Universal Transcranial Direct Current Stimulation (tDCS) Headset for targeting the bilateral Dorsolateral Prefrontal Cortex: Towards facilitating broader adoption.

Electrode position affects the brain current flow intensity and distribution induced by transcranial direct current stimulation (tDCS). The dorsolateral pre-frontal cortex (DLPFC) is a common target in neuropsychology and neuropsychiatry applications. A positioning scheme and subsequently a headgear has previously been developed to target the DLPFC automatically - devoid of any scalp ruler or neuronavigation method. This approach minimizes the time cost for pre-treatment measurements without compromising targeting accuracy and induced electric field focality. The goal of this study was to further develop this headgear to facilitate broader adoption while maintaining its core design elements intact. Briefly, we developed the headset to accommodate all adult head sizes (52-62 cm) rather than having multiple sizes, to have increased robustness, enhanced visual aesthetics, and have improved usability.We recruited 8 subjects and tested the accuracy of electrode placement on various head sizes. We also tested usability with the System Usability Scale (SUS) and asked the subjects to rate visual appeal. Our study demonstrated that the newly developed headset had greater usability and was more visually appealing than its predecessor without compromising targeting accuracy.Clinical Relevance- This study introduces a headset for routine tDCS administration targeting bilateral DLPFC. The headset is highly usable, robust, and is expected to facilitate home and high-volume use.

Galvanic Vestibular Stimulation Headset balancing robust and simple administration with subject comfort: A Usability Analysis.

The vestibular system is responsible for spatial orientation and stability. It can be stimulated with a weak electric current, a mechanism known as Galvanic Vestibular Stimulation (GVS). Typical GVS administration involves holding down electrodes on the mastoids either with a strap (or bandage) wrapped around the head or by positioning a self-adhesive electrode at the mastoid location. While the latter approach is simple to administer, it is limited to exposed skin application as hair impedes adhesion. The reduced access area limits total current delivery allowable due to increased skin sensation. Accordingly the former approach is more typically employed but leads to inconsistent and inaccurate electrode placement. As current flow pattern is directly influenced by electrode position, this results in inconsistent stimulation and replicability issues. The primary goal of this study was to test usability and comfort while developing a GVS-specific headset named "Mastoid Adjustable Robust Stimulation (MARS)" compared to a conventional elastic strap. We recruited 10 subjects, 5 operators and 5 wearers, and tested usability using the System Usability Scale (SUS) as well as comfort levels over a typical 20 minute stimulation session. Additional questions were answered by the operators and wearers on visual appeal, interference, slippage, and electrode placement. The results of this testing guided the development of a final version meeting our requirements of robustness, simple to administer, and subject comfort.Clinical Relevance-This study introduces a headset for routine Bilateral-Bipolar GVS administration that is highly usable and ensures both flexible and consistent electrode application over typical approaches.