Xiao Yaqiong, Hu Yubin, Huang Kaiyu
Center for Language and Brain, Shenzhen Institute of Neuroscience, Shenzhen, China.
Front Aging Neurosci. 2023 Dec 12;15:1287122. doi: 10.3389/fnagi.2023.1287122. eCollection 2023.
It has been well documented that atrophy of hippocampus and hippocampal subfields is closely linked to cognitive decline in normal aging and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). However, evidence is still sparce regarding the atrophy of hippocampus and hippocampal subfields in normal aging adults who later developed MCI or AD.
To examine whether atrophy of hippocampus and hippocampal subfields has occurred in normal aging before a diagnosis of MCI or AD.
We analyzed structural magnetic resonance imaging (MRI) data of cognitively normal (CN, = 144), MCI ( = 90), and AD ( = 145) participants obtained from the Alzheimer's Disease Neuroimaging Initiative. The CN participants were categorized into early dementia converters (CN-C) and non-converters (CN-NC) based on their scores of clinical dementia rating after an average of 36.2 months (range: 6-105 months). We extracted the whole hippocampus and hippocampal subfields for each participant using FreeSurfer, and analyzed the differences in volumes of hippocampus and hippocampal subfields between groups. We then examined the associations between volume of hippocampal subfields and delayed recall scores in each group separately.
Hippocampus and most of the hippocampal subfields demonstrated significant atrophy during the progression of AD. The CN-C and CN-NC groups differed in the left hippocampus-amygdala transition area (HATA). Furthermore, the volume of presubiculum was significantly correlated with delayed recall scores in the CN-NC and AD groups, but not in the CN-C and MCI groups.
Hippocampal subfield atrophy (i.e., left HATA) had occurred in cognitively normal elderly individuals before clinical symptoms were recognized. Significant associations of presubiculum with delayed recall scores in the CN-NC and AD groups highlight the essential role of the hippocampal subfields in both early dementia detection and AD progression.
已有充分文献证明，海马体及海马体亚区萎缩与正常衰老、轻度认知障碍（MCI）及阿尔茨海默病（AD）患者的认知衰退密切相关。然而，关于正常衰老成年人后来发展为MCI或AD时海马体及海马体亚区萎缩的证据仍然稀少。
研究在诊断为MCI或AD之前，正常衰老过程中海马体及海马体亚区是否已发生萎缩。
我们分析了从阿尔茨海默病神经影像倡议组织获取的认知正常（CN，n = 144）、MCI（n = 90）和AD（n = 145）参与者的结构磁共振成像（MRI）数据。根据平均36.2个月（范围：6 - 105个月）后的临床痴呆评定分数，将CN参与者分为早期痴呆转化者（CN - C）和非转化者（CN - NC）。我们使用FreeSurfer为每位参与者提取整个海马体及海马体亚区，并分析各组之间海马体及海马体亚区体积的差异。然后我们分别检查每组中海马体亚区体积与延迟回忆分数之间的关联。
在AD进展过程中，海马体及大部分海马体亚区表现出显著萎缩。CN - C组和CN - NC组在左侧海马 - 杏仁核过渡区（HATA）存在差异。此外，前扣带回体积与CN - NC组和AD组的延迟回忆分数显著相关，但在CN - C组和MCI组中无此相关性。
在认知正常的老年人出现临床症状之前，海马体亚区萎缩（即左侧HATA）就已发生。CN - NC组及AD组中前扣带回与延迟回忆分数的显著关联突出了海马体亚区在早期痴呆检测和AD进展中的重要作用。
