Research And Development Of A Quantitative Human Current Perception Threshold Testing System

Lots of diseases come with dysfunctions to the sensory system, causing hypoesthesia or hyperesthesia. But most of the examinations for sensory system are not quantitative. By 1970th a novel method named Quantitative Sensory Testing makes it possible for doctors to trace the changes of the sensory threshold of patients. The Current Perception Threshold system we developed is one of these kinds of methods.First, the significance to evaluate the sensory function and the current methods are discussed. The development and application history of Quantitative Sensory Testing technology is also reviewed. Then, Current Perception Threshold system is discussed in details including three main aspects: physiological background, theory of UDTR and Forced Choice method and experiment basis providing the evidence for us to substitute heating, cooling and vibration signals with 5Hz, 250Hz, 2000Hz sine current signals, respectively.The most important part of this thesis is the design of the system. The CPT system has two work modes: the embedded system runs independently and system runs controlled by PC. The embedded system is powered up with a battery and DC/DC converters. And the CPU is TMS320LF2407. When the embedded system works independently, the DSP controls the interface and performances the algorithms while the analog part implements V/I converting, constant current output and feedback stage. The system has both software and hardware protections.Performance testing of the system and the clinical experiments are carried out. It shows in the result that the system works stably. The experiment results are almost repeatable under the same conditions.At last, future research of the method and system improvement is discussed.