Background: Hypertension is related with cognitive decline in the elderly. The frontal–parietal executive system plays an important role in cognitive aging and is also vulnerable to damage in elderly patients with hypertension. Examination of the brain's functional characteristics in frontal–parietal regions of hypertension is likely to be important for understanding the neural mechanisms of hypertension's effect on cognitive aging.
Methods: We address this issue by comparing hypertension and control-performers in a functional MRI study. Twenty-eight hypertensive patients and 32 elderly controls were tested with n-back task with two load levels.
Results: The hypertensive patients exhibited worse executive and memory abilities than control subjects. The patterns of brain activation changed under different working memory loads in the hypertensive patients, who exhibited reduced activation only in the precentral gyrus under low loads and reduced activation in the middle frontal gyrus, left medial superior frontal gyrus and right precuneus under high loads. Thus, more regions of diminished activation were observed in the frontal and parietal regions with increasing task difficulty. More importantly, we found that lower activation in changed frontal and parietal regions was associated with worse cognitive function in high loads.
Conclusion: The results demonstrate the relationship between cognitive function and frontoparietal functional activation in hypertension and their relevance to cognitive aging risk. Our findings provide a better understanding of the mechanism of cognitive decline in hypertension and highlight the importance of brain protection in hypertension.
aState Key Laboratory of Cognitive Neuroscience and Learning
bBABRI Centre, Beijing Normal University
cThe Laboratory Research Center of Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, PR China
Correspondence to Zhanjun Zhang, MD, State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, PR China. Tel: +86 10 5880 2005; fax: +86 10 5880 2005; e-mail: firstname.lastname@example.org
Abbreviations: AD, Alzheimer's disease; AVLT, auditory verbal learning; BOLD, blood oxygenation level-dependent; CDT, clock-drawing test; fMRI, functional MRI; FPG, fasting plasma glucose; MFG, middle frontal gyrus; MMSE, mini–mental state examination; PCUN, precuneus; PreCG, precentral gyrus; rCBF, regional cerebral blood flow; ROCF, Rey–Osterrieth complex figure tests; SDMT, symbol digit modalities test; SFGmed, medial superior frontal gyrus; TC, total cholesterol; TG, triglyceride; VaD, vascular dementia; WM, working memory
Received 15 December, 2015
Revised 21 October, 2016
Accepted 15 December, 2016