In the manuscript titled “Transcranial Pulsed Current Stimulation (tPCS) in Parkinson’s Disease: A Pilot Trial,” Kulshreshtha et al. have presented the results of a pilot trial investigating the feasibility and the clinical and electrophysiological effects of tPCS in individuals with mild-to-moderate stage Parkinson’s disease (PD).^{Reference Kulshreshtha, Samotus, Tamilselvam, Ganguly, Aur and Jog1} The article is pertinent and timely as it discusses the effects of an intriguing type of neuromodulation of the motor cortex, namely tPCS, within the context of PD using neurophysiological, clinical and objective kinematic outcome assessments.

In recent years, there has been a significant increase in research exploring the use of noninvasive brain stimulation to treat both motor and non-motor symptoms in individuals with PD. This includes a notable rise in studies involving transcranial electrical stimulation, particularly transcranial direct current stimulation and transcranial alternating current stimulation, with various protocols targeting different symptoms. However, no approved treatment protocols are currently available for clinical use.^{Reference Cosentino, Todisco and Blandini2,Reference Ganguly, Murgai, Sharma, Aur and Jog3}

The study by Kulshreshtha et al. specifically assessed the effects of a single session of tPCS on gait, bradykinesia and tremor in PD patients. It confirmed that tPCS is safe and well-tolerated, consistent with findings from a previous study that also used tPCS, showing good tolerability and no significant side effects in PD patients.^{Reference Alon, Yungher, Shulman and Rogers4} The study also noted a possible increase in the electroencephalogram (EEG) beta-band activity following tPCS stimulation. The exact clinical implications of this finding are yet to be investigated, but it is worth exploring, as beta-band activity is a known marker used in other neuromodulation protocols for PD.^{Reference Madrid and Benninger5} As the authors rightly point out in the study limitations, one session of tPCS showed limited positive results. Therefore, to thoroughly explore its efficacy as a therapeutic tool for PD, repeated sessions of stimulation may be necessary.

While this study is a welcome addition to the current literature on noninvasive brain stimulation as a potential therapy for targeting motor symptoms in PD, there is a clear need for systematically designed robust clinical trials to access the efficacy of such easy-to-administer and safe noninvasive brain stimulation techniques. Such approaches could potentially be delivered with minimal supervision, opening the possibility for in-home use in the future. Also, it would be beneficial to carefully select outcome measures based on symptoms that might respond to a particular paradigm, allowing one to assess its efficacy for a specific purpose moving forward.