Department of Neurology, Hospital Clinico San Carlos, San Carlos Institute for Health Research (IdiSSC), Universidad Complutense, Madrid, Spain.
Department of Nuclear Medicine, Hospital Clinico San Carlos, San Carlos Institute for Health Research (IdiSSC), Universidad Complutense, Madrid, Spain.
J Int Neuropsychol Soc. 2022 Oct;28(9):947-962. doi: 10.1017/S1355617721001144. Epub 2021 Sep 27.
Cognitive processes underlying verbal and design fluency, and their neural correlates in patients with Alzheimer's disease (AD) and behavioural variant Frontotemporal Dementia (bvFTD) remain unclear. We hypothesised that verbal and design fluency may be associated with distinct neuropsychological processes in AD and FTD, showing different patterns of impairment and neural basis.
We enrolled 142 participants including patients with AD (n = 80, mean age = 74.71), bvFTD (n = 34, mean age = 68.18), and healthy controls (HCs) (n = 28, mean age = 71.14), that underwent cognitive assessment and F-fluorodeoxyglucose positron emission tomography imaging.
Semantic and phonemic fluency showed the largest effect sizes between groups, showing lower scores in bvFTD than AD and HCs, and lower scores in AD than HC. Both AD and bvFTD showed a lower number of unique designs in design fluency in comparison to HC. Semantic fluency was correlated with left frontotemporal lobe in AD, and with left frontal, caudate, and thalamus in bvFTD. Percentage of unique designs in design fluency was associated with the metabolism of the bilateral fronto-temporo-parietal cortex in AD, and the bilateral frontal cortex with right predominance in bvFTD. Repetitions in AD were correlated with bilateral frontal, temporal, and parietal lobes, and with left prefrontal cortex in bvFTD.
Our findings demonstrate differential underlying cognitive processes in verbal and design fluency in AD and bvFTD. While memory and executive functioning associated with fronto-temporo-parietal regions were key in AD, attention and executive functions correlated with the frontal cortex and played a more significant role in bvFTD during fluency tasks.
阿尔茨海默病（AD）和行为变异额颞叶痴呆（bvFTD）患者言语流畅性和图形流畅性的认知过程及其神经相关性尚不清楚。我们假设言语流畅性和图形流畅性可能与 AD 和 FTD 中的不同神经心理过程相关，表现出不同的损伤模式和神经基础。
我们纳入了 142 名参与者，包括 AD 患者（n=80，平均年龄=74.71）、bvFTD 患者（n=34，平均年龄=68.18）和健康对照者（n=28，平均年龄=71.14），他们接受了认知评估和 F-氟脱氧葡萄糖正电子发射断层扫描成像。
语义流畅性和语音流畅性在组间的效应量最大，在 bvFTD 中得分低于 AD 和 HC，在 AD 中得分低于 HC。与 HC 相比，AD 和 bvFTD 在图形流畅性测试中设计的独特图形数量都较少。AD 患者的语义流畅性与左侧额颞叶相关，而 bvFTD 患者的语义流畅性与左侧额叶、尾状核和丘脑相关。图形流畅性测试中独特设计的比例与 AD 患者双侧额颞顶叶皮质的代谢相关，而 bvFTD 患者则与双侧额叶皮质且以右侧为主相关。AD 患者的重复次数与双侧额叶、颞叶和顶叶以及 bvFTD 患者的左侧前额叶皮质相关。
我们的研究结果表明，AD 和 bvFTD 患者的言语流畅性和图形流畅性存在不同的认知基础。在 AD 中，与额颞顶叶区域相关的记忆和执行功能是关键，而在 bvFTD 中，注意力和执行功能与额叶皮质相关，在流畅性任务中发挥更重要的作用。
