Department of Nuclear Medicine, Medical Center - University of Freiburg and Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Center of Geriatrics and Gerontology, Medical Center - University of Freiburg and Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Alzheimers Res Ther. 2023 Jan 10;15(1):11. doi: 10.1186/s13195-022-01146-w.
Left-predominant neurodegeneration of the anterior temporal lobe (ATL) and the associated syndrome termed semantic variant primary progressive aphasia (svPPA) are well characterized. Less is known about right-predominant neurodegeneration of the ATL, which has been associated with the clinical syndrome named right temporal variant of frontotemporal dementia (rtvFTD). Here, we assessed glucose metabolism across the brain, cognitive performance, and mortality in patients with right-predominant neurodegeneration of the ATL.
Patients with predominant hypometabolism of the ATL on FDG PET (as a measure of neurodegeneration) were retrospectively identified and categorized into those with asymmetrical right, left, or symmetric bilateral involvement (N = 10, 17, and 8). We compared whole-brain, normalized regional glucose metabolism using SPM12, cognitive performance on the CERAD Neuropsychological Assessment Battery, and mortality risk (age- and sex-adjusted Cox proportional hazard model) between groups.
Hypometabolism was most pronounced and extensive in patients with right-predominant neurodegeneration of the ATL. Beyond the right temporal lobe, right frontal and left temporal lobes were affected in these patients. Cognitive performance was similarly impaired in all three groups, with predominant naming and hippocampal-dependent memory deficits. Mortality risk was 6.1 times higher in patients with right- than left-predominant ATL neurodegeneration (p < 0.05). Median survival duration after PET was shortest in patients with right- and longest in patients with left-predominant ATL neurodegeneration (5.7 vs 8.3 years after examination).
More extensive neurodegeneration and shorter survival duration in patients with right- than left-predominant neurodegeneration of the ATL might indicate that the former consult memory clinics at a later disease stage, when symptoms like naming and episodic memory deficits have already emerged. At the time of diagnosis, the shorter survival duration of patients with right- than left-predominant ATL neurodegeneration should be kept in mind when counseling patients and caregivers.
左前颞叶（ATL）优势的神经退行性变以及与之相关的被称为语义变异原发性进行性失语症（svPPA）的综合征已得到很好的描述。关于 ATL 的右优势神经退行性变知之甚少，这种病变与被称为额颞叶痴呆的右侧颞叶变异型（rtvFTD）的临床综合征有关。在这里，我们评估了 ATL 右优势神经退行性变患者的大脑内葡萄糖代谢、认知表现和死亡率。
我们回顾性地确定了 FDG PET 上 ATL 代谢明显降低的患者（作为神经退行性变的一种衡量标准），并将其分为右侧、左侧或双侧不对称受累（N=10、17 和 8）。我们使用 SPM12 比较了全脑、正常化的区域葡萄糖代谢，使用 CERAD 神经心理评估电池进行认知表现评估，并使用年龄和性别调整的 Cox 比例风险模型比较死亡率风险。
ATL 右优势神经退行性变患者的代谢降低最为明显和广泛。除了右颞叶外，这些患者的右额叶和左颞叶也受到了影响。所有三组的认知表现都同样受损，主要表现为命名和海马依赖性记忆缺陷。与左优势 ATL 神经退行性变相比，右优势 ATL 神经退行性变患者的死亡率高 6.1 倍（p<0.05）。在接受 PET 检查后，右优势和左优势 ATL 神经退行性变患者的中位生存时间最短（分别为 5.7 年和 8.3 年）。
与左优势 ATL 神经退行性变相比，右优势 ATL 神经退行性变患者的神经退行性变更为广泛，生存时间更短，这可能表明前者在出现命名和情景记忆缺陷等症状时，已经处于疾病的晚期，因此到记忆诊所就诊的时间较晚。在诊断时，应考虑到右优势 ATL 神经退行性变患者的生存时间比左优势 ATL 神经退行性变患者更短，以便在向患者和照顾者提供咨询时进行考虑。
