Galvanic skin response and heart rate graph

Skin conductance is not under conscious control.

The amount of sweat glands varies across the human body, but is the highest in hand and foot regions (200вЂ“600 sweat glands per cm2 ), where the GSR signal is typically collected from. While sweat secretion plays a major role for thermoregulation and sensory discrimination, changes in skin conductance are also triggered robustly by emotional stimulation : the higher the arousal, the higher the skin conductance. This connection of emotional response to GSR signal has been explored in thousands of articles in the 120+ years since this seminal finding. Vigouroux was the first researcher to uncover a link between mental state and GSR activity, finding an association with the level of sedation in patients and skin resistance. The GSR signal is therefore not representative of the type of emotion, but the intensity of it. It is noteworthy that both positive (вЂњhappyвЂќ or вЂњjoyfulвЂќ) and negative (вЂњthreateningвЂќ or вЂњsaddeningвЂќ) stimuli can result in an increase in arousal вЂ“ and in an increase in skin conductance. Research has shown how this is linked to emotional arousal. Our level of emotional arousal changes in response to the environment weвЂ™re in вЂ“ if something is scary, threatening, joyful, or otherwise emotionally relevant, then the subsequent change in emotional response that we experience also increases eccrine sweat gland activity.

SSR is indicated as an additional test for the evaluation of sympathetic degeneration in patients with MSA.The galvanic skin response (GSR, which falls under the umbrella term of electrodermal activity, or EDA) refers to changes in sweat gland activity that are reflective of the intensity of our emotional state, otherwise known as emotional arousal. No correlation was found between SSR and CVTs that assess sympathetic function in patients and control subjects. CVTs showed severe sympathetic and parasympathetic hypofunction in patients with MSA, but not in patients with PD or control subjects. A statistically significant difference in SSR latencies and amplitudes was found between patients with PD and control subjects only when motor asymmetries were considered. In these patients, SSR latency was significantly longer and SSR amplitude was smaller when the side with more marked motor symptoms was stimulated, both ipsilaterally and contralaterally to the side of stimulation. For patients with PD, SSR did not differ from that of control subjects. For patients with MSA, SSR latency was significantly longer and amplitude was significantly smaller than that of patients with PD and control subjects. The SSR was normal in all patients with PD and control subjects but was abnormal or absent in all patients with MSA. CVTs included the following sympathetic and parasympathetic tests: orthostatism, head-up tilt, cold pressor test, deep breathing, Valsalva maneuver, and hyperventilation. SSR was elicited by electrical stimulation of the right and left median nerves and simultaneously recorded on the palms of both hands. The relationship between sympathetic skin response (SSR) and cardiovascular autonomic function tests (CVTs) was investigated in 15 patients with idiopathic Parkinson's disease (PD), 15 patients with clinical evidence of multiple system atrophy (MSA) with autonomic failure, and in 15 healthy control subjects.

Galvanic skin response and heart rate graph