Skin tremor induced by artery pulses are usually sensed by doctor's fingers in Traditional Chinese Medicine(TCM). On the other hand, vibration of acupuncture needle was also stated by Huang Di Nei Jing (Yellow Emperor). However; the characteristics of skin tremor and its correlation with vibrating acupuncture needles, how the skin tremor and vibration of needles varies from area to area, are not yet clarified.In this study, the abovementioned issues will be investigated experimentally through non-invasive method.

About 10 healthy volunteers, aged 20~65, will be recruited. The investigators will measure the needle and the skin tremor by video optical microscopy. The variation of skin tremor and needle vibration and their spectra will be analyzed digitally. The model correlating skin tremor, needle vibration and basic physiological parameters will be constructed.The fact that the skin tremor and the needle vibration come from the same origin is expected.

However; due to the leverage effects and different dynamical responses to the source vibrations at different frequencies, needle vibration might exhibit some difference from skin vibration in their power spectra. This study should be able to construct a clear model of the possible vibration sources such as heartbeat and breathing, the area dependence of vibrations, the correlation between the skin and the needle vibrations, and the correlation with other physiological parameters.

Inclusion Criteria:

• Healthy employees or students of National Central University aged between twenty to sixty-five.

Exclusion Criteria:

• With chronic diseases, severe psychological disorder or injury, or been in a surgery in the past twelve months.

Healthy volunteers who is

1. Aged 20~65
2. Without chronic disease
3. Didn't receive surgery in the past 12 months