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la démence d'Alzheimer (MA) est une maladie incurable à l'heure actuelle. Débutant de manière insidieuse par des troubles plus discrets, concernant principalement la mémoire épisodique, on utilise le plus souvent le terme de "troubles cognitifs légers" (Mild Cognitive impairment - MCI) pour décrire la catégorie de sujets présentant des troubles cognitifs débutants, sans conséquences sur les AVC. Néanmoins, seuls certains sujets MCI développeront une MA. Récemment, plusieurs marqueurs biologiques de la MA ("biomarqueurs") ont été développés,permettant de mieux définir ses stades précoces.Objectifs de l'étude : étudier l'intérêt des quantifications globales et sous-régionales sur les acquisitions en PET-FDG et leurs rapports aux autres biomarqueurs dans le diagnostic des troubles cognitifs légers.Type d'étude: transversale,prospective,expérimentale, analytique,contrôlée .Population et méthodes : basée sur la population de l'étude de la clinique de la mémoire (Eudract N° 2009- 013030-25) des Cliniques Universitaire de St-Luc à Bruxelles, deux groupes ont été mis en place: le groupe contrôles (n=31) et le groupe patients (n=60). Les moyennes d'âges respectives sont de 70 +/- 5,5 ans et de 70,9 +/- 8 ans. Les modules PALZ et PBRAIN du logiciel PMOD (Pmod Technologies Ltd ©) furent utilisés pour l'obtention de scores globaux et sous-régionaux après création d'une base de données à partir des sujets du groupe contrôles. Alors, des statistiques comparatives entre groupes contrôles et patients ainsi que groupes contrôles et sous-groupe de patients MCI ont permis d'observer les efficacités respectives de ces scores dans la discrimination de ces sujets et de les comparer. Enfin, une analyse conjointe des valeurs obtenues et des autres facteurs et biomarqueurs fut appliquée.Résultats : les résultats mettent en évidence un hypométabolisme sous-régional temporo-pa riétal et occipital (lobes temporaux, gyrus angulaires, lobe de Heschl G, régions hippocampiques, scissures calcar ines) significativement plus important chez les sujets patients. La Sensibilité Relative de certaines de ces sous-régions (lobes temporaux , gyrus angulaires) (37-41%) est comparable à celle du score global (PET-score) (38-44%) dans la discrimination des sujets patients MCI. Des compromis ont pu être trouvés pour ces scores et offrent des valeurs de sensibilités et spécificités autour de 75-85%. Ces résultats sont néanmoins à nuancer en raison de la présence probable d'un biais systématique dans les analyses sous-régionales. L'analyse du lien aux autres facteurs et biomarqueurs montre une corrélation positive du métabolisme des sous-régions temporo­ pariétales avec le volume hippocampique. On observe une différence significative de métabolisme dans certaines sous-régions temporo- pariétales (régions hippocampiques,lobes temporaux, gyrus fusiformes) entre les sujets HV+ et les HV-. Concernant le PET-Amyloïde,une corrélation négative est retrouvée. La comparaison des sujets PIB+ et PIB- montre un hypométabolisme significativement plus important dans les sous-régions temporo-pariéta les (lobes temporaux, gyrus angulaires, régions hippocampiques, gyrus fusiformes, lobe pariétal D,gyrus supramarginal G) chez les sujets PIB+.Conclusion : Les sous-régions temporo-pariétales et en particulier les lobes temporaux et gyrus angulaires semblent être les sous-régions les plus discriminantes entre les groupes contrôles et patients MCI et montrent des valeurs de sensibilités et spécificités similaires à celles du score global dans la discrimination des sujets patients MCI. En raison d'un probable biais systématique lié à la méthodologie appliquée, des analyses complémentaires des sous-régions présentant des atteintes métaboliques sévères et des investigations complémentaires dans des sous-groupes de patients MCI sont nécessaires afin d'augmenter la précision et spécificité des résultats. Des liens avec les autres facteurs sont observés, particulièrement au niveau des régions pariéto-temporales.Un suivi longitudinal et des investigations complémentaires en relation avec les autres facteurs sont nécessaires afin de préciser les résultats, d'optimaliser le diagnostic et d'envisager un monitoring thérapeutique. At the present time, the Alzheimer's dementia is an incurable disease. Starting insidiously by more discrete disorders mainly concerning episodic memory, the term "mild cognitive impairment"(MCI) is mostly used to describe this class of subjects with starting cognitive impairment without consequences on the ADL. However, only some MCI subjects will develop an AD.Recently,the development of several biomarkers of AD has allowed a better definition of AD early stages.Objectives of the study : to study the interest of the overall and subregional quantifications of FDG-PET acquisitions and their relation to other biomarkers in the diagnosis of mild cognitive impairment.Type of study: cross-sectional , prospective,exper imental,analytical,controled.Patients and methods : based on the population of a study by the memory clinic (Eudract N° 2009-013030 -25) of the University Hospital St-Luc in Brussels, two groups were set up: the controls (n=31) and the patients (n=60) groups. Mean ages are 70 +/- 5,5 years and 70,9 +/- 8 years. The PALZ and PBRAIN modules from the PMOD Software (Pmod Technologies Ltd ©) were used to obtain overall and subregional scores after creating a database of the controls subjects. Then, comparative statistics between controls and patients groups,on the one hand, controls group and patients MCI subgroup,on the other hand, allowed to observe and compare the relative the relative effectiveness of these scores in the MCIpatient's discrim ination. Finally,a joint analysis of the obtained values and other factors and biomarkers was done.Results: the results showed a temporo-parietal and occipital subregional hypometabolism (temporal lobes, angular gyrus, left Heschl's lobe, hippocampal and parahippocampa l regions, calcarine sulcus) significantly higher in the patients group. The relative sensitivity of some subregions (temporal lobes, angular gyrus) (37- 41%) is comparable to the overall metabolic score (PET-score)(38-44%) in the MCI patient's discrimination. Comprom ises have been found for these scores and offer sensitivity and specificity values of around 75-85 %. However, these results should be nuances due to the probable presence of a systematic bias. Analys is of the link to other factors and biomarkers showed a positive correlation in the temporo-parietal subregions with hippocampal volume. There were significant differenc es in the metabolism of some temporo-parietal subregions (hippocampal and parahippocampal regions, temporal lobes,fusiform gyrus) between HV- and HV+ patient's subgroups. With the amyloïd PET, a negative correlation was found. Comparison between PIB- and PIB+ patient's subgroups showed a significantly higher hypometabolism in temporo-pa rietal subregions (temporal lobes, angular gyrus, hippocampal and parahippocampal regions, fusiforms gyrus, right parietal lobe, left supramarginal gyrus) in the PIB+ patient's subgroup.Conclusions: Parieto-temporal subregions, particularly the temporal lobes and angular gyrus appear to be the most discriminating subregions between controls and MCI patients. These subreg ions show sensitivity and specificity similar to that of the overall score in the discrimination of MCIpatients. The probable presence of a systemat ic bias in the applied methodology lead to the necessity of additional analyzes of sub-regions with severe hypometabolic scores and further investigations in subgroups of MCIpatients to increase the accuracy and specificity of results relative to AD. Relation with other factors was observed, particularly in parieto­ temporal subregions. Longitudinal monitoring and further investigations in relation to other factors are needed to refine the results, to optimize the diagnosis and to plan therapeutic monitoring.

Mild Cognitive Impairment --- Mild Cognitive Impairment --- Alzheimer Disease

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Specific language impairment in children.

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Specific language impairment in children. --- Psycholinguistics

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Improving psychological well-being and cognitive health is now listed as the priority on the healthy aging agenda. Depression and cognitive impairment are great challenges for the elderly population. There have been numerous studies on depression and cognitive impairment and dementia. However, the neural correlates of depression and cognitive impairment have not yet been elucidated. With the development of neuroscience and relevant technologies, studies on anatomical and functional neural networks, neurobiological mechanisms of mood and cognition in old age will provide more insight into the potential diagnosis, prevention and intervention in depression and cognitive impairment. For example, longitudinal neuroimaging studies depicting the trajectories of patterns of structural and functional brain networks of mild cognitive impairment may provide potential imaging markers for the onset of dementia. Population-based studies have addressed the potential interaction between mood and cognitive impairment in old age. However, there are few studies to explore the potential neural mechanism of the relationship between depression and cognitive impairment in old age. In all of this process the contribution of multiple biological events cannot be neglected, particularly the underlying influence of chronic diseases and concomitant polymedication as well as the geriatric conditions, like frailty, frequently present in this elderly population, which also compromise the cognitive function and mood determining depression and conducing to worse outcomes with more morbidity and mortality.

mood disorder --- mild cognitive impairment --- Alzheimer

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Improving psychological well-being and cognitive health is now listed as the priority on the healthy aging agenda. Depression and cognitive impairment are great challenges for the elderly population. There have been numerous studies on depression and cognitive impairment and dementia. However, the neural correlates of depression and cognitive impairment have not yet been elucidated. With the development of neuroscience and relevant technologies, studies on anatomical and functional neural networks, neurobiological mechanisms of mood and cognition in old age will provide more insight into the potential diagnosis, prevention and intervention in depression and cognitive impairment. For example, longitudinal neuroimaging studies depicting the trajectories of patterns of structural and functional brain networks of mild cognitive impairment may provide potential imaging markers for the onset of dementia. Population-based studies have addressed the potential interaction between mood and cognitive impairment in old age. However, there are few studies to explore the potential neural mechanism of the relationship between depression and cognitive impairment in old age. In all of this process the contribution of multiple biological events cannot be neglected, particularly the underlying influence of chronic diseases and concomitant polymedication as well as the geriatric conditions, like frailty, frequently present in this elderly population, which also compromise the cognitive function and mood determining depression and conducing to worse outcomes with more morbidity and mortality.

mood disorder --- mild cognitive impairment --- Alzheimer