title: The remote sensing of mental stress from the electromagnetic reflection coefficient of human skin in the sub-THz range.
abstract: Recent work has demonstrated that the reflection coefficient of human skin in the frequency range from 95 to 110 GHz (W band) mirrors the temporal relaxation of stress induced by physical exercise. In this work, we extend these findings to show that in the event of a subtle trigger to stress, such as mental activity, a similar picture of response emerges. Furthermore, the findings are extended to cover not only the W band (75-110 GHz), but also the frequency band from 110 to 170 GHz (D band). We demonstrate that mental stress, induced by the Stroop effect and recorded by the galvanic skin response (GSR), can be correlated to the reflection coefficient in the aforementioned frequency bands. Intriguingly, a light physical stress caused by repeated hand gripping clearly showed an elevated stress level in the GSR signal, but was largely unnoted in the reflection coefficient in the D band. The implication of this observation requires further validation.
authors.affiliation: Department of Applied Physics, The Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel.
authors.forename: Eli
authors.initials: E
authors.lastname: Safrai
authors.forename: Paul Ben
authors.initials: PB
authors.lastname: Ishai
authors.forename: Andreas
authors.initials: A
authors.lastname: Caduff
authors.forename: Alexander
authors.initials: A
authors.lastname: Puzenko
authors.forename: Alexander
authors.initials: A
authors.lastname: Polsman
authors.forename: Aharon J
authors.initials: AJ
authors.lastname: Agranat
authors.forename: Yuri
authors.initials: Y
authors.lastname: Feldman
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000528:radiation effects; D003116:Color; D055590:Electromagnetic Phenomena; D005260:Female; D005712:Galvanic Skin Response / Q000528:radiation effects; D006339:Heart Rate / Q000528:radiation effects; D006801:Humans; D008297:Male; D011930:Reaction Time / Q000528:radiation effects; D012867:Skin / Q000503:physiopathology / Q000528:radiation effects*; D013312:Stress, Physiological / Q000528:radiation effects*; D013315:Stress, Psychological / Q000503:physiopathology*