A conceptual framework in the study of neuropsychological development in epidemiological studies.

Background: A wide range of neuropsychological development outcomes in children are currently measured in a large number of birth cohort and child cohort studies.

Methods: We summarized neuropsychological development assessment protocols from a number of birth cohort studies, reviews and specific books on child neuropsychology into a unifying conceptual framework.

Results: We suggest that neuropsychological development can be differentiated into two levels, i.e. functional and clinical. The functional level includes the skills, abilities, capacities and knowledge acquired during maturation of the brain as a result of the development of neural networks. It can be further divided into cognitive, psychomotor and social-emotional development subdomains. The clinical level includes the assessment of neurodevelopmental disorders or the presence of symptoms (subclinical symptomatology) of these disorders in populations under investigation in environmental epidemiology studies.

Conclusions: Through explicit recognition of these levels of outcomes, and in using this framework, epidemiologists will be better able to design research through the informed selection of individual levels of outcomes. The framework also serves to standardize disparate terminologies across this field and allows for pooling of epidemiological data on neuropsychological endpoints where essentially similar levels of outcomes have been analyzed using different tests.