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Objective To explore the diagnostic value of corneal confocal microscopy in the early small fibre neuropathy (SFN).Methods A total of 45 patients with small fibre neuropathy and 50 age-matched healthy subjects undertook a neurological evaluation,neurological deficits score (NDS),sural nerve conduction velocity,contact heat evoked potential (CHEP) and corneal confocal microscopy (CCM) to quantify small nerve fibre pathology.Four parameters including nerve fiber length (NFL),nerve branch density (NBD),nerve fiber density (NFD) and nerve fibre tortuosity (NFT) were calculated from the observation of corneal confocal microscopy.Results Compared with the control group,significantly decreased NFD and NBD were found in the SFN group [(42.00 ±25.26)/mm2 vs (72.38 ± 14.09) /mm2 ;(31.93 ± 13.21)/mm2 vs (46.24 ± 11.48)/mm2 ; with all P ＜ 0.05],while NFT were significantly increased in the SFN group [(2.48 ±0.87) levels vs (0.88 ±0.56) levels,P ＜0.001].The neurological deficits score was correlated with NFT,NFD and NBD (r =0.782,-0.376,-0.504 ; with all P ＜ 0.001).Conclusion CCM is a new and sensitive noninvasive clinical technique that may be used to detect early small fibre nerve damage in patients with SFN.
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Objective To establish the method of contact heat evoked potential(CHEP)and to explore the value of this evoked potential in pain testing of patients with cerebral infarction.Methods A total of 100 healthy volunteers and 30 patients were examined.The healthy volunteers were divided into 3 groups according to the length of their arms:(Group A:56.0～65.0 cm ;Group B :65.5～74.0 cm ;Group C :74.5～83.0 cm).A recently de- veloped heat-foil technique with a rapid temperature rising rate at 70℃/s was used to elicit pain and contact heat e- voked potentials.Contact heat was delivered via one circular thermode(diameter 27 mm,area 573 mm~2)and set at two intensity levels(49.5℃and 54.5℃)to three body sites:the thenar eminence,the dorsum of hand and proximal volar forearm.The subjects were asked to rate the pain with numerical rating scale after each stimulus and CHEP was recorded from Cz and Pz.The association between stimulus intensities and pain rating was explored,the main compo- nents of the evuked potential were watched.CHEP,sensory conduction velocity(SCV)and somatosensory evoked potentials(SEP)were performed in patients with hemi-anesthesia caused by cerebral infarction.Results The pain intensity ratings were 3.2?0.3 and 4.4?0.5 at thenar eminence,5.0?0.7 and 6.3?0.8 at the dorsum of hand and 5.3?0.6 and 7.2?0.5 at the proximal volar forearm when the temperature of 49.5℃and 54.5℃was applied, respectively;Three components,Cz/N550,Cz/P750 and Pz/P1000,were identified in the evoked potentials.Cz/ N550 and Cz/P750 appeared when the dorsum of hand and proximal volar forearm were stimulated.In contrast,Pz/ P1000 could be identified when nociceptors of thenar eminence and proximal volar fbrearm were excited.In the pa- tients with cerebral infarction,CHEP disappeared or became abnormal on one side,while SCV and SEP were normal on that side.Conclusion It was suggested that CHEP could be elicited reliably in the controls.CHEP is helpful in the assessment of analgesia in patients with cerebral infarction.