How Long Does the King-Devick Test Take?

Why King-Devick Test Times Can Vary by Age

Age can change King-Devick Test time because the test depends on rapid number naming, eye movements, attention, and reading fluency, which are still developing in children and may slow later in adulthood. In a study of 483 children and adolescents ages 8 to 18, baseline times improved steadily from ages 8 through 14, then began to level off; across ages 8 to 18, scores changed by about 31 seconds, showing why a younger child's result shouldn't be judged the same way as an older teen's. Another large youth study found that baseline scores became faster by about 1.4 seconds per age group, which is why repeat baseline testing can matter as children grow. Adult scores can vary too: in one adult sample ages 18 to 86, test times ranged from about 26 to 76 seconds, with an average of 42.2 seconds, and times tended to get slower with age, especially after midlife. For that reason, the fairest comparison is usually against the person's own baseline rather than a single normal number for everyone.

How Reading Errors Affect King-Devick Test Results

Reading errors can affect King-Devick Test results because the test is not based on speed alone; missed, skipped, repeated, or incorrectly read numbers may suggest trouble with visual tracking, attention, language processing, or rapid eye movements. Even if someone finishes quickly, uncorrected errors can still make the result concerning, since published guidance treats a slower-than-baseline time or errors after a suspected head injury as a reason for removal from play and medical evaluation.

For younger children, errors may be more common during baseline testing; one testing protocol notes that children under 10 who make 5 or more uncorrected errors may need a shortened card set and retesting so their baseline is still usable. Research in professional sport also shows why errors should be read with context: errors by themselves had low sensitivity at about 11.7%, but higher specificity at about 86.3%, meaning errors may not catch every concussion but can still be a meaningful warning sign when they appear.

What Happens If Your King-Devick Test Time Gets Worse?

When a King-Devick Test time gets worse, it means the person took longer than their own baseline to finish rapid number naming, which may point to a new problem with eye movements, attention, processing speed, or language after a head impact. In one adolescent hockey study, all 20 athletes with concussions had more than a 5-second slowdown from baseline, with an average worsening of 7.4 seconds, showing why even a few extra seconds can matter in the right context. A newer diagnostic study found that any increase in time from baseline detected about 81% of concussions, but its specificity was 56%, so a slower result is useful as a warning sign, not a standalone diagnosis. In practical terms, a worse King-Devick Test time after a suspected injury should lead to removal from play, no same-day return, and a fuller medical evaluation using symptom checks, balance testing, neurologic assessment, and clinical judgment. A normal or improved time also doesn't fully rule out a concussion, so the result should be read alongside the person's symptoms and the details of the injury.

King-Devick Test Timing for Athletes, Children, and Adults

King-Devick Test timing can look different for athletes, children, and adults because each group brings different baseline speed, reading fluency, attention control, and visual tracking habits into the test. In youth and collegiate athlete data, younger athletes averaged about 60.6 seconds, while collegiate athletes averaged about 38.4 seconds, so a fast or slow result depends heavily on the person's age and comparison group. Children and teens can show wide timing changes as they grow; one study of 483 participants ages 8 to 18 found about a 31-second difference across that age span, with the biggest speed gains happening before the mid-teen years. Adult timing is not one-size-fits-all either: in one adult sample ages 18 to 86, completion times ranged from about 26.2 to 76 seconds, with an average of 42.2 seconds. For that reason, King-Devick Test timing is most useful when it's compared against the person's own recent baseline, rather than judged against a single number for athletes, children, or adults.