ADHD: Volumetry, Motor, and Oculomotor Functions

Abstract

The use of quantitative neuroimaging (volumetry), motor, and oculomotor assessments for studying children with attention-deficit/hyperactivity disorder (ADHD) has grown dramatically in the past 20 years. Most evidence to date suggests that anomalous basal ganglia development plays an important role in early manifestation of ADHD; however, widespread cerebellar and cortical delays are also observed and are associated with the behavioral (cognitive, motor, oculomotor) phenotype in children with ADHD. These motor and "executive" control systems appear to develop in parallel, such that both systems display a similar protracted developmental trajectory, with periods of rapid growth in elementary years and continued maturation into young adulthood. Development of each system is dependent on the functional integrity and maturation of related brain regions, suggesting a shared neural circuitry that includes frontostriatal systems and the cerebellum (i.e., those identified as anomalous in studies of volumetry in ADHD). Motor and oculomotor paradigms provide unique opportunities to examine executive control processes that exist at the interface between movement and cognition in children with ADHD, also linking cognition and neurological development. The observed pattern of volumetric differences, together with the known parallel development of motor and executive control systems, appears to predict motor and oculomotor anomalies in ADHD, which are highly relevant, yet commonly overlooked in clinical settings.

Exercise Interventions in Children and Adolescents With ADHD: A Systematic Review

“…Further approaches exist, explaining the etiology of ADHD on neurobiological level. Structural brain abnormalities were found in frontostriatal areas, the tempoparietal lobes, the basalganglia, the thalamus, the corpus callosum, the cerebellum, and the amygdala (Cortese, 2012; Mahone, 2011). In addition, neurotransmitter dysfunctions were described as neurobiological pathology (Levy, 1991).…”

“…Therefore, treatment of ADHD commonly includes sympathomimetic drugs, such as methylphenidate, amphetamines, or atomoxetine, which enhance the level of dopamine and norepinephrine in the prefrontal cortex (Sharma & Couture, 2014; Zuvekas, Vitiello, & Norquist, 2006). Pharmacological treatment is confirmed to improve ADHD symptomatology as well as comorbid symptoms such as motor deficits (Kaiser et al, 2014; Mahone, 2011).…”

Effect of a visual tracking intervention on attention and behavior of attention deficit hyper activity children

“…The inability to control responses leads to disturbances in executive function, oculomotor function, and other aspects of motor and cognitive control (Shiels & Hawk, 2010). In addition to inattention, impulsivity (Rapport et al, 2009), and abnormalities in self-regulation (Shiels & Hawk, 2010), children with ADHD show abnormalities in the control of saccadic eye movements, abnormal eye movements and problems in visual fixation (Munoz et al, 2003;Pishyareh, Tehrani-Doost, Mahmoodi-Gharaie, Khorrami, & Rahmdar, 2015), and smooth pursuit movements (Bylsma & Pivik, 1989;Cairney et al, 2001;Castellanos et al, 2000;Mahone, 2011;S. H. Mostofsky, Lasker, Cutting, Denckla, & Zee, 2001;Ross, Hommer, Breiger, Varley, & Radant, 1994).…”

Is There a Functional Relation Between Set Shifting and Hyperactivity in Children with Attention-Deficit/Hyperactivity Disorder (ADHD)?

“…Attention-deficit/hyperactivity disorder (ADHD) is a chronic and heterogeneous neurodevelopmental disorder that affects approximately 5% of school-age children (Polanczyk, de Lima, Horta, Biederman, & Rohde, 2007;Polanczyk, Willcutt, Salum, Kieling, & Rohde, 2014). It has been proposed that underlying deficits in executive function(s) may drive ADHD's phenotypic behavioral presentation for many, if not most, children with ADHD (Barkley, 1997;Chacko, Kofler, & Jarrett, 2014;Kasper, Alderson, & Hudec, 2012;Mahone, 2011;Rapport et al, 2009;Sonuga-Barke, Bitsakou, & Thompson, 2010). Hyperactivity, or excess physical movement, is considered a core and impairing deficit in the clinical model of ADHD (APA, 2013).…”

“…Hyperactivity, or excess physical movement, is considered a core and impairing deficit in the clinical model of ADHD (APA, 2013). Recent meta-analytic evidence suggests that children with ADHD exhibit elevated motor activity compared to children without ADHD, regardless of subtype/current presentation, particularly during activities that challenge their underdeveloped executive functions (Kofler, Raiker, Sarver, Wells, & Soto, 2016;Mahone, 2011). However, the extent to which hyperactivity in ADHD is evoked by cognitively challenging tasks in general or by demands on specific executive functions remains unclear.…”