90 research outputs found

    Protective personality traits: High openness and low neuroticism linked to better memory in multiple sclerosis

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    Memory impairment in multiple sclerosis (MS) is common, although few risk/protective factors are known

    Cognitive reserve in granulin-related frontotemporal dementia: from preclinical to clinical stages

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    OBJECTIVE Consistent with the cognitive reserve hypothesis, higher education and occupation attainments may help persons with neurodegenerative dementias to better withstand neuropathology before developing cognitive impairment. We tested here the cognitive reserve hypothesis in patients with frontotemporal dementia (FTD), with or without pathogenetic granulin mutations (GRN+ and GRN-), and in presymptomatic GRN mutation carriers (aGRN+). METHODS Education and occupation attainments were assessed and combined to define Reserve Index (RI) in 32 FTD patients, i.e. 12 GRN+ and 20 GRN-, and in 17 aGRN+. Changes in functional connectivity were estimated by resting state fMRI, focusing on the salience network (SN), executive network (EN) and bilateral frontoparietal networks (FPNs). Cognitive status was measured by FTD-modified Clinical Dementia Rating Scale. RESULTS In FTD patients higher level of premorbid cognitive reserve was associated with reduced connectivity within the SN and the EN. EN was more involved in FTD patients without GRN mutations, while SN was more affected in GRN pathology. In aGRN+, cognitive reserve was associated with reduced SN. CONCLUSIONS This study suggests that cognitive reserve modulates functional connectivity in patients with FTD, even in monogenic disease. In GRN inherited FTD, cognitive reserve mechanisms operate even in presymptomatic to clinical stages

    Left frontal hub connectivity delays cognitive impairment in autosomal-dominant and sporadic Alzheimer's disease

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    Patients with Alzheimer's disease vary in their ability to sustain cognitive abilities in the presence of brain pathology. A major open question is which brain mechanisms may support higher reserve capacity, i.e. relatively high cognitive performance at a given level of Alzheimer's pathology. Higher functional MRI-assessed functional connectivity of a hub in the left frontal cortex is a core candidate brain mechanism underlying reserve as it is associated with education (i.e. a protective factor often associated with higher reserve) and attenuated cognitive impairment in prodromal Alzheimer's disease. However, no study has yet assessed whether such hub connectivity of the left frontal cortex supports reserve throughout the evolution of pathological brain changes in Alzheimer's disease, including the presymptomatic stage when cognitive decline is subtle. To address this research gap, we obtained cross-sectional resting state functional MRI in 74 participants with autosomal dominant Alzheimer's disease, 55 controls from the Dominantly Inherited Alzheimer's Network and 75 amyloid-positive elderly participants, as well as 41 amyloid-negative cognitively normal elderly subjects from the German Center of Neurodegenerative Diseases multicentre study on biomarkers in sporadic Alzheimer's disease. For each participant, global left frontal cortex connectivity was computed as the average resting state functional connectivity between the left frontal cortex (seed) and each voxel in the grey matter. As a marker of disease stage, we applied estimated years from symptom onset in autosomal dominantly inherited Alzheimer's disease and cerebrospinal fluid tau levels in sporadic Alzheimer's disease cases. In both autosomal dominant and sporadic Alzheimer's disease patients, higher levels of left frontal cortex connectivity were correlated with greater education. For autosomal dominant Alzheimer's disease, a significant left frontal cortex connectivity × estimated years of onset interaction was found, indicating slower decline of memory and global cognition at higher levels of connectivity. Similarly, in sporadic amyloid-positive elderly subjects, the effect of tau on cognition was attenuated at higher levels of left frontal cortex connectivity. Polynomial regression analysis showed that the trajectory of cognitive decline was shifted towards a later stage of Alzheimer's disease in patients with higher levels of left frontal cortex connectivity. Together, our findings suggest that higher resilience against the development of cognitive impairment throughout the early stages of Alzheimer's disease is at least partially attributable to higher left frontal cortex-hub connectivity

    Looking into cognitive impairment in primary-progressive multiple sclerosis

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    reserved6siBackground and purpose: Cognitive impairment in primary-progressive multiple sclerosis (PP-MS) is correlated with global brain atrophy. Unfortunately, brain volume computation requires processing resources that are not widely available in clinical practice. Therefore, we decided to test the predictive role of retinal atrophy metrics on cognitive decline, applying them as a proxy of gray matter atrophy in PP-MS. Methods: Twenty-five patients with PP-MS completed the Brief International Cognitive Assessment for Multiple Sclerosis and underwent spectral-domain optical coherence tomography (OCT) and 3.0-T magnetic resonance imaging. We tested, through a stepwise logistic regression, whether OCT metrics [retinal nerve fiber layer, ganglion cell + inner plexiform layer (GCIPL) and total macular volume] predicted cognitive impairment and explored the role of gray matter atrophy in mediating these correlations. Results: Among OCT metrics, only GCIPL was associated with cognitive impairment (rp = 0.448, P = 0.036) and predictive of objective cognitive impairment (Wald [1] = 4.40, P = 0.036). Controlling for demographics, normalized brain volume and thalamic volume were correlated with GCIPL (rp = 0.427, P = 0.047 and rp = 0.674, P = 0.001, respectively) and cognitive scores (rp = 0.593, P = 0.004 and rp = 0.501, P = 0.017, respectively), with thalamic volume nearly mediating the association between GCIPL and cognition (Sobel z = 1.86, P = 0.063). Conclusions: The GCIPL thickness is a suitable measure of neurodegeneration. In comparison with brain atrophy, GCIPL offers higher histopathological specificity, being a pure correlate of neuronal loss, and may be a non-invasive, easy-to-perform way to quantitatively evaluate and monitor neuronal loss related to cognitive impairment in PP-MS.mixedPetracca M.; Sumowski J.; Fabian M.; Miller A.; Lublin F.; Inglese M.Petracca, M.; Sumowski, J.; Fabian, M.; Miller, A.; Lublin, F.; Inglese, M
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