Deux études apportent une évidence supplémentaires sur le lien entre TDAH et une inhibition du cortex cérébral altérée
Petit résumé : Cette étude montre encore que les enfants atteints de déficit d'attention et d'hyperactivité (TDAH) présentent des mesures de stimulation magnétique transcraniens diminués (une inhibition corticale réduite) en correlation avec la sévérité de leur déficit d'attention et de leur développement moteur.
*Attention-deficit/hyperactivity disorder (ADHD) is a childhood-onset behavioral diagnosis in which children often fail to meet age norms in development of motor control, particularly timed repetitive and sequential movements, motor overflow, and balance. The neural substrate of this motor delay may include mechanisms of synaptic inhibition in or adjacent to the motor cortex. The primary objective of this study was to determine whether transcranial magnetic stimulation (TMS)-evoked measures, particularly short interval cortical inhibition (SICI), in motor cortex correlate with the presence and severity of ADHD in childhood as well as with commonly observed delays in motor control.
In this case-control study, behavioral ratings, motor skills, and motor cortex physiology were evaluated in 49 children with ADHD (mean age 10.6 years, 30 boys) and 49 typically developing children (mean age 10.5 years, 30 boys), all right-handed, aged 8-12 years. Motor skills were evaluated with the Physical and Neurological Examination for Subtle Signs (PANESS) and the Motor Assessment Battery for Children version 2. SICI and other physiologic measures were obtained using TMS in the left motor cortex.
In children with ADHD, mean SICI was reduced by 40% (p < 0.0001) and less SICI correlated with higher ADHD severity (r = -0.52; p = 0.002). Mean PANESS motor development scores were 59% worse in children with ADHD (p < 0.0001). Worse PANESS scores correlated modestly with less SICI (r = -.30; p = 0.01).
Reduced TMS-evoked SICI correlates with ADHD diagnosis and symptom severity and also reflects motor skill development in children.
Neurology. 2011 Feb 15;76(7):615-21. Motor cortex inhibition: a marker of ADHD behavior and motor development in children. Gilbert DL1, Isaacs KM, Augusta M, Macneil LK, Mostofsky SH.
Petit résumé : Cette étud emontre que les enfants atteints de déficit d'attention et hyperactivité (TDAH) présentent des phénomènes de débordement de la main qui est considérés comme un signe de manque de contrôle inhibiteur.
*Qualitative observations have revealed that children with attention-deficit/hyperactivity disorder (ADHD) show increased overflow movements, a motor sign thought to reflect impaired inhibitory control. The goal of this study was to develop and implement methods for quantifying excessive mirror overflow movements in children with ADHD.
Fifty right-handed children aged 8.2-13.3 years, 25 with ADHD (12 girls) and 25 typically developing (TD) control children (10 girls), performed a sequential finger-tapping task, completing both left-handed (LHFS) and right-handed finger sequencing (RHFS). Phasic overflow of the index and ring fingers was assessed in 34 children with video recording, and total overflow in 48 children was measured by calculating the total angular displacement of the index and ring fingers with electrogoniometer recordings.
Phasic overflow and total overflow across both hands were greater in children with ADHD than in TD children, particularly during LHFS. Separate gender analyses revealed that boys, but not girls, with ADHD showed significantly more total phasic overflow and total overflow than did their gender-matched control children.
The quantitative overflow measures used in this study support past qualitative findings that motor overflow persists to a greater degree in children with ADHD than in age-matched TD peers. The quantitative findings further suggest that persistence of mirror overflow is more prominent during task execution of the nondominant hand and reveal gender-based differences in developmental neural systems critical to motor control. These quantitative measures will assist future physiologic investigation of the brain basis of motor control in ADHD.
Neurology. 2011 Feb 15;76(7):622-8. Quantifying excessive mirror overflow in children with attention-deficit/hyperactivity disorder. Macneil LK1, Xavier P, Garvey MA, Gilbert DL, Ranta ME, Denckla MB, Mostofsky SH.
Programme CerebroStim :
Le programme cerebrostim est destiné aux enfants et adultes souffrant d'un spectre large de troubles y compris les troubles envahissants de développement, troubles de déficit d'attention, hyperactivité, dyslexie, troubles de comportements, etc. L'objectif est d'analyser les déficits de fonctionnement des parties du cerveau et planifier un programme de rééducation pour stimuler et renforcer les endroits ou hémisphères faibles.