Toward a model of neuropsychological activity.

The main purpose of this research was to establish the intercorrelations existing among different psychological and neuropsychological test scores in a normal and homogeneous population. A second purpose was to attempt further step in the component analysis of cognitive activity measured by means of neuropsychological tests. A comprehensive neuropsychological test battery was assembled and individually administered to a 300-subject sample, aged 17-25 year-old. All of them were right-handed male university students. The battery included some basic neuropsychological tests directed to assess language, calculation abilities, spatial cognition, praxic abilities, memory, perceptual abilities, and executive functions. In addition, the Wechsler Adult Intelligence Scale was administered. Forty-one different scores were calculated. Correlations among the different test scores were analyzed. It was found that some of the tests presented a quite complex intecorrelation system, whereas other tests presented few or no significant correlations. Mathematical ability tests and orthography knowledge represented the best predictors of Full Scale IQ. A factor analysis with varimax rotation disclosed five factors (verbal, visuoperceptual, executive function, fine movements, and memory) accounting for 63.6% of the total variance. Implications of these results for a neuropsychological model about brain organization of cognition were analyzed.