Transcranial Direct Current Stimulation for Global Cognition in Mild Cognitive Impairment

Mild cognitive impairment (MCI) is a condition characterized by noticeable deficits in memory retrieval or other cognitive domains than the individuals with the same age but do not significantly interfere with daily functioning. It represents an intermediate stage between normal aging and dementia, and a crucial opportunity for intervention prior to extensive cognitive decline. Transcranial direct current stimulation (tDCS), a non-invasive neuromodulation technique, has shown promise in enhancing global cognition in MCI. Current evidence suggests that tDCS provides short-term cognitive benefits, particularly in memory and attention, with moderate effects observed in processing speed. However, its impact on executive function and language remains inconsistent, highlighting variability in individual responses and study methodologies. While long-term efficacy remains uncertain due to limited longitudinal research and short follow-up periods, safety concerns, especially with self-administered tDCS such as in home-based tDCS, underscore the need for proper training and device innovation. Despite this, tDCS is a promising, portable tool for cognitive enhancement in MCI, with potential to delay progression to dementia. Addressing challenges such as optimizing stimulation protocols, accounting for individual neuroanatomical variability, and establishing long-term effectiveness will be essential for its broader clinical adoption. Future research should focus on standardizing methodologies, incorporating biomarkers to predict treatment response, and conducting large-scale, longitudinal studies to refine its therapeutic application.