Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
Department of Psychology, School of Behavioral Health, Loma Linda University, Loma Linda, CA, USA.
J Alzheimers Dis. 2014;39(2):261-9. doi: 10.3233/JAD-131481.
White matter abnormalities have been associated with both behavioral variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD).
Using MRI diffusion tensor imaging (DTI) measures, we compared white matter integrity between patients with bvFTD and those with early-onset AD and correlated these biomarkers with behavioral symptoms involving emotional blunting.
We studied 8 bvFTD and 12 AD patients as well as 12 demographically-matched healthy controls (NCs). Using four DTI metrics (fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity), we assessed the frontal lobes (FWM) and genu of the corpus callosum (GWM), which are vulnerable late-myelinating regions, and a contrasting early-myelinating region (splenium of the corpus callosum). The Scale for Emotional Blunting Scale (SEB) was used to assess emotional functioning of the study participants.
Compared to AD patients and NCs, the bvFTD subjects exhibited significantly worse FWM and GWM integrity on all four DTI metrics sensitive to myelin and axonal integrity. In contrast, AD patients showed a numerical trend toward worse splenium of the corpus callosum integrity than bvFTD and NC groups. Significant associations between SEB ratings and GWM DTI measures were demonstrated in the combined bvFTD and AD sample. When examined separately, these relationships remained robust for the bvFTD group but not the AD group.
The regional DTI alterations suggest that FTD and AD are each associated with a characteristic distribution of white matter degradation. White matter breakdown in late-myelinating regions was associated with symptoms of emotional blunting, particularly within the bvFTD group.
白质异常与行为变异额颞叶痴呆（bvFTD）和阿尔茨海默病（AD）都有关。
使用 MRI 扩散张量成像（DTI）测量，我们比较了 bvFTD 患者和早发性 AD 患者之间的白质完整性，并将这些生物标志物与涉及情感迟钝的行为症状相关联。
我们研究了 8 名 bvFTD 患者和 12 名 AD 患者以及 12 名年龄匹配的健康对照组（NC）。使用四个 DTI 指标（各向异性分数、轴向弥散度、径向弥散度和平均弥散度）评估额叶（FWM）和胼胝体膝部（GWM），这是易受晚期髓鞘形成区域和对比早期髓鞘形成区域（胼胝体体部）。使用情感迟钝量表（SEB）评估研究参与者的情感功能。
与 AD 患者和 NC 相比，bvFTD 患者在所有四个对髓鞘和轴突完整性敏感的 DTI 指标上表现出明显更差的 FWM 和 GWM 完整性。相比之下，AD 患者在胼胝体体部的完整性上表现出数值上比 bvFTD 和 NC 组更差的趋势。在 bvFTD 和 AD 联合样本中，SEB 评分与 GWM DTI 测量之间存在显著相关性。分别检查时，这些关系在 bvFTD 组中仍然稳健，但在 AD 组中则不稳健。
区域 DTI 改变表明 FTD 和 AD 各自与白质降解的特征分布有关。晚期髓鞘形成区域的白质破坏与情感迟钝症状有关，特别是在 bvFTD 组中。
