Using Home-based, Remotely Supervised, Transcranial Direct Current Stimulation for Phantom Limb Pain

Summary

The goal of this study is to describe a protocol for the home-based delivery of remotely supervised transcranial direct current stimulation (RS-tDCS) conserving the standard procedures of in-clinic practice, including safety, reproducibility, and tolerability. The participants included will be patients with phantom limb pain (PLP).

Abstract

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that uses low-amplitude direct currents to alter cortical excitability. Previous trials have established the safety and tolerability of tDCS, and its potential to mitigate symptoms. However, the effects are cumulative, making it more difficult to have adherence to the treatment since frequent visits to the clinic or outpatient center are required. Moreover, the time needed for transportation to the center and the related expenses limit the accessibility of the treatment for many participants.

Following guidelines for remotely supervised transcranial direct current stimulation (RS-tDCS) implementation, we propose a protocol designed for remotely supervised and home-based participation that uses specific devices and materials modified for patient use, with real-time monitoring by researchers through an encrypted video conferencing platform. We have developed detailed instructional materials and structured training procedures to allow for self- or proxy-administration while supervised remotely in real time. This protocol has a specific design to have a series of checkpoints during training and execution of the visit. This protocol is currently in use in a large pragmatic study of RS-tDCS for phantom limb pain (PLP). In this article, we will discuss the operational challenges of conducting a home-based RS-tDCS session and show methods to enhance its efficacy with supervised sessions.

Introduction

The sensation of pain and discomfort experienced in an amputated limb and referred to as phantom limb pain (PLP) is a complex condition, challenging to treat, consisting of a refractory nature that contributes to the difficulty in achieving complete and long-lasting pain relief and management. The lack of effective treatment owing to its neuropathic nature, resulting from abnormal nerve activity, or signaling, neural plasticity, psychological factors, and limited understanding and research, influences the complexity of the phenomenon in the pain presentation and the treatment outcomes. From all available treatments, recent studies using transcranial direct current sti....

Protocol

All procedures were conducted under institutionally approved protocols with patient consent. See Figure 1 for an image of the intervention kit and main components and Figure 2 for the RS-tDCS session structure.

1. Pre-intervention procedures

1. Perform recruitment pre-screening according to inclusion and exclusion criteria. Include patients who are adult amputees, who regularly experience phantom pain once a .......

Discussion

Aspects of training, challenges, and solutions
Given the nature of this research study and the type of intervention, being home-based, some challenges have risen; among them were day-to-day issues such as internet connection, contact quality of the operated device, and getting familiar with the devices. The potential challenges presented by RS-tDCS research have been overcome through several creative solutions. Prior to every session, the internet connection is checked on both ends to minimize inte.......

Materials

Name	Company	Catalog Number	Comments
1 x 1 tDCS mini-CT stimulator	Soterix		parameters preset to two milliamps of stimulation for 20 min
Lenovo Laptop	Lenovo		It contains a headstrap and disposable clip-on sponges for stimulation. A computer with Zoom access, to conduct the RS-tDCS sessions. The Zoom videocalls will be addressed to a secured account by Mass General Brigham (MGB)
Lenovo Smart Tab M8 8''	Lenovo		We also record the heart rate variability (HRV) and therefore, we provide a tablet with the Polar app installed and the chest HR monitor.
Polar H10 Heart Rate Monitor			POLAR device, in addition to the materials for the RS-tDCS intervention, we also record the heart rate variability (HRV) and therefore we provide a tablet with the Polar app installed and the chest HR monitor.
Saline solution with a syringe for application over the sponges
SNAP Headgear accessories
SNAPstrap, motor left (anode: C3, cathode: supraorbital) or motor right (anode: c4, cathode: supraorbital) according to the side of amputation (contralateral to stimulation)
SNAPpads, 5 x 7 CMS with pre-inserted carbon rubber snap electrode sites located on the SNAPstrap
Webcam			to ensure a proper visualization of the electrode placement