Critical steps within the protocol

As remotely-supervised tDCS is administered away from the direct supervision of a clinician, inclusion and exclusion criteria are designed to ensure that the participant has no contraindicated health conditions or environmental distractions, and are fully capable to use a laptop computer (including those with adaptive technology) for communication with the research team. In addition, participants must be able to tolerate a tDCS session and commit to the scheduled session time for the duration of the study.

While remote tDCS offers a convenience to the study and administration of the therapy, self-directed participant use is not advisable due to both safety concerns and the inability to monitor and standardize the stimulation that is delivered. Instead, our protocol follows the standards and guidelines for remotely-supervised tDCS16 to extend clinic standards through delivery in a remote location. The guidelines ensure that research staff are properly trained for participant interactions, that users have proper ability to participate in remote tDCS, and that there are ongoing training materials as well as assessments made of the participant at each step of the study. The stimulation was uniform and reproducible with exactly 20 min of 1.5 mA delivered at every session without any interruption or variation across sessions or individuals.

Modifications to the protocol and troubleshooting tips

The protocol includes several small modifications. Firstly, we expanded the use of this protocol to MS participants that have an EDSS score above 6.5 in the instance where there is a proxy accessible to administer each dose. In addition, we have implemented a procedure whereby we remotely access the participant's study provided laptop to initiate the web conference for those who need extra support and review measures of tolerability and study experiences through a shared document. A future modification to the current protocol includes allowing various degrees of remote supervision so that participants who prove most competent with the technique would only require early supervision to confirm device set up and to receive the unlock code.

Limitations of the technique

While our preliminary results support the feasibility of this protocol, the sample size is limited. As enrollment expands, analyses will be made for gaps in training, ways to streamline sessions, enhance the instructional video, and make the technique more accessible to those with motor impairment (i.e., adaptive mice for computer usage, sponge pocket/headset modification to further ease application). Some participants in the EDSS range below 6.5 (not requiring proxy), may still experience some difficulty in headset preparation and troubleshooting computer related issues. Furthermore, while this study recommends full remote monitoring of participants throughout all sessions, future studies may deem some participants sufficiently trained to operate the device without supervision for the entirety of a session.

Significance of the method with respect to existing methods

These initial results demonstrate the feasibility of our protocol for remotely-supervised tDCS delivery for clinical trials, following a set of guidelines and standards that must be employed to safely, and effectively administer tDCS under remote supervision. The protocol was designed to have a decision-tree series of checkpoints with "stop" criteria (section 2.5.1 above) that must be cleared in order to proceed at each step (see Figure 1). These checkpoints addressed tolerability (experiences of pain or adverse effects to the treatment) and compliance (timely session attendance and proper technique). For each session 1 through 10, participants completed brief adverse event reports before and after their sessions (with items derived from a list of the most common tDCS side-effects in previous trials). In addition, participants completed the self-report measures to address tolerability (before and after the session) and can complete symptom inventories as well. This study is significant in that it establishes a technique to examine a therapy in MS with adequate power while also providing broader access to tDCS treatment.

Future applications of the technique

Once the method for remotely-supervised tDCS has been fully piloted in the MS population, a larger, randomized controlled trial can be initiated to target symptom management. Through the use of the instructional training materials and structure around daily participant interactions, remotely-supervised tDCS can be accessed by a wider range of patient populations and expand clinical study of the technique.