Implication of Cognitive Reserve in Non-pharmacological Intervention Outcomes
NCT Number: NCT06563453
Status: RECRUITING
Study Type: INTERVENTIONAL
Phases: NA
Conditions: Aging|Mild Cognitive Impairment|Dementia With Lewy Bodies
Interventions: DEVICE: transcranial alternating current stimulation
Sponsor: Masaryk University
Sex: ALL
Age: ADULT, OLDER_ADULT
Enrollment: 55
Study Design: Allocation: RANDOMIZED|Intervention Model: CROSSOVER|Masking: SINGLE (PARTICIPANT)|Primary Purpose: SUPPORTIVE_CARE
Start Date: 2021-05-01
Completion Date: 2024-12-31
Locations: CEITEC Masaryk University, Brno, 62500, Czechia

Summary:
Cognitive reserve (CR) is defined as the gradual accumulation of neural resources and their adaptability (i.e., efficiency, capacity, flexibility) due to genetic and/or lifelong environmental factors that mitigate the cognitive effects of age-related processes and brain diseases. Transcranial alternating current stimulation (tACS) can be used to entrain underlying neuronal networks, promoting firing at specific frequencies. Recent studies have demonstrated that fronto-parietal theta oscillatory activity entrainment via tACS leads to working memory enhancement in healthy subjects. However, there remains significant variability in stimulation-induced aftereffects across individuals.

Emerging literature suggests that individual differences, such as CR levels, may be crucial in predicting the benefits of treatment interventions, as they reflect available neural capacity and flexibility. A novel interventional approach is proposed to study CR, utilizing both conventional static proxies, such as premorbid intellect and educational attainment, and dynamic markers, including pupillometry, resting-state, and task-induced functional MRI. By employing cutting-edge noninvasive brain stimulation (NIBS) techniques, the study will acutely modulate network properties to examine the influence of CR on immediate cognitive and brain functional aftereffects induced by the intervention. In addition to focusing on cognitively healthy older adults, this study will, for the first time, include patients with mild cognitive impairment with Lewy bodies (MCI-LB), a prodromal stage of the second most common degenerative dementia after Alzheimer's disease.

Primary Outcome Measures: Accuracy and reaction times of the visual N-back task in tACS conditions:tACS conditions, 'Online' working memory (WM) task accuracy and reaction times (RT) in both active and sham tACS conditions.

tACS conditions, 3.5 years|Accuracy and reaction times of the verbal N-back task in tACS conditions: tACS conditions, 'Offline' WM task accuracy and reaction times (RT) in both active and sham tACS conditions.

tACS conditions, 3.5 years
Secondary Outcome Measures: Cognitive reserve moderator:, Identification of which cognitive reserve proxies or indexes are most effective at moderating tACS-induced changes., 3.5 years|tACS-induced functional connectivity changes:, tACS-induced neural changes, including resting-state functional connectivity (rs-FC) within and between large-scale brain networks, dynamic rs-fMRI measures, and task-induced BOLD (Blood-Oxygen-Level Dependent) signal increases assessed at baseline and immediately after each stimulation., 3.5 years|Pupillary changes, Measures of pupil dilation during the N-back task performance., 3.5