López-Olóriz Jorge, López-Cancio Elena, Arenillas Juan F, Hernández María, Dorado Laura, Dacosta-Aguayo Rosalía, Barrios Maite, Soriano-Raya Juan José, Miralbell Júlia, Bargalló Núria, Cáceres Cynthia, Torán Pere, Alzamora Maite, Dávalos Antonio, Mataró Maria
Department of Psychiatry and Clinical Psychobiology, Universitat de Barcelona, Barcelona, Spain.
Cerebrovasc Dis. 2014;38(1):24-30. doi: 10.1159/000363620. Epub 2014 Sep 2.
The contribution of traditional vascular risk factors to cognitive impairment and dementia is well known. However, in order to obtain possible targets for prevention of vascular cognitive impairment (VCI), it may be important to identify other early and noninvasive markers in asymptomatic middle-aged adults. The calculation of middle cerebral artery-pulsatility index (MCA-PI) is an ultrasonologic, noninvasive, validated and easily reproducible technique to assess increased distal resistance to blood flow. This study aims to assess the relationship between MCA-PI, microstructural white matter (WM) integrity and cognition in a middle-aged asymptomatic population.
Ninety-five participants from the Barcelona-Asymptomatic Intracranial Atherosclerosis (AsIA) neuropsychology study were included. Subjects were 50-65 years old, free from dementia and without history of vascular disease. Transcranial color-coded duplex ultrasound examination was performed to assess MCA-PI as a measure of vascular resistance. WM integrity was evaluated by fractional anisotropy (FA) measurements of diffusion tensor images (DTI) acquired on a 3T-MRI. The neuropsychological battery was specifically selected to be sensitive to VCI, and included tests that were grouped into six cognitive domains: executive functioning, attention, verbal fluency, memory, visuospatial skills and psychomotor speed. A multivariate linear regression model adjusted for age, gender, years of education, diabetes and hypertension was performed.
MCA-PI was significantly associated with WM disintegration in different tracts (fornix, corticospinal and anterior thalamic), all p < 0.05 uncorrected. Both mean MCA-PI and mean FA of those significant tracts were independently associated with poor performance in attention, psychomotor speed, and visuospatial skills after adjustment for age, gender, years of education, and vascular risk factors (all p < 0.05). MCA-PI was independently associated with lower scores in all cognitive domains, except for visuospatial skills.
Our data suggest that MCA-PI may be related to WM disintegration and early vascular cognitive impairment in middle-aged subjects. Although further prospective studies are needed to provide evidence for its validity in longitudinal studies, our results support the proposal of including MCA-PI as part of clinical assessment in order to identify targets for VCI prevention.
传统血管危险因素对认知障碍和痴呆的影响已广为人知。然而，为了找到预防血管性认知障碍（VCI）的可能靶点，识别无症状中年成年人中的其他早期和非侵入性标志物可能很重要。大脑中动脉搏动指数（MCA-PI）的计算是一种超声检查、非侵入性、经过验证且易于重复的技术，用于评估远端血流阻力增加情况。本研究旨在评估中年无症状人群中MCA-PI、微观结构白质（WM）完整性与认知之间的关系。
纳入了来自巴塞罗那无症状颅内动脉粥样硬化（AsIA）神经心理学研究的95名参与者。受试者年龄在50至65岁之间，无痴呆且无血管疾病史。进行经颅彩色编码双功超声检查以评估MCA-PI作为血管阻力的指标。通过对在3T-MRI上获取的扩散张量图像（DTI）进行分数各向异性（FA）测量来评估WM完整性。专门选择了对VCI敏感的神经心理测试组，包括分为六个认知领域的测试：执行功能、注意力、语言流畅性、记忆、视觉空间技能和心理运动速度。进行了一项针对年龄、性别、教育年限、糖尿病和高血压进行调整的多元线性回归模型。
MCA-PI与不同脑区（穹窿、皮质脊髓束和丘脑前核）的WM解体显著相关（所有p<0.05，未校正）。在对年龄、性别、教育年限和血管危险因素进行调整后，那些显著脑区的平均MCA-PI和平均FA均与注意力、心理运动速度和视觉空间技能方面的不良表现独立相关（所有p<0.05）。除视觉空间技能外，MCA-PI与所有认知领域的较低分数独立相关。
我们的数据表明，MCA-PI可能与中年受试者的WM解体和早期血管性认知障碍有关。尽管需要进一步的前瞻性研究来为其在纵向研究中的有效性提供证据，但我们的结果支持将MCA-PI纳入临床评估以识别VCI预防靶点的提议。
