The SUN test of vision: Investigation in healthy volunteers and comparison to the mobile universal lexicon evaluation system (MULES)

Objective: Tests of rapid automatized naming (RAN) have been used for decades to evaluate neurological conditions. RAN tests require extensive brain pathways involving visual perception, memory, eye movements and language. To the extent that different naming tasks capture varied visual pathways and related networks, we developed the Staggered Uneven Number (SUN) test of rapid number naming to complement existing RAN tests, such as the Mobile Universal Lexicon Evaluation System (MULES). The purpose of this investigation was to determine values for time scores for SUN, and to compare test characteristics between SUN and MULES. Methods: We administered the SUN and MULES tests to healthy adult volunteers in a research office setting. MULES consists of 54 color photographs; the SUN includes 145 single- and multi-digit numbers. Participants are asked to name each number or picture aloud. Results: Among 54 healthy participants, aged 33 ± 13 years (range 20–66), the average SUN time score was 45.2 ± 8.3 s (range 30–66). MULES test times were 37.4 ± 9.9 s (range 20–68). SUN and MULES time scores did not differ by gender, but were greater (worse) among older participants for MULES (r_s = 0.43, P = .001). Learning effects between first and second trials were greater for the MULES; participants improved (reduced) their time scores between trials by 5% on SUN and 16% for MULES (P < .0001, Wilcoxon signed-rank test). Conclusion: The SUN is a new vision-based test that complements presently available picture- and number-based RAN tests. These assessments may require different brain pathways and networks for visual processing, visual memory, language and eye movements.