Functional Connectivity, Physical Activity, and Neurocognitive Performances in Patients with Vascular Cognitive Impairment, No Dementia

Effects of exercise on patients with vascular cognitive impairment based on ACSM recommendations: a systematic review of randomized controlled trials

BACKGROUND

Exercise is considered to be an effective method for functional recovery in patients with vascular cognitive impairment (VCI), but there is a paucity of research on exercise dosage. There has been no meta-analysis of the effects of exercise therapy for vascular cognitive impairment based on the American College of Sports Medicine (ACSM) exercise prescription for a seemingly healthy population. We therefore conducted a study to analyze the effects of various exercise therapies on cognitive functioning, physical functioning, and ability to perform activities of daily living in patients diagnosed with vascular cognitive impairment.

METHODS

Four electronic databases, namely PubMed, Embase, Web of Science, and Cochrane, were systematically searched for studies examining the effects of exercise on patients with VCI. The exercise interventions were categorized into an ACSM high adherence group versus an ACSM low or indeterminate adherence group, following the recommendations for exercise testing and prescribing for seemingly healthy populations developed by ACSM. Meta-analyses were conducted using a random effects model to compare results among subgroups.

RESULTS

The study encompassed 14 trials involving 1333 subjects. Among these, 8 studies adhered highly to ACSM recommendations, while 6 studies demonstrated low or uncertain adherence. Subgroup analyses revealed differing effects: in the high adherence group, SMDs for cognitive functioning, living ability, and physical functioning were 0.53 (95% CI 0.13-0.94), 0.53 (95% CI 0.11-0.94), and 0.66 (95% CI 0.45-0.87), respectively. Conversely, in the low or indeterminate adherence group, SMDs for cognitive functioning, living ability, and physical functioning were 0.09 (95% CI - 0.13 to 0.32), - 0.11 (95% CI - 0.57 to 0.34), and 0.65 (95% CI - 0.04 to 1.35). We performed subgroup analyses by type of vascular cognitive impairment, and meta-analyses showed positive SMDs of 0.59 (95% CI 0.22-0.97) and 0.68 (95% CI 0.47-0.90) for exercise on cognitive impairment after stroke in terms of cognitive function and physical function, respectively.

CONCLUSION

The results suggest that exercise interventions exhibiting high adherence to ACSM guidelines yield more favorable outcomes concerning cognitive functioning, physical functioning, and daily living abilities among patients with VCI compared to interventions with low or uncertain adherence to ACSM recommendations.

Quantifying Apathy in Late-Life Depression: Unraveling Neurobehavioral Links Through Daily Activity Patterns and Brain Connectivity Analysis

BACKGROUND

Better understanding apathy in late-life depression would help improve prediction of poor prognosis of diseases such as dementia. Actimetry provides an objective and ecological measure of apathy from patients' daily motor activity. We aimed to determine whether patterns of motor activity were associated with apathy and brain connectivity in networks that underlie goal-directed behaviors.

METHODS

Resting-state functional magnetic resonance imaging and diffusion magnetic resonance imaging were collected from 38 nondemented participants with late-life depression. Apathy was evaluated using the diagnostic criteria for apathy, Apathy Evaluation Scale, and Apathy Motivation Index. Functional principal components (fPCs) of motor activity were derived from actimetry recordings taken for 72 hours. Associations between fPCs and apathy were estimated by linear regression. Subnetworks whose connectivity was significantly associated with fPCs were identified via threshold-free network-based statistics. The relationship between apathy and microstructure metrics was estimated along fibers by diffusion tensor imaging and a multicompartment model called neurite orientation dispersion and density imaging via tractometry.

RESULTS

We found 2 fPCs associated with apathy: mean diurnal activity, negatively associated with Apathy Evaluation Scale scores, and an early chronotype, negatively associated with Apathy Motivation Index scores. Mean diurnal activity was associated with increased connectivity in the default mode, cingulo-opercular, and frontoparietal networks, while chronotype was associated with a more heterogeneous connectivity pattern in the same networks. We did not find significant associations between microstructural metrics and fPCs.

CONCLUSIONS

Our findings suggest that mean diurnal activity and chronotype could provide indirect ambulatory measures of apathy in late-life depression, associated with modified functional connectivity of brain networks that underlie goal-directed behaviors.

Neuroscience meets behavior: A systematic literature review on magnetic resonance imaging of the brain combined with real-world digital phenotyping

A primary goal of neuroscience is to understand the relationship between the brain and behavior. While magnetic resonance imaging (MRI) examines brain structure and function under controlled conditions, digital phenotyping via portable automatic devices (PAD) quantifies behavior in real-world settings. Combining these two technologies may bridge the gap between brain imaging, physiology, and real-time behavior, enhancing the generalizability of laboratory and clinical findings. However, the use of MRI and data from PADs outside the MRI scanner remains underexplored. Herein, we present a Preferred Reporting Items for Systematic Reviews and Meta-Analysis systematic literature review that identifies and analyzes the current state of research on the integration of brain MRI and PADs. PubMed and Scopus were automatically searched using keywords covering various MRI techniques and PADs. Abstracts were screened to only include articles that collected MRI brain data and PAD data outside the laboratory environment. Full-text screening was then conducted to ensure included articles combined quantitative data from MRI with data from PADs, yielding 94 selected papers for a total of N = 14,778 subjects. Results were reported as cross-frequency tables between brain imaging and behavior sampling methods and patterns were identified through network analysis. Furthermore, brain maps reported in the studies were synthesized according to the measurement modalities that were used. Results demonstrate the feasibility of integrating MRI and PADs across various study designs, patient and control populations, and age groups. The majority of published literature combines functional, T1-weighted, and diffusion weighted MRI with physical activity sensors, ecological momentary assessment via PADs, and sleep. The literature further highlights specific brain regions frequently correlated with distinct MRI-PAD combinations. These combinations enable in-depth studies on how physiology, brain function and behavior influence each other. Our review highlights the potential for constructing brain-behavior models that extend beyond the scanner and into real-world contexts.

A mini-review on functional magnetic resonance imaging on brain structure of vascular cognitive impairment

Vascular cognitive impairment (VCI) is the initial stage of vascular dementia (VaD). Early diagnosis and treatment of VCI are crucial to prevent the progression of VaD. In order to gain a better understanding of VCI, this study aimed to investigate the use of advanced imaging techniques such as structural magnetic resonance imaging (sMRI) and resting-state functional magnetic resonance imaging (rs-fMRI). These techniques allow researchers to observe the structural and functional changes in the brain that are associated with VCI. Functional magnetic resonance imaging (fMRI) and sMRI techniques have been widely used in studies focusing on gray matter, brain networks, and functional abnormalities during rest. By searching and summarizing recent literature, this study has provided valuable evidence on the use of advanced imaging techniques in understanding and treating VCI. The findings from this study can aid in the development of early intervention strategies for patients with VCI, potentially slowing down or even halting the progression of VCI to full-blown VaD.