Brain volumetric correlates of autism spectrum disorder symptoms in attention deficit/hyperactivity disorder.

Autism spectrum disorder (ASD) symptoms frequently occur in subjects with attention deficit/hyperactivity disorder (ADHD). While there is evidence that both ADHD and ASD have differential structural correlates, no study to date has investigated these structural correlates within a framework that robustly accounts for the phenotypic overlap between the two disorders. The presence of ASD symptoms was measured by the parent-reported Children's Social and Behavioural Questionnaire (CSBQ) in ADHD subjects (n = 180), their unaffected siblings (n = 118) and healthy controls (n = 146). ADHD symptoms were assessed by a structured interview (K-SADS-PL) and the Conners' ADHD questionnaires. Whole brain T1-weighted MPRAGE images were acquired and the structural MRI correlates of ASD symptom scores were analysed by modelling ASD symptom scores against white matter (WM) and grey matter (GM) volumes using mixed effects models which controlled for ADHD symptom levels. ASD symptoms were significantly elevated in ADHD subjects relative to both controls and unaffected siblings. ASD scores were predicted by the interaction between WM and GM volumes. Increasing ASD score was associated with greater GM volume. Equivocal results from previous structural studies in ADHD and ASD may be due to the fact that comorbidity has not been taken into account in studies to date. The current findings stress the need to account for issues of ASD comorbidity in ADHD.

Attention-related potentials allow for a highly accurate discrimination of mild cognitive impairment subtypes.

The three most frequent forms of mild cognitive impairment (MCI) are single-domain amnestic MCI (sd-aMCI), single-domain dysexecutive MCI (sd-dMCI) and multiple-domain amnestic MCI (md-aMCI). Brain imaging differences among single domain subgroups of MCI were recently reported supporting the idea that electroencephalography (EEG) functional hallmarks can be used to differentiate these subgroups. We performed event-related potential (ERP) measures and independent component analysis in 18 sd-aMCI, 13 sd-dMCI and 35 md-aMCI cases during the successful performance of the Attentional Network Test. Sensitivity and specificity analyses of ERP for the discrimination of MCI subgroups were also made. In center-cue and spatial-cue warning stimuli, contingent negative variation (CNV) was elicited in all MCI subgroups. Two independent components (ICA1 and 2) were superimposed in the time range on the CNV. The ICA2 was strongly reduced in sd-dMCI compared to sd-aMCI and md-aMCI (4.3 vs. 7.5% and 10.9% of the CNV component). The parietal P300 ERP latency increased significantly in sd-dMCI compared to md-aMCI and sd-aMCI for both congruent and incongruent conditions. This latency for incongruent targets allowed for a highly accurate separation of sd-dMCI from both sd-aMCI and md-aMCI with correct classification rates of 90 and 81%, respectively. This EEG parameter alone performed much better than neuropsychological testing in distinguishing sd-dMCI from md-aMCI. Our data reveal qualitative changes in the composition of the neural generators of CNV in sd-dMCI. In addition, they document an increased latency of the executive P300 component that may represent a highly accurate hallmark for the discrimination of this MCI subgroup in routine clinical settings.

Respiration, metabolic balance, and attention in affective picture processing

The respiratory behavior during affective states is not completely understood. We studied breathing pattern responses to picture series in 37 participants. We also measured end-tidal pCO2 (EtCO2) to determine if ventilation is in balance with metabolic demands and spontaneous eye-blinking to investigate the link between respiration and attention. Minute ventilation (MV) and inspiratory drive increased with self-rated arousal. These relationships reflected increases in inspiratory volume rather than shortening of the time parameters. EtCO2 covaried with pleasantness but not arousal. Eye-blink rate decreased with increasing unpleasantness in line with a negativity bias in attention. This study confirms that respiratory responses to affective stimuli are organized to a certain degree along the dimensions of valence and arousal. It shows, for the first time, that during picture viewing, ventilatory increases with increasing arousal are in balance with metabolic activity and that inspiratory volume is modulated by arousal. MV emerges as the most reliable respiratory index of self-perceived arousal

Trouble du déficit d'attention/hyperactivité (TDAH) et attachement: pistes convergentes ou parallèles ?

L'attachement offre un cadre pour investiguer et comprendre les problématiques parentales et développementales des enfants avec un TDAH. Des observations cliniques et des recherches récentes évoquent la présence assez fréquente d'attachements de type insecure chez les enfants avec un TDAH. Des études signalent la présence fréquente de symptômes évocateurs d'un TDAH chez des enfants ayant vécu des déprivations précoces dans des orphelinats. Les hypothèses sur la régulation des émotions et la qualité des relations interpersonnelles provenant de la théorie de l'attachement pourraient apporter des pistes intéressantes dans la compréhension des TDAH et comporter des points de jonction avec les hypothèses de Barkley (2010) sur le rôle de l'autorégulation et de l'inhibition émotionnelle dans le TDAH.

A fully-automatic caudate nucleus segmentation of brain MRI: application in volumetric analysis of pediatric attention-deficit/hyperactivity disorder

Background Accurate automatic segmentation of the caudate nucleus in magnetic resonance images (MRI) of the brain is of great interest in the analysis of developmental disorders. Segmentation methods based on a single atlas or on multiple atlases have been shown to suitably localize caudate structure. However, the atlas prior information may not represent the structure of interest correctly. It may therefore be useful to introduce a more flexible technique for accurate segmentations. Method We present Cau-dateCut: a new fully-automatic method of segmenting the caudate nucleus in MRI. CaudateCut combines an atlas-based segmentation strategy with the Graph Cut energy-minimization framework. We adapt the Graph Cut model to make it suitable for segmenting small, low-contrast structures, such as the caudate nucleus, by defining new energy function data and boundary potentials. In particular, we exploit information concerning the intensity and geometry, and we add supervised energies based on contextual brain structures. Furthermore, we reinforce boundary detection using a new multi-scale edgeness measure. Results We apply the novel CaudateCut method to the segmentation of the caudate nucleus to a new set of 39 pediatric attention-deficit/hyperactivity disorder (ADHD) patients and 40 control children, as well as to a public database of 18 subjects. We evaluate the quality of the segmentation using several volumetric and voxel by voxel measures. Our results show improved performance in terms of segmentation compared to state-of-the-art approaches, obtaining a mean overlap of 80.75%. Moreover, we present a quantitative volumetric analysis of caudate abnormalities in pediatric ADHD, the results of which show strong correlation with expert manual analysis. Conclusion CaudateCut generates segmentation results that are comparable to gold-standard segmentations and which are reliable in the analysis of differentiating neuroanatomical abnormalities between healthy controls and pediatric ADHD.

Hygiène des mains et utilisation de protection respiratoire : attention aux risques de contamination microbiologique imprévue!

Une mauvaise hygiène des mains peut représenter une perte économique importante pour les industries alimentaires ou les industries pharmaceutiques et constitue un gros problème de santé publique dans les établissements de soins. En effet, le risque de transmission manuportée de pathogènes d'un patient à l'autre via le personnel soignant est un problème récurrent dans tous les hôpitaux. C'est pourquoi, une hygiène irréprochable des mains du personnel soignant est une composante fondamentale de lutte contre les infections nosocomiales. En comparaison avec les autres techniques de séchage des mains, l'utilisation d'une serviette en papier à usage unique semble être la méthode la plus efficace pour éliminer les bactéries. En effet, les autres méthodes de séchage, utilisant des appareils à air chaud ou froid, peuvent générer un air contaminé ou remettre en suspension les germes restés sur la peau, facilitant ainsi leur dispersion et leur inhalation. C'est pourquoi, l'OMS a émis des recommandations déconseillant les sèche-mains électriques en milieu hospitalier au profit des serviettes en papiers. Cependant, ces serviettes à usage unique ne sont pas stériles et peuvent elles-mêmes déposer des germes, généralement non pathogènes, sur les mains lors du séchage. Le but du premier article analysé est d'évaluer le niveau de contamination de ces serviettes, ainsi que la possibilité de dépôt de ces bactéries présentes sur les serviettes, sur les mains. À côté du risque de propagation de pathogènes par contact direct, la contamination microbiologique par voie aérienne via les aérosols existe aussi. Pour éviter d'être contaminé par des personnes excrétrices de micro-organismes transmissibles par aérosols (tuberculose, grippe, grippe aviaire SRAS...), il faut porter des protections respiratoires de type FFP2 (1) (norme européenne équivalente à la norme anglosaxonne N95). Ces protections respiratoires ou masques filtrants (en formes de bec de canard) peuvent être portées théoriquement pendant 4 heures. Le but de l'étude du second article est d'évaluer le risque de remise en suspension dans l'air de particules virales présentes sur la face extérieure d'un masque de protection respiratoire lors de simulation d'épisodes de toux provenant du porteur de cette protection.

Dyslexia in a French-Spanish bilingual girl: behavioural and neural modulations following a visual attention span intervention.

We report the case study of a French-Spanish bilingual dyslexic girl, MP, who exhibited a severe visual attention (VA) span deficit but preserved phonological skills. Behavioural investigation showed a severe reduction of reading speed for both single items (words and pseudo-words) and texts in the two languages. However, performance was more affected in French than in Spanish. MP was administered an intensive VA span intervention programme. Pre-post intervention comparison revealed a positive effect of intervention on her VA span abilities. The intervention further transferred to reading. It primarily resulted in faster identification of the regular and irregular words in French. The effect of intervention was rather modest in Spanish that only showed a tendency for faster word reading. Text reading improved in the two languages with a stronger effect in French but pseudo-word reading did not improve in either French or Spanish. The overall results suggest that VA span intervention may primarily enhance the fast global reading procedure, with stronger effects in French than in Spanish. MP underwent two fMRI sessions to explore her brain activations before and after VA span training. Prior to the intervention, fMRI assessment showed that the striate and extrastriate visual cortices alone were activated but none of the regions typically involved in VA span. Post-training fMRI revealed increased activation of the superior and inferior parietal cortices. Comparison of pre- and post-training activations revealed significant activation increase of the superior parietal lobes (BA 7) bilaterally. Thus, we show that a specific VA span intervention not only modulates reading performance but further results in increased brain activity within the superior parietal lobes known to housing VA span abilities. Furthermore, positive effects of VA span intervention on reading suggest that the ability to process multiple visual elements simultaneously is one cause of successful reading acquisition.

Acides gras polyinsaturés pour le traitement du trouble de l'attention avec ou sans hyperactivité chez l'enfant et l'adolescent

Cet article présente les résultats d'une revue systématique publiée par la Collaboration Cochrane dans la Cochrane Library (www.cochrane.org) : Gillies D., Sinn J.K., Lad S.S., Leach M.J., Ross M.J., « Polyunsaturated fatty acids (PUFA) for attention deficit hyperactivity disorder (ADHD) in children and adolescents », Cochrane Database Syst. Rev., 2012 ; 7 : CD007986.