The Effects of Transcranial Direct Current Stimulation in Patients with Mild Cognitive Impairment

Transcranial direct current stimulation (tDCS) came into consideration in recent years as a promising, non-invasive form of neuromodulation for individuals suffering from mild cognitive impairment (MCI). MCI represents a transitional stage between normal cognitive aging and more severe cognitive decline, which appears in neurodegenerative diseases, such as Alzheimer's disease. Numerous studies have shown that tDCS can have several useful effects in patients with MCI. It is believed to enhance cognitive functions, including memory and attention, potentially slowing down the progression of neurodegeneration and cognitive decline. tDCS is believed to work by modulating neuronal activity and promoting synaptic plasticity in the brain regions associated with cognition. Moreover, tDCS is generally considered safe and well-tolerated, making it an attractive option for long-term therapeutic use in MCI. However, further research is needed to determine the optimal stimulation parameters and long-term effects of tDCS in this population, as well as its potential to serve as a complementary therapy alongside other interventions for MCI. In this review, we included 16 randomized clinical trials containing patients with MCI who were treated with tDCS. We aim to provide important evidence for the cognitive enhancement using tDCS in patients with MCI, summarizing the effects and conclusions found in several clinical trials, and discuss its main mechanisms.