# Sympathetic Skin Response | Symptoms, Causes, Tests and Treatment | OSANG > SSR is a non-invasive test that attaches electrodes to the palms and soles of the feet and records changes in skin potential that occur about 1.5 to 3 seconds after stim… - Official page: https://osns.co.kr/en/encyclopedia/sympathetic-skin-response - Organization: OSANG Neurosurgery ## Page content Diagnostic Tools ## Sympathetic Skin Response Sympathetic Skin Response (SSR) · Sympathetic skin response (SSR) is an autonomic nerve function test that measures changes in skin electrical resistance that occur when sympathetic nerve activity in skin sweat glands changes due to stimulation such as electrical stimulation or deep breathing. ## At a glance SSR is a non-invasive test that attaches electrodes to the palms and soles of the feet and records changes in skin potential that occur about 1.5 to 3 seconds after stimulation. SSR abnormalities are observed in approximately 72-87% of diabetic autonomic neuropathies, and are used to evaluate anhidrosis, Parkinson's disease, MSA, and small fiber neuropathy. Because standardization is difficult and there is variation between examiners, it is interpreted in parallel with other autonomic nerve tests. - 01Definition and Overview - 02Principle and measurement method - 03Clinical significance - 04diagnosis - 05treatment ## Definition and Overview Sympathetic skin response (SSR) is an autonomic nerve function test that measures changes in skin electrical resistance that occur when sympathetic nerve activity in skin sweat glands changes due to various stimuli such as electrical stimulation, deep breathing, and sudden auditory stimulation. SSR reflects the function of the sympathetic cholinergic pathway that innervates the eccrine sweat glands in the skin. A normal response occurs only when the efferent pathway from the brainstem through the lateral horn of the spinal cord to the postganglionic sympathetic fibers is intact. ## Principle and measurement method ### Inspection principle When stimulation is given, sympathetic nerve activity in the skin sweat glands increases, which changes the electrical conductivity of the skin surface. This change in potential is recorded with a surface electrode. ### stimulation method - Electrical stimulation: Apply single-shot electrical stimulation (0.1 to 1 ms, 10 to 30 mA) to the wrist or ankle. - Deep breathing stimulation: deep inspiration or Valsalva maneuver - Auditory stimulus: sudden loud sound ### Recording method Recording is performed by attaching the active electrode to the palm or sole of the foot, and the reference electrode to the back of the hand or the top of the foot. After stimulation, potential changes are observed after a latency of about 1.5 to 3 seconds. ### evaluation indicators - Latency: Time from stimulus to onset of response. - Amplitude: Magnitude of change in potential - Waveform type: single phase or complex waveform - Presence or absence of reaction: absent or present ## Clinical significance ### Diabetic autonomic neuropathy In patients with diabetic autonomic neuropathy, SSR abnormalities (disappearance or prolonged latency) are observed in approximately 72-87% of patients. SSR is useful for early detection because abnormalities may appear before clinical symptoms. ### Small Fiber Neuropathy SSR evaluates the sympathetic pathway via unmyelinated C fibers and small diameter Aδ fibers. Even if the nerve conduction test is normal, SSR abnormalities may appear, so it is used as an auxiliary tool in diagnosing small fiber neuropathy. ### Parkinson's Spectrum Disorders SSR abnormalities are reported in Parkinson's disease, multiple system atrophy (MSA), and pure autonomic failure (PAF). The loss of SSR in MSA and PAF is more pronounced than in Parkinson's disease, which serves as a reference for differential diagnosis. ### Anhidrosis It is used to evaluate the cause of local or generalized anhidrosis. Loss of SSR in the area suggests damage to peripheral sympathetic nerve fibers. ## diagnosis ### normal standard - Palm: Latency 1.5-2.5 seconds, based on upper extremity stimulation. - Soles: Incubation period 2.0-3.0 seconds - A normal baseline value according to age is needed, and the incubation period increases with age. ### abnormal findings Criteria for an abnormal SSR: - Absent response - Prolonged incubation period (exceeding normal standards) - Significant reduction in amplitude (criteria vary between studies) ### Limitations of the test SSR is influenced by various factors such as habituation by repeated stimulation, skin temperature, arousal state, anxiety, and drugs (anticholinergics, etc.). There is variation between examiners due to the absence of standardized testing protocols and normal reference values. For this reason, it is recommended to interpret it in conjunction with other autonomic nerve tests rather than as a standalone test. ## treatment Because SSR is a diagnostic test, there is no direct treatment. If SSR abnormalities are confirmed, treatment for the causative disease (diabetic autonomic neuropathy, small fiber neuropathy, Parkinson's spectrum disease) is given priority. In diabetic autonomic neuropathy, improving blood sugar control is important to preserve autonomic function, and in small fiber neuropathy, customized treatment depending on the cause is necessary. --- This information is provided for medical educational purposes and is not a substitute for individual medical care or treatment. If you have any symptoms, be sure to seek professional advice. Inquiries: Osang Neurosurgery 1599-5453 | osns.co.kr ## Related articles - Amyloid PET - Cognitive function test - Electromyography - pupillometry test This article provides general medical information and does not replace an individual diagnosis or treatment plan. Please seek a medical assessment if symptoms persist. ## Important notice This Markdown alternative helps search and AI tools understand the public page accurately. It provides general health information and does not replace an individual diagnosis or treatment.