健康人上肢节段性H反射检测方法及正常值

目的 研究上肢节段性H反射的检测方法并建立健康人正常值。方法 对50名健康受试者上肢的4根周围神经、5个脊髓节段分布的6～7块肌肉分别检测。受试者均采取持续中等度随意收缩，刺激强度相当于诱发最大M波阈值的20％～40％，要求重复刺激lO次～20次。轨迹由计算机平均，并重复3轮。测量H反射起点潜伏期、侧间差、峰-峰波幅、波幅侧间比(小／大)。所测潜伏期、波幅与身高和年龄进行相关性检验。结果 双上肢H反射总引出率为97％。H反射潜伏期呈正态分布，变异小，重复性好，与身高相关有显著意义，与年龄、性别不相关。H反射波幅呈偏态分布，变异大。波幅与身高、年龄、性别均不相关。结论 采用随意收缩和计算机平均技术可以在健康成人上肢的多块肌肉中获得可靠、恒定的H反射。因此，它对于常规神经电诊断方法在探查神经病变中可以成为一项有益的补充。

Segmental H-reflexes in upper extremities of healthy subjects

Objective To establish the method for recording the segmental H-reflexes in upper extremities and calculate its normal values. Methods The muscles in upper limbs innervated by four peripheral nerves and five spinal levels of 50 healthy subjects were tested. In each subject, studies were done bilaterally for H-reflexes in six to seven muscles of their upper extremities during a steadily moderate voluntary contraction. Stimulus intensities were set at 20% to 40% of threshold of maximal M response. To record H-reflex, trains of 10-to-20 stimuli at 0.5Hz were delivered. The tracings were averaged and studies were repeated three times of each session. The onset latency, side-to-side variation, peak-to-peak amplitude, and side-to-side amplitude ratios (smaller to larger) of the H-reflex were measured and correlation analysis was performed. Results H-reflexes were obtained in 650 of total 670 (97%) muscles with moderate contraction in arms of all subjects. The H-reflex latencies demonstrated a normal distribution and were significantly correlated with the body height of the subject but not with age or sex. The reflex amplitude value showed a biased distribution. Conclusion H-reflexes can be recorded consistently in upper extremities in healthy adults. In addition to conventional nerve conduction studies, recording of segmental H-reflexes is a valuable adjunct testing method for detection of neuropathy.