Matsumoto Hideyuki, Ugawa Yoshikazu
Department of Neurology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo 113-8655, Japan.
Brain Nerve. 2008 Dec;60(12):1409-14.
Spasticity is usually observed along with paralysis, hyperreflexia, Babinski sign and abnormal associated movements associated with dysfunction of central motor tracts. In spasticity, exaggeration of the stretch reflex results in increased resistance during passive movements. Therefore, spasticity is pathophysiologically described as increased muscle tone whose pathognomonic sign is decreased passivity. Resistance is more strongly felt during rapid passive movements than during slow movements. The resistance felt at the beginning of the passive movement abruptly diminishes, which is well known as the clasp-knife phenomenon. Another character of spasticity is the distribution of the increment in the muscle tone. Not only rigidity, dystonia, and muscle stiffness demonstrating increased muscle tone, but also Gegenhalten and contracture of joint with normal muscle tone should be differentiated. No neurophysiological parameters reflect the degree of spasticity in a strictly parallel fashion. However, neurophysiological examinations provide some supportive objective data. Surface electromyography is useful to distinguish spasticity from rigidity and other conditions with increase muscle tone. The increased amplitude ratio and the decreased threshold ratio of the H-wave to the M-wave, and increased amplitude and persistence of the F-wave are observed the patients with spasticity. Magnetic stimulation is a useful tool to detect corticospinal tract lesions that induce leading to spasticity. Transcranial magnetic stimulation, magnetic brainstem stimulation, and magnetic spinal motor root stimulation are used to examine the entire motor pathway. Since positive correlation between spasticity and shortening of the silent period is reported, many investigations including paired-pulse magnetic stimulation will be necessary for understanding pathophysiology of spasticity. Patients with mild and reversible spasticity are usually treated with medications. Significant variations exist in the use of these therapies, because the treatments often depend on the clinicians' experience. It will be necessary to clarify the action mechanism of drugs, to develop new effective drugs, and to perform randomized controlled trails so that clinicians can select the optimal medication based on evidence.
痉挛通常与瘫痪、反射亢进、巴宾斯基征以及与中枢运动传导束功能障碍相关的异常联合运动同时出现。在痉挛状态下，牵张反射亢进导致被动运动时阻力增加。因此，痉挛在病理生理学上被描述为肌张力增加，其特征性体征是被动性降低。快速被动运动时比缓慢运动时更能明显感觉到阻力。在被动运动开始时感觉到的阻力会突然减小，这就是众所周知的折刀现象。痉挛的另一个特点是肌张力增加的分布情况。不仅要区分表现为肌张力增加的僵硬、肌张力障碍和肌肉强直，还要区分肌张力正常的 gegenhalten 和关节挛缩。没有神经生理学参数能严格平行地反映痉挛的程度。然而，神经生理学检查能提供一些支持性的客观数据。表面肌电图有助于区分痉挛与僵硬以及其他肌张力增加的情况。痉挛患者会观察到 H 波与 M 波的振幅比增加、阈值比降低，以及 F 波的振幅和持续时间增加。磁刺激是检测导致痉挛的皮质脊髓束病变的有用工具。经颅磁刺激、脑干磁刺激和脊髓运动神经根磁刺激用于检查整个运动通路。由于有报道称痉挛与静息期缩短呈正相关，因此需要进行包括双脉冲磁刺激在内的许多研究来了解痉挛的病理生理学。轻度和可逆性痉挛患者通常采用药物治疗。这些疗法的使用存在很大差异，因为治疗往往取决于临床医生的经验。有必要阐明药物的作用机制，开发新的有效药物，并进行随机对照试验，以便临床医生能够根据证据选择最佳药物。
