Department of Neurology, University Hospital of Münster, Charitéplatz 1, Münster, Germany.
Hum Brain Mapp. 2013 Jun;34(6):1464-76. doi: 10.1002/hbm.22003. Epub 2012 Feb 14.
Ischemic small vessel disease (SVD) is a common finding on routine scans in older people, but cognitive sequelae vary considerably. To improve understanding of mechanisms underlying decline or preservation of cognitive function in this condition, we assessed cognition and cortical plasticity in 20 elderly subjects with severe SVD and 20 age-matched controls without SVD, as rated on conventional MRI. Cognitive status was determined with a neuropsychological test battery, cortical plasticity induced with a paired associative stimulation protocol. Microstructural white matter changes were further analyzed for fractional anisotrophy using diffusion tensor imaging. We found that cortical plasticity as well as memory functions were preserved in severe SVD, while executive functions showed trendwise or significant decreases. Within the SVD group, lower white matter integrity in parahippocampal regions and posterior parts of the corpus callosum was associated with larger cortical plasticity, an association not seen for prefrontal white matter tracts. Enhanced cortical plasticity in subjects with lower white matter integrity in memory-relevant areas might thus indicate a compensatory mechanism to counteract memory decline in severe SVD.
缺血性小血管病（SVD）是老年人常规扫描中的常见发现，但认知后果差异很大。为了更好地理解在这种情况下认知功能下降或保持的机制，我们评估了 20 名认知功能严重 SVD 患者和 20 名年龄匹配的无 SVD 对照者的认知功能和皮质可塑性，这些患者均根据常规 MRI 进行了评估。认知状态通过神经心理学测试进行了确定，皮质可塑性通过配对联想刺激方案进行了诱导。进一步使用弥散张量成像分析了各向异性分数，以分析白质微观结构的变化。我们发现，严重 SVD 患者的皮质可塑性和记忆功能得到了保持，而执行功能则出现了趋势性或显著下降。在 SVD 组中，海马旁区域和胼胝体后部的白质完整性较低与更大的皮质可塑性相关，而前额叶白质束则没有这种相关性。在与记忆相关区域白质完整性较低的患者中，增强的皮质可塑性可能表明一种补偿机制，以抵消严重 SVD 中的记忆下降。
