Comparison and utility of King-Devick and ImPACT® composite scores in adolescent concussion patients

The King-Devick (ICD) oculomotor test has recently been advocated for sideline diagnosis of concussion. Although visual processing and performance are often impaired in concussion patients, the utility of KD as a concussion diagnostic tool is not validated. Purpose: To examine the diagnostic value of KD, by comparing KD with post-concussion symptom scale (PCSS) and ImPACT (R) composite scores. We hypothesized that KD would be correlated with visual motor speed/memory (VMS, VIS) and reaction time (RI'), because all require cognitive visual processing. We also expected parallel changes in KD and PCSS across recovery. Methods: Thirty-five concussed individuals (12-19 y; 18 females, 17 males) were evaluated with PCSS, ImPACT composite and KD scores over four clinical visits (V). Results: LCD times improved with each visit (Delta V1-V2: 7.86 +/- 11.82; Delta V2-V3: 9.17 +/- 11.07; Delta V3-V4: 5.30 +/- 7.87 s) and paralleled improvements in PCSS (Delta V1-V2: 8.97 +/- 20.27; Delta V2-V3: 8.69 14.70; Delta V3-V4: 6.31 +/- 7.71), RT (Delta V1-V2: 0.05 +/- 021; Delta V2-V3: 0.09 +/- 0.19; Delta V3-V4 0.03 +/- 0.07) and VMS (Delta V1-V2: -5.27 +/- 6.98; Delta V2-V3: 2.61 +/- 6.48; Delta V3-V4: 2.35 +/- 5.22). Longer KD times were associated with slower RT (r = 0.67; P < 0.0001) and lower VMS (r = 0.70; P < 0.0001), respectively. Conclusion: Cognitive visual performance testing using KD has utility in concussion evaluation. Validation would further establish KD as an effective ancillary tool in longitudinal concussion management and research. (C) 2013 Elsevier B.V. All rights reserved.