Fig. 2.

Schematic diagram of the experimental setup for the skin-temperature recording experiment that included a temperature measurement system (TempTraq™, Blue Spark Technologies, Inc., Westlake, Ohio). The TempTraq unit/patch includes a small thermal sensor ($5\times 5{\mathrm{mm}}^2$), as shown in the figure, and a temperature circuit to determine the temperature value induced by TILS on the forehead skin surface. TILS was delivered on the right side of the TempTraq patch, which was connected via Bluetooth to a mobile device. Protection goggles were worn by the participants during the entire experimental procedure.