周波数の異なる薬指刺激による三次元SEFの応答特性の検討

概要

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We measured somatosensory evoked fields (SEFs) by giving electric stimulus to the fourth finger of the right hand (five normal subjects) with a 39-channel SQUID system, which can measure magnetic-field components perpendicular (Br) and tangential to the scalp (Bθ, Bφ) simultaneously. Singular value decomposition (SVD) was applied to the measured SEF data for preprocessing (noise reduction). To investigate the relationship between phase lag and stimulus repetition frequency (SRF), the delay time of a component synchronized with the SRFs was calculated by convoluting the reference signal and the measured SEF. The inter-stimulus interval (ISI) for the SRFs were ten patterns from 3.00 to 27.03Hz including two to six trains of stimulation-data length for analysis and also a recovery period of 500ms after the final train. A dominant slope appeared for two ranges (below 8Hz, and 8 to 20Hz) in all magnetic components. No marked slope was obtained at an SRF of more than 20Hz to the transient SEF waveforms. We tested the significance of the linear regression slope (β≠0, and P<0.05). Finally, we did a simulation based on the results of the phase lag characteristics.
社団法人日本磁気学会の論文
2008-09-01