Chiappa K H, Hill R A, Huang-Hellinger F, Jenkins B G
Neurology Department, Massachuetts General Hospital, Boston 02214, USA.
Epilepsia. 1999;40 Suppl 4:3-7. doi: 10.1111/j.1528-1157.1999.tb00899.x.
To study metabolic and hemodynamic correlates of photic stimulation-triggered discharges.
Simultaneous EEG, functional MRI (tMRI) and magnetic resonance spectroscopy (MRS) were performed in nine patients with photosensitive epilepsy and in 12 normal subjects.
Prominent visual cortex activation was seen in all normal subjects and patients, and no tMRI-registered hemodynamic abnormalities were correlated with the brief photoparoxysmal spike-wave activity evoked in the photosensitive patients. However, irrespective of the presence of a spike-wave response to the photic stimulation, the photosensitive patients showed four findings not seen in the normal subjects: (a) slightly, but significantly, elevated lactate levels in the occipital cortex in the resting state; (b) an increased area of visual cortical activation with photic stimulation; (c) simultaneous with the occipital cortex stimulus-induced increased fMRI signal, there were noncontiguous areas of signal attenuation most prominent in perirolandic regions; and (d) a marked decrement (undershoot) of fMRI signal intensity immediately after the photic stimulation in the occipital cortex and in the region of the posterior cingulate gyrus.
These findings suggest abnormal interictal metabolism and increased vascular reactivity in the photosensitive patients.
研究光刺激引发放电的代谢和血流动力学相关性。
对9例光敏性癫痫患者和12名正常受试者进行同步脑电图（EEG）、功能磁共振成像（tMRI）和磁共振波谱（MRS）检查。
所有正常受试者和患者均可见显著的视觉皮层激活，且在光敏性患者中诱发的短暂光阵发性棘波活动与tMRI记录的血流动力学异常无关。然而，无论对光刺激是否存在棘波反应，光敏性患者均表现出正常受试者未出现的四个发现：（a）静息状态下枕叶皮质乳酸水平轻度但显著升高；（b）光刺激时视觉皮层激活面积增加；（c）与枕叶皮质刺激诱导的fMRI信号增加同时，在中央前回周围区域出现最明显的非连续信号衰减区域；（d）光刺激后枕叶皮质和后扣带回区域的fMRI信号强度显著下降（负向波）。
这些发现提示光敏性患者发作间期代谢异常和血管反应性增加。
