Neurodevelopmental Pathways of Childhood ADHD into Adulthood: Maturational Lag, Deviation, or Both?

Abstract

The DSM-[ ], which should be published in , will in all likelihood have a category named Neurodevelopmental Disorders, under which "DHD will resort. This shift in nosology lays the foundation of the argument that will be put forward in this chapter, therefore the following points need to be emphasised and warrants further discussion. Firstly, this categorisation is based on shared aetiology, rather than shared symptoms or shared developmental stage as was the case with the DSM-IV-TR . Historically, disorders were classified according to shared aetiology as was the case with DSMI and DSM-II , as opposed to shared symptomatology as was the case with DSM-III and DSM-IVTR . The DSM-is to a greater, or lesser, extent a combination of these as it proposes a change to the categorisation, but not the symptoms of this disorder.The second point is that the shared aetiology is a neurobiological based aetiology. The name of the category implies that these disorders have a common, underlying, neurobiological cause. The question which arises is to what extent these disorders do have an underlying neurobiological cause, to what extent this is shared, and even to what extent these causes are shared within the sub-categories of disorders, for example "DHD. Grouping these disorders together implies a relatively homogenous group of disorders, and even further that the subcategories are homogenous within themselves. The DSM-makes provision for sub-categories of "DHD, i.e. the Combined, Predominantly Inattentive, Inattentive Restrictive and predominantly Hyperactive/ Impulsive, presentations. Does the grouping of these sub-categories necessarily imply that they share the same neurobiological aetiology? The argument that will be put forward in this chapter is that although they all share a neurobiological cause, this cause is not common and that the sub-categories may have subtle or gross, differences in these neurobiological factors.

Machine-based classification of ADHD and nonADHD participants using time/frequency features of event-related neuroelectric activity

“…Consistent with the maturational lag hypothesis, the oscillatory activity in children with ADHD looks like that of younger children. Consistent with the maturational deviance hypothesis, there is a characteristic topographical distribution of the oscillatory activity regardless of age (Burke and Edge, 2013). Overall, there are increased relative and/or absolute delta and theta activities (slow activity) specifically in the frontal and midline sites (for a review, see Barry et al, 2004;Mann et al, 1992).…”

The Brain of Binge Drinkers at Rest: Alterations in Theta and Beta Oscillations in First-Year College Students with a Binge Drinking Pattern

“…In addition to alcoholics, enhanced tonic theta power has been observed in a variety of neurological disorders including Alzheimer's disease (Dauwels et al, 2010 ), vascular dementia (Babiloni et al, 2004 ), or attention deficit hyperactivity disorder (Burke and Edge, 2013 ). Likewise, increases in the tonic theta band have been remarked in altered neurophysiological states of the brain such as, drowsy and sleep states (Makeig et al, 2000 ; Tanaka et al, 2000 ) and after consumption of anesthetic drugs (Voss and Sleigh, 2007 ) or depressant substances such as, alcohol (Stenberg et al, 1994 ; Ehlers et al, 1998 ; Ilan and Gevins, 2001 ), which appears to suggest that when the ability to respond to external stimuli decreases, spontaneous theta activity increases (Klimesch, 1999 ).…”

Neural Dynamics for Facilitating ADHD Diagnosis in Preschoolers: Central and Parietal Delta Synchronization in the Kiddie Continuous Performance Test

“…In the present study, and somewhat different from the conclusions of previous studies, instead of theta power, delta relative power had a profound effect on group differentiation. Some studies have proposed that an increase in the power of the delta band reflects the maturation lag of the brain in children with ADHD [55], [63], [64]. A longitudinal neuroanatomic study revealed that the cortical maturation trajectory in children with ADHD is approximately 3 years behind that of children with TD [65].…”

“…A longitudinal neuroanatomic study revealed that the cortical maturation trajectory in children with ADHD is approximately 3 years behind that of children with TD [65]. From an electrophysiological perspective, an increase in slow-wave activity (delta and theta) and a decrease in fast-wave activity (alpha and beta) are reminiscent of normal, but immature, cortical activity patterns that are frequently observed in younger children with TD [63], [64]. Based on the aforementioned facts, researchers have suggested that the increased slow-wave activity in children and adolescents with ADHD in the resting condition is associated with a maturational lag [55], [63].…”