Nenert Rodolphe, Allendorfer Jane B, Martin Amber M, Banks Christi, Vannest Jennifer, Holland Scott K, Szaflarski Jerzy P
Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
Department of Neurology, University of Alabama at Birmingham, Birmingham, AL, USA.
Brain Res. 2017 Nov 1;1674:20-35. doi: 10.1016/j.brainres.2017.08.021. Epub 2017 Aug 19.
Previous studies focusing on the relationship between lateralization of language function and age suffer from lack of a balanced distribution of age and handedness among participants, especially in the extremes of age. This limits our understanding of the influence of these factors on lateralization of language circuitry. The hemispheric asymmetry reduction in older adults (HAROLD) model suggests that under similar circumstances, involvement in cognitive processes of prefrontal (and potentially other) cortical areas tends to be less lateralized with age. In this study, we aimed to investigate the link between age, gender, and language lateralization in a large group of healthy participants with a relatively even distribution of age and handedness in order to further test the HAROLD model. 99 healthy men (33 left-handed; age range 18-74years) and 125 women (44 left-handed; age range 19-76) were recruited. All participants underwent fMRI at 3T with a semantic decision and a verb generation tasks and received a battery of linguistic tests. Lateralization indexes (LI) were calculated for each participant based on fMRI results for each task separately. LIs were found to be significantly decreasing with age only in right-handed men and only in temporo-parietal cortical area. LIs did not change with age in other brain regions or in left-handed subjects. Our results do not support the HAROLD model and suggest a potentially different relationship between aging and lateralization of language functions.
以往关注语言功能侧化与年龄关系的研究存在参与者年龄和利手分布不均衡的问题，尤其是在年龄极端值方面。这限制了我们对这些因素对语言回路侧化影响的理解。老年人半球不对称性降低（HAROLD）模型表明，在类似情况下，随着年龄增长，前额叶（可能还有其他）皮质区域参与认知过程的侧化程度往往会降低。在本研究中，我们旨在调查一大群年龄和利手分布相对均匀的健康参与者中年龄、性别与语言侧化之间的联系，以进一步检验HAROLD模型。招募了99名健康男性（33名左利手；年龄范围18 - 74岁）和125名女性（44名左利手；年龄范围19 - 76岁）。所有参与者在3T条件下接受功能磁共振成像（fMRI）检查，进行语义判断和动词生成任务，并接受一系列语言测试。根据每个任务的fMRI结果分别为每个参与者计算侧化指数（LI）。结果发现，仅在右利手男性的颞顶叶皮质区域，LI随年龄显著降低。在其他脑区或左利手受试者中，LI不随年龄变化。我们的结果不支持HAROLD模型，并表明衰老与语言功能侧化之间可能存在不同的关系。
