Author: Zhou, Zhixing
Title: The mechanisms underlying poor attention and working memory performance in older adults with chronic low back pain
Advisors: Wong, Arnold (RS)
Degree: DHSc
Year: 2023
Subject: Backache
Chronic pain -- Psychological aspects
Older people
Short-term memory
Hong Kong Polytechnic University -- Dissertations
Department: Faculty of Health and Social Sciences
Pages: x, 136 pages : color illustrations
Language: English
Abstract: Background: Chronic low back pain (CLBP) not only may limit physical function, but also may accelerate cognitive decline. While some studies have found poor cognitive performance in multiple domains in people with CLBP, the underlying mechanisms remain unclear. Unfortunately, findings from previous studies remain inconclusive, which might be because these studies only evaluated task-related brain activity. Even when the same cognitive domain is measured, slightly different experimental designs may cause significant variations in brain activities. Because the resting-state can reflect intrinsic and spontaneous brain activity, the assessment of the resting-state brain activities may be a better way to discover the shared underlying brain changes. Before the conduction of experiments in this dissertation, no study has examined both the resting-state and task-related state of the brain in functional magnetic resonance imaging (fMRI) among people with CLBP to explain the potential mechanisms underlying their poor cognitive performance. In addition, previous studies have yet investigated the cognitive performance and the corresponding brain changes in older adults with CLBP, who are more likely to experience CLBP-related cognitive decline due to their pre-existing age-related deterioration in cognitive function.
Objective: To investigate the attention and working memory in older adults with CLBP by examining both resting-state and task-related brain activity using fMRI.
Methods: To achieve the objective, one scoping review, and a cross-sectional study was performed. In particular, the scoping review collated information and evidence regarding the potential mechanisms for cognitive decline in people with CLBP. A cross-sectional study was conducted to compare the brain activity between older adults with and without CLBP during the psychomotor vigilance task (PVT), n-back tasks, and resting-state using fMRI.
Results: The scoping review summarized five potential mechanisms based on 34 included studies regarding the suboptimal cognitive performance or cognitive decline in people with CLBP, and discussed future research directions. Five potential mechanisms are: (1) altered activity in the cortex and neural networks; (2) grey matter atrophy; (3) microglial activation and neuroinflammation; (4) comorbidities associated with CLBP; and (5) gut microbiota dysbiosis.
From the brain image of resting-state and n-back task in 37 older people with and without CLBP, we found that older adults with CLBP showed significant decreased activity in the visual cortex during n-back tasks than healthy controls (HCs). Meanwhile, older adults with moderate to high intensity pain showed significant decreased activity in the left dorsal lateral prefrontal cortex than HCs. These alterations were found to be significantly correlated with impaired inverse correlation between the default mode network (DMN) and task-positive networks (TPNs) among older adults with CLBP.
From the brain image of resting-state and PVT in 39 older people with and without CLBP, we found that the impaired inverse correlation between DMN and TPNs were associated with less deactivation of DMN during PVT in older adults with CLBP. The less deactivation of DMN during PVT may reflect the impaired resource utilization strategy of the brain in older adults with CLBP, which negatively affect their concentration.
Conclusions: The impaired inverse correlation between DMN and TPNs observed in older adults with CLBP may indicate an impaired resource usage strategy within this population. This may be one shared mechanism underlying poor cognitive performance in older adults with CLBP. As such, this work has laid a foundation for investigating the mechanisms underlying the accelerated decline in older adults with CLBP.
Rights: All rights reserved
Access: restricted access

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