Characteristics of the King-Devick test in the assessment of concussed patients in the subacute and later stages after injury

Abstract

Although the King-Devick (K-D) test has been used frequently in assessing sports related concussion early after injury, its characteristics over time after injury and in patients with prolonged persistent symptoms are unknown. The purpose of this paper was to: evaluate the ability of the K-D Test to distinguish patients seen early after concussion from those with symptoms persisting more than 3 months compared to controls, assess changes in the K-D test times over time after concussion, and determine the relationship of K-D times to the Stroop Color and Word Test scores. We performed cross-sectional comparisons of patients with recent concussive brain injury (acute group) and those with symptoms persisting more than 3 months to healthy controls on the K-D test, the Sports Concussion Assessment Tool 3 (SCAT3), and the Stroop Color and Word Test. Longitudinal comparisons of the acute group over time within the first month after injury were also made. Post-concussive syndrome (PCS) patients had significantly higher K-D times compared to controls (p = 0.01), while the acute group did not differ from controls(p = 0.33). K-D times at the second visit for the acute group were similar to those of controls (54.7 vs. 49.6, p = 0.31). While SCAT3 scores improved over time in the acute group, the K-D scores did not change between the first and second visit (55.2 vs. 54.7, p = 0.94). K-D scores correlated significantly with the Stroop scores for all three participant groups. The K-D test is likely useful very early after concussion in conjunction with baseline scores, and while scores in PCS patients remain elevated, they can be confounded by factors such as pre-morbid depression and medication use. High correlations with Stroop scores also suggest that performance on the K-D test can by proxy provide additional insight about cognitive function and predict performance on more cognitively demanding tasks.

Spotlight on the Developmental Eye Movement (DEM) Test

“…The DEM test has demonstrated its use in developmental-age applications, compared to King Devick which has been used in stroke, sport, and concussion. [65][66][67] Nevertheless, since research and application cannot be limited, these differences in clinical use have become less significant, 22,68 and DEM and KD could coexist in the same field of application.…”

The King-Devick test in an outpatient concussion clinic: Assessing the diagnostic and prognostic value of a vision test in conjunction with exercise testing among acutely concussed adolescents

“…Relatively few studies have evaluated the K-D test in an outpatient clinical setting. Subotic et al [24] assessed the diagnostic value of the K-D test in a cross-sectional comparison among acutely concussed patients, persistent post-concussive syndrome (PPCS) patients, and in healthy controls. PPCS patients took longer than healthy controls to complete the K-D test but participants with PPCS did not differ from acutely concussed patients and no differences were found between acutely concussed patients and controls.…”

“…PPCS patients took longer than healthy controls to complete the K-D test but participants with PPCS did not differ from acutely concussed patients and no differences were found between acutely concussed patients and controls. The authors concluded that the K-D test has more assessment value immediately following a concussive hit on the sideline and was most useful when athletes had pre-injury baseline scores [24]. Unfortunately, baseline K-D test scores are not available for every athlete.…”

Serum SNTF, a Surrogate Marker of Axonal Injury, Is Prognostic for Lasting Brain Dysfunction in Mild TBI Treated in the Emergency Department

“…The association between serum SNTF elevations and the lasting effects of mTBI on cognitive performance is complex, with many tests failing to uncover any significant prognostic relationship. This issue is complicated by the well-established influences of subject intelligence level and degree of education on performance of a number of cognitive tests (39)(40)(41)(42)(43)(44)(45)(46)(61)(62)(63)(64)(65)(66)(67). When applying tests in which performance varies widely across cases independently of mTBI, it can be challenging to discern the long-lasting effects of the injury itself.…”