Effects of tDCS on Cognitive Function in Older Adults With Subjective Cognitive Decline: Randomized Sham-Controlled Trial

NCT07531888 | Enrolling By Invitation DMC

• 1 other identifier: UniversidadAEH
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

This randomized, double-blind, sham-controlled clinical trial evaluates the effects of transcranial direct current stimulation (tDCS) using the Sooma Oy device on cognitive function in older adults with Subjective Cognitive Decline (SCD). The study investigates changes in memory, executive function, attention, and global cognition after a structured intervention consisting of 22 intensive sessions and 8 maintenance sessions. Assessments occur at baseline, Week 4, Week 8, and Week 12.

Conditions

Cognitive Dysfunction ( MMSE < 24 )

Keywords

tDCS Randomized Controlled Trial Sham-Controlled Cognitive Intervention Aging Brain

Outcome Measures

Primary Outcomes (1)

• Global cognitive function

  Executive Function, Working Memory, Verbal Fluency, Episodic Memory, Planning, and Global Cognition Executive function will be assessed using the Five Digits Test (time/errors; lower = better; no fixed range). Verbal working memory will be measured with Digit Span (approx. 0-16 forward, 0-14 backward; higher = better) and visuospatial working memory with the Corsi Block-Tapping Test (span 2-9; higher = better). Verbal fluency will be assessed using phonemic fluency (letter F; no fixed range; higher = better). Episodic memory will be measured with the Hopkins Verbal Learning Test-Revised (HVLT-R; immediate recall 0-36, delayed recall 0-12; higher = better). Planning ability will be evaluated with the Tower of London (moves/time; lower = better; no fixed range). Global cognition will be assessed using the Montreal Cognitive Assessment (MoCA; 0-30; higher = better). \[Time Frame: Baseline, Week 5, Week 8, and Week 12\]

  Participants will undergo a 1-week baseline assessment, followed by a 5-week intensive intervention phase. A post-intervention assessment will be conducted at Week 6. Follow-up assessments will be performed at Weeks 10, 14, and 18. The total study durati

Secondary Outcomes (1)

• Calcium-related molecular biomarkers (STIM and ORAI gene expression)

  Baseline (pre-intervention), post-intervention (after completion of the intensive phase, Week 5), and follow-up assessments (Weeks 8 and 12)

Study Arms (2)

Treatment

EXPERIMENTAL

Participants assigned to the experimental group will receive active transcranial direct current stimulation (tDCS) using the Sooma tDCS system (Sooma Oy, Finland). The intervention consists of delivering a 2 mA current for 30 minutes per session, with the anode positioned over F3 (left dorsolateral prefrontal cortex) and the cathode over F4 (right dorsolateral prefrontal cortex), according to the international 10-20 system. The stimulation protocol includes 22 intensive sessions administered five days per week, followed by 8 weekly maintenance sessions. All sessions will be conducted under established safety and monitoring guidelines for non-invasive brain stimulation.

Device: Transcranial Direct Current Stimulation

Sham

PLACEBO COMPARATOR

Participants assigned to the control (sham/placebo) group will receive sham transcranial direct current stimulation (tDCS) using the Sooma tDCS system (Sooma Oy, Finland). The procedure will replicate the experimental group conditions, including electrode placement over F3 (left dorsolateral prefrontal cortex) and F4 (right dorsolateral prefrontal cortex), as well as identical session duration. However, active stimulation will be delivered only during an initial 30-second ramp-up and ramp-down period, with no sustained current administered for the remainder of the session. This approach ensures proper blinding of both participants and outcome assessors.

Device: Transcranial Direct Current Stimulation

Interventions

Transcranial Direct Current Stimulation DEVICE

Transcranial direct current stimulation (tDCS) is administered using the Sooma tDCS system (Sooma Oy, Finland). Active stimulation consists of delivering a constant current of 2 mA for 30 minutes per session, with the anode positioned over F3 (left dorsolateral prefrontal cortex) and the cathode over F4 (right dorsolateral prefrontal cortex) according to the international 10-20 EEG system. Participants receive 22 intensive sessions delivered five days per week, followed by 8 weekly maintenance sessions. For the sham condition, the same electrode placement and session duration are used; however, stimulation is applied only during a 30-second ramp-up and ramp-down period, with no sustained current delivered for the remainder of the session. This procedure is designed to maintain participant and assessor blinding.

Sham; Treatment

Eligibility Criteria

• Age: 60 Years - 75 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Right-handed (for MRI purposes)
• Age 60 to 75 years
• years or more of schooling
• Proficiency in Spanish
• Amnestic Mild Cognitive Impairment established by clinical examination
• Adequate visual and auditory acuity to perform neuropsychological tests and undergo cognitive rehabilitation
• If receiving psychotropic medication, to have started it at least 12 weeks prior to the start of the study, remain at stable doses, or have discontinued it for at least 4 weeks
• Good general health without medical or psychiatric illnesses that would interfere with the study
• An informant capable of responding to clinimetric assessments throughout the study and willing to accompany the patient for at least 10 hours per week

You may not qualify if:

• \. Any neurological disease other than Alzheimer's disease that raises suspicion of cognitive impairment, such as Parkinson's disease, multiple infarct dementia, Huntington's disease, hydrocephalus, brain tumor, progressive supranuclear palsy, seizure disorder, subdural hematoma, multiple sclerosis, or a history of traumatic brain injury with loss of consciousness.
• \. Participants with a history of severe psychiatric disorders according to the DSM-5 (bipolar disorder, schizophrenia, chronic depression) or with psychotic features, agitation, or behavioral problems in the last three months that could lead to difficulties in complying with the protocol.
• \. History of psychoactive substance abuse and current alcohol consumption with a pattern of abuse or dependence in the last two years.
• \. Participants with abnormalities on a conventional electroencephalogram (paroxysmal phenomena identified by a neurophysiologist). 5. Participants with pacemakers, intracranial metallic objects or a history of brain surgery, aneurysm clips, artificial heart valves, ear implants, metal fragments or foreign objects in the eyes, skin or body.
• \. Participants with pacemakers, intracranial metallic objects or a history of brain surgery, aneurysm clips, artificial heart valves, ear implants, metal fragments, or foreign objects in the eyes, skin, or body.
• \. Participation in clinical studies with neuropsychological measures taken more than once a year.
• \. Having received prior treatment.

Sponsors & Collaborators

• Universidad Autónoma del Estado de Hidalgo: lead

Study Sites (1)

Universidad Autonoma del Estado de Hidalgo

Pachuca, Hidalgo, 42082, Mexico

Location

Related Publications (4)

• Dedoncker, J., Brunoni, A. R., Baeken, C., & Vanderhasselt, M. A. (2016). The effect of the interval-between-sessions on prefrontal transcranial direct current stimulation (tDCS) on cognitive outcomes: a systematic review and meta-analysis. Journal of neural transmission (Vienna, Austria : 1996), 123(10), 1159-1172. https://doi.org/10.1007/s00702-016-1558-x

  BACKGROUND

• Galli, G., Vadillo, M. A., Sirota, M., Feurra, M., & Medvedeva, A. (2019). A systematic review and meta-analysis of the effects of transcranial direct current stimulation (tDCS) on episodic memory. Brain stimulation, 12(2), 231-241. https://doi.org/10.1016/j.brs.2018.11.008

  BACKGROUND

• Huo, L., Zhu, X., Zheng, Z., Ma, J., Ma, Z., Gui, W., & Li, J. (2021). Effects of Transcranial Direct Current Stimulation on Episodic Memory in Older Adults: A Meta-analysis. The journals of gerontology. Series B, Psychological sciences and social sciences, 76(4), 692-702. https://doi.org/10.1093/geronb/gbz130

  BACKGROUND

• Manenti, R., Sandrini, M., Gobbi, E., Binetti, G., & Cotelli, M. (2020). Effects of Transcranial Direct Current Stimulation on Episodic Memory in Amnestic Mild Cognitive Impairment: A Pilot Study. The journals of gerontology. Series B, Psychological sciences and social sciences, 75(7), 1403-1413. https://doi.org/10.1093/geronb/gby134

  BACKGROUND

MeSH Terms

Conditions

Cognitive Dysfunction

Interventions

Transcranial Direct Current Stimulation

Condition Hierarchy (Ancestors)

Cognition Disorders; Neurocognitive Disorders; Mental Disorders

Intervention Hierarchy (Ancestors)

Electric Stimulation Therapy; Therapeutics; Convulsive Therapy; Psychiatric Somatic Therapies; Behavioral Disciplines and Activities; Electroshock; Psychological Techniques

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, CARE PROVIDER
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Head of the Gerontology Academic Area

Model Details: This study is a randomized clinical trial with two parallel groups, using a double-blind design, in which an active treatment group receiving transcranial direct current stimulation (tDCS) is compared with a sham (placebo) control group. Participants are randomly assigned to each group, and blinding is maintained for both participants and outcome assessors. This design allows for rigorous control of bias and a valid evaluation of treatment efficacy.

Study Record Dates

• First Submitted: February 12, 2026
• First Posted: April 15, 2026
• Study Start: April 17, 2026
• Primary Completion (Estimated): November 1, 2026
• Study Completion (Estimated): December 30, 2026
• Last Updated: April 15, 2026

Record last verified: 2026-04

Locations

ME (1)