Dynamic analysis for mental sweating of a group of eccrine sweat glands on a human fingertip by optical coherence tomography

Background An important function of skin physiology is mental sweating, where sweating is accelerated via the sympathetic nerve by mental or physical stress externally applied to a volunteer. Aim Activity of the sympathetic nerve (ASN) is evaluated by quantitative measurement of mental sweating. Material and Methods Optical coherence tomography (OCT) is highly potential for in vivo observation of human sweating dynamics which affects ASN. We demonstrate dynamic OCT analysis of mental sweating of a group of eccrine sweat glands. The sweating dynamics is tracked simultaneously for 19 sweat glands by time-sequential piled-up en-face OCT images with the frame spacing of 3.3 s. The en-face OCT images of the spiral lumen of the eccrine sweat gland are constructed by data acquisition of the 128 B-mode OCT images. Results It is thus found that the response to mental stress is different for each sweat gland even though the sweat glands are adjacent to each other. Such strong non-uniformity is observed in mental sweating where the amount of excess sweat is different for each sweat gland although the sweat glands are adjacent to each other. Discussion The non-uniformity should be necessary to adjust as precisely the total amount of excess sweat as possible through the sympathetic nerve in response to strength of the stress.