Bleton Héloïse, Perera Subashan, Sejdić Ervin
Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
Division of Geriatric Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
BMC Med Imaging. 2016 Mar 12;16:22. doi: 10.1186/s12880-016-0125-0.
Functional transcanial Doppler ultrasound (fTCD) is a convenient approach to examine cerebral blood flow velocity (CBFV) in major cerebral arteries.
In this study, the anterior cerebral artery (ACA) was insonated on both sides, that is, right ACA (R-ACA) and left ACA (L-ACA). The envelope signals (the maximum velocity) and the raw signals were analyzed during cognitive processes, i.e. word-generation tasks, geometric tasks and resting state periods separating each task. Data which were collected from 20 healthy participants were used to investigate the changes and the hemispheric functioning while performing cognitive tasks. Signal characteristics were analyzed in time domain, frequency domain and time-frequency domain.
Significant results have been obtained through the use of both classic/modern methods (i.e. envelope/raw, time and frequency/information-theoretic and time-frequency domains). The frequency features extracted from the raw signals highlighted sex effects on cerebral blood flow which revealed distinct brain response during each process and during resting periods. In the time-frequency analysis, the distribution of wavelet energies on the envelope signals moved around the low frequencies during mental processes and did not experience any lateralization during cognitive tasks.
Even if no lateralization effects were noticed during resting-state, verbal and geometric tasks, understanding CBFV in ACA during cognitive tasks could complement information extracted from cerebral blood flow in middle cerebral arteries during similar cognitive tasks (i.e. sex effects).
功能性经颅多普勒超声（fTCD）是一种检测大脑主要动脉血流速度（CBFV）的便捷方法。
在本研究中，对双侧大脑前动脉（ACA）进行超声检测，即右侧ACA（R-ACA）和左侧ACA（L-ACA）。在认知过程中，即词语生成任务、几何任务以及分隔每个任务的静息期，分析包络信号（最大速度）和原始信号。从20名健康参与者收集的数据用于研究执行认知任务时的变化和半球功能。在时域、频域和时频域分析信号特征。
通过使用经典/现代方法（即包络/原始、时域和频域/信息论以及时频域）均获得了显著结果。从原始信号中提取的频率特征突出了性别对脑血流的影响，这揭示了每个过程及静息期不同的大脑反应。在时频分析中，包络信号上小波能量的分布在心理过程中围绕低频移动，在认知任务期间未出现任何偏侧化。
即使在静息状态、言语和几何任务期间未观察到偏侧化效应，但了解认知任务期间ACA中的CBFV可以补充在类似认知任务（即性别效应）期间从中脑动脉血流中提取的信息。
