title: Electrodes for high-definition transcutaneous DC stimulation for applications in drug delivery and electrotherapy, including tDCS.
abstract: Transcutaneous electrical stimulation is applied in a range of biomedical applications including transcranial direct current stimulation (tDCS). tDCS is a non-invasive procedure where a weak direct current (<2 mA) is applied across the scalp to modulate brain function. High-definition tDCS (HD-tDCS) is a technique used to increase the spatial focality of tDCS by passing current across the scalp using <12 mm diameter electrodes. The purpose of this study was to design and optimize "high-definition" electrode-gel parameters for electrode durability, skin safety and subjective pain. Anode and cathode electrode potential, temperature, pH and subjective sensation over time were assessed during application of 2 mA direct current, for up to 22 min on agar gel or subject forearms. A selection of five types of solid-conductors (Ag pellet, Ag/AgCl pellet, rubber pellet, Ag/AgCl ring and Ag/AgCl disc) and seven conductive gels (Signa, Spectra, Tensive, Redux, BioGel, Lectron and CCNY-4) were investigated. The Ag/AgCl ring in combination with CCNY-4 gel resulted in the most favorable outcomes. Under anode stimulations, electrode potential and temperature rises were generally observed in all electrode-gel combinations except for Ag/AgCl ring and disc electrodes. pH remained constant for all solid-conductors except for both Ag and rubber pellet electrodes with Signa and CCNY-4 gels. Sensation ratings were independent of stimulation polarity. Ag/AgCl ring electrodes were found to be the most comfortable followed by Ag, rubber and Ag/AgCl pellet electrodes across all gels.
authors.affiliation: Department of Biomedical Engineering, The City College of New York of CUNY, NY 10031, USA.
authors.forename: Preet
authors.initials: P
authors.lastname: Minhas
authors.forename: Varun
authors.initials: V
authors.lastname: Bansal
authors.forename: Jinal
authors.initials: J
authors.lastname: Patel
authors.forename: Johnson S
authors.initials: JS
authors.lastname: Ho
authors.forename: Julian
authors.initials: J
authors.lastname: Diaz
authors.forename: Abhishek
authors.initials: A
authors.lastname: Datta
authors.forename: Marom
authors.initials: M
authors.lastname: Bikson
mesh_terms: D000328:Adult; D016503:Drug Delivery Systems / Q000295:instrumentation; D004599:Electric Stimulation Therapy / Q000295:instrumentation; D004566:Electrodes / Q000009:adverse effects; D005260:Female; D005542:Forearm; D005782:Gels / Q000009:adverse effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D010146:Pain / Q000209:etiology; D010147:Pain Measurement; D013696:Temperature; D013997:Time Factors; D004561:Transcutaneous Electric Nerve Stimulation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D055815:Young Adult
chemical_list: D005782:Gels