Department of Psychiatry and Psychotherapy, University of Tuebingen, Tuebingen, Germany.
Neurobiol Aging. 2013 Feb;34(2):439-50. doi: 10.1016/j.neurobiolaging.2012.05.021. Epub 2012 Jul 6.
While progressive neurocognitive impairments are associated with aging and Alzheimer's disease (AD), cortical reorganization might delay difficulties in effortful word retrieval, which represent one of the earliest cognitive signs of AD. Using functional near-infrared spectroscopy (fNIRS), we investigated cortical hemodynamic responses elicited by phonological and semantic verbal fluency in non-demented, healthy subjects (n = 325; age: 51-82 years). Age predicted bilaterally reduced inferior frontal junction (IFJ) and increased middle frontal and supramarginal gyri activity in both task conditions using multiple regressions. Compared with age the years of education as well as sex (IFJ activation in females > males) partly predicted opposite effects on activation, while task performance was not significant predictor. All predictors showed small effect sizes. IFJ activation was more pronounced during phonological compared with semantic fluency, and higher in the left hemisphere. Age only marginally predicted relative lateralization. Middle frontal and supramarginal gyri activity may compensate for an aging-related decrease in IFJ recruitment during verbal fluency. Longitudinal observations will further investigate these neural changes regarding an early AD prediction, while individuals are still cognitively healthy.
虽然进行性神经认知障碍与衰老和阿尔茨海默病（AD）有关，但皮质重组可能会延迟费力的单词检索困难，这是 AD 的最早认知迹象之一。使用功能近红外光谱（fNIRS），我们研究了非痴呆健康受试者（n=325；年龄：51-82 岁）在语音和语义流畅性任务中引发的皮质血流动力学反应。使用多元回归，年龄预测在两种任务条件下双侧下额额连接（IFJ）减少，以及中额和缘上回活动增加。与年龄相比，受教育年限以及性别（女性的 IFJ 激活高于男性）部分预测了激活的相反作用，而任务表现不是显著的预测因子。所有预测因子的效应量都较小。与语义流畅性相比，IFJ 在语音流畅性任务中激活更明显，并且在左半球中更明显。年龄仅略微预测相对侧化。在言语流畅性任务中，中额和缘上回的活动可能会补偿 IFJ 募集在衰老相关下降。纵向观察将进一步研究这些神经变化，以预测早期 AD，而个体仍然认知健康。
