Personalized Assessment of High-definition Slow-oscillatory Transcranial Direct Current Stimulation (So-tDCS) in Older Adults With Subjective Cognitive and Sleep Complaints

February 19, 2026 updated by: LU Hanna, Chinese University of Hong Kong
Background: Subjective cognitive decline (SCD) is considered to be the early risk stage of dementia. Untreated SCD comorbid with sleep disturbances may accelerate the progression of neurodegeneration (β-amyloid and tau) and lead to cognitive deficits. At present, non-pharmacological interventions for managing SCD and sleep disturbances are very limited. High-definition slow-oscillatory transcranial direct current stimulation (so-tDCS) is a newly developed frequency-specific modality of brain stimulation for promoting brain health and cognition. Notably, neurophysiological feature (impedance) during tDCS was found to be related to treatment outcomes and adverse effects (skin injury). Objectives: We propose to 1) develop a high-performing neurophysiological signal detector for tDCS and test its feasibility and flexibility in a randomized clinical trial; 2) investigate the short-term and long-term effects of high-definition so-tDCS on SCD, sleep quality and plasma Aβ and p-tau levels; 3) examine the values of neurophysiological signals in predicting the treatment outcomes at individual level. Design: A randomized, double-blind, sham-controlled trial. Methods: Chinese right-handed older adults with SCD and sleep disturbances will be randomly assigned to a 4-week intervention of either high-definition 0.75 Hz so-tDCS or sham tDCS, with 40 participants per arm. Pre-treatment magnetic resonance imaging (MRI) scans will be collected to exclude the cases with major neurological disease and quantify individual's brain features. Galvanic skin response, subjective cognitive complaints, sleep quality, plasma p-tau and β-amyloid levels and domain-specific cognition will be assessed at baseline, 4th week, 8th week and 12th week. Program adherence and adverse effects will be monitored throughout the whole intervention.

Study Overview

Status

Status

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Not yet recruiting

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This study aims to investigate the efficacy and sustainability of high-definition so-tDCS for managing SCD and sleep disturbances in older adults. The neurophysiological signal detector will be featured with a compact and high-performing GSR assessor with the state-of-the-art personalized measurement during so-tDCS. The successful implement of this signal detector will provide researchers assess to an "add-on" setting that allows them easily, quickly and quantitatively evaluate real-time neurophysiological signals and further incorporate transcranial brain stimulation in clinical practice.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
80

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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Study Contact

Study Contact

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Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Chinese, right-handed, aged from 60 to 85 years.
  • Normal global cognition defined as a total score of the Montreal Cognitive Assessment Hong Kong version (HK MoCA) > 26.
  • Subjective cognitive decline (SCD) is evaluated by a 10-item questionnaire that covers subjective cognitive complaints (SCC) in the core cognitive domains.
  • Sleep disturbances or poor sleep quality is assessed and defined with a total score of the Pittsburgh Sleep Quality Index (PSQI) greater than 5.

Exclusion Criteria:

  • Previous diagnosis of age-related neurodegenerative diseases, such as Alzheimer's disease, Parkinson disease.
  • History of neurological diseases including brain tumor, and stroke.
  • History of psychiatric disorders including schizophrenia and depression.
  • Presence of positive neurological diseases, such as stroke, brain tumor, dementia.
  • Physically unable to attend the sessions of intervention.
  • Currently enrolled in another intervention study.
  • Currently taking a psychiatric or other medication that may affect sleep quality and cognition.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Sham Comparator: Sham transcranial direct current stimulation
Device: Sham so-tDCS
Sham so-tDCS: With a same setting of high-definition as active so-tDCS, the stimulation of sham so-tDCS only lasts for 30 seconds. The electrodes will be left in place for a further 20 minutes.
Active Comparator: Slow-oscillatory transcranial direct current stimulation
Device: so-tDCS
The so-tDCS is delivered by a battery driven direct current stimulator (DC-Stimulator Plus, NeuroConn, Ilmenau, Germany). The high-definition setting is applied by placing an anodal electrode over the center of the treatment target and placing four cathodal electrodes surrounded the anodal electrod. Each electrode in the "4 × 1" montages had a diameter of 1.2 cm. We place the anodal electrode over the center of left dorsolateral prefrontal cortex (DLPFC) (i.e., F3 according to the international 10-20 EEG system).

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Impedance
Time Frame: 12 weeks
A neurophysiological signal recorded and measured by a built-in wearable Galvanic Skin Response (GSR) sensor. The GSR sensor is placed on the fingers to detect the impedance of the skin when the participant is receiving the so-tDCS intervention
12 weeks
Subjective cognitive complaints (SCC)
Time Frame: 12 weeks
SCC is a 10-item questionnaire that covers subjective complaints in the core cognitive domains. Participants will answer ten yes/no questions relating to the presence of cognitive complaints in the last six months. The answers of SCC are codified as 0 (no complaints) or 1 (presence of complaints). Answers will be summed up and the total of complaints will be obtained ranging from 0 to 10.
12 weeks
Pittsburg Sleep Quality Index (PSQI)
Time Frame: 12 weeks
The PSQI is a 19-item questionnaire that includes seven areas of subjective sleep quality and patterns in adults over the last month including the following components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, SDs, use of sleeping medications, and daytime dysfunction. Each item in the scale is scored from 0 to 3 scale (0 = no difficulty; 3 = severe difficulty). The scores are added to yield a global score ranging from 0 to 21 (0 = no difficulty; 21 = severe difficulties in all areas). This scale has good reliability and validity psychometrics and is widely used in research: Cronbach's alpha (0.77 to 0.83), sensitivity (89.6%), specificity (86.5%). Greater score of PSQI indicates worse sleep quality.
12 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Intra-individual variability of reaction time (IIV-RT)
Time Frame: 12 weeks
IIV-RT, representing the within-person fluctuations, is calculated based on the performance of attention network test (ANT). For correcting the increased RT in elderly, Intraindividual coefficient of variation of reaction time (ICV-RT) is used for assessing the IIV-RT enumerated with the formula: ICV-RT = (Standard deviation of RT/mean RT) × 100.
12 weeks
Objective sleep quality
Time Frame: 12 weeks
Actigraphy records will be used to quantify sleep-wake cycle during treatment.
12 weeks
The levels of saliva Aβ
Time Frame: 12 weeks
The levels of saliva Aβ , are assessed at the baseline and post-intervention time points.
12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Chinese University of Hong Kong

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
May 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
February 19, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 19, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
February 25, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 25, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 19, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2025.118

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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