High Definition Transcranial Direct Current Stimulation (HD-tDCS) for Early Alzheimer's Disease

Summary

This completed randomized trial evaluated the clinical and neural effects of high-definition transcranial direct current stimulation (HD-tDCS) combined with computerized cognitive training in patients with Alzheimer's disease. Participants were assigned to active HD-tDCS plus computerized cognitive training, computerized cognitive training control, or active HD-tDCS control. The study assessed whether combined neuromodulation and cognitive training produced greater cognitive and clinical benefit than either component condition, and whether treatment-related benefit was associated with changes in brain network organization.

Conditions

• Transcranial Direct Current Stimulation
• Functional Magnetic Resonance Imaging
• Early Alzheimer's Disease

Interventions

OTHER

HD-tDCS

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation tool that alters cortical excitability and activity via application of weak direct currents.HD-tDCS was administered using the Soterix 1×1 tDCS Low-Intensity Stimulator and the Soterix 4×1 Adapter. The selection of the electrode montage was based on computational models generating simulated current topography using HD Explore, which demonstrated good current distribution in the left dorsolateral prefrontal cortex (DLPFC). For left DLPFC stimulation, the anodal electrode was placed at the F3 position (using the International 10-20 EEG system), and the 4 return electrodes (cathodes) were placed at positions AFz, FCz, F7, and C5 (4-6 cm from the anode). The center position CZ was aligned with the vertex of the head. During anodal DLPFC stimulation, participants received stimulation at 2 mA for 30 minutes, including a 30-second ramp-up period at the start and a 30-second ramp-down period at the end.

OTHER

computer-based cognitive training

Computer-based cognitive training (CCT) is a potentially important tool for individuals at risk of dementia. This trial will employ a computerized multi-domain adaptive training program. This program and training model have been demonstrated to be effective and beneficial in patients with vascular cognitive impairment. In the CCT intervention group, participants will undergo 2 weeks of computerized, multi-domain, adaptive training. The training domains include processing speed, attention, perception, long-term memory, working memory, calculation, executive control, reasoning, and problem-solving. Task rigor varies across domains and determines task grouping. Participants are required to complete 30 minutes of daily training(one session each of six 5-minute tasks).

OTHER

Sham tDCS

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation tool that alters cortical excitability and activity via application of weak direct currents.HD-tDCS was administered using the Soterix 1×1 tDCS Low-Intensity Stimulator and the Soterix 4×1 Adapter. The selection of the electrode montage was based on computational models generating simulated current topography using HD Explore, which demonstrated good current distribution in the left dorsolateral prefrontal cortex (DLPFC). For left DLPFC stimulation, the anodal electrode was placed at the F3 position (using the International 10-20 EEG system), and the 4 return electrodes (cathodes) were placed at positions AFz, FCz, F7, and C5 (4-6 cm from the anode). The center position CZ was aligned with the vertex of the head. For sham stimulation, participants received only the initial 30-second ramp-up to 2 mA, after which stimulation was immediately terminated.

BEHAVIORAL

Control cognitive training

Control cognitive training consisted of a structured, computer-based cognitive activity matched to the adaptive computerized cognitive training program for session duration, screen exposure, task instructions, and participant contact. The control tasks used fixed or minimally adaptive task difficulty and did not provide individualized, performance-based progression. This condition was designed to control for nonspecific effects of computer use, task engagement, therapist contact, and repeated cognitive activity, while minimizing the adaptive cognitive-training component.

Sponsors & Collaborators

• Anhui Medical University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

50 Years

Max Age

85 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2020-06-01

Primary Completion

2025-12-01

Completion

2025-12-01

Countries

• China

Study Locations