Diurnal variation in a visual-motor coordination test in healthy humans

Before a rehabilitation therapy, a variety of tests are used to investigate the sensory-motor system condition of the patient. Since some parameters evaluated by those tests exhibit temporal variations, this work was conducted to investigate the performance of healthy subjects at different times during the day in a visual-motor coordination test, consisting in perfectly drawing a diagonal in as many 1 x 1 cm squares as possible during a 1 min interval. The test was applied to 14 diurnally active subjects (7 men and 7 women; 18-25 years old) in sessions at 3 h intervals from 06:00 to 00:00 h during four days divided in two blocks of two days each. Oral temperature was digitally measured before each test session in order to check the synchronization of the subjects. The results showed a significant difference (Anova, p < 0.001) between sexes with women (122.4 +/- 16.4 sq/min; x +/- SD) being faster than men (110.1 +/- 22.8 sq/min), although daily profiles for both sexes were quite similar with better performances occurring between 09:00 and 15:00 h. Single Cosinor analysis detected significant circadian rhythmicity for 5 individuals (1 men and 4 women) with acrophases distributed between 09:15 and 13:03 h. The profiles for oral temperature and test performance were very similar with significant correlation (R = 0.26, p = 0.0002) only for men. The variation coefficient shows lower values at 15:00 h for both sexes, suggesting this time as the appropriate moment to apply the test.