1000 Section - The effect of transcranial direct current stimulation over dorsolateral prefrontal cortex in neurological disorders

This systematic review aimed to consolidate the findings of research on transcranial direct current stimulation (tDCS) applied over the dorsolateral prefrontal cortex (DLPFC) in various neurological disorders.

Design:

Literature search on PubMed, Wed of Science, Cochrane Library and CINAHL (last search done on 12nd June 2025) was performed to collect information from clinical and preclinical studies that applied tDCS on DLPFC in people with neurological disorders. Studies with control conditions (e.g., sham tDCS, active comparators, or no intervention) were eligible. Data on the specific stimulation sites, stimulation parameters, and the overall effects on measured outcomes were extracted and synthesized.

Results:

This review included forty randomized controlled trials, covering the following conditions: Parkinson’s disease (11 studies), Alzheimer’s disease (6 studies), stroke (6 studies), multiple sclerosis (5 studies), dementia and mild cognitive impairment (10 studies), and traumatic brain injury (2 studies). Most RCTs (67%) had a low risk of bias. Active tDCS combined with other therapy was superior to controls in stroke patients regarding endpoint global cognition scores (Standardized mean difference [SMD]: 0.71, 95% confidence interval [CI]: 0.22-0.70). tDCS enhanced memory and executive function in stroke, and improved memory, executive function, attention, and language in mild cognitive impairment, dementia, Alzheimer’s disease, and multiple sclerosis. Traumatic brain injury patients benefitted from heightened attention ability following tDCS. Additionally, tDCS augmented balance and gait in Parkinson’s disease and multiple sclerosis.

Conclusion:

The emerging evidence of efficacy on DLPFC tDCS in parallel with intensive cognitive or motor training yields positive results in several neurological disorders. However, the stimulation parameters differ across studies. The sustained effect of the stimulation is uncertain. Larger clinical studies will be needed to determine the optimal stimulation parameters in different neurological conditions.