Abstract：
Functional transcranial Doppler sonography (fTCD) is a time- and cost-effective, non-invasive approach to determining real time hemispheric lateralization and is well-suited for repetitive study designs comprising multiple days. To date, no study has examined the reproducibility of the direction and degree (strength) of lateralization during word fluency (WF) over multiple, consecutive sessions within a single person, although there are many studies of lateralization during language processing. Moreover, there is conflicting evidence as to whether there is a relationship between the degree of laterality and the word fluency performance. In this study, one right-handed male (aged 24 years) completed a total of seven examination sessions in the time span of 10 days. Each session comprised multiple phonological and semantic WF tasks. The maximum difference of relative cerebral blood flow velocity (CBFV) changes between the left and right middle cerebral artery (MCA) during WF was defined as the Lateralization Index (LI). The word-fluency performance and the LIs were used in a linear regression model to detect relative changes in the direction and degree of lateralization during repetitive WF tasks. The reproducibility of the direction of language-related lateralization is very stable over multiple sessions within this single person and the processed LIs were left-lateralized in every session for both WF tasks. In addition, performance during phonological WF could significantly predict the variability in the degree of lateralization. This result could not be confirmed for the semantic WF task. The results of this pilot study support the usage of fTCD as a reliable method for examining lateralization patterns, especially in longitudinal study designs. They also provide evidence for the notion that performance in WF tasks can be related to the degree of lateralization, at least intra-individually.
摘要：
功能性经颅多普勒超声（FTCD）是一种具有时间和成本效益的，非侵入性的方法来确定实时半球侧向化，非常适合重复研究设计，包括多日。迄今为止,没有研究检查了单词流畅性（WF）期间横向化的方向和程度（强度）在多个，一个人的连续会话，尽管有许多关于语言处理过程中偏侧化的研究。此外，关于横向程度与单词流畅性表现之间是否存在关系，存在相互矛盾的证据。在这项研究中,一名惯用右手的男性(24岁)在10天的时间内完成了总共7次考试。每个会话包括多个语音和语义WF任务。WF期间左右大脑中动脉（MCA）之间相对脑血流速度（CBFV）变化的最大差异定义为侧向指数（LI）。在线性回归模型中使用了单词流畅性表现和LI，以检测重复性WF任务中侧向化方向和程度的相对变化。与语言相关的横向化方向的再现性在该单个人的多个会话中非常稳定，并且对于两个WF任务，处理后的LI在每个会话中都被左横向化。此外,语音WF的表现可以显着预测偏侧化程度的变异性。无法为语义WF任务确认此结果。这项试点研究的结果支持使用FTCD作为检查侧化模式的可靠方法，特别是在纵向研究设计中。它们还为以下概念提供了证据：WF任务中的性能可能与侧化程度有关，至少个人内部。
