Dementia Research Centre, Box 16, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK.
J Neurol Neurosurg Psychiatry. 2013 Apr;84(4):460-6. doi: 10.1136/jnnp-2012-303309. Epub 2012 Nov 8.
Posterior cortical atrophy (PCA) is typically considered to be a visual syndrome, primarily characterised by progressive impairment of visuoperceptual and visuospatial skills. However, patients commonly describe early difficulties with word retrieval. This paper details the first systematic analysis of linguistic function in PCA. Characterising and quantifying the aphasia associated with PCA is important for clarifying diagnostic and selection criteria for clinical and research studies.
15 patients with PCA, seven patients with logopenic/phonological aphasia (LPA) and 18 age matched healthy participants completed a detailed battery of linguistic tests evaluating auditory input processing, repetition and working memory, lexical and grammatical comprehension, single word retrieval and fluency, and spontaneous speech.
Relative to healthy controls, PCA patients exhibited language impairments across all of the domains examined, but with anomia, reduced phonemic fluency and slowed speech rate the most prominent deficits. PCA performance most closely resembled that of LPA patients on tests of auditory input processing, repetition and digit span, but was relatively stronger on tasks of comprehension and spontaneous speech.
The study demonstrates that in addition to the well reported degradation of vision, literacy and numeracy, PCA is characterised by progressive oral language dysfunction with prominent word retrieval difficulties. Overlap in the linguistic profiles of PCA and LPA, which are both most commonly caused by Alzheimer's disease, further emphasises the notion of a phenotypic continuum between typical and atypical manifestations of the disease. Clarifying the boundaries between Alzheimer's disease phenotypes has important implications for diagnosis, clinical trial recruitment and investigations into biological factors driving phenotypic heterogeneity in Alzheimer's disease. Rehabilitation strategies to ameliorate the phonological deficit in PCA are required.
后部皮质萎缩症（PCA）通常被认为是一种视觉综合征，主要表现为视知觉和视空间技能的逐渐受损。然而，患者通常会较早地出现单词检索困难。本文详细介绍了 PCA 中语言功能的首次系统分析。对 PCA 相关失语症进行特征描述和量化对于阐明临床和研究研究的诊断和选择标准非常重要。
15 名 PCA 患者、7 名语义性失语症（LPA）患者和 18 名年龄匹配的健康参与者完成了详细的语言测试，评估了听觉输入处理、复述和工作记忆、词汇和语法理解、单个单词检索和流畅性以及口语。
与健康对照组相比，PCA 患者在所有检查的领域都表现出语言障碍，但以命名障碍、语音流畅性降低和语速减慢最为突出。PCA 的表现与 LPA 患者在听觉输入处理、复述和数字广度测试上最为相似，但在理解和口语任务上的表现相对较强。
该研究表明，除了众所周知的视觉、读写和计算能力下降外，PCA 还表现为渐进性口语语言功能障碍，突出表现为单词检索困难。PCA 和 LPA 的语言特征重叠，这两者最常见的病因都是阿尔茨海默病，进一步强调了疾病典型和非典型表现之间存在表型连续体的概念。阐明阿尔茨海默病表型之间的界限对于诊断、临床试验招募以及对导致阿尔茨海默病表型异质性的生物学因素的研究具有重要意义。需要制定改善 PCA 语音缺陷的康复策略。
