San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA.
Center for Multimodal Imaging and Genetics, University of California, San Diego, CA, USA.
Epilepsia. 2018 May;59(5):1037-1047. doi: 10.1111/epi.14072. Epub 2018 Apr 16.
Bilingual healthy adults have been shown to exhibit an advantage in executive functioning (EF) that is associated with microstructural changes in white matter (WM) networks. Patients with temporal lobe epilepsy (TLE) often show EF deficits that are associated with WM compromise. In this study, we investigate whether bilingualism can increase cognitive reserve and/or brain reserve in bilingual patients with TLE, mitigating EF impairment and WM compromise.
Diffusion tensor imaging was obtained in 19 bilingual and 26 monolingual patients with TLE, 12 bilingual healthy controls (HC), and 21 monolingual HC. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated for the uncinate fasciculus (Unc) and cingulum (Cing), superior frontostriatal tract (SFS), and inferior frontostriatal tract (IFS). Measures of EF included Trail Making Test-B (TMT-B) and Delis-Kaplan Executive Function System Color-Word Inhibition/Switching. Analyses of covariance were conducted to compare FA and MD of the Unc, Cing, SFS, and IFS and EF performance across groups.
In bilingual patients, FA was lower in the ipsilateral Cing and Unc compared to all other groups. For both patient groups, MD of the ipsilateral Unc was higher relative to HC. Despite more pronounced reductions in WM integrity, bilingual patients performed similarly to monolingual TLE and both HC groups on EF measures. By contrast, monolingual patients performed worse than HC on TMT-B. In addition, differences in group means between bilingual and monolingual patients on TMT-B approached significance when controlling for the extent of WM damage (P = .071; d = 0.62), suggesting a tendency toward higher performance for bilingual patients.
Despite poorer integrity of regional frontal lobe WM, bilingual patients performed similarly to monolingual patients and HC on EF measures. These findings align with studies suggesting that bilingualism may provide a protective factor for individuals with neurological disease, potentially through reorganization of EF networks that promote greater cognitive reserve.
双语健康成年人在执行功能（EF）方面表现出优势，这与白质（WM）网络的微观结构变化有关。颞叶癫痫（TLE）患者通常表现出与 WM 损伤相关的 EF 缺陷。在这项研究中，我们研究了双语是否可以增加双语 TLE 患者的认知储备和/或脑储备，从而减轻 EF 损伤和 WM 损伤。
对 19 名双语和 26 名单语 TLE 患者、12 名双语健康对照者（HC）和 21 名单语 HC 进行了弥散张量成像。计算了钩束（Unc）和扣带（Cing）、上额额纹束（SFS）和下额额纹束（IFS）的分数各向异性（FA）和平均弥散度（MD）。EF 测量包括连线测试 B（TMT-B）和 Delis-Kaplan 执行功能系统颜色-词抑制/转换。协方差分析比较了 Unc、Cing、SFS 和 IFS 的 FA 和 MD 以及各组 EF 表现。
在双语患者中，与所有其他组相比，同侧 Cing 和 Unc 的 FA 较低。对于两个患者组，同侧 Unc 的 MD 高于 HC。尽管 WM 完整性的降低更为明显，但双语患者在 EF 测量上与单语 TLE 和 HC 组表现相似。相比之下，单语患者在 TMT-B 上的表现不如 HC。此外，当控制 WM 损伤程度时（P =.071；d = 0.62），双语和单语患者之间的 TMT-B 组间差异接近显著性，表明双语患者的表现倾向更高。
尽管区域额 WM 的完整性较差，但双语患者在 EF 测量上与单语患者和 HC 表现相似。这些发现与表明双语可能为神经疾病患者提供保护因素的研究一致，这可能是通过促进更大的认知储备来重组 EF 网络。
