The pattern of cortical thickness associated with executive dysfunction in MCI and SCC: The MEMENTO cohort.

BACKGROUND: The association between the pattern of cortical thickness (CT) and executive dysfunction (ED) in mild cognitive impairment (MCI) and subjective cognitive complaints (SCC) is still poorly understood. We aimed to investigate the association between CT and ED in a large French cohort (MEMENTO) of 2323 participants with MCI or SCC. METHODS: All participants with available CT and executive function data (verbal fluency and Trail Making Test [TMT]) were selected (n=1924). Linear regressions were performed to determine relationships between executive performance and the brain parenchymal fraction (BPF) and CT using FreeSurfer. RESULTS: The global executive function score was related to the BPF (sß: 0.091, P<0.001) and CT in the right supramarginal (sß: 0.060, P=0.041) and right isthmus cingulate (sß: 0.062, P=0.011) regions. Literal verbal fluency was related to the BPF (sß: 0.125, P<0.001) and CT in the left parsorbitalis region (sß: 0.045, P=0.045). Semantic verbal fluency was related to the BPF (sß: 0.101, P<0.001) and CT in the right supramarginal region (sß: 0.061, P=0.042). The time difference between the TMT parts B and A was related to the BPF (sß: 0.048, P=0.045) and CT in the right precuneus (sß: 0.073, P=0.019) and right isthmus cingulate region (sß: 0.054, P=0.032). CONCLUSIONS: In a large clinically based cohort of participants presenting with either MCI or SCC (a potential early stage of Alzheimer's disease [AD]), ED was related to the BPF and CT in the left pars orbitalis, right precuneus, right supramarginal, and right isthmus cingulate regions. This pattern of lesions adds knowledge to the conventional anatomy of ED and could contribute to the early diagnosis of AD.

Detection of depressive symptomatology in elderly people: a short version of the CES-D scale.

This study aims to test a short form of the Center for Epidemiological Studies--Depression Scale (CES-D) which can be a useful screening tool for depressive symptomatology in epidemiological studies of elderly patients. The study was conducted on 2792 subjects from the PAQUID (Personnes Agées QUID?) cohort, an epidemiological survey of community dwellers living in South-West France. CES-D items with high sensitivity and good specificity were selected for the short form, then the best cut-off scores were determined with Receiver Operating Characteristics (ROC) curves. The external validity of the 5-item scale was then assessed against the full scale at different PAQUID follow-ups. Sensitivity was 99% and specificity 81% for detecting depressive symptomatology when compared to the 20-item scale. The external validity on the different follow-ups was good, yielding a sensitivity varying from 95 to 100%, and a specificity from 83 to 89%. In conclusion, the 5-item CES-D is a simple, rapid and reliable tool which could be useful for screening depressive symptoms in epidemiological studies of the elderly.

Deterioration of controlled processes in the preclinical phase of dementia: a confirmatory analysis.

Preclinical deficits in dementia have recently been investigated in the PAQUID cohort by means of a principal component analysis (PCA) performed from various test scores. According to the interpretation of the first PCA factor, which was found to be an independent predictor of dementia 2 years later, the authors suggested that cognitive deficits occurring in the preclinical phase of dementia may reflect the deterioration of controlled processes. Because this hypothesis relies essentially on the interpretation of PCA factors, the present study was designed to test it within the same cohort. The analyses were focused on one of the tests administered to the subjects, the Wechsler Paired Associate Test (WPAT) divided into two subscores in order to provide a measure of controlled processes of memory functioning (i.e. retrieval of unrelated pairs) as well as of more automatic processes (i.e. retrieval of related pairs). The results showed that the future demented subjects, although significantly impaired compared to elderly controls, were able to increase their performance across trials. More importantly, a new PCA including the subscores of the WPAT showed that the unrelated pair scores were strongly correlated to factor 1, which remained the only factor associated with subsequent dementia, whereas the related pair scores were rather correlated to factor 2. Therefore, these results confirm our previous PCA interpretation, lending more weight to our hypothesis of a preclinical impairment of controlled processes in dementia.