What is the Impact of Direct Transcranial Stimulation on the Quality of Life of Patients With Parkinson's Disease and How Do These Effects Compare With Those of Standard Treatments?

Introduction: Parkinson's disease (PD) is a neurodegenerative disorder that affects cognitive and motor function, making it difficult to perform daily activities. Current strategies, both pharmacological and surgical, are mainly aimed at alleviating the symptoms of the disease. In general, initial treatment is based on drugs that replace dopamine in the brain; however, their effectiveness decreases over time and can cause side effects. In this context, non-invasive brain stimulation techniques emerge as possible complementary interventions. Our approach focuses on how direct transcranial stimulation (tDCS) and its subtypes (anodal, cathodal, sham, multichannel), as well as its localization in specific regions of the brain and cerebellum, impact on improving the quality of life of PD patients.

Methods: To increase the precision of the search, the descriptors were limited to (“Parkinson's disease” OR “Parkinson disease”) AND (“transcranial direct current stimulation” OR “tDCS”) AND (“quality of life” OR “QoL”). The search was performed in PUBMED and the VHL Regional Portal, restricting the review to randomized trials, case-control studies and publications from the last 5 years, obtaining a total of 42 articles. Subsequently, 4 articles were discarded due to their study design and limitations in answering our PICO question.

Results: The reported results agree that tDCS has the potential to improve cognitive functions, although long-term follow-up is necessary. Direct stimulation is reported to facilitate dopaminergic circuit activity, modulate the central cholinergic system, and improve balance, gait cadence, neuroplasticity, and swallowing. These findings suggest that combining neurorehabilitation strategies with anodal tDCS is a promising approach to improve gait in patients with PD.

Conclusion : The effect on motor symptoms requires additional strategies, such as focusing stimulation on specific areas or complementing it with other neurorehabilitation therapies. Variability in tDCS methods and in parameters to assess quality of life limits the findings, highlighting the need for larger controlled trials to improve reproducibility.