Novel Non-invasive Transcranial Electrical Stimulation for Parkinson’s Disease

Abstract

Conventional transcranial electrical stimulation (tES) is a non-invasive method to modulate brain activity and has been extensively used in the treatment of Parkinson’s disease (PD). Despite promising prospects, the efficacy of conventional tES in PD treatment is highly variable across different studies. Therefore, many have tried to optimize tES for an improved therapeutic efficacy by developing novel tES intervention strategies. Until now, these novel clinical interventions have not been discussed or reviewed in the context of PD therapy. In this review, we focused on the efficacy of these novel strategies in PD mitigation, classified them into three categories based on their distinct technical approach to circumvent conventional tES problems. The first category has novel stimulation modes to target different modulating mechanisms, expanding the rang of stimulation choices hence enabling the ability to modulate complex brain circuit or functional networks. The second category applies tES as a supplementary intervention for PD hence amplifies neurological or behavioral improvements. Lastly, the closed loop tES stimulation can provide self-adaptive individualized stimulation, which enables a more specialized intervention. In summary, these novel tES have validated potential in both alleviating PD symptoms and improving understanding of the pathophysiological mechanisms of PD. However, to assure wide clinical used of tES therapy for PD patients, further large-scale trials are required.

Short-term effects of transcranial direct current stimulation on motor speech in Parkinson’s disease: a pilot study

“…The main difference between the effects of rTMS and tDCS is that rTMS can trigger an action potential and tDCS can only modulate resting membrane potential and change the probability of the action potential occurrence (Nitsche et al 2008). Thus, tDCS affects active neurons and is usually combined with behavioral training for more pronounced and long-term effects (Ni et al 2022). In clinical practice, the gold standard for treatment of HD is currently the LSVT (Yuan et al 2020).…”

“…To achieve our goal, we chose transcranial direct current stimulation (tDCS) that can be used remotely by patients at home together with a concurrent Lee Silverman Voice Treatment (LSVT), i.e., the best documented therapy for symptoms of HD in PD (Yuan et al 2020). In PD patients, tDCS and other modes of temporal electrical stimulation (tES) have mostly been used to modulate gait speed, freezing of gait, limb bradykinesia, attention and executive functions, and brain excitability (Ni et al 2022). Studies also provided evidence that homebased tDCS treatment is feasible and safe for PD patients (Dobbs et al 2018).…”

“…In this pilot study, we particularly concentrated on identifying a suitable electrode montage and examined immediate aftereffects of a single session of tDCS on HD symptoms. These acute effects could last up to an hour (Nitsche et al 2008;Brunoni et al 2012). Studies have also shown that different current flow directions may result in different aftereffects, and the direction of the excitability shift might be divergent, dependent not only on stimulation polarity, but also on the specific electrode montage (Nitsche et al 2008).…”

“…These acute effects could last up to an hour (Nitsche et al 2008;Brunoni et al 2012). Studies have also shown that different current flow directions may result in different aftereffects, and the direction of the excitability shift might be divergent, dependent not only on stimulation polarity, but also on the specific electrode montage (Nitsche et al 2008). Therefore, we applied both anodal and cathodal tDCS to the right STG.…”

Exploring the Frontiers of Neuroimaging: A Review of Recent Advances in Understanding Brain Functioning and Disorders

“…Some studies have reported improvements in motor symptoms, tremors, and gait following TES with PD [60,131]. One type of TES studied in PD is tDCS, which involves the application of a weak electrical current to the scalp to modulate cortical excitability.…”