Peripheral electrical stimulation to reduce pathological tremor: a review

Abstract

Interventions to reduce tremor in essential tremor (ET) and Parkinson’s disease (PD) clinical populations often utilize pharmacological or surgical therapies. However, there can be significant side effects, decline in effectiveness over time, or clinical contraindications for these interventions. Therefore, alternative approaches must be considered and developed. Some non-pharmacological strategies include assistive devices, orthoses and mechanical loading of the tremorgenic limb, while others propose peripheral electrical stimulation. Specifically, peripheral electrical stimulation encompasses strategies that activate motor and sensory pathways to evoke muscle contractions and impact sensorimotor function. Numerous studies report the efficacy of peripheral electrical stimulation to alter tremor generation, thereby opening new perspectives for both short- and long-term tremor reduction. Therefore, it is timely to explore this promising modality in a comprehensive review. In this review, we analyzed 27 studies that reported the use of peripheral electrical stimulation to reduce tremor and discuss various considerations regarding peripheral electrical stimulation: the stimulation strategies and parameters, electrodes, experimental designs, results, and mechanisms hypothesized to reduce tremor. From our review, we identified a high degree of disparity across studies with regard to stimulation patterns, experimental designs and methods of assessing tremor. Having standardized experimental methodology is a critical step in the field and is needed in order to accurately compare results across studies. With this review, we explore peripheral electrical stimulation as an intervention for tremor reduction, identify the limitations and benefits of the current state-of-the-art studies, and provide ideas to guide the development of novel approaches based on the neural circuitries and mechanical properties implied in tremor generation.

A Review on Wearable Technologies for Tremor Suppression

“…Although these works present promising results, not all patients respond successfully to the afferent strategy for suppressing tremor, and the mechanisms that mediate their effects are not fully understood. In addition, as the physiopathological hypothesis that supports each device is different ( 106 ), it is difficult to compare their effectiveness.…”

“…However, their effectiveness was lower, and some patients did not respond to this treatment. Another drawback that hampered a direct comparison between tremor management results is the fact that each of the different devices described in the literature was based on a different physiopathological hypothesis ( 106 ). More profound studies are required to properly characterize the interaction between the afferent pathways and the neural structures involved in tremor generation.…”

Analyzing the Effects of Parameters for Tremor Modulation via Phase-Locked Electrical Stimulation on a Peripheral Nerve

“…Most published accounts of efforts to use sub-threshold electrical stimulation of afferent pathway to treat tremor [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] utilized a bulky (desktop) stimulation setup and showed tremor reductions of 14-60%. A few other studies introduced wearable setups that applied electrical stimulation [41,43,51].…”

“…It is possible that this type of stimulation modulates neurological pathways that produce tremor. Among these studies [48][49][50], a few (including ours [47]) entailed the use of a wearable setup that applies electrical stimulation to afferent pathways while collecting tremor movements via a motion sensor. One wearable device is commercially available [51] and has been used successfully.…”

Electrostimulus-associated PD-L1 expression on cell membrane revealed by immune SERS nanoprobes

“…Electrostimulation (ES) is considered an effective method for the treatment of various diseases, such as Parkinson's, 11 neuro repair diseases, 12 and cancers. 13 It has also been adopted to actualise the controlled release of drugs and gene regulation.…”