Search

Kim H Tran,1,2 Andrew P McDonald,1,3 Ryan CN D’Arcy,2,3 Xiaowei Song1,2 1Clinical Research Centre, Surrey Memorial Hospital, Fraser Health Authority, Surrey, BC, Canada; 2Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada; 3Department of Medicine, University of British Columbia, Vancouver, BC, CanadaCorrespondence: Xiaowei Song 13750 96th Avenue, Surrey, BC V3V 1Z2, CanadaTel +1 604 585 5666 ext. 774 986Email xiaowei.song@fraserhealth.caAbstract: Contextual processing (or context processing; CP) is an integral component of cognition. CP allows people to manage their thoughts and actions by adjusting to surroundings. CP involves the formation of an internal representation of context in relation to the environment, maintenance of this information over a period of time, and the updating of mental representations to reflect changes in the environment. Each of these functions can be affected by aging and associated conditions. Here, we introduced contextual processing research and summarized the literature studying the impact of normal aging and neurodegeneration-related cognitive decline on CP. Through searching the PubMed, PsycINFO, and Google Scholar databases, 23 studies were retrieved that focused on the impact of aging, mild cogniitve impairment (MCI), Alzheimer’s disease (AD), and Parkinson’s disease (PD) on CP. Results indicated that CP is particularly vulnerable to aging and neurodegeneration. Older adults had a delayed onset and reduced amplitude of electrophysiological response to information detection, comparison, and execution. MCI patients demonstrated clear signs of impaired CP compared to normal aging. The only study on AD suggested a decreased proactive control in AD participants in maintaining contextual information, but seemingly intact reactive control. Studies on PD restricted to non-demented older participants, who showed limited ability to use contextual information in cognitive and motor processes, exhibiting impaired reactive control but more or less intact proactive control. These data suggest that the decline in CP with age is further impacted by accelerated aging and neurodegeneration, providing insights for improving intervention strategies. This review highlights the need for increased attention to research this important but understudied field.Keywords: Alzheimer’s disease, Parkinson’s disease, mild-cognitive impairment, aging, dementia, contextual processing, EEG-ERP, behavior

Tao Gu,1,2 Lei Lin,3 Yun Jiang,4 Juan Chen,1 Ryan CN D’Arcy,2,5,6 Min Chen,1 Xiaowei Song2,5,6 1Department of Radiology, Beijing Hospital, National Center of Gerontology, Beijing, China; 2Simon Fraser University ImageTech Laboratory, Surrey Memorial Hospital, Surrey, BC, Canada; 3Department of Acupuncture and Moxibustion, Beijing Hospital, National Centre of Gerontology, Beijing, China; 4Department of Neurology, Beijing Hospital, NationalCentre of Gerontology, Beijing, China; 5Department of AppliedSciences and Computing Science, Simon Fraser University, Burnaby, BC, Canada; 6Health Sciences and Innovation, Surrey Memorial Hospital, Fraser Health Authority, Surrey, BC, Canada Background: Acupuncture has been proven to be effective as an alternative therapy in treating migraine, but the pathophysiological mechanisms of the treatment remain unclear. This study investigated possible neurochemical responses to acupuncture treatment. Patients and methods: Proton magnetic resonance spectroscopy imaging was used to investigate biochemical levels pre- and post-acupuncture treatment. Participants (N=45) included subjects diagnosed with: 1) migraine without aura; 2) cervicogenic headache; and 3) healthy controls. Participants in the two patient groups received verum acupuncture using acupoints that target migraine without aura but not cervicogenic headache, while the healthy controls received a sham treatment. All participants had magnetic resonance spectroscopy scans before and after the acupuncture therapy. Levels of brain metabolites were examined in relation to clinical headache assessment scores. Results: A significant increase in N-acetylaspartate/creatine was observed in bilateral thalamus in migraine without aura after the acupuncture treatment, which was significantly correlated with the headache intensity score. Conclusion: The data demonstrate brain biochemical changes underlying the effect of acupuncture treatment of migraine. Keywords: acupuncture, metabolites, migraine, magnetic resonance spectroscopy imaging, brain, pain transmission pathways

Hui Guo,1,2 William Siu,1,3 Ryan CN D’Arcy,1,4 Sandra E Black,5,6 Lukas A Grajauskas,1,4 Sonia Singh,7,8 Yunting Zhang,2 Kenneth Rockwood,9,10 Xiaowei Song1,4,9 On behalf of The Alzheimer’s Disease Neuroimaging Initiative and the National Alzheimer’s Coordinating Center 1Health Sciences and Innovation, ImageTech Laboratory, Fraser Health Authority, Surrey, BC, Canada; 2Department of Diagnostic Imaging, Tianjin Medical University General Hospital, Tianjin, China; 3Department of Medical Imaging, Fraser Health Authority, Surrey, 4Departments of Applied Sciences and Computing Science, Simon Fraser University, Burnaby, BC, 5Department of Medicine (Neurology), 6LC Campbell Cognitive Neurology Research Unit, Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Sunnybrook Health Sciences Centre& University of Toronto, Toronto, ON, 7Department of Family Medicine, University of British Columbia, Vancouver, BC, 8Department of Research and Evaluation, Fraser Health, Surrey, BC, 9Department of Medicine (Geriatric Medicine), Dalhousie University, 10Centre for Healthcare of the Elderly, Nova Scotia Health Authority, Halifax, NS, Canada Purpose: One of the central features of brain aging is the accumulation of multiple age-related structural changes, which occur heterogeneously in individuals and can have immediate or potential clinical consequences. Each of these deficits can coexist and interact, producing both independent and additive impacts on brain health. Many of the changes can be visualized using MRI. To collectively assess whole-brain structural changes, the MRI-based Brain Atrophy and Lesion Index (BALI) has been developed. In this study, we validate this whole-brain health assessment approach using several clinical MRI examinations.Materials and methods: Data came from three independent studies: the Alzheimer’s Disease Neuroimaging Initiative Phase II (n=950; women =47.9%; age =72.7±7.4 years); the National Alzheimer’s Coordinating Center (n=722; women =55.1%; age =72.7±9.9 years); and the Tianjin Medical University General Hospital Research database on older adults (n=170; women =60.0%; age =62.9±9.3 years). The 3.0-Tesla MRI scans were evaluated using the BALI rating scheme on the basis of T1-weighted (T1WI), T2-weighted (T2WI), T2-weighted fluid-attenuated inversion recovery (T2-FLAIR), and T2*-weighted gradient-recalled echo (T2*GRE) images.Results: Atrophy and lesion changes were commonly seen in each MRI test. The BALI scores based on different sequences were highly correlated (Spearman r2>0.69; P0.29; P26.48, P