Ageing, Executive Functioning, Transcranial Direct Current Stimulation (tDCS), Transcranial Electric Stimulation
Conditions
Keywords
Randomised Controlled Trial, Non-Invasive Brain Stimulation, Executive Functioning, Transcranial Direct Current Stimulation, Transcranial Pulsed Current Stimulation, Healthy Adults, Ageing
Brief summary
The goal of this randomised controlled trial is to investigate the effects of a 2-week high-frequency transcranial pulsed current stimulation (tPCS) on cognitive outcomes in older and healthy adults. The main questions it aims to answer are: 1. Would a single session of anodal tPCS over the left prefrontal cortex improve working memory, task inhibition, and task switching in healthy young and older adults, compared to anodal transcranial direct current stimulation (tDCS) and sham-tPCS? 2. Would repeated session of anodal-tPCS (2-weeks) lead to improvements in working memory, task inhibition, and task switching in healthy young and older adults, compared to tDCS and sham-tPCS? 3. Will tPCS be better tolerated among healthy adults, compared to tDCS? Researchers will compare tPCS / tDCS / sham-tPCS to see if there are any differences in cognitive outcomes after 1 session and after repeated sessions, as well as to compare the tolerance of tPCS against tDCS and sham-tPCS. Participants will be requested to: * Undergo 1 of 3 of the following conditions: tDCS / tPCS / sham-tPCS * Complete three sessions of cognitive tasks testing working memory, inhibition and task switching at baseline (pre-stimulation), after day 1 of brain stimulation and after 10 sessions of brain stimulation (post- repeated stimulation) * Undergo fNIRS-EEG brain measurements concurrently with the cognitive tasks
Detailed description
tPCS / tDCS and sham-tPCS will be administered between 0.6 to 0.7 mA for 20 minutes. This will take place over 10 consecutive sessions, with a 2 day break between days 5 and 6 of brain stimulation. The setup of the stimulation consists of a saline-soaked sponge anode electrode placed over the left forehead area over the left dorsal lateral prefrontal cortex, and the cathode will be placed over the right parietal cortex. Participants will be randomly assigned to 1 of 3 conditions and this will be blinded to both the participants and the researcher (double-blinded). Cognitive tasks will be administered at baseline, after 1 session of stimulation and after 10 sessions of stimulation (post-stimulation). These cognitive tasks consist of a working memory task (1/2/3 back tasks), a cognitive inhibition task (go/no-go task) and a cognitive flexibility task (Stroop task). Concurrent with the cognitive task will be the administration of fNIRS-EEG recording to measure changes in brain activation and patterns during the tasks. The experiment will take place in the Motor Behaviour Lab at the National Institute of Education, Nanyang Technological University in Singapore.
Interventions
DEVICENon-Invasive Brain Stimulation (tDCS / tPCS / sham-tPCS)
This is a novel non-invasive brain stimulation technique that we hope to be investigating, and this technique will be compared with an active control (tDCS) and a control (sham-tPCS).
Sponsors
Ministry of Education, Singapore
National Institute of Education, Singapore
Nanyang Technological University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
Participants will be randomly assigned to 1 of 3 conditions.
Eligibility
Sex/Gender
ALL
Age
21 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
* Male and female young (21 to 30 years) and older adults (60 to 75 years) * Right-handed * Must be a native English speaker * No clinical diagnosis of neurodevelopmental, mood, neurological or neurodegenerative disorders * Adults with cardiometabolic or cardiovascular conditions may participate if their condition is controlled and stable with medication and / or lifestyle interventions
Exclusion criteria
* Currently on long-term medication for pain or migraines / headaches * Adults with metallic implants in the chest or head region * Adults with epilepsy, or known seizure or immediate family members that have had a seizure before * Had a recent head injury that resulted in a temporary loss of consciousness or of memory in the last 12 months * Had prior head surgery * Prone to fainting * Sensitive skin or prone to skin allergies
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Executive Functioning | Baseline, after day 1 of stimulation, 3 to 4 days after the 10 sessions of stimulation | Working memory through 1-, 2- and 3-back tasks performance Behavioural inhibitory control through Go / No-Go task performance Cognitive flexibility through Stroop task performance |
| Task-based activation and functional connectivity during executive functioning tasks | Baseline, after day 1 of stimulation, 3 to 4 days after the 10 sessions of stimulation | Measuring changes in hemodynamic (oxyhaemoglobin) responses in the brain using Functional Near-Infrared Spectroscopy (fNIRS) |
| Neural function associated with executive functioning tasks | Baseline, after day 1 of stimulation, 3 to 4 days after the 10 sessions of stimulation | Measuring neural activity using electroencephaogram (EEG) whereby traditional EEG bands (e.g. Alpha, Beta, Theta, Delta) will be assessed. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Tolerance of tPCS (intervention) | Immediately after the intervention | Questionnaires on participants' well-being after stimulation sessions \[adapted and modified from Antal et al. (2017)\]. The participants will rate their symptoms / discomfort as follows: none, mild, moderate, or strong and state the extent to which the symptoms / discomfort is / are affecting their general state from a scale of 'Not at all' to 'Very much'. |
Contacts
Primary ContactWei Peng Teo, Associate Professor
Backup ContactShun Xin Koong
Outcome results
None listed