| Objective:Neurophysiological examination plays an important role in the diagnosis and pathogenesis of diabetic peripheral neuropathy. Motor conduction velocity (MCV), distal potention latency (DPL), waveform of compound muscle action potential (CMAP) has become a routine parameters. Now, the report in duration,wave area of CMAP was few. There was no report about analyzing the waveform distortion characteristics quantitatively. We detect the peroneal nerve in patients with DM and analyse the parameters quantitatively to investigate the characters of electrophysiology in diabetic peripheral neuropathy (DPN) further.Methods:150 patients with NIDDM were individed into group A (95 cases with neurologic symptoms or signs) and group B (55 cases without neurologic symptoms or signs).Group C (80 cases) served as a control group. We detect the peroneal nerve in three groups. At the bases of routine parameters including MCV, DPL, amplitude of CMAP, we analyse the duration,wave area and waveform of CMAP with t orχ2 test. We use mathematical analysis software(metlab software) to analyse the distorted wave curve of CMAP quantitatively.Compared the distorted wave curve to idea wave curve, find the difference between the two curves, including mean values, maximum values,minimum values and variation values.Results:1. Compared to group C, group A and group B have longer duration of CMAP(P <0.05).2. The wave area of fibular head to ankle was smaller in group A (P<0.05).3. IN NIDDM patients,33 cases (22%) have waveform distortion, the rates were different significantly between group A and group B (P<0.05).4. Excluded general parameters were normal,33 cases (33.3%) have extended duration,9 cases (9.0%) have reduced wave area, and 14 cases (9.3%) have waveform distortion.5. In 150 patients the duration was prolonged (42%), MCV decreased (24.7%), waveform distorted (22.0%), DPL extended (13.3%), the wave area decreased (10.7%) and the amplitude reduced (7.3%). General parameters included MCV, DPL, and amplitude, of which abnormal rate was 35.8%, when added the parameters of duration, waveform and wave area,the abnormal rate increased to 64.7%. 6. If make the general parameters as criteria of DPN, the sensitivity of duration is 58.8%, the specificity is 67.2%; the sensitivity of area under the curve is 5.9% and specificity is 93%7. Normal wave curve of CMAP was smooth, non-discrete, no spike-wave and no multi-phase. It coincided with its idea sine curve, the difference between the two curve is that maximum 138.0μv, minimum 1.5μv and mean44.4μv.8. In 55 pieces of distorted curve, there were 39 pieces(70.9%) have normal amplitude, the least mean is 102.2μv (1.2μv-269.0μv), the biggest is 2064.3μv (0.7μv-3982.4μv), the least variation value is 267.8μv, the biggest is 3981.7μv; there were 16 pieces (29.1%) have lower amplitude, the biggest is 4160.9μv (16.3μv-9129.2μv), the least mean is 171.6μv (2.1μv-377.9μv), the least variation value is 375.8μv,the biggest is 9112.9μv.Conclusions:At the bases of routine parameters,adding the duration,wave area and waveform of CMAP can improve the rate of electrophysiological abnormality in DPN. Motor axonal damage can occur early in DPN.The duration wave area and waveform distortion of CMAP can determine axonal damage early. Analysing the waveform variation of CMAP by mathematic quantitatively, is worthyful of Diagnosis and evaluated the motor nerve axonal injury, can provide objective, quantifiable neurophysiological basis. |
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