Department of Neurology, Christian Doppler Medical Centre, Paracelsus Medical University, Salzburg, Austria.
Rehabilitation Center of the Pensionsversicherungsanstalt, Großgmain, Austria.
Curr Alzheimer Res. 2019;16(9):843-851. doi: 10.2174/1567205016666190827115138.
Growing evidence suggests that pathological processes leading to Alzheimer's disease occurs gradually and begins to develop decades before the earliest clinical symptoms occur. The use of biomarkers has been proposed to detect evidence of preclinical Alzheimer's pathologic change in asymptomatic subjects. Subjective cognitive complaints (SCC) i.e. self-reported cognitive decline with normal cognition have been reported as an indicator of future cognitive decline, however, this condition is unspecific.
In the present study we used the regional brain perfusion measured by HMPAO-SPECT as Biomarker of neurodegeneration to compare the regional brain perfusion of patient with subjective cognitive complaints with and without minimal cognitive dysfunction (SCC+ and SCC- respectively) in respect to patients with mild cognitive impairment (MCI).
We retrospectively examined 736 Patients who referred to our Memory Clinic because of suspected cognitive dysfunction. After exclusion of patients with overt dementia, automated, quantitatively assessed relative cerebral blood flow of 10 forebrain regions (thalamus, parietotemporal, medial temporal, posterior temporal, posterior cingulate gyrus, each region left hemispheric and right hemispheric) and neuropsychological assessment of 64 SCC (32 SCC+; 32 SCC-) and 28 MCI subjects were analysed.
.The most relevant differences between groups in cognitive performance concerned verbal memory. Left hemispheric medial temporal region could significantly discriminate between all three groups, with a progressive decrease n perfusion from SCC towards MCI. Area under the curve of left medial temporal region showed a sensitivity of 0,61 and a specificity of 0,78 for discriminating MCI from SCC.
Automated analysis of HMPAO-SPECT data of MCI and SCC+ patients showed significant perfusion differences in medial temporal region and impaired verbal memory, both of which are known features of Alzheimer's disease. Perfusion patterns and verbal memory performance in SCC+ are more similar to MCI than SCC-. Thus, SPECT analysis could distinguish those subjects whose perfusion pattern resembles that of an MCI from those who do not. In our opinion, this could identify two populations with a different risk of progression to AD, with SCC+ subjects needing further diagnostic examination and repeated follow-up.
越来越多的证据表明，导致阿尔茨海默病的病理过程是逐渐发生的，并且在最早的临床症状出现之前几十年就开始发展。已经提出使用生物标志物来检测无症状受试者中临床前阿尔茨海默病病理变化的证据。主观认知主诉（SCC），即自我报告的认知能力下降而认知正常，已被报道为未来认知能力下降的指标，但这种情况并不特异。
在本研究中，我们使用 HMPAO-SPECT 测量的区域脑灌注作为神经退行性变的生物标志物，比较有和无轻微认知功能障碍（分别为 SCC+和 SCC-）的主观认知主诉患者与轻度认知障碍（MCI）患者的区域脑灌注。
我们回顾性检查了 736 名因疑似认知功能障碍而到我们记忆诊所就诊的患者。排除明显痴呆的患者后，对 10 个前脑区域（丘脑、顶颞叶、内侧颞叶、颞后叶、后扣带回，每个区域的左半球和右半球）的自动、定量评估的相对脑血流和 64 名 SCC（32 名 SCC+；32 名 SCC-）和 28 名 MCI 受试者进行了神经心理学评估。
.在认知表现方面，组间最相关的差异涉及语言记忆。左侧半球内侧颞叶区域可显著区分所有三组，灌注从 SCC 逐渐减少到 MCI。左内侧颞叶区域的曲线下面积显示出 0.61 的敏感性和 0.78 的特异性，用于区分 MCI 和 SCC。
MCI 和 SCC+患者 HMPAO-SPECT 数据的自动分析显示内侧颞叶区域存在明显的灌注差异和言语记忆受损，这两者都是阿尔茨海默病的已知特征。SCC+的灌注模式和言语记忆表现与 MCI 更为相似，而与 SCC-不同。因此，SPECT 分析可以区分那些灌注模式类似于 MCI 的患者和那些不相似的患者。在我们看来，这可以识别出具有不同进展为 AD 风险的两个人群，SCC+患者需要进一步的诊断检查和重复随访。
