To investigate the normal data of pain-related evoked potentials (PREP) elicited with a concentric surface electrode among normal, healthy adults and the relationship between PREP and pain intensity.
Sixty healthy volunteers (22 men and 38 women; aged 36.4±10.7 years; height, 165.4±7.8 cm) were enrolled. Routine nerve conduction study (NCS) was done to measure PREP following electrical stimulation of hands (C7 dermatome) and feet (L5 dermatome). Negative peak (N), positive peak (P) latencies, peak to peak (NP) amplitudes, conduction velocity (CV), and verbal rating scale (VRS) score were obtained. Linear regression analysis tested for significant relevance between variables of PREP and VRS score.
Normal NCS results were obtained in all subjects. N latency of hand PREP was 163.8 ±40.0 ms (right) and 161.0±39.9 ms (left). N latency of foot PREP was 178.0±43.9 ms (right), 180.4±43.4 ms (left). NP amplitude of hands was 20.6±10.6 µV (right) and 21.9±11.6 µV (left). NP amplitude of feet was 18.8±8.3 µV (right) and 19.0±8.4 µV (left). The calculated CV was 13.2±4.7 m/s and VRS score was 3.8±1.0. A highly significant positive correlation was evident between VRS score and NP amplitude (y=0.1069x+1.781, r=0.877, n=60, p<0.0001).
PREP among normal, healthy adults revealed a statistically significant correlation between PREP amplitude and VRS score.
Citations
Objective: This study was designed to investigate the effect of different sites of recording electrodes on auditory evoked potentials (AEPs) in healthy adults and to analyse these potentials properly.
Method: Eleven healthy adults, 7 males and 4 females, without any history of disease or conditions causing hearing difficulties were selected. AEPs were performed on these subjects with 4 different methods, i.e. different recording sites, Cz-Ai, Cz-Fpz, Ai-Ac, and Ai-Cs7. Auditory stimulation was given by rarefaction clicks of 75dB intensity and 11.1 Hz frequency, and responses were recorded with surface electrodes.
Results: The amplitudes of peak I and V were larger with vertical recordings, that is the vertex-auricle (Cz-Ai) or vertex-7th cervical spine (Cz-Cs7) recordings, compared to horizontal recordings of both auricle (Ai-Ac) or extracephalic electrodes. The largest amplitude ratio of peak V/I was with vertex-7th cervical spine (Cz-Cs7) recording.
Conclusion: Changes in AEPs with respect to the sites of recording and reference electrodes are thought to be due to the vector of brain stem auditory nuclei and pathways. It might be helpful to consider these changes in the evaluation of brain stem lesions.
Objective: To explore the effects of different recording electrodes on motor nerve conduction latencies.
Method: Median motor conduction study was performed in 10 healthy subjects. Motor conduction latency was determined by placing different recording electrodes (surface disc, monopolar needle and concentric needle) at the motor point of the left abductor pollicis brevis muscle, and reference electrodes on the proximal interphalangeal joint of the thumb. Motor nerve conduction recording was performed by using a surface disc, monopolar needle, and concentric needle. For the intramuscular recordings, needles were inserted both superficially and deep. The stimulus electrodes were secured 8 cm proximal to the recording electrodes, and the same intensity was applied throughout the tests.
Results: Deep intramuscular monopolar and concentric needle electrodes recorded the shorter latencies, 3.0⁑0.4 ms and 3.0⁑0.3 ms, respectively. Superficial concentric needle electrode recorded the longest latency of 3.4⁑0.3 ms. Motor nerve conduction latencies using a surface disc and superficial monopolar electrode were 3.2⁑0.3 ms and 3.2⁑0.3 ms, respectively.
Conclusion: We conclude that the distal motor nerve conduction latency is variable depending on the type of recording electrodes.
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