Research Center on Aging

Sherbrooke, Canada

Research Center on Aging

Sherbrooke, Canada
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Bernier M.,Université de Sherbrooke | Croteau E.,Université de Sherbrooke | Croteau E.,Research Center on Aging | Castellano C.-A.,Research Center on Aging | And 3 more authors.
NeuroImage | Year: 2017

Positron emission tomography using [18F]-fluorodeoxyglucose (PET-FDG) is the primary imaging modality used to measure glucose metabolism in the brain (CMRGlu). CMRGlu has been used as a biomarker of brain aging and neurodegenerative diseases, but the complexity and invasive nature of PET often limits its use in research. There is therefore great interest in developing non-invasive metrics for estimating brain CMRGlu. We therefore investigated resting state fMRI metrics such as regional homogeneity (ReHo), amplitude of low-frequency fluctuations (ALFF) and regional global connectivity (Closeness) with multiple analytical approaches to determine their relationship to CMRGlu. We investigated this relation in two distinct cognitively healthy populations separated by age (27 young adults and 35 older adults). Overall, we found that both regionally and across participants, ReHo strongly correlated with CMRGlu in healthy young and older adults. Moreover, ReHo demonstrated the same age-related differences as CMRGlu throughout all cortical regions, particularly in the default network and frontal areas. © 2017 Elsevier Inc.

Apinis C.,Research Center on Aging | Tousignant M.,Research Center on Aging | Tousignant M.,Université de Sherbrooke | Arcand M.,Research Center on Aging | Tousignant-Laflamme Y.,Université de Sherbrooke
Pain Medicine (United States) | Year: 2014

Objective: The prevalence of chronic pain ranges from 40% to 80% in long-term care facilities, and it is especially high among older adults who are unable to communicate due to cognitive impairments. Although validated assessment tools exist, pain detection in this population is often done by interdisciplinary evaluation (IE), which largely relies on the subjective impression of health care providers. The aim of this study was to examine the agreement between the IE and validated observational pain tools. Setting: We recruited 59 residents with limited ability to communicate. The pain behaviors of each participant were assessed with two validated tools, the Pain Assessment Checklist for Seniors with Limited Ability to Communicate (PACSLAC) and the Pain Assessment in Advanced Dementia (PAINAD), during transfer or mobilization. The results were then compared with the findings of the IE. Results: The correlation between the PACSLAC and PAINAD was high (r=0.79 [95% CI: 0.67-0.87]). However, we found a low to moderate association between the PACSLAC and the IE (r=0.34 [95% CI: 0.09-0.55]), and a weaker association was observed between the PAINAD and the IE (r=0.25 [95% CI: -0.02-0.48]). When the IE concluded that there was an absence of pain behavior, the PAINAD and the PACSLAC detected the presence of pain in 13.6% and 27.1% of the cases respectively. Conclusion: These results may be explained by an inability of IE to assess pain correctly or by instruments providing false positive results. Nevertheless, as detection of pain is difficult in this population, our research supports the use of validated tools to complement assessment of pain by the IE and make sure that no pain goes undetected. © 2014 Original Research Article Wiley Periodicals, Inc.

Carbonneau E.,Research Center on Aging | Carbonneau E.,Université de Sherbrooke | Carbonneau E.,Human Performance and Safety Research Group PERSEUS | Smeesters C.,Research Center on Aging | And 2 more authors.
Gait and Posture | Year: 2014

Several studies have quantified and compared balance recovery between healthy younger and older adults, using a variety of large postural perturbations and loss of balance directions. However, to the best of our knowledge, no studies at the threshold of balance recovery, where avoiding a fall is not always possible, have included middle-aged adults. We thus determined the maximum lean angle from which 20 younger, 16 middle-aged and 16 older healthy adults could be suddenly released and still recover balance using a single step for forward, sideways and backward leans. Results showed that the maximum lean angles of younger adults were 23% greater than middle-aged adults and 48% greater than older adults. The maximum lean angles for forward leans were 23% greater than sideways leans and 22% greater than backward leans. These declines with age and lean direction were associated with declines in response initiation, execution and geometry. Finally exponential regressions showed that the critical ages at which the ability to recover balance and avoid a fall significantly decreases were 51.0, 60.6 and 69.9 yrs for forward, sideways and backward leans, respectively. Therefore, we have demonstrated that age affects the ability to recover balance nearly a decade earlier than the rate of falls. Future studies should thus not only include older adults over 65 yrs, but also middle-aged adults under 65 yrs, or recruit all ages from 18 to 85 yrs. Finally, the critical ages identified in this study may justify an earlier screening of aging adults to prevent future falls, especially the first fall. © 2013 Elsevier B.V.

Helal O.,Research Center on Aging | Berrougui H.,Research Center on Aging | Loued S.,Research Center on Aging | Khalil A.,Research Center on Aging | Khalil A.,Université de Sherbrooke
British Journal of Nutrition | Year: 2013

The present study was aimed to investigate the effect of 12 weeks of extra-virgin olive oil (EVOO) consumption on the capacity of HDL to promote cholesterol efflux (CE) and to determine which CE pathways are modulated by EVOO consumption. Whole HDL and HDL2/HDL3 subclasses were isolated from the plasma of twenty-six healthy volunteers before and after 12 weeks of EVOO consumption (25 ml/d). EVOO consumption increased the capacity of serum and HDL to mediate CE from THP-1, J774 macrophages and Fu5AH cells by 9.8-24.57 %, depending on the cell type. The increase in CE was independent of both HDL concentration and subclass distribution. The three HDL-mediated CE pathways (ATP-binding cassette (ABC) A1, ABCG1 and scavenger receptor class B type I (SR-BI)) were modulated by EVOO consumption. The fluidity of the phospholipidic layer of HDL increased by 13 % (P< 0.001) following EVOO consumption compared with baseline. EVOO consumption also increased the release of excess cholesterol from human monocyte-derived macrophages (HMDM) by 44 % (P< 0.001), and ABCA1 and ABCG1 mRNA transcription by 16.08 % (P< 0.001) and 35.79 % (P< 0.01), respectively. The protein expression of these two cholesterol transporters also increased after EVOO consumption. In contrast, SR-BI mRNA and protein expression in HMDM were significantly lower after 12 weeks of EVOO consumption. Incubating J774 macrophages with EVOO polyphenol extracts induced a concentration- dependent up-regulation of ABCA1 and ABCG1 expression in macrophages. After 12 weeks of EVOO consumption, the capacity of HDL to mediate CE was improved and the ability of HMDM to release excess cholesterol was enhanced by increasing the expression of ABCA1 and ABCG1 transporters. © 2012 The Authors.

Normand-Lauziere F.,Université de Sherbrooke | Frisch F.,Université de Sherbrooke | Labbe S.M.,Université de Sherbrooke | Bherer P.,Université de Sherbrooke | And 3 more authors.
PLoS ONE | Year: 2010

Background: It has been proposed that abnormal postprandial plasma nonesterified fatty acid (NEFA) metabolism may participate in the development of tissue lipotoxicity and type 2 diabetes (T2D). We previously found that non-diabetic offspring of two parents with T2D display increased plasma NEFA appearance and oxidation rates during intravenous administration of a fat emulsion. However, it is currently unknown whether plasma NEFA appearance and oxidation are abnormal during the postprandial state in these subjects at high-risk of developing T2D. Methodology: Palmitate appearance and oxidation rates and glycerol appearance rate were determined in eleven healthy offspring of two parents with T2D (positive family history, FH+), 13 healthy subjects without first-degree relatives with T2D (FH-) and 12 subjects with T2D at fasting, during normoglycemic hyperinsulinemic clamp and during continuous oral intake of a standard liquid meal to achieve steady postprandial NEFA and triacylglycerols (TG) without and with insulin infusion to maintain similar glycemia in all three groups. Principal Findings: Plasma palmitate appearance and oxidation were higher at fasting and during the clamp conditions in the T2D group (all P<0.05). In the postprandial state, palmitate appearance, oxidative and non oxidative rates were all elevated in T2D (all P<0.05) but not in FH+. Both T2D and FH+ displayed elevated postprandial TG vs. FH- (P<0.001). Acute correction of hyperglycemia during the postprandial state did not affect these group differences. Increased waist circumference and BMI were positively associated with elevated postprandial plasma palmitate appearance and oxidation. Conclusions/Significance: Postprandial plasma NEFA intolerance observed in subjects with T2D is not fully established in non-diabetic offspring of both parents with T2D, despite the presence of increased postprandial plasma TG in the later. Elevated postprandial plasma NEFA appearance and oxidation in T2D is observed despite acute correction of the exaggerated glycemic excursion in this group. © 2010 Normand-Lauziére et al.

Loued S.,Research Center on Aging | Berrougui H.,Research Center on Aging | Componova P.,Research Center on Aging | Ikhlef S.,Research Center on Aging | And 3 more authors.
British Journal of Nutrition | Year: 2013

Paraoxonase 1 (PON1) is associated with HDL and modulates the antioxidant and anti-inflammatory role of HDL. The goals of the present study were to investigate the effect of ageing and the role of PON1 on the anti-inflammatory activity of HDL, and to determine whether extra-virgin olive oil (EVOO) consumption could improve the atheroprotective activity of HDL. HDL and PON1 were isolated from the plasma of ten young (Y-HDL and Y-PON1) and ten elderly (E-HDL and E-PON1) healthy volunteers before and after 12 weeks of EVOO consumption. Inflammation was assessed by measuring intracellular adhesion molecule 1 (ICAM-1) expression. THP-1 (human acute monocytic leukaemia cell line) monocyte chemotaxis was measured using a Boyden chamber. Oxidative damage to HDL was assessed by measuring conjugated diene formation and changes in electrophoretic migration. Y-HDL had more anti-inflammatory activity than E-HDL. The conjugated diene content and the electrophoretic mobility of E-HDL were higher than those of Y-HDL. Y-PON1 had significant anti-inflammatory activity, reducing ICAM-1 expression by 32·64 (sd 2·63)Â %, while E-PON1 had no significant effect. THP-1 chemotaxis measurements confirmed the ICAM-1 expression results. The 12 weeks of EVOO consumption significantly increased the anti-inflammatory activities of both HDL and PON1. The anti-inflammatory activity of HDL was modulated by PON1 and was lower in the elderly volunteers. EVOO consumption increased the anti-inflammatory effect of HDL and reduced the age-related decrease in anti-atherogenic activity. Copyright © The Authors 2013.

Lebel K.,Université de Sherbrooke | Lebel K.,Research Center on Aging | Boissy P.,Université de Sherbrooke | Boissy P.,Research Center on Aging | And 2 more authors.
PLoS ONE | Year: 2015

Background: Interest in 3D inertial motion tracking devices (AHRS) has been growing rapidly among the biomechanical community. Although the convenience of such tracking devices seems to open a whole new world of possibilities for evaluation in clinical biomechanics, its limitations haven't been extensively documented. The objectives of this study are: 1) to assess the change in absolute and relative accuracy of multiple units of 3 commercially available AHRS over time; and 2) to identify different sources of errors affecting AHRS accuracy and to document how they may affect the measurements over time. Methods: This study used an instrumented Gimbal table on which AHRS modules were carefully attached and put through a series of velocity-controlled sustained motions including 2 minutes motion trials (2MT) and 12 minutes multiple dynamic phases motion trials (12MDP). Absolute accuracy was assessed by comparison of the AHRS orientation measurements to those of an optical gold standard. Relative accuracy was evaluated using the variation in relative orientation between modules during the trials. Findings: Both absolute and relative accuracy decreased over time during 2MT. 12MDP trials showed a significant decrease in accuracy over multiple phases, but accuracy could be enhanced significantly by resetting the reference point and/or compensating for initial Inertial frame estimation reference for each phase. Interpretation: The variation in AHRS accuracy observed between the different systems and with time can be attributed in part to the dynamic estimation error, but also and foremost, to the ability of AHRS units to locate the same Inertial frame. Conclusions: Mean accuracies obtained under the Gimbal table sustained conditions of motion suggest that AHRS are promising tools for clinical mobility assessment under constrained conditions of use. However, improvement in magnetic compensation and alignment between AHRS modules are desirable in order for AHRS to reach their full potential in capturing clinical outcomes. © 2015 Lebel et al.

Lebel K.,Université de Sherbrooke | Lebel K.,Research Center on Aging | Boissy P.,Université de Sherbrooke | Boissy P.,Research Center on Aging | And 3 more authors.
PLoS ONE | Year: 2013

Background: Inertial measurement of motion with Attitude and Heading Reference Systems (AHRS) is emerging as an alternative to 3D motion capture systems in biomechanics. The objectives of this study are: 1) to describe the absolute and relative accuracy of multiple units of commercially available AHRS under various types of motion; and 2) to evaluate the effect of motion velocity on the accuracy of these measurements. Methods: The criterion validity of accuracy was established under controlled conditions using an instrumented Gimbal table. AHRS modules were carefully attached to the center plate of the Gimbal table and put through experimental static and dynamic conditions. Static and absolute accuracy was assessed by comparing the AHRS orientation measurement to those obtained using an optical gold standard. Relative accuracy was assessed by measuring the variation in relative orientation between modules during trials. Findings: Evaluated AHRS systems demonstrated good absolute static accuracy (mean error < 0.5°) and clinically acceptable absolute accuracy under condition of slow motions (mean error between 0.5° and 3.1°). In slow motions, relative accuracy varied from 2° to 7° depending on the type of AHRS and the type of rotation. Absolute and relative accuracy were significantly affected (p<0.05) by velocity during sustained motions. The extent of that effect varied across AHRS. Interpretation: Absolute and relative accuracy of AHRS are affected by environmental magnetic perturbations and conditions of motions. Relative accuracy of AHRS is mostly affected by the ability of all modules to locate the same global reference coordinate system at all time. Conclusions: Existing AHRS systems can be considered for use in clinical biomechanics under constrained conditions of use. While their individual capacity to track absolute motion is relatively consistent, the use of multiple AHRS modules to compute relative motion between rigid bodies needs to be optimized according to the conditions of operation. © 2013 Lebel et al.

Ducharme F.,University of Montréal | Couture M.,University of Montréal | Lamontagne J.,Research Center on Aging
Home Health Care Services Quarterly | Year: 2012

Grounded theory served to develop a model of the family caregiver decision-making process regarding placement of a cognitively impaired elderly relative. Eighteen caregivers were interviewed every 6 months over an average 20 months. Results show the process is activated when the caregiver or a health care professional introduces the possibility of placement. The caregiver's assessment of the pros and cons of placement is modulated primarily by interactions with the formal and informal social network. Three types of longitudinal trajectory emerged from the data suggesting avenues of intervention to support caregivers during this painful process. © 2012 Copyright Taylor and Francis Group, LLC.

Couture M.,University of Montréal | Ducharme F.,University of Montréal | Lamontagne J.,Research Center on Aging
Home Health Care Management and Practice | Year: 2012

In this article, we explore the role of health care professionals within the decision-making process of family caregivers regarding placement of a cognitively impaired elderly relative. Grounded theory was used to describe interactions with health care professionals, modulating the caregivers' decision-making process. A total of 18 caregivers of cognitively impaired elderly relatives were interviewed every 6 months over an average of 20 months. Results showed that health care professionals were involved in the decision-making process in three ways: (a) in assessing the need for placement; (b) in helping caregivers navigate through the health care system; and (c) in taking care of family dynamics. There were great variations in the way health care professionals supported caregivers. Future research is needed to identify professional interventions that are helpful for caregivers and in which context. © 2012 SAGE Publications.

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