A Multi-Frequency Electro-Mechanical Exciter Instrument for Diabetic Neuropathy Assessment

The Vibrotactile Perception Threshold (VPT) test is a clinical measure used to assess the function of skin mechanoreceptors that can detect vibrations. It provides a noninvasive indicator for diagnosing Diabetic Peripheral Neuropathy (DPN). The goal of this project is the design and development of a multi-frequency electromechanical exciter instrument that will deliver vibration stimuli for determining VPT. The instrument works by generating vibration stimuli applied to the fingers or feet of the subject and receiving his/her response when the stimulus is felt via a button. For this purpose, an electromechanical exciter is used to deliver vertical motion to a probe that meets the skin of the subject. The stimuli can vary in frequency as well as acceleration (intensity). The instrument uses a psychophysical algorithm that complies with international standards, and generates a report at the end of the test in the form of a vibrogram. Moreover, the design of the instrument incorporates a mechanism for preventing excessive pressure from being applied by the subject, as this may affect the accuracy of VPT. We have successfully implemented a prototype and validated its performance according to specifications and the relevant ISO standards.