The Mobile Universal Lexicon Evaluation System (MULES) is a test of rapid picture naming under investigation.  Recent changes to the MULES test were made to improve ease of use on the sidelines, including re-sizing to a laminated 8.5x11-inch double-sided version.  We examined feasibility for MULES testing in youth, collegiate and professional athletes for pre-season baseline testing and for sideline post-injury assessment.

Measures of rapid automatic naming (RAN) have been used for over 50 years to capture vision-based aspects of cognition.  MULES was designed as a series of 54 grouped color photographs (fruits, random objects, animals) that integrates saccades, color perception and contextual object identification.  

Among 740 athletes (age 17±5 years, range 6-37, 42% female), average test times at baseline were 42.1±12.4 seconds. The most common sports were ice hockey (27%), soccer (17%) and football (10%).  Age was a predictor of MULES test times, with longer times noted for younger participants (P<0.001, linear regression).  Consistent with other timed performance measures, significant learning effects were noted for the MULES during baseline testing with trial 1 test times (50.1±14.1 seconds) exceeding those for trial 2 (42.3±12.5 seconds, P<0.0001, paired t-test).  Among 13 athletes with concussion during the sports seasons (age 18±3 years) all showed prolongation (worsening) of MULES scores from pre-season baseline (median 14±4 seconds, range 1.0-164.2, P=0.002, Wilcoxon signed-rank test).  

The MULES test is feasibly administered by non-medical personnel among athletes within organizations ranging from recreational leagues to high schools to college teams.  Within this diverse athlete cohort, the MULES shows evidence of capacity to identify athletes with sports-related concussion.