Brown P, Ridding M C, Werhahn K J, Rothwell J C, Marsden C D
National Hospital for Neurology and Neurosurgery, London, UK.
Brain. 1996 Feb;119 ( Pt 1):309-317. doi: 10.1093/brain/119.1.309.
Patients with cortical myoclonus may have purely focal or multifocal jerks, or they may have additional bilateral or generalized jerks, suggesting the spread of excitatory myoclonic activity between the cerebral hemispheres and across the sensorimotor cortex. The factors contributing to this spread of activity were investigated in 10 patients with multifocal cortical myoclonus and eight patients with multifocal and bilateral or generalized cortical myoclonus. The two groups were termed 'non- spreaders' and 'spreaders' respectively. Eight of the patients were also epileptic. Motor thresholds to single transcranial magnetic shocks at rest were higher in 'non- spreaders' (median 88%, range 45-100% of stimulator output) than either 'spreaders' (50%, range 26-90%, P=0.023) or health controls (38%, range 28-53%, P<0.001). This pathological elevation in motor threshold was not simply an effect of treatment with antiepileptic drugs. Paired transcranial magnetic stimuli were used to investigate ipsilateral cortico-cortical and transcallosal inhibition, There was less (MANOVA, P<0.05) ipsilateral inhibition at interstimulus intervals (ISIs) of 1-6 ms in 'spreaders' (mean 107+/-SEM 23% of control) compared with 'non- spreaders' (75+/-15%) or healthy subjects (59+/-10%). There was also less (P<0.05) transcallosal inhibition across inhibitory timings (10, 12 and 14 ms) in the 'spreaders' (98+/-6% of control) compared with the 'non-spreaders' (64+/-8%) or healthy subjects (59+/-6%). There was no relationship between ipsilateral cortico-cortical and transcallosal inhibition and the presence or absence of epilepsy, although non-epileptic patients did have higher motor thresholds (median 85%, range 32-100% of stimulator output) than either epileptic patients (50%, range 26-90%, P<0.001) or healthy controls (38%, range 28-53%, P=0.002). Abnormalities in ipsilateral and transcallosal inhibition appear to facilitate the spread of the cortical myoclonic activity responsible for bilateral and generalized jerks. However, these abnormalities in inhibition do not play a major role in the development of generalized seizures in patients with cortical myoclonus.
皮质肌阵挛患者可能仅有局灶性或多灶性抽搐，或者可能伴有额外的双侧或全身性抽搐，这表明兴奋性肌阵挛活动在大脑半球之间以及整个感觉运动皮层扩散。对10例多灶性皮质肌阵挛患者和8例多灶性合并双侧或全身性皮质肌阵挛患者，研究了促成这种活动扩散的因素。这两组分别称为“非扩散者”和“扩散者”。其中8例患者也患有癫痫。“非扩散者”静息时对单次经颅磁刺激的运动阈值较高（中位数88%，范围为刺激器输出的45 - 100%），高于“扩散者”（50%，范围26 - 90%，P = 0.023）或健康对照者（38%，范围28 - 53%，P < 0.001）。这种运动阈值的病理性升高并非简单地由抗癫痫药物治疗所致。采用配对经颅磁刺激来研究同侧皮质 - 皮质和胼胝体抑制，与“非扩散者”（75 ± 15%）或健康受试者（59 ± 10%）相比，“扩散者”在1 - 6毫秒的刺激间隔（ISI）时同侧抑制较少（多变量方差分析，P < 0.05）（平均为对照的107 ± 标准误23%）。在抑制时间（10、12和14毫秒）内，“扩散者”（对照的98 ± 6%）的胼胝体抑制也比“非扩散者”（64 ± 8%）或健康受试者（59 ± 6%）少（P < 0.05）。同侧皮质 - 皮质和胼胝体抑制与癫痫的有无之间没有关系，尽管非癫痫患者的运动阈值（中位数85%，范围为刺激器输出的32 - 100%）高于癫痫患者（50%，范围26 - 90%，P < 0.001）或健康对照者（38%，范围28 - 53%，P = 0.002）。同侧和胼胝体抑制异常似乎促进了导致双侧和全身性抽搐的皮质肌阵挛活动的扩散。然而，这些抑制异常在皮质肌阵挛患者全身性癫痫发作的发生中并不起主要作用。
