The overall goal of this study is to demonstrate the home-based transcranial direct current stimulation device development:updated protocol use at home in healthy subjects and fibromyalgia patients. For that, we will describe step-by-step all the procedures of the device with figures, table, and a video demonstration. The transcranial direct stimulation or tDCS is an unphased brain simulation that modulates the quarter of a centimeter.

The tDCS is a technique we found vast possibility in applying therapy in neuropsychiatric and rehabilitation fields. Nowadays, one limitation of this technique is the patient needs to come to the center to receive these sessions, so it is unpractical to use this technique for many patients in long treatments. We develop an easy-to-use device, with the safety protection features and suitable for home-based use.

The device is portable and powered by a chargeable batteries. The stimulation parameters suggest current intensity, contact impedance and the time of session are stored in internal memory and can be downloaded by the physician. To solve the difficulty of correct placement of the electrodes without help of another person, we created a neoprene cap that allows the use of two electrodes in any assembly and that is fixed in the chosen place.

To moisten the sponges, two clear silicone probes were attached to the cap connecting the field sponges and syringes to the saline solution. The cap allows facilitated contact of the sponges to the scalp, keeping the sponges fixed at the stimulation site, and has three sizes. The device could only be programmed by the team responsible for the research, and it was possible to define the fixed number of stimulations, the minimum interval between two consecutive stimulations, intensity of the electric current, duration of stimulation, rise and descent time of the current, stimulation mode:active or sham.

The researcher would have chosen the appropriate cap size, putting it on the participant and measuring and marking the chosen region. The next step is to drill the cap at the desired location, attach the electrodes and the silicone cannulas to the electrodes. Application of the direct current occurred by using 35 centimeters squared conductive rubber electrodes coated with a vegetable sponge, which was moistened with saline solution before the start of the stimulation, by means of two silicone cannulas attached to the electrode.

The participant received a case containing a neoprene cap with two electrodes and two silicone cannulas attached to the electrodes, a tDCS device, a battery charger, a cable to connect to the electrodes, 20 syringes with 10 milliliters of saline, two syringes of extra physiological saline solution, and one bottle of extra physiological saline solution. Participant received tDCS training by qualified clinician who informed them about the details of the device and the step-by-step process for self-stimulation administration. Furthermore, they watched an instructional video about the use of tDCS at home and attended a training session in which they were taught how to handle the device.

It's necessary to inspect the skin and look for any injury or something that contraindicates the use of tDCS. The participant was instructed to stand in front of the mirror and move away their hair in order to reveal the area to be stimulated, according to the protocol of the study. Then, they are instructed to clean the surface of the skin to remove creams, dirt, or grease.

Afterwards, the cap was to be placed on the head and for the front seam of the cap, to be between the eyebrows. The cap was to be neither tight nor loose but comfortable. The sequence of screens that appears on the display is as follows:opening screen, battery status, date and time, command, Wear the cap.

The participant should push the central button after making sure the cap is well-secured. Command, Inject saline. It's necessary to make sure the saline is fed slowly to the electrodes using the already connected syringe.

Using six milliliters for each electrode and to press the central button after injecting the saline. Command to start the session. Participants should press the central button when they are ready to start the stimulation.

Beginning of the stimulation. On this screen, the following will appear. Session duration, battery charge, and two lines.

The upper line shows the intensity, and the bottom line the resistance. The intensity will gradually increase until reaching two milliamps or another defined intensity. The resistance should approximately reach the middle of this line, five kilohms.

If resistance is too high, the device will issue an alarm warning. Adjust the cap and inject extra saline. At this point, it is necessary to adjust the electrodes on the head and inject some more saline, trying not to go over 10 milliliters.

This will occur when there is not enough contact, or there is a low amount of saline. If necessary, it is possible to stop the session during stimulation. The central button will need to be pressed for a few seconds, followed by pressing the switch off button after which a message, Shut down?

will appear. After 20 minutes, the tDCS device powers off and stimulation ceases, saving the session. The device records each stimulation, including the day and time of stimulation, resistance, and total minutes of stimulation.

At the end of the treatment, researchers can access the recorded information, because it will be saved in a flash memory and the data will be downloaded after use. With this monitoring, it is possible to control the adherence and resistance for each session. The device contains a nine-volt battery which is rechargeable.

When the battery is at 50%it is necessary to already charge it. For this, it is necessary to disconnect the electrode cable and swap it with the charger cable, because it is not possible to charge the battery during a stimulation session. After putting on the cap, we recommend that the participant choose a quiet moment in his or her day for the session, in order to be not interrupted and to avoid having to stop the procedure.

During the stimulation, participants are instructed to remain in silence with eyes open in a silent room. If the session lasted at least 50%of the total time, it is possible to repeat it again on the same day. However, if the session lasted more than 50%of the total time, it isn't possible to repeat the session on the same day, as the initial session will be considered a valid one.

At the end of the stimulation, participants complete a diary of adverse events and are instructed to complete it immediately after the tDCS home session. Participants receive all the information in written form and a contact phone number which is available 24 hours a day. The researcher responsible for the study stays in contact with the participant daily, either by messaging or through WhatsApp.

Participants can get in touch with the researcher at any time, ask questions, and record a video showing how they used the device, or, in order to report any malfunction of the device. The patients performed a total of 650 sessions, and the other was 93%The impedance contact had a mean value of 2.87 kilohms. These low electrodes contact impedance is important to ensure the safety rules of tDCS.

The results of adverse effects found in healthy subjects and fibromyalgia patients active tDCS was similar. The sham group had adverse effects. However, these were smaller than those found in the other groups.

The home-based tDCS equipment developed in our lab proved it should be suitable for long-term use, since our data was higher than 90%when participants were instructed to perform 60 home-based sessions. So it enabled the possibility of research conditions for the idealization and confidence in the study's swiftness of device. The use of home-based tDCS without direct assisting for the replicator center allows participants choice of time, short plan incryptive.

High impedance may be related to poor coupling between the electrode and skin, or a literal dryness. This may increase the co-intensity skin lesions. In our study, the electrodes were wet with a 0.9%saline solution, and it insured the low contact impedance.

The participants had few side effects as it relates to tDCS use. In general, mild and moderate, and very similar to the effects described in other trials.