NCT07531888

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

Effects of Transcranial Direct Current Stimulation (tDCS) on Cognitive Function in Older Adults With Subjective Cognitive Decline: A Randomized, Double-Blind, Sham-Controlled Trial.

• Status: Enrolling By Invitation
• Phase: N/A
• Study type: Interventional
• Enrollment: 20 (estimated)
• Sponsor: Universidad Autónoma del Estado de Hidalgo · Academic / Other
• Sex: All
• Age: 60 Years – 75 Years
• Healthy volunteers: Accepted

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.

Detailed description

This study uses the Sooma tDCS system (Sooma Oy, Finland) to deliver a current of 2 mA for 30 minutes per session. The anode is positioned over F3 (left dorsolateral prefrontal cortex) and the cathode over F4 (right dorsolateral prefrontal cortex), according to the international 10-20 system. Participants receive 22 intensive sessions (five days per week) followed by 8 weekly maintenance sessions. The sham condition mimics the stimulation procedure through a 30-second ramp-up and ramp-down period without sustained active stimulation. Primary and secondary outcomes focus on changes in cognitive function, assessed using validated neuropsychological instruments. In addition, the study includes the analysis of molecular biomarkers associated with calcium (Ca²⁺) homeostasis, as age-related changes disrupt multiple electrophysiological processes within the hippocampus. These alterations have been proposed as potential biomarkers of brain aging and are closely linked to cognitive decline. Biological samples will be obtained through buccal swabs using sterile cotton applicators from participating older adults. Total RNA will then be extracted using the TRIzol method, followed by the design of specific primer oligonucleotides and amplification using a commercial RT-PCR kit. This clinical trial aims to generate evidence on the therapeutic utility of tDCS in individuals with Subjective Cognitive Decline, supporting early intervention strategies and contributing to the identification of molecular correlates associated with cognitive changes.

Conditions

• Cognitive Dysfunction ( MMSE < 24 )

Interventions

Type	Name	Description
DEVICE	Transcranial Direct Current Stimulation	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.

Timeline

• Start date: 2026-04-17
• Primary completion: 2026-11-01
• Completion: 2026-12-30
• First posted: 2026-04-15
• Last updated: 2026-04-15

Locations

1 site across 1 country: Mexico