CLINICAL APPLICATION OF TDCS ON MOTOR SYMPTOMS IN PARKINSON’S DISEASE: A LITERATURE REVIEW

Parkinson’s disease (PD) is a progressive, long-term neurodegenerative disorder and its clinical presentation is characterized by cognitive and motor symptoms. Particularly, PD is common cause of gait and postural instability. Different treatments have been developed and applied (pharmacological and non-pharmacological therapy) but despite it the effects of those interventions still remain inconclusive. The development of more effective therapeutic options on PD motor symptoms is a pivotal aim of the rehabilitative medicine. Therefore, the aim of this review was to study the effects of transcranial direct current stimulation (tDCS) on motor symptoms. The second objective was to identify the best tDCS parameters and recommendations available demonstrated by the analyzed studies. In order to identify suitable publications for inclusion, an online search on PubMed and Scopus databases was conducted using the following search terms: “tDCS and Parkinson”, “tDCS and motors symptoms”, “tDCS and tremor” and “tDCS and bradykinesia”. The year of publications hasn’t been limited. To date, the vast majority of the studies differ on the sites of stimulation, parameters and type of stimulation. The main targeted areas were the primary motor cortex and the dorsolateral prefrontal cortex. Findings highlighted significant effects on the reduction of motor dysfunctions particularly related to: a) gait; b) balance; c) bradykinesia; d) freezing of gait and e) diskynesia. In conclusion, tDCS represents one of the most promising tool available, in order to promote adaptive plasticity with significant rehabilitative motor effects in PD patients. Future studies with larger sample sizes and high-quality studies are needed to further corroborate the reported findings and to identify the optimal tDCS parameters and protocols.