Combined tDCS and Cognitive Training in Alzheimer's

The stimulation will use a neoprene cap with carbon rubber electrodes and sponges soaked in saline solution (5x5 cm). The anode will be placed over the left dorsolateral prefrontal cortex (DLPFC), and the cathode over the right supraorbital area (rSO). Constant current intensity of 2mA and a stimulation time of 20 minutes per day for 12 days will be applied, with an initial and final ramp of 30 seconds.

Participants assigned to the sham tDCS group will also receive 12 home-based sessions of 20 minutes each. However, to mimic the sensation of active stimulation without delivering therapeutic current, the stimulator will only apply current during the initial and final 30-second ramp periods. The device will remain on for 20 minutes, but no current will be applied after the first ramp, simulating an active procedure without physiological effect.

All participants will complete 12 home-based cognitive training sessions, each lasting 50 minutes. The training will include structured tasks focused on executive function and memory, such as categorization, problem-solving, autobiographical recall, planning, and schedule analysis. Instructions will be provided at the start of each session, and participants will work independently or with caregiver support.