Hamer H M, Reis J, Mueller H-H, Knake S, Overhof M, Oertel W H, Rosenow F
Department of Neurology, University of Marburg, Rudolf-Bultmann-Str. 8, 35033 Marburg, Germany.
Brain. 2005 Apr;128(Pt 4):811-8. doi: 10.1093/brain/awh398. Epub 2005 Feb 23.
It is unclear whether focal epilepsies chronically influence the processing of cortex distant to the epileptogenic zone. Therefore, motor cortex excitability was analysed in patients with temporal and extratemporal epilepsies whose epileptogenic zones did not include the primary motor area. Single and paired-pulse transcranial magnetic stimulation (TMS) was applied to the primary motor cortex in 20 healthy controls and 23 patients with focal epilepsy (39.4 +/- 13.2 years; 12 left, 11 right; 14 temporal, nine extratemporal: six frontal, three parieto-occipital) ipsi- and contralateral to the epileptogenic zone. In all patients, the epileptogenic zone did not include the primary motor cortex. The resting motor threshold (RMT), the cortical silent period (CSP), the intracortical inhibition [ICI; combined interstimulus intervals (ISI) 2 and 3 ms] and the intracortical facilitation (ICF; combined ISI 10 and 15 ms) were determined. The measures obtained ipsilateral to the epileptogenic zone were compared with those elicited in contralateral hemispheres and, in exploratory analyses, with controls using non-parametric tests, including Hodges-Lehmann estimates of median differences (HLE) with 95% confidence intervals (CI). In the patient group, the CSP elicited in the ipsilateral motor cortex (median 162.3 ms) was shortened compared with the contralateral CSP (median 174.6 ms; HLE 15.9 ms; CI 6.2, 27.0 ms; P = 0.002). This interhemispheric difference was more pronounced in extratemporal epilepsies (HLE 23.4 ms; CI -3.2, 67.6 ms) compared with temporal epilepsies (HLE 14.3 ms; CI 4.7, 26.2 ms). Patients with parieto-occipital epilepsies showed the greatest interhemispheric differences in CSP (HLE 33.5 ms) and patients with mesial temporal epilepsies the smallest (HLE 9.9 ms). No significant differences were found between ipsi- and contralateral RMT, ICI or ICF. In analyses of subgroups, the CSP was shorter in epileptic hemispheres of patients with extratemporal epilepsies (141.4 ms) than in controls (173.4 ms; HLE 40.0 ms; CI 3.2, 83.4 ms; P = 0.029). ICF was increased in epileptic hemispheres of extratemporal epilepsies (147.6%) compared with temporal epilepsies (114.6%; HLE 33.0%; CI 4.1, 68.3%; P = 0.038). The results suggest that focal epilepsies influence chronically distant cortex, leading to decreased inhibition and increased facilitation in the ipsilateral motor cortex even when the epileptogenic zone is apart from it. This alteration may be due to synaptic reorganization and appears to be more pronounced in extratemporal and neocortical temporal than in mesial temporal epilepsies. This may have diagnostic implications.
局灶性癫痫是否长期影响癫痫灶以外的皮质处理尚不清楚。因此，我们分析了颞叶癫痫和颞叶外癫痫患者的运动皮质兴奋性，这些患者的癫痫灶不包括初级运动区。对20名健康对照者和23名局灶性癫痫患者（年龄39.4±13.2岁；12名左侧，11名右侧；14名颞叶癫痫，9名颞叶外癫痫：6名额叶癫痫，3名顶枕叶癫痫）癫痫灶同侧和对侧的初级运动皮质进行单脉冲和双脉冲经颅磁刺激（TMS）。所有患者的癫痫灶均不包括初级运动皮质。测定静息运动阈值（RMT）、皮质静息期（CSP）、皮质内抑制[ICI；联合刺激间隔（ISI）2和3毫秒]和皮质内易化（ICF；联合ISI 10和15毫秒）。将癫痫灶同侧获得的测量值与对侧半球获得的测量值进行比较，并在探索性分析中与对照组进行比较，采用非参数检验，包括中位数差异的霍奇斯-莱曼估计值（HLE）和95%置信区间（CI）。在患者组中，同侧运动皮质引出的CSP（中位数162.3毫秒）较对侧CSP（中位数174.6毫秒；HLE 15.9毫秒；CI 6.2，27.0毫秒；P = 0.002）缩短。与颞叶癫痫（HLE 14.3毫秒；CI 4.7，26.2毫秒）相比，这种半球间差异在颞叶外癫痫中更明显（HLE 23.4毫秒；CI -3.2，67.6毫秒）。顶枕叶癫痫患者的CSP半球间差异最大（HLE 33.5毫秒），而内侧颞叶癫痫患者最小（HLE 9.9毫秒）。同侧和对侧的RMT、ICI或ICF未发现显著差异。在亚组分析中，颞叶外癫痫患者癫痫侧半球的CSP（141.4毫秒）比对照组（173.4毫秒；HLE 40.0毫秒；CI 3.2，83.4毫秒；P = 0.029）短。与颞叶癫痫（114.6%；HLE 33.0%；CI 4.1，68.3%；P = 0.038）相比，颞叶外癫痫患者癫痫侧半球的ICF增加（147.6%）。结果表明，局灶性癫痫长期影响远处皮质，导致同侧运动皮质抑制减少和易化增加，即使癫痫灶与之分离。这种改变可能是由于突触重组，并且在颞叶外和新皮质颞叶癫痫中似乎比内侧颞叶癫痫更明显。这可能具有诊断意义。
