Britton Jeffrey W, Ghearing Gena R, Benarroch Eduardo E, Cascino Gregory D
Divisions of Epilepsy and Clinical Neurophysiology-EEG, Department of Neurology, Mayo Clinic Rochester, Rochester, Minnesota 55905, USA.
Epilepsia. 2006 Apr;47(4):737-44. doi: 10.1111/j.1528-1167.2006.00509.x.
Previous studies have established the importance of the insular cortex and temporal lobe in cardiovascular autonomic modulation. Some investigators, based on the results of cortical stimulation response, functional imaging, EEG recordings of seizures, and lesional studies, have suggested that cardiac sympathetic and parasympathetic function may be lateralized, with sympathetic representation lateralized to the right insula, and parasympathetic, to the left. These studies have suggested that ictal bradycardia is most commonly a manifestation of activation of the left temporal and insular cortex. However, the evidence for this is inconsistent. We sought to assess critically the predictable value of ictal bradycardia for seizure localization and lateralization.
In this study, we reviewed the localization of seizure activity in 13 consecutive patients with ictal bradycardia diagnosed during prolonged video-EEG monitoring at Mayo Clinic Rochester. The localization of electrographic seizure activity at seizure onset and bradycardia onset was identified in all patients. In addition, we performed a comprehensive review of the ictal bradycardia literature focusing on localization of seizure activity in ictal bradycardia cases.
All occurrences of ictal bradycardia in the 13 identified patients were associated with temporal lobe-onset seizures. However, no consistent lateralization of seizure activity was found at onset of seizure activity or at onset of bradycardia in this population. Seizure activity was bilateral at bradycardia onset in nine of 13 patients. The results from the literature review also showed that a predominance of patients had bilateral activity at bradycardia onset; however, more of the ictal bradycardia cases from the literature had left hemispheric localization of seizure onset.
Ictal bradycardia most often occurs in association with bilateral hemispheric seizure activity and is not a consistent lateralizing sign in localizing seizure onset. Our data do not support the existence of a strictly unilateral parasympathetic cardiomotor representation in the left hemisphere, as has been suggested.
既往研究已证实岛叶皮质和颞叶在心血管自主神经调节中的重要性。一些研究者基于皮质刺激反应、功能成像、癫痫发作的脑电图记录及病灶研究结果，提出心脏交感神经和副交感神经功能可能存在偏侧化，交感神经代表区位于右侧岛叶，副交感神经代表区位于左侧。这些研究提示发作期心动过缓最常见的表现是左侧颞叶和岛叶皮质激活。然而，支持这一观点的证据并不一致。我们旨在严格评估发作期心动过缓对癫痫灶定位和偏侧化的预测价值。
在本研究中，我们回顾了梅奥诊所罗切斯特分院在长时间视频脑电图监测期间诊断为发作期心动过缓的13例连续患者的癫痫发作活动定位情况。确定了所有患者癫痫发作起始时和心动过缓起始时的脑电图癫痫发作活动定位。此外，我们对发作期心动过缓的文献进行了全面回顾，重点关注发作期心动过缓病例中癫痫发作活动的定位。
13例确诊患者的所有发作期心动过缓均与颞叶起始的癫痫发作相关。然而，在该人群中，癫痫发作活动起始时或心动过缓起始时均未发现一致的偏侧化情况。13例患者中有9例在心动过缓起始时癫痫发作活动为双侧性。文献回顾结果还显示，大多数患者在心动过缓起始时为双侧活动；然而，文献中更多的发作期心动过缓病例癫痫发作起始于左侧半球。
发作期心动过缓最常与双侧半球癫痫发作活动相关，并非癫痫发作起始定位的一致偏侧化征象。我们的数据不支持如所提出的那样在左半球存在严格单侧的副交感神经心脏运动代表区。
