Norwich Medical School, University of East Anglia, Norwich, UK.
Centre de Référence Démence Rares, Pitié-Salpêtrière, INSERM UMRS 975, Paris, France.
J Alzheimers Dis. 2018;62(4):1887-1900. doi: 10.3233/JAD-170771.
Although a growing body of work has shown that behavioral variant frontotemporal dementia (bvFTD) could present with severe amnesia in approximately half of cases, memory assessment is currently the clinical standard to distinguish bvFTD from Alzheimer's disease (AD). Thus, the concept of "relatively preserved episodic memory" in bvFTD remains the basis of its clinical distinction from AD and a criterion for bvFTD's diagnosis. This view is supported by the idea that bvFTD is not characterized by genuine amnesia and hippocampal degeneration, by contrast to AD. In this multicenter study, we aimed to investigate the neural correlates of memory performance in bvFTD as assessed by the Free and Cued Selective Reminding Test (FCSRT). Imaging explorations followed a two-step procedure, first relying on a visual rating of atrophy of 35 bvFTD and 34 AD patients' MRI, contrasted with 29 controls; and then using voxel-based morphometry (VBM) in a subset of bvFTD patients. Results showed that 43% of bvFTD patients presented with a genuine amnesia. Data-driven analysis on visual rating data showed that, in bvFTD, memory recall & storage performances were significantly predicted by atrophy in rostral prefrontal and hippocampal/perihippocampal regions, similar to mild AD. VBM results in bvFTD (pFWE<0.05) showed similar prefrontal and hippocampal regions in addition to striatal and lateral temporal involvement. Our findings showed the involvement of prefrontal as well as medial/lateral temporal atrophy in memory deficits of bvFTD patients. This contradicts the common view that only frontal deficits explain memory impairment in this disease and plead for an updated view on memory dysfunctions in bvFTD.
虽然越来越多的研究表明，行为变异型额颞叶痴呆（bvFTD）在大约一半的病例中可能表现出严重的健忘症，但目前的临床标准是通过记忆评估来区分 bvFTD 和阿尔茨海默病（AD）。因此，bvFTD 中“相对保存的情景记忆”的概念仍然是其与 AD 临床区分的基础，也是 bvFTD 诊断的标准。这一观点得到了以下观点的支持，即与 AD 不同，bvFTD 不是以真正的健忘症和海马体退化为特征。在这项多中心研究中，我们旨在通过自由和提示选择性提醒测试（FCSRT）评估 bvFTD 的记忆表现，研究其神经相关性。影像学探索采用两步程序，首先依赖于对 35 名 bvFTD 和 34 名 AD 患者 MRI 的萎缩的视觉评估，与 29 名对照进行对比；然后在 bvFTD 患者的亚组中使用基于体素的形态测量学（VBM）。结果显示，43%的 bvFTD 患者表现出真正的健忘症。基于视觉评估数据的数据分析显示，在 bvFTD 中，记忆回忆和存储表现与额前皮质和海马/海马旁区域的萎缩显著相关，类似于轻度 AD。bvFTD 的 VBM 结果（pFWE<0.05）显示了额前皮质和海马旁区域的相似性，此外还包括纹状体和外侧颞叶的参与。我们的研究结果显示，记忆缺陷的 bvFTD 患者涉及额前皮质以及内侧/外侧颞叶的萎缩。这与普遍认为只有额叶缺陷才能解释该疾病的记忆障碍的观点相矛盾，并呼吁对 bvFTD 的记忆功能障碍进行更新的观点。
