The Effects of Transcranial ‎Direct Current Stimulation Over the Dorsolateral Prefrontal Cortex ‎on Cognitive Dysfunction in Alzheimer’s Disease: A Narrative Review

Context: Patients with mild cognitive impairment (MCI) and Alzheimer’s disease (AD) are more likely to suffer from cognitive dysfunction due to dementia. Transcranial direct current stimulation (tDCS) as a non-invasive treatment strategy has been used as an efficient strategy to improve cognitive function. Evidence Acquisition: Several studies investigating tDCS over the dorsolateral prefrontal cortex (dlPFC) were reviewed. Results: Most of these studies have targeted the left dlPFC, indicating that tDCS over the dlPFC can improve cognitive function, such as memory, visual recognition, attention, decision-making, and cognitive decline. However, there are still many unanswered questions about the effect of tDCS over the dlPFC on the connectivity of this brain region as a key node for cognitive function. Meanwhile, further research should be conducted to elucidate the effects of tDCS over the dlPFC on brain connectivity and AD biomarkers. In addition, more investigations should be conducted to identify the exact mechanisms affecting dlPFC stimulation on cognitive dysfunction in AD patients. Conclusions: Based on the results, tDCS over the DlPFC could improve cognitive function in AD patients.