Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
Psychiatry and Psychology (Neuropsychology), Mayo Clinic, Rochester, Minnesota, USA.
Eur J Neurol. 2022 Jul;29(7):2138-2143. doi: 10.1111/ene.15327. Epub 2022 Mar 30.
Posterior cortical atrophy (PCA) is one of the atypical Alzheimer's disease variants, characterized by predominant visuospatial and visuoperceptual deficits, with established dorsal and ventral subtypes. A third primary occipital (caudal) variant has been suggested. We aimed to determine its demographics, clinical manifestations, and biomarker findings.
Fifty-two PCA patients were investigated. Patients underwent neuropsychological assessment, magnetic resonance imaging, and fluorodeoxyglucose (FDG)-, amyloid-, and tau-positron emission tomography (tau-PET) scans. Normalized regional FDG-PET values were represented as z-scores relative to a control population. Patients were divided into "primary occipital" and "other PCA" subgroups according to FDG-PET-defined criteria, with primary occipital defined as patients in which the z-scores for occipital subregions were at least one standard deviation lower (SD) (i.e., more abnormal) than the z-scores in all other brain regions. Global amyloid-PET, temporo-parietal FDG-PET, and temporal tau-PET regions-of-interest (ROIs) were calculated.
Nine patients were classified as primary occipital; they were older (p = 0.034) and had more years of education (p = 0.007) than other PCA patients. The primary occipital group performed worse on the Ishihara test for color perception (p < 0.001), while other PCA patients performed worse on the Western Aphasia Battery (WAB) praxis scale (p = 0.005). Overall neuropsychiatric symptom burden was lower in the primary occipital group (p < 0.001). The FDG-PET meta-ROI was higher in the primary occipital subtype (p = 0.006), but no differences were observed in amyloid- and tau-PET.
Our findings suggest that primary occipital PCA is characterized by an older age at onset, more color perception dysfunction, less severe ideomotor apraxia, and less hypometabolism in temporo-parietal meta-ROI compared to established phenotypes.
后部皮质萎缩症（PCA）是阿尔茨海默病的非典型变异之一，其特征是主要存在视空间和视知觉缺陷，并已确定存在背侧和腹侧亚型。有人提出了第三种原发性枕叶（尾部）变异。我们旨在确定其人口统计学、临床表现和生物标志物发现。
对 52 名 PCA 患者进行了调查。患者接受了神经心理学评估、磁共振成像以及氟脱氧葡萄糖（FDG）、淀粉样蛋白和 tau-正电子发射断层扫描（tau-PET）扫描。正常化的区域性 FDG-PET 值表示为与对照人群相比的 z 分数。根据 FDG-PET 定义的标准，患者分为“原发性枕叶”和“其他 PCA”亚组，原发性枕叶定义为枕叶亚区的 z 分数至少比所有其他脑区的 z 分数低一个标准差（即更异常）。计算了全局淀粉样蛋白-PET、颞顶叶 FDG-PET 和颞叶 tau-PET 的感兴趣区（ROI）。
9 名患者被归类为原发性枕叶；他们比其他 PCA 患者年龄更大（p=0.034），受教育程度更高（p=0.007）。原发性枕叶组在石原色觉测试（Ishihara test for color perception）中表现更差（p<0.001），而其他 PCA 患者在西方失语症成套测验（WAB）的执行功能量表（praxis scale）中表现更差（p=0.005）。原发性枕叶组的总体神经精神症状负担较低（p<0.001）。原发性枕叶亚型的 FDG-PET 元 ROI 较高（p=0.006），但在淀粉样蛋白和 tau-PET 中没有差异。
我们的发现表明，与已确定的表型相比，原发性枕叶 PCA 的发病年龄较大，颜色知觉障碍更严重，意念运动性失用症较轻，颞顶叶 meta-ROI 的代谢率较低。
