A conceptual nervous system for the neuropsychological diagnosis

Abstract

Although tests are an important aspect of the neuropsychological practice, neuropsychology is not limited to nomothetically validated tests. The objective of this paper is to examine, from the perspective of a “conceptual nervous system”, meta-diagnostic aspects of neuropsychology, which go beyond testing. The nomothetic approach to diagnosis is compared to an idiographic one, in which diagnosis is conceived as hypothesis testing according to information processing models. The construction and use of these models is plausible due to the modular organization of the mental system, evidenced by double-dissociations. In this study, the diagnostic process in neuropsychology is examined, particularly the functional and topographic diagnoses. In most cases, the topographic diagnosis is only virtual, and uses the conceptual nervous system to correlate the observed functional deficit to lesional loci established in the literature. The models of information processing must be anatomically specified, since they will be used to establish structural-functional correlations. The human brain-mind can be seen as a computational system, in which cognition is located between perception (input) and action (output). Mental functions are divided into material (content possessing) and formal (organizers of mental processes). Brain lesions with different causes and locations disrupt these mental functions in different ways. The traditional nomothetic model of neuropsychological diagnosis must be complemented by an idiographic approach, testing hypotheses based on a model of structure-function correlation that is adequate to the anatomo-clinical relations observed in the different lesions.

Key words: neuropsychology, structural-functional correlation, cognition.