Figure 2. . Demonstration and test cards for the King-Devick test, a candidate rapid sideline screening for concussion based on speed of rapid number naming.

To perform the King-Devick test, participants are asked to read the numbers on each card from left to right as quickly as possible, but without making any errors. Following completion of the demonstration card (upper left), subjects are then asked to read each of the three test cards in the same manner. The times required to complete each card are recorded in seconds using a stopwatch. The sum of the three test card time scores constitutes the summary score for the entire test, the King-Devick time score. Numbers of errors made in reading the test cards are also recorded; misspeaks on numbers are recorded as errors only if the subject does not immediately correct the mistake before going on to the next number.