Vascular Cognitive Impairment

People with vascular conditions are at risk of having memory problems, and these memory problems increase the risk for further cognitive decline. Brain stimulation has been used to improve mood and memory. Transcranial direct current stimulation (tDCS) is believed to work best on brain cells that are active or "primed" before stimulation. The purpose of this study is to compare the effects of exercise and tDCS on memory performance in patients who have completed cardiac rehabilitation and are at risk of cognitive decline.

The Mini-Mental State Examination (MMSE) is the most widely used cognitive screening and monitoring test for neurocognitive disorders in current clinical practice. Its French version was published in 1998 by the GRECO group (MMSE-GRECO). However, some items of this French version are not adapted to local Reunionese particularities. The main objective is to propose and validate the psychometric properties of an adapted version of the MMSE, to the Reunionese culture (MMSE-RUN) in a healthy population and in a sick population (Alzheimer's Disease and Vascular Cognitive Disorder), and to compare its performance with the MMSE-GRECO.

The overall goal of the DISCOVERY study is to better understand what factors contribute to changes in cognitive (i.e., thinking and memory) abilities in patients who experienced a stroke. The purpose of the study is to help doctors identify patients at risk for dementia (decline in memory, thinking and other mental abilities that significantly affects daily functioning) after their stroke so that future treatments may be developed to improve outcomes in stroke patients. For this study, a "stroke" is defined as either (1) an acute ischemic stroke (AIS, or blood clot in the brain), (2) an intracerebral hemorrhage (ICH, or bleeding in the brain), (3) or an aneurysmal subarachnoid hemorrhage (aSAH, or bleeding around the brain caused by an abnormal bulge in a blood vessel that bursts). The investigators hypothesize that: 1. The size, type and location of the stroke play an important role in recovery of thinking and memory abilities after stroke, and pre-existing indicators of brain health further determine the extent of this recovery. 2. Specific stroke events occurring in individuals with underlying genetic or biological risk factors can cause further declines in brain heath, leading to changes in thinking and memory abilities after stroke. 3. Studying thinking and memory alongside brain imaging and blood samples in patients who have had a stroke allows for earlier identification of declining brain health and development of individualized treatment plans to improve patient outcomes in the future.

The mechanism underlying memory impairment caused by white matter lesions of cerebral small vessel disease is still unclear. The disrupted synchronization of gamma oscillations in the prefrontal-hippocampal circuit is a potential key mechanism. Our study has demonstrated that white matter lesions lead to demyelination of the connection tracts between the prefrontal lobe and hippocampus, which is closely related to memory dysfunction. However, further studies are required to explore if these microstructural changes in white matter tracts influence memory function by affecting gamma oscillations. Thus, this project will use the previously established episodic memory task and event-related potential to determine the changes in gamma oscillations in the prefrontal-hippocampal circuit and the effects on memory encoding and retrieval. Combining multimodal imaging, we will explore the mediating role of white matter microstructure damage, and establish a machine learning prediction model for memory impairment. In addition, transcranial alternation current stimulation (tACS) will be used to investigate the mechanisms of memory improvement by regulating the prefrontal-hippocampal gamma oscillations. This project will clarify the neural oscillation mechanism underlying memory impairment caused by white matter lesions of cerebral small vessel disease, with the expectation of providing new predictive indicators and interventions.

A study conducted in Finland discovered that a multidomain intervention, consisting of physical activity, nutritional guidance, cognitive training, social activities, and management of vascular risk factors, effectively decelerated cognitive decline in healthy older adults who were at an increased risk of cognitive decline. The HERITAGE study is a 2-year clustered randomized controlled trial (clustered-RCT) that explores the efficacy of a multidomain intervention among 1200 elderly residents with a higher risk of cognitive decline and dementia in Zhejiang Province, China