Developmental Trajectory of Motor Deficits in Preschool Children with ADHD.

Motor deficits persisting into childhood (>7 years) are associated with increased executive and cognitive dysfunction, likely due to parallel neural circuitry. This study assessed the longitudinal trajectory of motor deficits in preschool children with ADHD, compared to typically developing (TD) children, in order to identify individuals at risk for anomalous neurological development. Participants included 47 children (21 ADHD, 26 TD) ages 4-7 years who participated in three visits (V1, V2, V3), each one year apart (V1=48-71 months, V2=60-83 months, V3=72-95 months). Motor variables assessed included speed (finger tapping and sequencing), total overflow, and axial movements from the Revised Physical and Neurological Examination for Subtle Signs (PANESS). Effects for group, visit, and group-by-visit interaction were examined. There were significant effects for group (favoring TD) for finger tapping speed and total axial movements, visit (performance improving with age for all 4 variables), and a significant group-by-visit interaction for finger tapping speed. Motor speed (repetitive finger tapping) and quality of axial movements are sensitive markers of anomalous motor development associated with ADHD in children as young as 4 years. Conversely, motor overflow and finger sequencing speed may be less sensitive in preschool, due to ongoing wide variations in attainment of these milestones.

Anomalous Brain Development Is Evident in Preschoolers With Attention-Deficit/Hyperactivity Disorder.

OBJECTIVES: Attention-deficit/hyperactivity disorder (ADHD) is a common neurological disorder with symptom onset early in childhood. Growing evidence suggests anomalous brain development across multiple brain regions is evident in school-aged children; however, few studies have examined whether such differences are notable in the preschool years when symptom onset typically occurs. METHODS: High resolution anatomical (MPRAGE) images and cognitive and behavioral measures were analyzed in a total of 90 medication-naïve preschoolers, ages 4-5 years (52 with ADHD, 38 controls; 64.4% boys). RESULTS: Results revealed reductions in bilateral frontal, parietal, and temporal lobe gray matter volumes in children with ADHD relative to typically developing children, with largest effect sizes noted for right frontal and left temporal lobe volumes. Examining frontal lobe sub-regions, the largest between group effect sizes were evident for left orbitofrontal cortex, left primary motor cortex (M1), and left supplementary motor complex (SMC). ADHD-related reductions in specific sub-regions (left prefrontal, left premotor, left frontal eye field, left M1, and right SMC) were significantly correlated with symptom severity, such that higher ratings of hyperactive/impulsive symptoms were associated with reduced cortical volumes. CONCLUSIONS: These findings represent the first comprehensive examination of cortical volume in preschool children with ADHD, providing evidence that anomalous brain structure in ADHD is evident very early in development. Furthermore, findings set the stage for developing our understanding of the way in which developmental trajectories of anomalous brain development are associated with the unfolding of symptoms in childhood ADHD. (JINS, 2018, 24, 531-539).

Development and validation of an attention-deficit/hyperactivity disorder (ADHD) executive function and behavior rating screening battery.

Attention problems are ubiquitous in clinical practice, commonly found in many childhood learning and behavior disorders. Practitioners need cost- and time-effective methods for determining whether children have attention problems due to attention-deficit/hyperactivity disorder (ADHD) or numerous other conditions. This study examined the utility of a 15-minute ADHD screening battery designed to differentiate ADHD (including inattentive, IT, and combined, CT, subtypes), specific learning disability (SLD), and typical child samples. Results for the 368 children (age 6 to 12 years) revealed that the Trail Making Test-Part B (Time/Errors), Hale-Denckla Cancellation Test (Time/Correct), and Child Attention Profile (Inattention/Overactivity) teacher ratings discriminated between typical and ADHD groups (87% correct classification; sensitivity = .64; specificity = .92) and differentiated between IT, CT, and SLD groups (80% correct classification; IT sensitivity = .82, and specificity = .96; CT sensitivity = .84, and specificity = .82). Discriminant function and Bonferroni post hoc results revealed different neuropsychological and behavioral patterns among groups.

Attention-deficit hyperactivity disorder (ADHD) comorbidity: a case for "pure" Tourette syndrome?

More than a decade of research regarding the motoric characteristics of the attention-deficit hyperactivity disorder (ADHD) that accompanies Tourette syndrome has revealed unique anatomic and neurobehavioral differences and highlighted the importance of distinguishing children with this form from the 40% of children with Tourette syndrome who do not have ADHD. This distinction is important in providing guidance to parents and to patients and in formulating expectations for short- and long-term prognoses. In addition, study methodologies that fail to categorize patients in this way and instead involve covarying for dimensional symptoms of ADHD obscure biologically distinctive circuits and clinically meaningful patient characteristics.

Attention deficit hyperactivity disorder: the childhood co-morbidity that most influences the disability burden in Tourette syndrome.

ADHD is a complex co-morbidity, as it is heteregeneous in terms of the clinical subtypes, but also in terms of the circuits involved and the level of involvement within those circuits. Specially focusing on the relationship of ADHD to TS, this author's studies have added some neurobehavioral and some anatomical magnetic resonance imaging evidence suggesting the ADHD occurring with TS, appears like "garden-variety" ADHD, at least in the matched research sample. The similarities of neuroanatomical findings in the TS plus ADHD and ADHD groups and their distinctness from neuroanatomical findings in childdren with "pure TS provide some parallels to the observed similarity of functional deficit in TS plus ADHD and ADHD alone groups and the relative lack of functional deficits in children with TS only. More specifically, the results of a decade of this author's research with the approximately 40% of children with TS who are free of ADHD indicate that they are entirely free of the motor control and executive control deficits of children with ADHD alone or TS plus ADHD, but they do have oculomotor control deficits in the initiation of prosaccades, regardless of their ADHD status. The neuroanatomical data in TS only is also of interest because it reflects increased white matter, particularly in the right frontal lobe and four out of five regions of the corps callosum, including the rostral portion most affiliated with the frontal lobes. It should be emphasized that almost everything summarized abouve is true for boys, whereas samples of girls grouped similarly have not yielded the same results.

Performance on measures of executive function following pediatric traumatic brain injury.

OBJECTIVE: To investigate the relationships among age at injury, neuroanatomic lesion location, and measures of executive function (EF) following paediatric traumatic brain injury (TBI). METHODS: EF was assessed in 68 children (aged 7-15) with moderate-to-severe TBI 1 year post-injury. EF tests included: (1) Tower of Hanoi (TOH), a measure of problem solving ability, (2) Wisconsin Card Sorting Test (WCST), a measure of categorization and ability to shift cognitive strategies, (3) Letter Fluency (LF), a measure of novel lexical search and rule-governed word generation. EF variables included number of moves needed to achieve a 3-ring solution on the TOH, number of perseverative and non-perseverative errors on the WCST, and number of words generated on LF. Intellectual functioning was also assessed using the Verbal Intellectual Quotient (VIQ) from the Wechsler Intelligence Scale from Children-3rd edn (WISC-III). Data from standardized MRIs, performed at 3-months post-injury, were available for all subjects and were used to determine lesion location, lesion volumes, and total number of lesions. The relationships among EF, lesion variables (frontal lesion volume, extrafrontal lesion volume, total number of lesions) and age at injury were examined. Pre-injury special education services and attention deficit hyperactivity disorder (ADHD) were controlled for. RESULTS: Younger age at injury was associated with more perseverative errors on the WCST and worse performance on LF. Frontal lesion volume was not predictive of performance on any measures of EF. Greater extrafrontal lesion volume and total number of lesions were predictive of worse performance on LF. When controlling for pre-injury special education placement and pre-injury ADHD, there was little change in the results. CONCLUSIONS: Younger age at injury places children at greater risk of impairment on measures of EF. Performance on measures of EF depends on brain variables other than frontal lobes including extrafrontal cortical brain areas and total number of lesions. The relationship between extrafrontal brain regions and EF suggests that domain-specific cognitive content (i.e. language or visuospatial analysis), mediated by the parietal or temporal lobes, may disrupt underlying cognitive processes necessary for successful performance on measures of EF. In addition, the association between total number of lesions and EF may be related to disconnections and disruption of frontal/subcortical systems.