Personalized Transcranial Direct Current Stimulation for Behavioral and Neurophysiologic Outcomes

Area of Science:

• Neuroscience
• Neurotechnology
• Clinical Research

Background:

• Transcranial direct current stimulation (tDCS) is a promising home-based intervention for neuropsychiatric disorders and cognitive enhancement.
• Current tDCS effectiveness is limited by interindividual variability due to fixed-dose protocols failing to account for anatomical differences.
• Computational modeling suggests individualized dosing can improve tDCS consistency, but experimental validation is scarce.

Purpose of the Study:

• To compare the behavioral and neurophysiologic outcomes of fixed-dose versus individualized-dose tDCS.
• To evaluate the effectiveness of personalized tDCS protocols in improving treatment consistency.

Main Methods:

• A within-participant, double-masked, crossover design study was conducted with 16 adult participants.
• Participants received three sessions of tDCS: fixed-dose, individualized-dose, and sham stimulation, in a counterbalanced order.
• Individualized doses were determined using a custom simulation toolbox; behavioral outcomes (reaction time) and neurophysiologic effects (motor-evoked potentials) were measured.

Main Results:

• Individualized-dose tDCS demonstrated significantly greater reaction time improvements compared to sham stimulation, outperforming fixed-dose tDCS.
• Lower variability in outcomes was observed with individualized-dose tDCS, indicating enhanced consistency.
• Sex-stratified analysis revealed that women benefited from both fixed and individualized tDCS, while men showed improvement only with individualized tDCS. Motor-evoked potentials also showed greater amplitude increases with individualized dosing.

Conclusions:

• Dose-controlled tDCS, particularly individualized dosing, is associated with consistent behavioral and neurophysiologic improvements.
• This personalized approach holds significant translational importance for optimizing tDCS in treating neuropsychiatric disorders.
• Individualized tDCS converted nonresponders to responders, underscoring its potential to broaden treatment efficacy.