Reproducibility of computer based neuropsychological testing among Norwegian elite football players

Background: Head injuries account for 4-22% of all football injuries. The rate of brain injuries is difficult to assess, due to the problem of defining and grading concussion. Thus computerised testing programs for cognitive function have been developed. Objective: To assess the reliability of a computerised neuropsychological test battery (CogSport) among Norwegian professional football players. Methods: Norwegian professional football league players (90.3% participation) performed two consecutive baseline Cogsport tests before the 2004 season. CogSport consists of seven different subtasks: simple reaction time (SRT), choice reaction time (ChRT), congruent reaction time (CgRT), monitoring (MON), one-back (OBK), matching (Match) and learning (Learn). Results: There was a small but significant improvement from repeated testing for the reaction time measurements of all seven subtasks (SRT: 0.7%, ChRT: 0.4%, CgRT: 1.2%, MON: 1.3%, OBK: 2.7%, Match: 2.0%, Learn: 1.1%). The coefficient of variation (CV) ranged from 1.0% to 2.7%; corresponding intraclass correlation coefficients ranged from 0.45 (0.34 to 0.55) to 0.79 (0.74 to 0.84). The standard deviation data showed higher CVs, ranging from 3.7% (Learn) to 14.2% (SRT). Thus, the variance decreased wit increasing complexity of the task. The accuracy data displayed uniformly high CV (10.4-12.2) and corresponding low intraclass correlation coefficient (0.14 (0.01 to 0.26) to 0.31 (0.19 to 0.42)). Conclusion: The reproducibility for the mean reaction time measures was excellent, but less good for measures of accuracy and consistency. Consecutive testing revealed a slight learning effect from test 1 to test 2, and double baseline testing is recommended to minimise this effect.