Alzaid Haidar, Ethofer Thomas, Kardatzki Bernd, Erb Michael, Scheffler Klaus, Berg Daniela, Maetzler Walter, Hobert Markus A
Department of Biomedical Magnetic Resonance, Tübingen University Hospital, Tübingen, Germany.
Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany.
Front Aging Neurosci. 2022 Sep 29;14:934241. doi: 10.3389/fnagi.2022.934241. eCollection 2022.
Loss of white matter integrity (WMI) is associated with gait deficits in middle-aged and older adults. However, these deficits are often only apparent under cognitively demanding situations, such as walking and simultaneously performing a secondary cognitive task. Moreover, evidence suggests that declining executive functions (EF) are linked to gait decline, and their co-occurrence may point to a common underlying pathology, i.e., degeneration of shared brain regions. In this study, we applied diffusion tensor imaging (DTI) and a standardized gait assessment under single- and dual-tasking (DT) conditions (walking and subtracting) in 74 middle-aged and older adults without any significant gait or cognitive impairments to detect subtle WM alterations associated with gait decline under DT conditions. Additionally, the Trail Making Test (TMT) was used to assess EF, classify participants into three groups based on their performance, and examine a possible interaction between gait, EF, and WMI. Gait speed and subtracting speed while dual-tasking correlated significantly with the fractional anisotropy (FA) in the bilateral anterior corona radiata (highest = 0.51/ < 0.0125 FWE-corrected). Dual-task costs (DTC) of gait speed correlated significantly with FA in widespread pathways, including the corpus callosum, bilateral anterior and superior corona radiata, as well as the left superior longitudinal fasciculus (highest = -0.47/ < 0.0125 FWE-corrected). EF performance was associated with FA in the left anterior corona radiata ( < 0.05); however, EF did not significantly mediate the effects of WMI on DTC of gait speed. There were no significant correlations between TMT and DTC of gait and subtracting speed, respectively. Our findings indicate that gait decline under DT conditions is associated with widespread WM deterioration even in middle-aged and older adults without any significant gait or cognitive impairments. However, this relationship was not mediated by EF.
白质完整性（WMI）的丧失与中老年人的步态缺陷有关。然而，这些缺陷通常仅在认知要求较高的情况下才会显现，比如行走并同时执行一项次要认知任务时。此外，有证据表明，执行功能（EF）下降与步态衰退有关，它们的共同出现可能指向一种共同的潜在病理，即共享脑区的退化。在本研究中，我们对74名没有任何明显步态或认知障碍的中老年人，在单任务和双任务（DT）条件下（行走和减法运算）应用了扩散张量成像（DTI）和标准化步态评估，以检测与DT条件下步态衰退相关的细微白质改变。此外，使用连线测验（TMT）来评估EF，根据参与者的表现将其分为三组，并研究步态、EF和WMI之间可能的相互作用。双任务时的步态速度和减法运算速度与双侧前放射冠的分数各向异性（FA）显著相关（最高 = 0.51/ < 0.0125 FWE校正）。步态速度的双任务成本（DTC）与广泛通路中的FA显著相关，包括胼胝体、双侧前放射冠和上放射冠，以及左侧上纵束（最高 = -0.47/ < 0.0125 FWE校正）。EF表现与左侧前放射冠的FA相关（ < 0.05）；然而，EF并未显著介导WMI对步态速度DTC的影响。TMT与步态和减法运算速度的DTC之间分别没有显著相关性。我们的研究结果表明，即使在没有任何明显步态或认知障碍的中老年人中，DT条件下的步态衰退也与广泛的白质退化有关。然而，这种关系并未由EF介导。
