Leila Sellami

Distinct neuroanatomical correlates of neuropsychiatric symptoms in the three main forms of genetic frontotemporal dementia in the GENFI Cohort

Background: The overlap between frontotemporal dementia (FTD) and primary psychiatric disorders has been brought to light by reports of prominent neuropsychiatric symptoms (NPS) in FTD-related genetic mutations, particularly among C9orf72 and GRN carriers. It has been recently demonstrated that early neuroanatomical changes in genetic FTD may be different across the major disease-causing mutations. Objective: We aimed to identify whether NPS could be driven by distinct structural correlates. Methods: One hundred and sixty-seven mutation carriers (75 GRN, 60 C9orf72, and 32 MAPT) were included from the Genetic FTD Initiative (GENFI) study, a large international cohort of genetic FTD. Neuropsychiatric symptoms including delusions, hallucinations (visual, auditory, and tactile), depression, and anxiety were investigated using a structured interview. Voxel-based morphometry was performed to identify neuroanatomical correlates of NPS. Results: Psychotic symptoms correlated mainly with grey matter (GM) atrophy in the anterior insula, left thalamus, cerebellum, and cortical regions including frontal, parietal, and occipital lobes in GRN mutations carriers. GM atrophy in posterior structures of the default-mode network was associated with anxiety in the GRN group. Delusions in C9orf72 expansion carriers were mainly associated with left frontal cortical atrophy. Cerebellar atrophy was found to be correlated only with anxiety in C9orf72 carriers. NPS in the MAPT group were mainly associated with volume loss in the temporal lobe. Conclusion: Neuroanatomical correlates of NPS appear to be distinct across the main forms of genetic FTD. Overall, our findings support overlapping brain structural changes between FTD and primary psychiatric disorders.

Validation of the Dépistage Cognitif de Québec: A New Cognitive Screening Tool for Atypical Dementias

Objective This study aimed to validate and provide normative data for the Dépistage Cognitif de Québec (DCQ; www.dcqtest.org), a new cognitive screening tool for atypical dementias. Method The DCQ was developed by expert behavioral neurologists and clinical neuropsychologists based on updated criteria for Alzheimers disease, primary progressive aphasia, and behavioral variant frontotemporal dementia. It targets five relevant domains: Memory, Visuospatial, Executive, Language, and Behavior. Validation was performed in a population-based sample of 410 healthy French-speaking Canadians aged between 50 and 89 years old. Normative data were derived from a subsample of 285 participants. Results Mean DCQ total score (out of 100) was 89.17 (SD = 7.36). Pearsons correlation coefficient showed a strong and significant correlation (r = .71, p < .001) with the Montreal Cognitive Assessment. Internal consistency for the cognitive domains assessed by Cronbachs alpha was satisfactory (.74). Test-retest reliability was adequate (Pearsons coefficient = . 70, p < .001) and interrater reliability, excellent (intraclass correlation = .99, p < .001). Normative data shown in percentiles were stratified by age and education. Conclusions This study suggests that the DCQ is a valid and reliable cognitive screening test. Application of the DCQ on populations with atypical dementias is underway to derive sensitivity and specificity values for various dementias.

Molecular imaging in dementia: Past, present, and future

Molecular imaging techniques using 18F‐fluorodeoxyglucose, amyloid tracers, and, more recently, tau ligands have taken dementia research by storm and undoubtedly improved our understanding of neurodegenerative diseases. The ability to image in vivo the pathological substrates of degenerative diseases and visualize their downstream impact has led to improved models of pathogenesis, better differential diagnosis of atypical conditions, as well as focused subject selection and monitoring of treatment in clinical trials aimed at delaying or preventing the symptomatic phase of Alzheimers disease. In this article, we present the main molecular imaging techniques used in research and practice. We further summarize the key findings brought about by each technique individually and more recently, as adjuncts to each other. Specific limitations of each imaging modality are discussed, as well as recommendations to overcome them. A nonvalidated clinical algorithm is proposed for earlier and more accurate identification of complex/atypical neurodegenerative diseases.

DÉ́PISTAGE COGNITIF DE QUÉBÉC (DCQ): VALIDATION AND NORMATIVE DATA FOR A NOVEL COGNITIVE SCREENING TOOL FOR ATYPICAL DEMENTIAS

Mental State Examination, the original version of the MoCA, and the quality of life scale CASP-19. A multiple regression analysis was performed to verify the influence of age and education and the predictive capacity of the original version of the test on its alternative version. Results: Cronbach’s alpha coefficient was .76. Elimination of any of the items of the 2 version of MoCA never reduces the reliability to below .73. Convergent validity was .65 (p<.001), and divergent validity was .03 (p1⁄40.79). Correlation between the 1 and the 2 version of MoCA was significant and high (r1⁄40.86). There was a negative effect of age (b 1⁄4–0.141, p < 0.01) and a positive effect of education (b 1⁄4–0.549, p < 0.001), but these two effects did not remained significant when the total score of the original form of MoCA was included in the regression model (b1⁄4–0.691, p < 0.001) (Figure1). Conclusions: Our preliminary results showed good psychometrical properties for the 2nd alternative form of the Spanish version and strong relations between forms. Further analyses are required in order to guarantee the use of the alternate Spanish version of the MoCA test in clinical follow-ups and longitudinal studies.

Early-onset versus late-onset Alzheimer’s disease in tunisia

to unknown time of symptom onset. The head MRI demonstrated acute infarction at the left posterior insular cortex. MRA of the head and neck showed only hypoplastic A1 segment of the right anterior cerebral artery and 50 % stenosis of the right internal carotid artery which were not contributory to the acute infarction. 48 hours later, facial droop, disarticulation and word-finding difficulty completely improved. However, multiple domains of cognitive impairment were detected. He scored 20/30 on the Montreal Cognitive Assessment. He had significant impairment in delayed recall, letter & animal fluency and repetition tasks. The memory impairment characterized as retrieval deficit which improved with word cues. Naming was intact either in the MoCA or shortened version of Boston Naming Test. Conclusions: Isolated left posterior insular infarction is extremely rare. This case demonstrates the role of this area in multiple cognitive domains including language-related and verbal memory function. Moreover, this is the first report of the verbal fluency deficit associated with isolated left posterior insular lesion. This area is a convergent structure connecting with multiple brain regions, thus the deficits caused by the left posterior insular lesion is more likely to be a consequence of diaschisis rather than the damage of a specialized or isolated center.