Galvanic skin resistance--a marker for endothelial damage in diabetes.
BACKGROUND
Aging and diabetes are both associated with impaired vascular endothelial function. This causes a reduction in the resting blood flow and the blood flow response to autonomic stressors. Further, skin moisture and the ability to sweat are also reduced with aging and diabetes. The present investigation was undertaken to determine if the extent of damage from aging and diabetes could be accurately assessed by simply examining the electrodermal skin response (galvanic skin resistance) to a thermal stress.


METHODS
Forty-five subjects whose average age was 31.2 +/- 8.3 years (younger group), 62.4 +/- 9.6 years (older group), and 61.8 +/- 11.3 years (diabetes group) were divided into three groups of 15 subjects. Subjects were exposed to environmental temperatures of 15 degrees C, 23 degrees C, or 32 degrees C for 30 min. During this period of time, sweat rate, skin blood flow, the electrodermal skin response, and skin moisture were measured.


RESULTS
There were significant impairments in skin moisture, sweat, skin blood flow, and the galvanic skin response at any of the three environmental temperatures in subjects with diabetes compared to older subjects compared to younger subjects (analysis of variance, P < 0.01). Both a reduction in skin blood flow and impaired sweating contributed to the higher galvanic skin resistance seen in subjects with diabetes. The greatest contributor was impaired sweating.


CONCLUSIONS
The results show that galvanic skin resistance, at any environmental temperature, may be a good means of assessing vascular damage and impaired sweat response in people with diabetes.
Petrofsky
Jerrold S
JS
Department of Physical Therapy, School of Allied Health, Loma Linda University, Loma Linda, California 92350, USA. jpetrofsky@llu.edu
McLellan
Katie
K
D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology; D015415:Biomarkers; D001783:Blood Flow Velocity; D003920:Diabetes Mellitus / Q000503:physiopathology*; D004566:Electrodes; D004730:Endothelium, Vascular / Q000503:physiopathology*; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology*; D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008297:Male; D008875:Middle Aged; D012867:Skin / Q000098:blood supply* / Q000503:physiopathology; D015595:Skin Aging / Q000502:physiology*; D012881:Skin Temperature / Q000502:physiology; D013546:Sweating / Q000502:physiology; D055815:Young Adult
D015415:Biomarkers