Investigation of the relationship between hand and neck sympathetic skin responses with blood pressure

It has been discussed for many years that sympathetic overactivity is among the risk factors, although there is no identified cause of essential hypertension. This study is carried out to investigate whether the recording of sympathetic skin response (SSR) measurements from the neck is more sensitive than hand recording in showing cardiac sympathetic innervation. Furthermore, it is performed to provide a better understanding of sympathetic neural mechanisms in newly diagnosed hypertensive patients with different stages of the disease. 22 stage-1 hypertensive (10 females and 12 males, with an average age of 34.4 ± 8.6), 30 stage-2 hypertensive (2 women and 28 men, with an average age of 37.2 ± 8.8), and 28 healthy control (17 women and 11 men, with an average age of 32.3 ± 8.3) patients with no known chronic disease and/or drug use history participate in the study. Bilateral blood pressure values are measured for each case from the right and left side, and then bilateral SSRs from the neck and hand regions are studied. In the stage-1 hypertension group, neck and hand SSR amplitude values are statistically significantly higher than healthy control and stage-2 hypertension group (p<0.05). Besides, bilateral neck SSR is obtained in all patients with stage-1 hypertension, while bilateral neck SSR is obtained in 50% of the healthy control group and 70% of the stage-2 hypertension group. When the groups with bilateral responses are evaluated, a statistically significant difference is found between the subgroups of the maximum amplitudes compared to those that appear simultaneously with the same stimuli and different stimuli in four recording positions (p<0.05). This study shows that in the initial period of hypertension, there is an increase that is regressed in the following periods in sympathetic activity, and neck SSR measurements indicate better results than the hand measurements in denoting this early increase. Keywords: Hypertension, blood pressure, autonomic nervous system, sympathetic activation, sympathetic skin response