Urrestarazu E, LeVan P, Gotman J
Montreal Neurological Institute and Hospital, McGill University, 3801 University Street, Montreal, Que., Canada H3A 2B4.
Clin Neurophysiol. 2006 Mar;117(3):549-61. doi: 10.1016/j.clinph.2005.10.015. Epub 2006 Feb 7.
To apply independent component analysis (ICA) in intracranial recordings to analyze interactions during temporal lobe seizures.
Seizures from 20 patients with bitemporal implantation were classified as unilateral or bilateral and analyzed with ICA. During the period preceding bilateral activity, correlation coefficients were calculated between ICA components having ictal activity during the unilateral seizure phase (early ICA components) and every channel of the original EEG. ICA components were classified as unilateral if the correlation was >0.2 exclusively with channels in one hemisphere; and bilateral if both hemispheres were involved.
One hundred twenty-three seizures were analyzed. Thirty-two percent of visually classified unilateral seizures and 64% of bilateral seizures (during the unilateral phase) had bilateral ICA components. The proportion of early ICA components that were bilateral and the proportion of channels contralateral to the visually identified seizure with correlation higher than 0.2 with at least one early ICA component were significantly lower in seizures that stayed unilateral than in seizures that later became bilateral by visual inspection (11 and 10%, respectively, in unilateral seizures; 33 and 28% in bilateral seizures; P=0.001).
In patients with bitemporal epilepsy, approximately 20% of the components extracted using ICA have a bitemporal distribution even at the time when the seizures are apparently unilateral. The presence of early contralateral ictal activity is more frequent and extensive in seizures that later become evidently bilateral.
Minimal contralateral seizure activity is present even when the discharge appears unilateral and this is more frequent in seizures which later spread to the contralateral temporal lobe.
将独立成分分析（ICA）应用于颅内记录，以分析颞叶癫痫发作期间的相互作用。
对20例双侧颞叶植入患者的癫痫发作进行单侧或双侧分类，并采用ICA进行分析。在双侧活动之前的时间段内，计算单侧癫痫发作期（早期ICA成分）具有发作期活动的ICA成分与原始脑电图的每个通道之间的相关系数。如果相关性仅与一个半球的通道大于0.2，则将ICA成分分类为单侧；如果涉及两个半球，则分类为双侧。
共分析了123次癫痫发作。视觉分类的单侧癫痫发作中有32%以及双侧癫痫发作（在单侧期）中有64%具有双侧ICA成分。与至少一个早期ICA成分相关性高于0.2的、在视觉上识别出的癫痫发作对侧的通道比例以及双侧早期ICA成分的比例，在保持单侧的癫痫发作中显著低于通过视觉检查后来变为双侧的癫痫发作（单侧癫痫发作中分别为11%和10%；双侧癫痫发作中为33%和28%；P = 0.001）。
在双侧颞叶癫痫患者中，即使在癫痫发作明显单侧时，使用ICA提取的成分中约20%具有双侧颞叶分布。在后来明显变为双侧的癫痫发作中，早期对侧发作期活动的出现更频繁且更广泛。
即使放电看起来是单侧的，也存在最小程度的对侧癫痫发作活动，并且在后来扩散到对侧颞叶的癫痫发作中更频繁。
