ABSTRACT
UNLABELLED: This pilot study shows results of an experiment comparing reaction times (RTs) and attentional performance between an ADHD group of 30 children and 30 controls, both Spanish speaking. The experiment was carried out using the Seville computerized neuropsychological battery (SNB). OBJECTIVE: This study had two goals: One was to test sensitivity of SNB for attention deficits in ADHD and the second was to detect differences in RTs between ADHD and controls. Possible explanations and implications of such differences are also discussed. METHOD: SNB computerized system was used to assess RTs and accuracy, and alternate forms of continuous performance task were used. RESULTS: Results showed high sensitivity of some of the SNB tests, especially cancellation tests. RTs were significantly different between groups. CONCLUSION: SNB represents a helpful tool for detection of attention deficits, and RT indices represent the most significant variable in differentiation of both groups studied.
Subject(s)
Attention Deficit Disorder with Hyperactivity/physiopathology , Attention/physiology , Neuropsychological Tests/standards , Reaction Time/physiology , Task Performance and Analysis , Adolescent , Attention Deficit Disorder with Hyperactivity/psychology , Case-Control Studies , Child , Female , Humans , Inhibition, Psychological , Male , Pilot Projects , Psychometrics , Reproducibility of Results , Sensitivity and Specificity , Time FactorsABSTRACT
In this work we present the formulas for the calculation of exact three-center electron sharing indices (3c-ESI) and introduce two new approximate expressions for correlated wave functions. The 3c-ESI uses the third-order density, the diagonal of the third-order reduced density matrix, but the approximations suggested in this work only involve natural orbitals and occupancies. In addition, the first calculations of 3c-ESI using Valdemoro's, Nakatsuji's and Mazziotti's approximation for the third-order reduced density matrix are also presented for comparison. Our results on a test set of molecules, including 32 3c-ESI values, prove that the new approximation based on the cubic root of natural occupancies performs the best, yielding absolute errors below 0.07 and an average absolute error of 0.015. Furthemore, this approximation seems to be rather insensitive to the amount of electron correlation present in the system. This newly developed methodology provides a computational inexpensive method to calculate 3c-ESI from correlated wave functions and opens new avenues to approximate high-order reduced density matrices in other contexts, such as the contracted Schrödinger equation and the anti-Hermitian contracted Schrödinger equation.
