Demura Ai, Demura Yutaka, Sato Kazuaki, Kinoshita Masako
Sakurai Clinic, Otsu, Japan.
Department of Clinical Laboratory, National Hospital Organization Utano National Hospital, Kyoto, Japan.
J Clin Neurophysiol. 2024 Mar 1;41(3):285-290. doi: 10.1097/WNP.0000000000000966. Epub 2022 Aug 26.
Giant somatosensory evoked potentials (SEPs) with enhanced long-loop reflex (C-reflex) are useful to detect cortical motor hyperexcitability in patients with myoclonic epilepsy. The recording conditions of giant SEPs are different from those of short-latency SEPs (SSEPs). We investigated the waveform characteristics obtained for each condition.
Forty-eight upper limbs of 24 adult normal subjects (12 men, age 35.5 ± 9.7 years [mean ± SD]) were investigated. Somatosensory evoked potentials of each subject were recorded in both conditions on the same day. The main differences in recording conditions were reference electrodes (SSEP: Fz vs. giant SEP: the earlobe electrode ipsilateral to the stimulated limb), stimulus rate (5 vs. 1 Hz), and bandpass filter (20 Hz-3 kHz vs. 1 Hz-1 kHz). Somatosensory evoked potentials were elicited by unilateral percutaneous electrical stimulation of the median nerve at the wrist with intensity of 110% of the movement threshold and recoded at C3'/C4'.
The amplitudes of N20 onset-N20 and N20-P25 were significantly larger in giant SEP condition than in SSEP condition ( p < 0.001). The mean + 3SD of N20-P25 amplitude was 10.0 μV in giant SEP condition and 7.8 μV in SSEP condition. The N20-P25 amplitude was significantly correlated between giant SEP condition and SSEP condition ( R = 0.64, p < 0.001). C-reflex was not elicited.
The amplitude of SEPs in SSEP condition is equivalent to 80% of that in giant SEP condition. The information is useful for detecting cortical hyperexcitability in various neurological disorders including myoclonic epilepsy.
伴有增强的长环反射（C反射）的巨大体感诱发电位（SEPs）有助于检测肌阵挛性癫痫患者的皮质运动兴奋性过高。巨大SEPs的记录条件与短潜伏期SEPs（SSEPs）不同。我们研究了每种条件下获得的波形特征。
对24名成年正常受试者（12名男性，年龄35.5±9.7岁[平均值±标准差]）的48条上肢进行了研究。在同一天对每个受试者在两种条件下记录体感诱发电位。记录条件的主要差异在于参考电极（SSEPs：Fz；巨大SEPs：受刺激肢体同侧的耳垂电极）、刺激频率（5Hz对1Hz）和带通滤波器（20Hz - 3kHz对1Hz - 1kHz）。通过在手腕处对正中神经进行单侧经皮电刺激，强度为运动阈值的110%来引出体感诱发电位，并在C3'/C4'处进行记录。
在巨大SEP条件下，N20起始 - N20和N20 - P25的波幅明显大于SSEP条件下（p < 0.001）。在巨大SEP条件下，N20 - P25波幅的平均值 + 3标准差为10.0μV，在SSEP条件下为7.8μV。巨大SEP条件和SSEP条件下的N20 - P25波幅显著相关（R = 0.64，p < 0.001）。未引出C反射。
SSEP条件下SEPs的波幅相当于巨大SEP条件下的80%。该信息有助于检测包括肌阵挛性癫痫在内的各种神经系统疾病中的皮质兴奋性过高。
