The Effects of Transcranial Temporal Interferential Electrical Stimulation on Cognitive Function, Dual-Task Performance and Neuroplasticity in Individuals With Mild Cognitive Impairment
Phase: NA
Conditions: Mild Cognitive Impairment (MCI)
Sponsor: Shanghai University of Sport

STUDY PROTOCOL 
Study Official Title: 
The Effects of Transcranial Temporal Interferential Electrical Stimulation on 
Cognitive Function, Dual-Task Performance and Neuroplasticity in Individuals 
with Mild Cognitive Impairment 
 
Unique Protocol ID: 102772025RT208 
NCT Number: not yet assigned 
Secondary ID: ChiCTR2600119709 
 
Sponsor: 
Shanghai University of Sport 
No. 650 Qingyuan Ring Road, Yangpu District, Shanghai, 200438, China 
 
Principal Investigator: 
Weijie Fu, PhD 
Shanghai University of Sport 
Tel: +86 21 6550 7368 
Email: fuweijie@sus.edu.cn 
 
Funding Source: 
National Natural Science Foundation of China (NSFC) 
 
Protocol Version: 1.3 
Date: April 4, 2026 
 
 
 

1. ABSTRACT 
Background: Mild cognitive impairment (MCI) is a critical window for 
Alzheimer’s disease (AD) intervention. Patients with MCI often exhibit both 
cognitive decline and impaired dual-task performance (e.g., walking while 
talking). Non-invasive deep brain stimulation using temporal interference 
(tTIS) can target the hippocampus, a key region for memory and motor-
cognitive integration. 
Objective: To investigate the immediate effects of a single session of 
individualized hippocampal tTIS on cognitive function, dual-task performance, 
and working memory in MCI, and to elucidate the underlying neuroplasticity 
mechanisms using multimodal neuroimaging. 
Design: Randomized, double-blind, sham-controlled, crossover trial. 
Population: 40 community-dwelling adults aged 60–80 years with MCI 
(MoCA < 26, CDR = 0.5, ADL < 26, no dementia). 
Intervention: Single 20-minute session of individualized 5 Hz tTIS targeting 
the left hippocampus (2 mA, 2000/2005 Hz carriers) vs. sham stimulation, with 
a 7-day washout. 
Outcomes: Primary: change in MoCA score, gait and balance dual-task cost, 
and working memory performance. Secondary: change in brain function 
(fMRI, EEG) and brain structure (MRI). 
 
2. INTRODUCTION 
2.1 Background and Rationale 
MCI affects 15–20% of older adults in China, with an annual conversion rate 
to AD of 10–15%. Current pharmacological treatments have limited efficacy, 
highlighting an urgent need for non-pharmacological interventions. The 
hippocampus is one of the earliest brain regions affected in AD and is crucial 
for memory and motor-cognitive integration. Non-invasive brain stimulation 
techniques such as tTIS can modulate deep brain structures without surgery. 
Preliminary data from our pilot study (n=14) showed that a single session of 

hippocampal tTIS significantly increased left hippocampal neural complexity 
(p<0.001) and improved face-name memory accuracy (p=0.003), with 
excellent tolerability. 
 
2.2 Study Objectives 
Primary Objective: 
• 
To determine whether a single session of individualized 5 Hz 
hippocampal tTIS, compared to sham, improves cognitive function 
(MoCA), dual-task performance (gait and balance), and working 
memory in MCI patients. 
Secondary Objectives: 
• 
To evaluate the safety, tolerability, and blinding effectiveness of tTIS in 
MCI. 
• 
To elucidate the immediate neuroplasticity mechanisms using 
multimodal MRI (fMRI, MRS, ASL, QSM, DTI) and EEG, focusing on 
changes in brain function and brain structure. 
 
3. STUDY DESIGN 
3.1 Overall Design 
This is a randomized, double-blind, sham-controlled, crossover trial. 
Participants will receive both active and sham tTIS in random order, with a 7-
day washout period between sessions. 
 
Study Flow Diagram: 
Visit 
Activity 
Screening (V0) 
Informed consent, medical history, MoCA, CDR, ADL, 
GDS, MRI safety check. 

Visit 
Activity 
Visit 1 (Baseline) 
Randomization, T1 MRI for individualized modeling, 
baseline assessments (cognitive, dual-task, fMRI, 
EEG). 
Visit 2 
(Intervention 1) 
First stimulation (active or sham), post-stimulation 
assessments (MoCA, dual-task, working memory, 
fMRI, EEG). 
Washout (7 days) 
No intervention. 
Visit 3 
(Intervention 2) 
Second stimulation (the opposite type), post-
stimulation assessments. 
 
3.2 Study Population 
Inclusion Criteria: 
• 
Age 60–80 years, community-dwelling 
• 
Montreal Cognitive Assessment (MoCA) score < 26 
• 
Clinical Dementia Rating (CDR) score = 0.5 
• 
Activities of Daily Living (ADL) score < 26 (intact daily function) 
• 
Does not meet criteria for dementia (DSM-5) 
• 
No MRI contraindications (no metallic implants, no claustrophobia) 
• 
Able to provide written informed consent 
Exclusion Criteria: 
• 
Neurological disorders (e.g., stroke, Parkinson’s disease) 
• 
Severe sensory or communication impairments 
• 
Severe depression (Geriatric Depression Scale > 10) 
• 
History of epilepsy or seizures 
• 
Prior brain surgery or deep brain stimulation 
• 
Alcohol or substance abuse 

• 
Concurrent participation in another interventional trial 
• 
Contraindications for tTIS or MRI (as above) 
Vulnerable Population Protection: 
Given that this study enrolls older adults (aged 60–80 years) with mild 
cognitive impairment, additional safeguards are implemented. A 
multidisciplinary team (including a geriatrician, a neuropsychologist, and a 
clinical pharmacist) will conduct comprehensive assessments of cognitive 
function, psychological status, and social support systems before enrollment. 
Potential participants with severe comorbid conditions (e.g., uncontrolled 
hypertension, heart failure, malignancy) or severe psychiatric disorders (e.g., 
major depression, schizophrenia) will be excluded. Participants with unstable 
living situations or inadequate caregiver support will also be excluded to 
ensure safety throughout the study. 
 
3.3 Randomization and Blinding 
Randomization will be performed by an independent statistician using a 
computer-generated sequence (1:1 allocation to sequence “Active→Sham” or 
“Sham→Active”). Allocation concealment will be maintained using 
sequentially numbered opaque envelopes. 
Blinding: Participants, outcome assessors, and data analysts will be blinded to 
treatment assignment. The interventionist (not involved in assessments) will 
program the stimulator. Sham stimulation will use the same ramp-up/down 
and sensory experience but no effective current during the stimulation period. 
 
4. INTERVENTIONS 
4.1 Individualized tTIS (Active) 
• 
Target: Left hippocampus (individualized based on each participant’s 
T1-weighted MRI using finite element modeling). 
• 
Parameters: 5 Hz target frequency, 2000 Hz and 2005 Hz carrier 
frequencies, 2 mA baseline-to-peak intensity. 

• 
Duration: 20 minutes, with 30-second ramp-up and ramp-down. 
• 
Electrode placement: Determined by SimNIBS simulation to 
maximize electric field in the left hippocampus. 
 
4.2 Sham Stimulation 
• 
Same electrode placement, same ramp-up/down, and same total 
duration. 
• 
Active current delivered only during the 30-second ramp-up and ramp-
down; no current during the 20-minute stimulation period. 
5. OUTCOME MEASURES 
5.1 Primary Outcome Measures 
# 
Outcome 
Description 
Time 
Frame 
1 
Change in 
Montreal 
Cognitive 
Assessment 
(MoCA) Score 
MoCA assesses multiple 
cognitive domains (memory, 
attention, executive function). 
Score range 0–30; higher scores 
indicate better cognition. 
Baseline, 
immediately 
post-
intervention 
2 
Change in 
Gait-Related 
and Balance-
Related Dual-
Task Cost 
Gait dual-task cost: (Single-
Task Gait Speed – Dual-Task 
Gait Speed) / Single-Task Gait 
Speed × 100% during walking + 
serial subtraction. Balance dual-
task cost: Center of pressure 
sway path length and area during 
standing + serial subtraction. 
Baseline, 
immediately 
post-
intervention 

# 
Outcome 
Description 
Time 
Frame 
3 
Change in 
Working 
Memory 
Performance 
Working memory assessed using 
the n-back task (1-back and 2-
back conditions) during fMRI, with 
accuracy and reaction time as 
primary metrics. 
Baseline, 
immediately 
post-
intervention 
 
5.2 Secondary Outcome Measures 
# 
Outcome 
Description 
Time Frame 
4 
Change in 
Brain 
Function 
Multimodal assessment including: 
hippocampal neural complexity 
(resting-state fMRI multi-scale 
sample entropy), theta-gamma 
coupling (EEG), functional network 
efficiency (graph theory metrics), 
and cerebral blood flow (ASL). 
Baseline, 
immediately 
post-
intervention 
5 
Change in 
Brain 
Structure 
Multimodal assessment including: 
hippocampal subfield volumes (T1 
MRI), white matter integrity (DTI: FA, 
MD, AD, RD), and iron deposition 
(QSM). 
Baseline, 
immediately 
post-
intervention 
 
5.3 Safety Outcomes 
• 
Adverse events (structured questionnaire after each session) 

• 
Tolerability (0–10 scale for each symptom: itching, tingling, burning, 
headache, etc.) 
• 
Blinding effectiveness (participant guess of treatment assignment) 
 
6. SAMPLE SIZE AND POWER 
Based on our pilot study (n=14) and a previous meta-analysis of tDCS in MCI, 
we anticipate a moderate effect size (Cohen’s d = 0.65) for the primary 
outcome (MoCA). For a crossover design with a correlation of r = 0.5 between 
periods, α = 0.05 (two-tailed), and power = 85%, the required sample size is 
32. Accounting for 20% dropout, we will enroll 40 participants. 
 
7. STATISTICAL ANALYSIS 
7.1 Analysis Sets 
• 
Full Analysis Set (FAS): All randomized participants who received at 
least one intervention. 
• 
Per Protocol Set (PPS): FAS participants with no major protocol 
deviations. 
• 
Safety Set (SS): All participants who received any intervention. 
 
7.2 Primary Analysis 
For the crossover design, a linear mixed-effects model will be used with fixed 
effects for period, treatment, and sequence, and a random effect for 
participant. Baseline MoCA score will be included as a covariate. The primary 
contrast is the difference between active and sham conditions. 
 
7.3 Secondary Analysis 
Continuous secondary outcomes will be analyzed similarly. Categorical 
variables (e.g., adverse events) will be analyzed using generalized estimating 
equations. 
 

7.4 Missing Data 
Missing data will be handled using multiple imputation (chained equations) for 
sensitivity analyses. 
 
7.5 Neuroimaging Analysis 
• 
fMRI: Preprocessing with SPM12; group-level analysis using general 
linear models; network metrics computed with GRETNA. 
• 
EEG: Preprocessing with FieldTrip; time-frequency analysis; phase-
amplitude coupling. 
• 
MRI Structural: VBM and surface-based morphometry with CAT12; 
DTI with FSL; QSM with STI Suite. 
 
7.6 Mediation Analysis 
• 
To test the hypothesized cascade (“neural oscillation → brain network 
→ brain structure → cognitive improvement”), mediation analysis will 
be conducted using the PROCESS macro for SPSS or the *lavaan* 
package in R. The intervention (active vs. sham) will serve as the 
independent variable, changes in neuroimaging/EEG metrics as 
mediators, and changes in cognitive outcomes as dependent variables. 
The indirect effect will be estimated using bootstrapping (5,000 
resamples) with 95% confidence intervals. 
 
8. DATA MANAGEMENT AND MONITORING 
8.1 Data Collection and Storage 
• 
Case report forms (CRFs) will be used for all assessments. 
• 
Data will be entered into a secure electronic database (password-
protected, encrypted). 
• 
Backup copies will be stored on a secure institutional server. 
 
8.2 Data Safety Monitoring Board (DSMB) 

An independent DSMB comprising a neurologist, a biostatistician, and an 
ethicist will review safety data every 6 months and will have the authority to 
recommend study termination if serious adverse events occur. 
 
8.3 Adverse Event Reporting 
All adverse events will be recorded and reported to the ethics committee and 
DSMB within 24 hours if serious. Mild events will be reported quarterly. 
 
8.4 Safety Monitoring for Older Adults with MCI 
Pre‑intervention preparation: Before each stimulation session, vital signs 
(blood pressure, heart rate) will be recorded. Participants will be screened for 
any acute illness or discomfort that may affect participation. 
 
Real‑time monitoring: During stimulation, a trained investigator will remain 
with the participant, monitor for any signs of distress, and inquire about 
subjective sensations every 5 minutes. If any participant reports intolerable 
discomfort, stimulation will be stopped immediately. 
 
Emergency preparedness: Emergency equipment (e.g., oxygen, suction) 
and medications (e.g., antihypertensives, glucose) will be readily available. All 
investigators have completed basic life support training. A direct emergency 
contact with a nearby tertiary hospital (Yangpu District Central Hospital) will 
be established for rapid transfer in case of serious adverse events. 
 
Fatigue prevention: Each study visit is limited to a maximum of 2.5 hours, 
with mandatory rest breaks. Participants may rest or postpone tasks if they 
feel tired. 
 
9. ETHICS AND REGULATORY COMPLIANCE 
9.1 Ethics Approval 

The study protocol has been approved by the Shanghai University of Sport 
Research Ethics Committee (Approval No. 102772025RT208, date: January 
28, 2026). Approval from the partner hospital (Yangpu District Central 
Hospital, Shanghai) is pending and will be obtained before recruitment begins 
at that site. 
 
9.2 Informed Consent 
All participants will provide written informed consent after a full explanation of 
the study, including potential risks and benefits. The consent form will be 
approved by the ethics committee. 
 
9.3 Confidentiality 
Participant data will be coded and stored separately from identifiers. Only the 
principal investigator and authorized study staff will have access to the key. 
 
9.4 Registration 
The study is registered with the Chinese Clinical Trial Registry (ChiCTR) and 
ClinicalTrials.gov (pending final approval). 
 
9.5 Additional Safeguards for Cognitively Impaired Older Adults 
Dual consent: For participants with MCI who retain decision‑making capacity, 
both the participant and a legally authorized representative (e.g., family 
member) will co‑sign the informed consent form. For participants with 
impaired capacity, the legal representative will make the primary decision, 
while the participant is still informed and asked for assent. 
 
Simplified consent materials: The informed consent form will be written in 
plain language (font size ≥ 12 pt) with key information highlighted. An 
illustrated information sheet and an audio‑recorded explanation (slow‑paced, 
gentle tone) will be provided to facilitate understanding. 

 
Extended discussion period: The consent discussion will be conducted by 
two trained investigators in a quiet, comfortable setting, lasting at least 30 
minutes. All questions will be answered thoroughly before signature. 
 
Ongoing assent monitoring: Throughout the study, investigators will monitor 
participants’ willingness to continue. If a participant shows signs of distress or 
reluctance, participation will be paused and reassessed. 
 
10. PUBLICATION AND DATA SHARING 
10.1 Publication Plan 
Results will be published in peer-reviewed journals regardless of outcome. 
Authorship will follow ICMJE guidelines. 
 
10.2 Data Sharing 
De-identified individual participant data for primary and secondary outcomes 
will be made available on Figshare or OpenNeuro within 6 months of 
publication. The study protocol, SAP, and ICF will be posted 
on ClinicalTrials.gov.  
 
12. DECLARATIONS 
12.1 Integrity Statement 
All investigators involved in this study commit to strictly adhering to the study 
protocol and relevant clinical trial regulations. All study data will be recorded 
truthfully, completely, and in a traceable manner. No fabrication, falsification, 
or manipulation of research data will occur. The study procedures, 
intervention protocols, and assessment standards will be followed rigorously 
to ensure the scientific validity and reliability of the research outcomes. 
 
 

12.2 Conflict of Interest 
All investigators declare no commercial or academic conflicts of interest 
related to this study. The study is funded by the National Natural Science 
Foundation of China (NSFC). All funds are allocated solely for participant 
recruitment, data collection, participant compensation, and other direct 
research expenses. No improper financial relationships exist. 
 
12.3 Intellectual Property 
The data, results, manuscripts, and any patents arising from this study will be 
owned by Shanghai University of Sport. The principal investigator and major 
contributors will have authorship rights in accordance with ICMJE 
recommendations. Collaborating institutions (e.g., Yangpu District Central 
Hospital, Shanghai) will be acknowledged based on their contributions. 
 
12.4 Publication Plan 
Results will be submitted for publication in peer-reviewed journals (e.g., Brain 
Stimulation, NeuroImage, Alzheimer’s & Dementia) within 6 months of study 
completion, regardless of outcome. Authorship will follow ICMJE guidelines. 
Interim findings may be presented at scientific conferences but will be clearly 
marked as preliminary. 
 
12.5 Data Sharing 
De-identified individual participant data for primary and secondary outcomes 
will be made available upon reasonable request to the corresponding author 
after publication of the main results. Data requestors must agree to: (1) not 
attempt to re-identify participants; (2) cite the original study; and (3) not use 
data for commercial purposes.