Department of Psychiatry and Psychotherapy, University of Mainz, Mainz, Germany.
Neuropsychologia. 2010 Apr;48(5):1447-53. doi: 10.1016/j.neuropsychologia.2010.01.014. Epub 2010 Jan 28.
Recent neuroanatomical and functional neuroimaging studies indicate that the anterior part of the hippocampus, rather than the whole structure, may be specifically involved in episodic memory. In the present work, we examined whether anterior structural measurements are superior to other regional or global measurements in mapping functionally relevant degenerative alterations of the hippocampus in Alzheimer's disease (AD). Twenty patients with early AD (MMSE 25.7+/-1.7) and 18 healthy controls were studied using magnetic resonance and diffusion-tensor imaging. Using a regions-of-interest analysis, we obtained volumetric and diffusivity measures of the hippocampal head and body-tail-section as well as of the whole hippocampus. Detailed cognitive evaluation was based on the CERAD battery. All volumetric measures as well as diffusivity of the hippocampus head were significantly (p<0.01) altered in patients as compared to controls. In patients, increased left head diffusivity significantly (p<0.01) correlated with performance on free delayed verbal recall test (DVR) (r=-0.74, p=0.0002) and with the CERAD global score. Reduced volume of the left body-tail was also associated with performance on DVR (r=0.62, p=0.004). Stepwise regression analyses revealed that increased left head diffusivity was the only predictor for performance on DVR (R(2)=52%, p<0.0005). These findings suggest that anterior hippocampus diffusivity is more closely related to verbal episodic memory impairment than other regional or global structural measures. Our data support the hypothesis of functional differentiation in general and the specific role of the anterior hippocampus in episodic memory in particular. Diffusivity measurements might be highly sensitive to functionally relevant degenerative alterations of the hippocampus.
最近的神经解剖学和功能神经影像学研究表明，海马体的前部而非整个结构可能专门参与情景记忆。在本研究中，我们研究了在阿尔茨海默病（AD）中，是否海马体的前部结构测量比其他区域或整体测量更能预测与功能相关的退行性改变。使用磁共振和弥散张量成像对 20 名早期 AD 患者（MMSE 25.7±1.7）和 18 名健康对照者进行了研究。通过感兴趣区分析，我们获得了海马头和体尾节的体积和弥散率测量值，以及整个海马体的体积和弥散率测量值。详细的认知评估基于 CERAD 测试。与对照组相比，所有的体积测量值和海马体头部的弥散率在患者中都显著改变（p<0.01）。在患者中，左侧海马头弥散率的增加与自由延迟言语回忆测试（DVR）（r=-0.74，p=0.0002）和 CERAD 总分显著相关（p<0.01）。左侧体尾体积的减少也与 DVR 表现相关（r=0.62，p=0.004）。逐步回归分析显示，左侧海马头弥散率的增加是 DVR 表现的唯一预测因素（R(2)=52%，p<0.0005）。这些发现表明，左侧海马体前部的弥散率与言语情景记忆障碍的关系比其他区域或整体结构测量更密切。我们的数据支持一般功能分化的假说，特别是前海马体在情景记忆中的特定作用的假说。弥散率测量可能对与功能相关的海马体退行性改变高度敏感。
