Brown P, Rothwell J C, Thompson P D, Britton T C, Day B L, Marsden C D
MRC Human Movement and Balance Unit, Institute of Neurology, London, UK.
Brain. 1991 Aug;114 ( Pt 4):1903-28. doi: 10.1093/brain/114.4.1903.
The startle response to unexpected auditory and somaesthetic stimulation was studied in 8 patients with hereditary or symptomatic hyperekplexia. It was abnormal in its resistance to habituation and in its exaggerated motor response. Both noise and taps to the face and head elicited a normal early blink response, separate from the subsequent true startle reflex. The earliest reflex EMG activity recorded after the blink was in sternocleidomastoid. EMG activity in masseter, and trunk and limb muscles followed later. This pattern of muscle recruitment suggests a brainstem origin for the abnormal startle responses. In addition, the abnormal startle responses exhibited disproportionately long latencies to the intrinsic hand and foot muscles and relatively slow recruitment of caudal muscles. The pattern of muscle recruitment was similar between patients, irrespective of the absolute latency of the response, and regardless of whether stimulation was auditory or somaesthetic. This suggests that auditory and somaesthetic afferents converge on a common brainstem efferent system, and that this system forms the final common pathway for abnormal startle responses of differing latency. The characteristics of this efferent system differ from those previously described in brainstem reticular reflex myoclonus, but are similar to those described in the normal auditory startle reflex in man. This suggests that the abnormal startle response in hyperekplexia, and the normal startle reflex represent pathological and physiological activity in the same brainstem efferent system.
对8例遗传性或症状性惊跳亢进患者的意外听觉和躯体感觉刺激的惊跳反应进行了研究。其对习惯化的抵抗和夸张的运动反应均异常。噪声以及对面部和头部的轻敲均引发正常的早期眨眼反应，这与随后真正的惊跳反射不同。眨眼后记录到的最早反射肌电图活动出现在胸锁乳突肌。咬肌以及躯干和肢体肌肉的肌电图活动随后出现。这种肌肉募集模式表明异常惊跳反应起源于脑干。此外，异常惊跳反应对手部和足部固有肌肉的潜伏期异常延长，且尾部肌肉的募集相对缓慢。患者之间的肌肉募集模式相似，无论反应的绝对潜伏期如何，也无论刺激是听觉还是躯体感觉。这表明听觉和躯体感觉传入汇聚于一个共同的脑干传出系统，并且该系统构成了不同潜伏期异常惊跳反应的最终共同通路。该传出系统的特征与先前在脑干网状反射性肌阵挛中描述的不同，但与人类正常听觉惊跳反射中描述的相似。这表明惊跳亢进中的异常惊跳反应和正常惊跳反射代表了同一脑干传出系统中的病理和生理活动。
