions? The investigators hypothesize that individuals with a history of multiple concussions will perform significantly worse (longer test durations, more errors) than individuals with no concussion history on the R-L KDT. On the other hand, the investigators hypothesize that baseline performance on the traditional L-R KDT will not be able to discriminate individuals with a history of multiple concussions from those with no concussion history.

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