Reul Sophia, Lohmann Hubertus, Wiendl Heinz, Duning Thomas, Johnen Andreas
Department of Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Germany.
Alzheimers Res Ther. 2017 Aug 9;9(1):61. doi: 10.1186/s13195-017-0287-1.
Neuropsychological testing is considered crucial for differential diagnosis of Alzheimer's disease (AD) and behavioural variant frontotemporal dementia (bvFTD). In-depth neuropsychological assessment revealed specific dysfunctions in the two dementia syndromes. However, a significant overlap of cognitive impairments exists in early disease stages. We questioned whether a standard neuropsychological assessment at initial clinical presentation can delineate patients with AD versus bvFTD.
In a retrospective approach, we evaluated and compared how cognitive profiles assessed at initial clinical presentation predicted the diagnosis of later verified AD (n = 43) and bvFTD (n = 26). Additionally, the neuropsychological standard domains memory, language, visuospatial skills, executive functions, praxis and social cognition were subjected to stepwise discriminant analysis to compare their differential contribution to diagnosis.
Regardless of diagnosis, a percentage of patients presented with major deterioration in a wide range of cognitive domains when compared with age-matched normative data. Only few significant differences were detected on the group level: Patients with AD were relatively more impaired in the verbal recall, verbal recognition, figure copy, and surprisingly in the executive subdomains, set shifting and processing speed whereas bvFTD was characterised by more deficits in imitation of face postures. A combination of tests for verbal recall, imitation of limb and face postures, and figure copy showed the greatest discriminatory power.
Our results imply that the contribution of a standard neuropsychological assessment is limited for differential diagnosis of AD and bvFTD at initial presentation. In contrast to current clinical guidelines, executive functions are neither particularly nor exclusively impaired in patients with bvFTD when assessed within a standard clinical neuropsychological test battery. The significant overlap of bvFTD and AD concerning the profile of cognitive impairments questions current neuropsychological diagnostic criteria and calls for revision, regarding both the degree and the profile of cognitive deficits.
神经心理学测试被认为对阿尔茨海默病（AD）和行为变异型额颞叶痴呆（bvFTD）的鉴别诊断至关重要。深入的神经心理学评估揭示了这两种痴呆综合征的特定功能障碍。然而，在疾病早期阶段存在明显的认知障碍重叠。我们质疑在初次临床就诊时进行的标准神经心理学评估能否区分AD患者和bvFTD患者。
采用回顾性方法，我们评估并比较了初次临床就诊时评估的认知概况如何预测后来确诊的AD（n = 43）和bvFTD（n = 26）。此外，对神经心理学标准领域记忆、语言、视觉空间技能、执行功能、运用和社会认知进行逐步判别分析，以比较它们对诊断的不同贡献。
无论诊断如何，与年龄匹配的正常数据相比，一定比例的患者在广泛的认知领域出现了严重恶化。在组水平上仅检测到少数显著差异：AD患者在言语回忆、言语识别、图形临摹方面相对受损更严重，令人惊讶的是在执行功能子领域、定势转换和处理速度方面也是如此，而bvFTD的特征是在模仿面部姿势方面有更多缺陷。言语回忆、肢体和面部姿势模仿以及图形临摹测试的组合显示出最大的鉴别力。
我们的结果表明，在初次就诊时，标准神经心理学评估对AD和bvFTD的鉴别诊断贡献有限。与当前临床指南相反，在标准临床神经心理学测试组合中评估时，bvFTD患者的执行功能既没有特别受损也没有唯一受损。bvFTD和AD在认知障碍概况方面的显著重叠对当前神经心理学诊断标准提出了质疑，并呼吁在认知缺陷的程度和概况方面进行修订。
