Abstract des Autors

Background: Reaction tests are a part of the neuropsychological assessment of the individual. The design of these tests and selection of the appropriate measures of reaction time (RT) should come out from the distribution qualities of RTs. According to the newer general theory of RT distribution, the quality of RTs also depends on the specific properties of a reaction task. Objective: The aim of the study was to examine the dependency of RT distribution on an amount of processed information in a visual reaction test, and to verify the stability of RT distribution between two series of RTs in male adolescents. Methods: 25 male adolescents, aged 17.1 +/- 1.1 years, performed four different eye-hand visual reaction tests which differed in a number of choices - simple reaction test (RT1), two, three and four-choice RT tests (RT2, RT3, RT4). Each test involved 2 series with 20 reaction trials in each series, using the computer-based reactometer device. The first, second and third moments of the RT distribution were assessed - the measures of central tendency (mean, median), variability (% CV, median absolute deviation/median ratio - MAD/Mdn, interquartile range) and normality (Kolmogorov-Smirnov test, skewness and kurtosis coefficient α and β). Significance of differences of RTs was assessed by the Wilcoxon test (α = .05). Results: The analysis showed the non-Gaussian distributions of RTs (α = .01) with the skew to the right (α = 1.18-4.38) and leptocurtic distribution (β = 1.89-34.15) in all types of the RT tests. The measures of RT variability % CV and MAD/Mdn (%) were lower for the RT1 test as compared to the RT2, RT3 and RT4 tests. No significant differences in RTs measured in the 1st and 2nd series of trials were found in the RT1 test and RT2 test in contrast to significantly shorter RTs in the 2nd series of trials in the RT3 test and RT4 test (p = .006 and p < .001). RTs measured in the 2nd series of trials of RT1, RT2 and RT4 tests manifested distribution with a higher skewness to the right and higher peakedness than the RTs in the 1st series. Conclusions: The study supported the hypothesis on asymmetric distribution of RTs, specifically when measured in the both eye-hand visual simple and multiple-choice reaction tasks with two up to four choices. Thus, the nonparametric statistics show to be more appropriate for analysis of RTs than the parametric statistics. For both clinical and research purposes, the two series of twenty reaction trials in a computer-based test can provide a sufficient number of the RT data for reliable assessment of visual simple and choice-reaction abilities in the male adolescents. Verf.-Referat