Christie A, Lester S, LaPierre D, Gabriel D A
Raymond Nelson Reid Biomechanics Laboratory, Brock University, St. Catharines, ON, Canada L2S 3A1.
Clin Neurophysiol. 2004 Jan;115(1):116-23. doi: 10.1016/s1388-2457(03)00306-7.
This study examined the intraclass reliability of different measures extracted from Hoffmann reflex (H-reflex) stimulus-response curve that are used to assess neuromuscular excitability. The following measures were compared: (1) the peak-to-peak amplitude of the H-reflex at a stimulus intensity associated with 5% of the maximum M-wave; (2) the slope of the regression line of the H-reflex stimulus-response curve; and (3) the peak of the first derivative of the H-reflex stimulus-response curve, a new measure introduced in this paper.
The H-reflex was elicited in the soleus for 24 subjects (12 males and 12 females) on 5 separate days. Vibration was applied to the Achilles tendon prior to stimulation to test the sensitivity of the measures on test day 4. The stimulus intensity was gradually increased from below the threshold for an H-reflex response to above the maximum M-wave (Mmax) response. The means of 5 evoked potentials at each intensity level were used to create both the H-reflex and M-wave stimulus-response curves for each subject across test days. Determination of reliability involves the consideration of both the stability and consistency of the measures. A repeated measures analysis of variance evaluated the stability of the group means across test sessions. The consistency of scores within individuals was determined by calculating the intraclass correlation coefficient (ICC). Calculation of the 95% confidence interval of estimation was used to assess significant differences between ICCs.
The H-reflex measures were both stable and consistent across the first 3 test days. Achilles tendon vibration resulted in a profound reduction (59-70%) on test day 4, and then there was a return to baseline levels on test day 5. The ICC for H-reflex at a stimulus intensity associated with 5% of the maximum M-wave was 0.85. The ICC for the slope of the regression line of the H-reflex stimulus-response curve was 0.79, while it was 0.89 for the peak of the first derivative of the H-reflex stimulus-response curve. However, there was no statistical significance (P>0.05) between the 3 EMG measures of the H-reflex arc. Maximum M-wave amplitude had an ICC of 0.96 attesting to careful methodological controls.
The peak of the first derivative of the H-reflex stimulus-response curve was shown to have comparable sensitivity and reliability as other more established measures.
The first derivative of the H-reflex stimulus-response curve provides the rate of change, rather than amplitude, making it a robust measure of reflex arc excitability. The higher ICC for the first derivative offers greater statistical power, which is of practical significance.
本研究检测了从霍夫曼反射（H反射）刺激 - 反应曲线中提取的用于评估神经肌肉兴奋性的不同测量指标的组内信度。比较了以下测量指标：（1）在与最大M波的5%相关的刺激强度下H反射的峰 - 峰值幅度；（2）H反射刺激 - 反应曲线的回归线斜率；（3）H反射刺激 - 反应曲线一阶导数的峰值，这是本文引入的一项新测量指标。
对24名受试者（12名男性和12名女性）的比目鱼肌进行H反射检测，共检测5天。在第4天检测前对跟腱施加振动以测试测量指标的敏感性。刺激强度从低于H反射反应阈值逐渐增加到高于最大M波（Mmax）反应。每个强度水平下5次诱发电位的平均值用于为每个受试者在测试期间创建H反射和M波刺激 - 反应曲线。信度的测定涉及测量指标的稳定性和一致性。重复测量方差分析评估测试期间组均值的稳定性。个体内分数的一致性通过计算组内相关系数（ICC）来确定。计算95%置信区间估计用于评估ICC之间的显著差异。
在前3天测试中，H反射测量指标既稳定又具有一致性。跟腱振动在第4天导致显著降低（59 - 70%），然后在第5天恢复到基线水平。与最大M波的5%相关的刺激强度下H反射的ICC为0.85。H反射刺激 - 反应曲线回归线斜率的ICC为0.79，而H反射刺激 - 反应曲线一阶导数峰值的ICC为0.89。然而，H反射弧的3个肌电图测量指标之间无统计学意义（P>0.05）。最大M波幅度的ICC为0.96，证明方法学控制严谨。
H反射刺激 - 反应曲线一阶导数的峰值显示出与其他更成熟的测量指标具有相当的敏感性和信度。
H反射刺激 - 反应曲线的一阶导数提供的是变化率而非幅度，使其成为反射弧兴奋性的可靠测量指标。一阶导数更高的ICC提供了更大的统计效力，具有实际意义。
