Cerebral hemodynamic responses of subjective cognitive decline evoked by loaded N‐back tasks: Neuroimaging / Optimal neuroimaging measures for early detection. (7th December 2020)

• Record Type: Journal Article
• Authors: Du, Wenying; Zhang, Yaoyu; Gao, Jiahong; Han, Ying
• Is Part Of: Alzheimer's & dementia. Volume 16(2020)Supplement 5
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-07
• Subjects: Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1002/alz.041794
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Background: Subjective cognitive decline (SCD) is a high risk for Alzheimer's disease. The physiological mechanisms of SCD is largely unknown. Most of the existing studies made their observations during the resting state of the brain. How the SCD group performs differently from the normal controls (NC) during functional tasks is less studied. This study compared the responses of SCD and NC evoked by loaded working memory tasks. The results of this study help clarify the underlying hemodynamic mechanisms of SCD. Methods: 15 NC (8 females) and 23 SCD subjects (14 females) participated in the study. Table 1 shows the biographical and behavioral data of the two groups. All subjects participated block‐designed 0‐back, 1‐back, 2‐back and 3‐back working memory tasks. Followed by the N‐back tasks, each subject underwent a hypercapnic challenge during which the subject breathed a gas mixture (5% CO2, 20% O2, 75%N2 ) through a non‐rebreather mask. A pulse sequence which simultaneously acquires cerebral blood volume (CBV), cerebral blood flow (CBF), blood oxygen‐level dependent (BOLD)‐weighted signals was implemented on a 3.0 T GE MR750 system. At the group level, holding sex, age and education as covariates, a general linear model was applied to compare the above parameters between the two groups, and a partial correlation test was performed to relate the imaging results with the behavior data. P < 0.05 was considered statistically significant. Results: The group averages of δCBV, δCBF, δBOLD and δCMRO2 evoked by 1‐, 2‐ and 3‐back, with respect to 0‐back, in the frontal cortex were displayed in Figure 1. In general, all parameters show a load‐dependent effect, where 1‐back caused minimum signal changes. Among all parameters, δCBF evoked by 3‐back, with respect to 0‐back, was significantly lower (p = 0.04) in the SCD group compared to the NC group. None of the other parameters showed statistical differences between the two groups. In addition, δCBF at 3‐back was found to be significantly correlated with the MoCA (p = 0.04) and AFT (p 0.03) scores of the subjects. Conclusion: This study may help understand the physiological mechanisms and develop early diagnostic strategies of SCD.