Dementia Research Centre, UCL Institute of Neurology, University College London, London, UK.
Alzheimers Dement. 2012 Nov;8(6):502-12. doi: 10.1016/j.jalz.2011.09.225. Epub 2012 Feb 23.
Posterior cortical atrophy (PCA) is a neurodegenerative condition predominantly associated with Alzheimer's disease (AD) pathology. Cross-sectional imaging studies have shown different atrophy patterns in PCA patients compared with typical amnestic Alzheimer's disease (tAD) patients, with greatest atrophy commonly found in posterior regions in the PCA group, whereas in the tAD group, atrophy is most prominent in medial temporal lobe regions. However, differential longitudinal atrophy patterns are not well understood.
This study assessed longitudinal changes in brain and gray matter volumes in 17 PCA patients, 16 tAD patients, and 18 healthy control subjects. Both patient groups had symptom durations of approximately 5 years.
Progressive gray matter losses in both PCA and tAD patients were relatively widespread throughout the cortex, compared with control subjects, and were not confined to areas related to initial symptomatology. A multivariate classification analysis revealed a statistically significant group separation between PCA and tAD patients, with 72.7% accuracy (P < .01).
Progression from an initially focal presentation to a more global pattern suggests that these different clinical presentations of AD might converge pathologically over time.
后部皮质萎缩（PCA）是一种主要与阿尔茨海默病（AD）病理学相关的神经退行性疾病。横断面影像学研究表明，与典型遗忘型 AD（tAD）患者相比，PCA 患者的萎缩模式不同，PCA 组中最常见的萎缩部位在后脑区域，而 tAD 组中最明显的萎缩部位则在海马体区域。然而，关于纵向萎缩模式的差异尚未得到很好的理解。
本研究评估了 17 名 PCA 患者、16 名 tAD 患者和 18 名健康对照组的大脑和灰质体积的纵向变化。两组患者的症状持续时间均约为 5 年。
与对照组相比，PCA 和 tAD 患者的灰质逐渐丧失相对广泛地分布于整个皮层，而不仅仅局限于与初始症状相关的区域。多元分类分析显示，PCA 和 tAD 患者之间存在统计学上显著的组间分离，准确率为 72.7%（P<0.01）。
从最初的局灶性表现进展为更广泛的模式表明，AD 的这些不同临床表现可能随着时间的推移在病理上趋于一致。
