Skin impedance at acupuncture point Dingchuan in subjects with and without asthma

Objective: Asthma can be a disabling disease and despite advances in pharmacology, the prevalence of this condition globally remains high and accounts for a significant proportion of public health care costs. While pharmacology is the mainstay of asthma managemen4 drug side effects have promoted alternative therapeutic interventions, such as acupuncture. Acupuncture points have a lower skin impedance compared to non-acupuncture points. Health impairment is associated with changes in skin impedance at system-specific acupuncture points. Detection of skin impedance changes may assist in the early diagnosis of asthma and monitoring the effectiveness of therapeutic interventions for this condition. Method: This study compared skin impedance at acupuncture point Dingchuan (EX-BI), in 92 subjects with normal health (47 subjects, age 32.6±1.67yr) and those diagnosed with asthma (45 subjects, age 42.4±1.80 yr). Skin impedance was measured using a 2-electrode impedance meter bilaterally at EX-BI, 0.5 "curt" lateral to the lower border of 7th cervical vertebra. Result: The study showed that skin impedance was significantly higher at acupuncture point EX-B1 in subjects with asthma (29.4±21 kΩ) compared to subjects with normal health (13.8±7.9 kΩ) (P=0.013). Skin impedance was negatively correlated to forced expiratory volume in 1 second (FEV1, r=-0.59, P=0.012 in females; and r=-0.68, P=0.015 in males). A receiver operator characteristic (ROC) curve revealed an optimum cut-off point of 35 kΩ for male and 10 kΩ for female subjects. Conclusion: We conclude that EX-B1 skin impedance is higher in patients with asthma and skin impedance might be a possible adjunctive parameter for assisting diagnosis and monitoring asthmatic status.