Motor overflow in children with attention-deficit/hyperactivity disorder is associated with decreased extent of neural activation in the motor cortex

Abstract

Motor overflow is a developmental phenomenon that typically disappears by late childhood. Abnormal persistence of motor overflow is often present in children with attention-deficit/hyperactivity disorder (ADHD). This study employed functional magnetic resonance imaging (fMRI) during a finger-sequencing task to examine whether excessive motor overflow in children with ADHD is associated with decreased extent of motor circuit activation. Thirty-four right-handed children (18 typically developing controls, 16 ADHD) completed fMRI while performing a finger-sequencing task. Motor overflow was evaluated during a finger-sequencing task and a motor examination (the PANESS) performed outside the scanner. Diagnostic differences in behavioral measures of overflow and extent of activation in the contralateral and ipsilateral motor network ROIs were examined, along with correlations between overflow and extent of activation. Children with ADHD demonstrated greater overflow and lesser extent of activation in left primary motor cortex (BA4) and bilateral premotor cortex (BA6) and supplementary motor area (SMA) during right-hand finger-sequencing compared to controls. Decreased extent of primary motor and premotor activation correlated with increased hand-related overflow movements in children with ADHD but not controls. These findings suggest that overflow movements in children with ADHD may reflect decreased recruitment of neural circuitry involved in active inhibition of homologous motor circuitry unnecessary to task execution.

Anomalous subcortical morphology in boys, but not girls, with ADHD compared to typically developing controls and correlates with emotion dysregulation

“…(Leisman and Melillo, 2013; Middleton and Strick, 2001) This pattern of localized compression may suggest that the impact of abnormal reward and motivation signaling in the basal ganglia in boys with ADHD is most apparent within circuits involved in basic response selection complementing findings of abnormalities in motor and premotor cortical regions in children with ADHD. (Dirlikov et al, 2015; Gaddis et al, 2015; Jacobson et al, 2015; Mostofsky et al, 2002; Mostofsky et al, 2006; Suskauer et al, 2008)…”

“…(American Psychiatric Association, 2013) While fronto-striatal regions have been extensively examined and implicated in the pathophysiology of ADHD(Cubillo et al, 2012; Sagvolden et al, 2005; Sonuga-Barke, 2005), less attention has been paid to subcortical structures such as the globus pallidus, amygdala, hippocampus and thalamus. Morphological differences in these structures may be particularly important in the pathophysiology of ADHD as they may contribute to deficient motor control(Gaddis et al, 2015; Mostofsky et al, 2003a), atypical response to reward(Luman et al, 2010), and problems with emotional processing and regulation(Shaw et al, 2014b) in individuals with ADHD…”

Subtle Motor Findings During Recovery from Pediatric Traumatic Brain Injury: A Preliminary Report

“…In addition to evaluation of standardized assessments of fine motor control that are commonly used in clinical settings (i.e., the D-KEFS Trails and LGP), we also included the PANESS to examine more subtle motor deficits. The PANESS has been used in other pediatric neurodevelopmental populations to identify subtle motor dysfunction, such as ADHD (Gaddis et al, 2015) and autism (MacNeil & Mostofsky, 2012), but the PANESS has not previously been used after TBI.…”

“…As an exploratory analysis, between-group and within-group analyses were repeated for component task scores from the PANESS to identify which, if any, component tasks were driving observed performance differences. Finally, as only one child had a severe TBI and another participant in the TBI group had a premorbid ADHD diagnosis which has been associated with motor problems in previous research (e.g., (Gaddis et al, 2015), all aforementioned analyses were repeated with each participant’s data removed to assess whether either participant was driving findings. Findings were not significantly altered, unless otherwise stated.…”

Utility of the General Ability Index (GAI) and Cognitive Proficiency Index (CPI) with survivors of pediatric brain tumors: Comparison to Full Scale IQ and premorbid IQ estimates

“…Similarly, a GAI > CPI profile is frequently represented in patients with neurologically-based pediatric disorders, including ADHD, high functioning Autism Spectrum Disorder, Specific Learning Disorder, as well as in patients following open- and closed-head traumatic brain injuries (Cornoldi, Giofrè, Orsini, & Pezzuti, 2014; Devena & Watkins, 2012; Poletti, 2014 Weiss & Gable, 2008). Given these patterns, the GAI is considered by some to be a more appropriate measure of broad intellectual ability than the FSIQ in these populations (Cornoldi, et al, 2014; Foley-Nicpon, Assouline, & Stinson, 2012; Gaddis, et al, 2015; Poletti, 2014; Whitaker, Bell, Houskamp, & O’Callaghan, 2015). The potential exists for suppression of FSIQ due to relative weaknesses in cognitive proficiency in children from these and other clinical populations at risk for true working memory and processing speed deficits.…”