The Development Of A SEP Stimulator Based On The Multimedia Sound Resources Of The Computer And The Single Tiral Of SEP

In this paper, a stimulator based on the multimedia resources of the computer which was invented by ourself was reported. And an Auto-reference and Autocorrelation and Adaptation Interference Cancellation Theories and Techniques (called AAA-ICT) which is proposed by our lab are used to extract somatosensory evoked potentials (called SEP) successfully.This paper will report a research about the SEP for 40 young individuals and 40 old individuals. In the young group, there are 11 males and 29 females whose age are 22.7±3.1 years old, ranged 18 to 30years old. While in the old group, there are 19 males and 21 females whose age are 72.3±5.5 years old, ranged 60 to 80 years old. The research includes the study for the wave groups of N1-P2, P300 and N20. Finally we got the reference values of the main waveforms of the SEP for our lab, which are: the latency of N20: 19.97±0.8ms, of P1: 98.1±7.9 ms, of N1: 149±14.9ms,of P2: 205.6±16.8ms,of N2: 259.4±16.9ms,of P3:330.1±18.7ms, and the contrast of results of the superposition averaging to the averaging single trial for the young and old individuals and so on.With regard to the SLSEP wave of N20, whatever the single trial, the superposiyion averaging or the averaging single trial in the young individuals, the latencies of N20 are all shorter than that in the old individuals and the differences have statistical significance (P<0.05). Meanwhile, the amplitudes of N20 in the young individuals are all bigger than that in the old individuals and the differences have statistical significance (P<0.05). Among the five long-latency waveforms, the latency and the amplitude of the waveform btween the young individuals and the old individuals both have some differences. The latencies of P1,N1,P3 in the young individuals are all shorter than that in the old individuals and the differences have statistical significance (P<0.05). The amplitudes of P2,P3 in the young individuals are both bigger than that in the old individuals and the differences have statistical significance (P<0.05). While the differences that the latencies of P2,N2 between the young individuals and the old individuals have no statistical significance (P>0.05).What's more, whatever the old individuals or the young individuals and whatever the long-latency SEP or the short-latency SEP, on the comparison of the latency of waveform, there are no statistical significance (P>0.05) between the superposition averaging and the averaging single trial. But on the comparison of the amplitudes of the waveform, the amplitude of the averaging is bigger than the averaging single trial and the differences have statistical significance (P<0.05). This further proves that the traditional averaging results inculde the remaining the background brain electricity components besides the evoked potential, while the technique of single trial does not have the defect.Conclusions and discussion: (1) A SEP stimulator based on the multimedia sound resources of the computer makes full use of the multimedia resources of the computer. It can generate many kinds of the required waveforms conveniently; (2)By this stimulator, we can extract successfully the waveform groups of N1-P2,P300 and N20 of human SEP through single trial; (3)It is easy to development the portable device for the SEP single trial.The innovation of this study is as follows: (1) Which is different to the traditional stimulator, the stimulus waveform of our stimulator is generated by the sofeware of the computer. Therefore, the stimulus signal is more exact than the signal generated from the traditional hardware circuit and it has the long-term stability.(2) The D/A circuit of the traditional stimulator is replaced by the D/A function of the multimedia sound card of modern computer. This saves resources. As a part of the national natural scientific foundation, it can be well integrated with the evoked potential collection system of our lab.(3) This stimulator can be well transplanted. Besides it can be connected to the common PC, it can be connected to the mobie computer. This is what the traditional stimulator cannot do.(4) We have implemented the single trial of SEP based on the AAA-ICT.(5) This study not only provides the traditional averaging results of SEP but also the averaging results based on the single trial. The comprasion shows that the traditional averaging results conclude much more remnant components of brain electricity.(6) There are new parameters for the clinic,which are the mean and the standard deviation of the single trial of SEP which cannot provided by the traditional averaging technique.