Differential spatial distribution of white matter lesions in Parkinson's and Alzheimer's diseases and cognitive sequelae.

White Matter Lesions (WML) are a radiological finding common in aged subjects. We explored the impact of WML on underlying neurodegenerative processes. We focused on the impact of WML on two neurodegenerative diseases with different pathology. In this cross-sectional study of 137 subjects (78 female, 59 men, mean age 67.2; 43-87 years), we compared WML in healthy controls (HC; n = 55), patients with Alzheimer's disease and amnestic Mild Cognitive Impairment (aMCI), and Parkinson's disease patients with normal cognition and with MCI. Subjects with AD and aMCI were treated as one group (n = 40), subjects with PD and PDMCI were another group (n = 42). MRI T2_FLAIR sequences were analyzed. WML were divided into periventricular (pWML) or subcortical (sWML) depending on their distance from the ventricles. Subjects from the AD + aMCI group, had a significantly greater volume of WML than both HC and the PD + PDMCI group. The volume of WML was greater in the PD + PDMCI than in HC but the difference was not significant. In AD + aMCI subjects, sWML and not pWML were related to a decrease in global cognitive functioning despite greater volume of pWML. In PD + PDMCI, pWML correlate with decline in executive functions and working memory. In HC, pWML correlated with the multidomain decrease corresponding with the aging. This points to a difference between normal aging and pathological aging due to AD and PD brain pathology. The WML location together with underlying disease related neurodegeneration may play a role in determining the effect of WML on cognition. Our results suggest that the impact of WML is not uniform in all patients; rather, their volume, location and cognitive effect may be disease-specific.

Impact of cognitive reserve on dance intervention-induced changes in brain plasticity.

Dance is a complex sensorimotor activity with positive effects on physical fitness, cognition, and brain plasticity in the aging population. We explored whether individual levels of cognitive reserve (CR) proxied by education moderate dance intervention (DI)-induced plasticity assessed by resting-state functional connectivity (rs-FC) changes of the sensorimotor network (SMN), and between the dorsal attention network (DAN) and anterior default mode network (aDMN). Our cohort consisted of 99 subjects, randomly assigned to either a DI group who underwent a 6-month intervention (n = 49, Mage = 69.02 ± 5.40) or a control group (n = 50, Mage = 69.37 ± 6.10). Moderation analyses revealed that CR moderated DI-induced increase of the SMN rs-FC with significant changes observed in participants with ≥ 15 years of education (b = 0.05, t(62) = 3.17, p = 0.002). Only DI alone was a significant predictor of the DAN-aDMN crosstalk change (b = 0.06, t(64) = 2.16, p = 0.035). The rs-FC increase in the SMN was correlated with an improved physical fitness measure, and changes in the DAN-aDMN connectivity were linked to better performance on figural fluency. Consistent with the passive CR hypothesis, we observed that CR correlated only with baseline behavioral scores, not their change.

Dynamic Functional Connectivity Signifies the Joint Impact of Dance Intervention and Cognitive Reserve.

Research on dance interventions (DIs) in the elderly has shown promising benefits to physical and cognitive outcomes. The effect of DIs on resting-state functional connectivity (rs-FC) varies, which is possibly due to individual variability. In this study, we assessed the moderation effects of residual cognitive reserve (CR) on DI-induced changes in dynamic rs-FC and their association on cognitive outcomes. Dynamic rs-FC (rs-dFC) and cognitive functions were evaluated in non-demented elderly subjects before and after a 6-month DI (n = 36) and a control group, referred to as the life-as-usual (LAU) group (n = 32). Using linear mixed models and moderation, we examined the interaction effect of DIs and CR on changes in the dwell time and coverage of rs-dFC. Cognitive reserve was calculated as the residual difference between the observed memory performance and the performance predicted by brain state. Partial correlations accounting for CR evaluated the unique association between changes in rs-dFC and cognition in the DI group. In subjects with lower residual CR, we observed DI-induced increases in dwell time [t(58) = -2.14, p = 0.036] and coverage [t(58) = -2.22, p = 0.030] of a rs-dFC state, which was implicated in bottom-up information processing. Increased dwell time was also correlated with a DI-induced improvement in Symbol Search (r = 0.42, p = 0.02). In subjects with higher residual CR, we observed a DI-induced increase in coverage [t(58) = 2.11, p = 0.039] of another rs-dFC state, which was implicated in top-down information processing. The study showed that DIs have a differential and behaviorally relevant effect on dynamic rs-dFC, but these benefits depend on the current CR level.

Cognitive effects of dance-movement intervention in a mixed group of seniors are not dependent on hippocampal atrophy.

Dance-movement intervention (DMI) offers multi-component stimulation of cognitive functions, and it may ameliorate cognitive deficits in the elderly. We investigated the effects of intensive DMI on the cognitive performances of healthy seniors (HS) and patients with mild cognitive impairment (MCI). In addition, we evaluated whether the baseline MRI hippocampus-to-cortex volume (HV:CTV) ratio (i.e., a marker of a typical AD-specific brain atrophy and of distribution of neurofibrillary tangles in the brain) has any impact on the DMI-induced cognitive changes. The research cohort consisted of 99 subjects who were randomly assigned (in a 1:1 ratio) to a DMI group or to a control (life-as-usual) group. The DMI group consisted of 49 subjects with an average age of 69.16 years (SD = 5.36), of which 34 were HS (69.4%) and 15 had MCI (30.6%). The control group consisted of 50 subjects aged 68.37 years (SD = 6.10), of which 31 were HC (62%) and 19 (38%) had MCI. The DMI group underwent a 6-month intervention, which consisted of 60 lessons supervised by a qualified instructor. Statistical analysis yielded a significant improvement of the figural fluency task as measured by the five-point test in the DMI group as compared to the control group [t (97) = 2.72; p = 0.008]. The baseline HV:CTV ratio was not associated with cognitive changes on that task or with changes in any cognitive domain's Z scores. We observed DMI-induced effect on the test evaluating executive functions across the spectrum of HS and MCI, which was not dependent on the magnitude of AD-related brain pathology.