ABSTRACT
Objective: To investigate the value of the trigeminocervical response (TCR) for revealing bulbar involvement in patients with spinal and bulbar muscular atrophy (SBMA). Methods: Thirty patients with SBMA and 30 healthy male controls were included in this study. In all of the normal controls, stimulation of the infraorbital nerve on one side produced bilateral short latency waves consisting of a positive/negative wave, p19/n31, the mean latency of which was measured. The mean square root of the ratio between the amplitude of p19/n31 and the mean rectifi ed surface electromyography (EMG) activity preceding the stimulus, the A value, was estimated. The parameters of the TCR were compared between the two groups. Results: Among the patients with SBMA, 21 (70.0%) had delayed latencies of p19/n31 (P < 0.01) and all (100%) had reduced A values (P < 0.01) relative to the normal controls. Conclusions: All parameters of the TCR were signifi cantly different between the patients with SBMA and the normal controls. T
ABSTRACT
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.
ABSTRACT
Objective To evoke cerebral potentials by stimulating nociceptive fibers with contact heat evoked potentials stimulator (CHEPS)and estimate the nerve conduction velocities of peripheral nerve fibers mediating these responses.Methods Subjects were set in supine position.A heat-foil technology with a rapid rising speed at 70 ℃/s was used to elicit pain and contact heat evoked potentials(CHEP).Contact heat was delivered via one circular thermode (diameter 27 mm,area 573 mm~2).Thermal stimuli were sent at two intensity levels (49.5 ℃ and 54.5 ℃) to three body sites:thenar eminence,the dorsum of hand and proximal volar forarm.Contact heat evoked potentials were recorded from Cz and Pz.A systemic effect between stimulus intensities and pain rating were observed,the main components of this evoked potential were observed.Nerve conduction velocity was calculated from latency difference of CHEP and center to center distance of distal and proximal stimulus arrays.Results The pain intensity rating was 3.2?0.3 and 4.4?0.5 when thenar eminence was stimulated at the temperature of 49.5 ℃ and 54.5 ℃ respectively;the rating was 6.3?0.8 and 7.2?0.5 when the dorsum of hand and proximal volar forarm were stimulated at the temperature of 54.5 ℃ respectively.Three components,Cz/N550,Cz/P750 and Pz/P1000,were found in the evoked potentials.Nerve conduction velocities of the fibers were (12.9?7.5) and (1.7?0.4) m/s respectively,which were corresponding to those of A8 fiber and C fiber.Conclusions CHEPs can be elicited reliably and stably.Velocities of peripheral nerve fibers demonstrate that A8 fiber and C fiber mediate the response.