This review describes a research program aimed at evaluating the validity and specificity of the Wisconsin Card Sorting Test (WCST), one of the most widely used tests of prefrontal function in clinical and experimental neuropsychology. In spite of its extensive use, voices of caution have arisen against the use of WCST scores as direct markers of prefrontal damage or dysfunction. Adopting a cognitive neuroscience approach, the present research program integrates behavioral, physiological, and anatomical information to investigate the cognitive and neural mechanisms behind WCST performance. The results show that WCST performance evokes conspicuous physiological changes over frontal as well as posterior brain regions. Moreover, WCST scores confound very heterogeneous cognitive and neural processes. This confounding effect may have led many authors to overlook the relative importance of certain dysfunctional states such as those indexed by random errors. These findings strongly suggest that WCST scores cannot be regarded as valid nor specific markers of prefrontal lobe function. However, they do provide some relevant clues to update our current knowledge about prefrontal function. In the long run, the integrative approach of cognitive neuroscience may help us design and develop more valid and sensitive tools for neuropsychological assessment.

Neuropsychological assessment reveals that certain cognitive changes that take place during the neural development process may be associated with biopsychosocial issues. A substantial body of research has focused on cognitive development in children and adults, but few such studies have been carried out on adolescents. Therefore, research into the processing of neuropsychological functions in adolescents, taking into account the role of major socio-cultural factors such as school type (public vs. private), is highly relevant. The present study sought to assess whether differences in neuropsychological development exist between adolescent students of public (government-funded) and private schools. A total of 373 grade-matched students between the ages of 12 and 18, 190 from public schools and 183 from private schools, took part in the study. All subjects had no self-reported neurologic or psychiatric conditions and sensory disorders. The NEUPSILIN Brazilian Brief Neuropsychological Assessment Battery was administered to this sample. Comparison of mean scores (one-way ANCOVA with socioeconomic score and age as covariates) showed that adolescents attending private schools generally outperformed their public-school peers in tasks involving sustained attention, memory (working and visual), dictated writing, and constructional and reflective abilities. We conclude that school type should be taken into account during standardization of neuropsychological assessment instruments for adolescent and, probably, child populations.

Numerical cognition is based on two components - number processing and calculation. Its development is influenced by biological, cognitive, educational, and cultural factors. The objectives of the present study were to: i) assess number processing and calculation in Brazilian children aged 7-12 years from public schools using the Zareki-R (Battery of neuropsychological tests for number processing and calculation in children, Revised; von Aster & Dellatolas, 2006) in order to obtain normative data for Portuguese speakers; ii) identify how environment, age, and gender influences the development of these mathematical skills; iii) investigate the construct validity of the Zareki-R by the contrast with the Arithmetic subtest of WISC-III. The sample included 172 children, both genders, divided in two groups: urban (N = 119) and rural (N = 53) assessed by the Zareki-R. Rural children presented lower scores in one aspect of number processing; children aged 7-8 years demonstrated an inferior global score than older; boys presented a superior performance in both number processing and calculation. Construct validity of Zareki-R was demonstrated by high to moderate correlations with Arithmetic subtest of WISC-III. The Zareki-R therefore is a suitable instrument to assess the development of mathematical skills, which is influenced by factors such as environment, age, and gender.