Assessing executive functions in children: biological, psychological, and developmental considerationst.

Executive functions may be defined as those skills necessary for purposeful, goal-directed activity, and are generally considered to be largely mediated by the frontal and prefrontal cortices of the brain. These cerebral regions are relatively immature during childhood, with development thought to be a protracted process which continues into early adolescence. While early theorists suggested that executive skills were not functional until cerebral maturity, recent research provides evidence that such skills can be elicited in early childhood. The aim of this paper is to review current theories of development of executive functions throughout childhood. In keeping with contemporary approaches to child neuropsychology, three critical dimensions will be evaluated; biological factors, psychological dimensions, and developmental trajectories. In addition, the literature which addresses assessment of these functions will be examined, with reference to developmental trajectories observed in normal populations, and in brain-damaged samples, where there may be disruption to the underlying neural substrates thought to be subsuming these functions.