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Objective To establish a method to evoke cerebral potentials by stimulating nociceptive fibers with contact heat evoked potential stimulator,evaluate the state of nociceptive system in patients with multiple sclerosis and assess the value of the potentials in multiple sclerosis(MS).Methods Thirty-six definite MS patients and 40 sex-,height-and aged-matched healthy persons underwent stimulation of contact heat delivered via a circular thermode to excite selectively nociceptors with a rapid rising time at 70℃/s to elicit pain and contact heat evoked potentiaI(CHEP).Thermal stimuli were sent at two intensity levels (47 ℃ and 51℃)to 3 body sites:volar surface of the forearm,the skin of leg 5 cm proximal to the medial malleolus and lumbar part.The CHEP were recorded from Cz.The relationship between the stimulus intensity and pain rating was observed,and the main components of the evoked potential were recorded.Then,somatosensory evoked potential(SEP)was examined in 36 patients with MS.Results CHEP were elicited reliably and stably in all control subjects.In contrast,in 4 patients there were no recordable CHEP on stimulation of the upper limb,and in some cases of lower limb(n=5).Conduction velocity of Aδ fihers was(18.1±7.3)m/s.The 21 MS cases had hypesthesia in upper limb and 29 cases in lower limb.The visual analog scale(VAS)for pain perception was higher in control subjects(upper limb:8.0±0.7;lower limb:7.9±0.7)than MS with hypesthesia(upper limb:6.1±0.9;lower limb:5.6±1.3,Z=-3.249 and -5.272,both P＜0.01).The group of patients (MS) with hypesthesia(upper limb 17 cases,lower limb 24 cases)had markedly reduced N-P amplitudes(upper limb:(30.5±12.8)μV;lower limb:(28.2±16.2)μV,t=-4.612 and -3.144,both P＜0.01)and prolonged N-wave latencies(upper limb:(387.3±34.2)ms;lower limb:(489.9±70.2)ms,t=4.790 and 4.798,both P＜0.01)compared with the control group in CHEP mediated by Aδ fibers.CHEP abnormality was observed more often in the lower(26/36,72.2%)than the upper limb(16/36,44.4%,P=0.031)and SEP(19/36,52.8%,χ~2=4.261,P=0.039).CHEP were abnormal in 3 of 15 skin areas with clinically normal nociception in upper limb,and in some cases of lower limb(2 of 7).Conclusions CHEP provides a clinically practical,non-invasive and objective measure,and can be a useful additional tool for the assessment of nocieptive system.Combined assessment of other Eps can help to document dissemination of demyelinating CNS lesions and detect subclinical lesions thus contribute to the diagnosis of multiple sclerosis.
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Objective To study the value of contact heat evoked potentials (CHEPs) for the early diagnosis of diabetic peripheral polyneuropathy. Methods Seventy-five diabetic patients were examined by conventional nerve conduction velocity studies and then divided into 2 groups: diabetics with normal nerve conduction and diabetics with abnormal nerve conduction. Thirty-three normal subjects were used as controls. Toronto Clinical Neuropathy Sco-ring System was used to evaluate the patients. CHEPs were recorded using different stimulation intensities at different temperatures. Results The peak latencies of 45℃ , 50℃, 53℃ in diabetics with normal nerve conduction group were longer than those in normal control group, with a significant difference between the 2 groups(P<0.05). The peak latencies of diabetics were positively related to Toronto scores. Conclusion CHEPs could detect the impair-ment of diabetic peripheral nerve and reveal the impairment earlier than conventional nerve conduction velocity exami-nation, The prolongation of peak latency in diabetics group was significantly and positively related to clinical condi-tion.
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Objective To assess the dlagnostic value of a triple stimulation technique(TST)for benign monomelic amyotrophy(BMA). Methods A total of 15 BMA patients and 15 healthy control subiects were exam-ined with the TST.The latent periods,amplitudes,areas and durations of the negative waves of the compound muscle action potential(CMAP)and motor evoked potential(MEP)induced by the stimulation were recorded,and the de-creasing ratio of amplitudes and areas in the two groups were analyzed. Results There were significant differences in amplitude and area ratios between the BMA patients and the healthy control subjects.Both ratios were significantly lower in the BMA patients. Conclusion TST has some value in diagnosis of BMA.
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Objective To study the therapeutic effects of low frequency repetitive transcranial magnetic stimulation(rTMS)in cranial dystonia.Methods Twenty cranial dystoina patients were treated with low frequency rTMS.Their motor threshold,cortical silent period(CSP)were evaluated before and after the rTMS and after 1,2,6 months as well as the spares and Toronto Western Spasmodic Torticollis Rating Scale(TWSTRS)to evaluate the effects of rTMS in the treatment of cranial dvstonia.Results The patients scored(23.5±14.0)significantly lower after l and 2 months(17.6 ±14.3,18.5±14.2,t=2.632,2.149.both P<0.05).But there was an increasing tendeney of the score after 2 months.The 2-month efficient rate of low-frequency rTMS Was 60%(12/20),yet the long-term effect of rTMS was still to be studied.There was a very significant improvment of relaxed(46.5%±7.3%vs49.9%±9.2%,t=-3.235.P<0.05)and active threshold(40.2%±5.9%/)5 43.9%±8.8%,t=-2.339,P<0.05),prolongation of CSP((96.1±24.5)ms vs(121.6±27.7)ms,t=-7.223,P=0.000).Conclusion The low frequency rTMS is efficient to relieve the clinical symptoms of cranial dystonia.
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Objective To characterize the changes of motor nerve conduction velocity (MCV) and F wave in patients with definite amyotrophic lateral sclerosis (DALS) as related to the duration and severity of the disease. Methods A total of 46 patients with DALS were recruited for the ALS group and 35 healthy adults for the control group. MCV and F wave were examined with median, ulnar, tibial and peroneal nerves in all the patients and compared with those in the controls. Results It was found that the distal motor latencies (DML) and MCV of the median, ulnar, tibial and peroneal profundus nerves in the ALS group were all significantly delayed as compared to those in the control group. The F wave occurrence frequency was lower, the central latencies as well as its side-to-side difference of the F wave in the 4 nerves were significantly longer in the ALS group than those in the control group. For those with more severe conditions, their central latencies of F wave and DML in the 4 nerves of ALS patients were significantly longer, and the MCV were significantly slower than those with milder conditions. A 3-year of follow-up of the patient revealed that there were progressive delay in DML and F wave central latencies, as well as a progressive decrease in MCV or CAMP amplitude. Conclusion The duration and severity of ALS has significant effects on the MCV and F wave of nerves in the upper and lower limbs. MCV and F wave can be used as valuable electrodiagnostic tools for DALS.
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Objective To investigate clinically applied value of P300 with influential factors in olivopontocerebellar atrophy (OPCA). Methods The P300 and cognitive ability sifting investigation (CASI) were tested in 34 OPCA cases and normal controls with equal age, gender and educational levels. Results The P300 latency was significantly longer in OPCA group of different ages than that in the normal control group (P
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Objective Investigate MR resonance diffusion tensor im-aging (DTI) characteristics of non-pyramid tracts in the patients with amyotrophic lateral sclerosis(ALS). Methods 21 patients with ALS were served as case group.20 healthy volunteers were served as healthy controls. All subjects underwent a DTI sequence, chose region of interest (ROI) to measure fractional anisotropy (FA) and mean diffusivity (MD).Results In case group, FA decreased on the splenium of corpus callosum (0.73?0.087)(u=-2.004,P