Leal Alberto, Calado Eulália, Vieira José P, Mendonça Carla, Ferreira José C, Ferreira Hugo, Carvalho Daniel, Furtado Fátima, Gomes Roseli, Monteiro José P
Department of Neurophysiology, Centro Hospitalar Psiquiátrico de Lisboa, Avenida do Brasil 53, 1749.002 Lisbon, Portugal.
Centro Hospitalar Lisboa Central, Pediatric Neurology Department, Lisbon, Portugal.
Epilepsy Behav. 2018 Jan;78:243-255. doi: 10.1016/j.yebeh.2017.08.027. Epub 2017 Nov 11.
Early neonatal thalamic lesions account for about 14% of continuous spike-wave of sleep (CSWS) syndrome, representing the most common etiology in this epileptic encephalopathy in children, and promise useful insights into the pathophysiology of the disease.
We describe nine patients with unilateral neonatal thalamic lesions which progressed to CSWS. Longitudinal whole-night and high-density electroencephalograms (EEGs) were performed, as well as detailed imaging and clinical evaluation. Visual evoked potentials were used to probe cortical excitability.
Thalamic volume loss ranged from 19% to 94%, predominantly on medial and dorsal nuclei and sparing the ventral thalamus. Lesions produced white matter loss and ventricle enlargement on the same hemisphere, which in four patients was associated with selective loss of thalamic-cortical fibers. Cortical thickness quantification failed to reveal hemispheric asymmetries. Impact on EEG rhythms was mild, with a volume-loss-related decrease in alpha power and preservation of sleep spindles. The sleep continuous spiking was lateralized to the hemisphere with the lesion. Visual cortex stimulation in five patients with posterior cortex spiking revealed an abnormal frequency-dependent excitability at 10-20Hz on the side of the lesion.
Unilateral selective thalamic-cortical disconnection is a common feature in our patients and is associated with both a focal pattern of CSWS and a pathological type of frequency-dependent excitability (peak: 10-20Hz). We propose that this excitability represents an abnormal synaptic plasticity previously described as the augmenting response. This synaptic plasticity has been described as absent in the corticocortical interactions in healthy experimental animals, emerging after ablation of the thalamus and producing a frequency-dependent potentiation with a peak at 10-20Hz. Because this response is potentiated by sleep states of reduced brainstem activation and by appropriate stimulating rhythms, such as sleep spindles, the simultaneous occurrence of these two factors in nonrapid-eye-movement sleep is proposed as an explanation for CSWS in our patients.
新生儿早期丘脑病变约占睡眠期持续性棘慢波（CSWS）综合征的14%，是儿童这种癫痫性脑病最常见的病因，有望为该疾病的病理生理学提供有益见解。
我们描述了9例单侧新生儿丘脑病变进展为CSWS的患者。进行了纵向全夜和高密度脑电图（EEG）检查，以及详细的影像学和临床评估。视觉诱发电位用于探测皮质兴奋性。
丘脑体积损失率为19%至94%，主要累及内侧核和背侧核，腹侧丘脑未受累。病变导致同一半球白质损失和脑室扩大，4例患者伴有丘脑皮质纤维选择性损失。皮质厚度定量分析未发现半球不对称。对EEG节律的影响较轻，α波功率随体积损失而降低，睡眠纺锤波保留。睡眠期持续性棘波定位于病变侧半球。对5例后皮质出现棘波的患者进行视觉皮质刺激，发现病变侧在10 - 20Hz频率下存在异常的频率依赖性兴奋性。
单侧选择性丘脑皮质脱连接是我们患者的常见特征，与CSWS的局灶性模式和频率依赖性兴奋性的病理类型（峰值：10 - 20Hz）相关。我们提出这种兴奋性代表了先前描述的增强反应这种异常的突触可塑性。这种突触可塑性在健康实验动物的皮质皮质相互作用中不存在，在丘脑切除后出现，并产生频率依赖性增强，峰值在10 - 20Hz。由于这种反应在脑干激活降低的睡眠状态和适当的刺激节律（如睡眠纺锤波）作用下增强，因此提出这两个因素在非快速眼动睡眠中同时出现可解释我们患者的CSWS。
