Neural Correlates of Repeated tDCS

Study Overview
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Brief Summary
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Healthy ageing and pathological ageing in the context of a neurodegenerative disease are both associated with changes in brain network integrity. Episodic memory is especially affected in Alzheimer's disease, but is also decreased in healthy ageing. Consequently, the memory-relevant brain networks are especially altered. Transcranial direct current stimulation (tDCS) has previously been implemented in different clinical- and non-clinical settings and has shown to beneficially influence network connectivity. The neural correlates of single-session tDCS have been investigated, however, the neural effects of repeated tDCS remain unknown. Furthermore, knowledge about the (long-term) neural mechanisms of repeated tDCS can give valuable insights and possibly pave the ground for exploring tDCS as a treatment option in future studies.

Official Title
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Investigating the Neural Correlates of Repeated tDCS in MCI and Healthy Ageing With fMRI

Conditions
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Mild Cognitive Impairment

Intervention / Treatment
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* Device: active tDCS
* Device: sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients Diagnosis of MCI based on the latest research criteria (clinical assessment at the memory clinic (prof. Frans RJ Verhey): presence of at least a memory impairment, memory complaints expressed by the patient or informant, no problems in daily life functioning, no dementia and presence of biomarkers (Albert et al., 2011) Clinical Dementia Rating score of 0.5 (CDR distinguishes a stage of questionable dementia (CDR 0.5) from people termed healthy (CDR 0) and those with mild dementia (CDR 1) Mini-Mental State Examination (MMSE) 23 and being mentally competent (in general, individuals with a MMSE 18 are considered mentally competent) Age: between 60 and 85 years old 50% female Right-handedness Average level of education (CBS level 3-4-5-6) Healthy controls Average neuropsychological test results, in accordance with normative data, corrected for age, education and gender No substantial memory complaints (according to the participant) Age: between 60 and 85 years old 50% female Right-handedness Average level of education (CBS level 3-4-5-6) Normal or corrected to normal vision Exclusion Criteria: Psychoactive medication use Abuse of alcohol and drugs Cognitive impairment due to alcohol/drug abuse or abuse of other substances Past or present psychiatric or neurological disorders (major depression, schizophrenia, bipolar disorder, psychotic disorder (or treatment for it), epilepsy, stroke, Parkinson's disease, multiple sclerosis, brain surgery, brain trauma, electroshock therapy, kidney dialysis, Menière's disease, brain infections) Major vascular disorders (e.g. stroke) Heart diseases or pacemakers Contraindications for scanning (e.g. brain surgery, cardiac pacemaker, metal implants, claustrophobia, body tattoos) Large scars or fresh wounds on the scalp

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: MCI-active<br>Patients will receive verum tDCS over the angular gyrus on five consecutive days. | Device: active tDCS<br>* Participants will receive active tDCS over the angular gyrus on five consecutive days<br>|
| Sham Comparator: MCI-sham<br>Patients will receive sham tDCS over the angular gyrus on five consecutive days. | Device: sham tDCS<br>* Participants will receive sham tDCS over the angular gyrus on five consecutive days<br>|
| Experimental: Healthy Old-active<br>Participants will receive verum tDCS over the angular gyrus on five consecutive days. | Device: active tDCS<br>* Participants will receive active tDCS over the angular gyrus on five consecutive days<br>|
| Sham Comparator: Healthy old-sham<br>Participants will receive sham tDCS over the angular gyrus on five consecutive days. | Device: sham tDCS<br>* Participants will receive sham tDCS over the angular gyrus on five consecutive days<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| neural changes after multi-session tDCS | fMRI-BOLD response | 5-12 days | 
| network changes after multi-session tDCS | functional connectivity between network hubs | 5-12 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Task performance changes after multi-session tDCS | BPS-score | 5-12 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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tDCS, Mild Cognitive Impairment, fMRI, Healthy ageing