Cross-sectional and longitudinal neural predictors of physical activity and sedentary behaviour from a 6-month randomized controlled trial.

A sedentary lifestyle offers immediate gratification, but at the expense of long-term health. It is thus critical to understand how the brain evaluates immediate rewards and long-term health effects in the context of deciding whether to engage in moderate-to-vigorous physical activity (MVPA) or sedentary behaviour (SB). In this secondary analysis of a 6-month randomized controlled trial to increase MVPA and reduce SB among community-dwelling adults, we explored how neural activity during an executive control task was associated with MVPA and SB levels. At baseline, a subset of participants (n = 26/61) underwent task-based functional magnetic resonance imaging (fMRI) to examine neural activity underlying executive control using the Now/Later task. MVPA and SB were measured objectively using the Sensewear Mini at baseline, and 2, 4, and 6 months follow-up. We then examined the associations of baseline neural activation underlying executive control with: (1) baseline MVPA or SB; and (2) changes in MVPA and SB over 6 months. Our results determined that there is a complex neurocognitive system associated with MVPA levels, while SB appears to lack any neurocognitive control. In other words, MVPA appears to require neurocognitive effort, while SB may be the default behavioural pattern in adults.

Resistance Training Maintains White Matter and Physical Function in Older Women with Cerebral Small Vessel Disease: An Exploratory Analysis of a Randomized Controlled Trial.

Background: As the aging population grows, there is an increasing need to develop accessible interventions against risk factors for cognitive impairment and dementia, such as cerebral small vessel disease (CSVD). The progression of white matter hyperintensities (WMHs), a key hallmark of CSVD, can be slowed by resistance training (RT). We hypothesize RT preserves white matter integrity and that this preservation is associated with improved cognitive and physical function. Objective: To determine if RT preserves regional white matter integrity and if any changes are associated with cognitive and physical outcomes. Methods: Using magnetic resonance imaging data from a 12-month randomized controlled trial, we compared the effects of a twice-weekly 60-minute RT intervention versus active control on T1-weighted over T2-weighted ratio (T1w/T2w; a non-invasive proxy measure of white matter integrity) in a subset of study participants (N = 21 females, mean age = 69.7 years). We also examined the association between changes in T1w/T2w with two key outcomes of the parent study: (1) selective attention and conflict resolution, and (2) peak muscle power. Results: Compared with an active control group, RT increased T1w/T2w in the external capsule (p = 0.024) and posterior thalamic radiations (p = 0.013) to a greater degree. Increased T1w/T2w in the external capsule was associated with an increase in peak muscle power (p = 0.043) in the RT group. Conclusion: By maintaining white matter integrity, RT may be a promising intervention to counteract the pathological changes that accompany CSVD, while improving functional outcomes such as muscle power.

Effects of malnutrition on outcomes of patients with femoral head osteonecrosis undergoing total hip arthroplasty: A population-based study.

BACKGROUND: This study aimed to evaluate the impact of malnutrition on in-hospital outcomes in patients undergoing total hip arthroplasty (THA) for osteonecrosis of the femoral head (ONFH). METHODS: This population-based retrospective study extracted data of patients undergoing THA for ONFH in the US National Inpatient Sample between 2005 and 2018. Factors associated with in-hospital mortality, medical and surgical complications, unfavorable discharge, and prolonged hospital stay were determined by logistic regression analysis. RESULTS: A total of 72,304 adults ≥18 years old with nontraumatic ONFH admitted for primary THA were included. Malnutrition was detected in 7152 (9.9%) patients using validated discharge codes. In-hospital mortality was 0.8% vs 0.1% for patients who were malnourished vs nonmalnourished. After adjusting for confounders, malnutrition was significantly associated with an increased risk of in-hospital death (adjusted odds ratio [aOR], 4.67; 95% CI, 2.43-8.97), medical complications (aOR, 1.49; 95% CI, 1.32-1.68), surgical complications (aOR, 1.78; 95% CI, 1.61-1.96), unfavorable discharge (aOR, 1.24; 95% CI, 1.11-1.39), and prolonged hospital stay (aOR, 1.90; 95% CI, 1.67-2.16) compared with adequate nutrition. Malnutrition was also associated with higher total hospital costs (adjusted ß = $9620; 95% CI, 7.87-11.36). Furthermore, the association between malnutrition, any medical or surgical complications, and unfavorable discharge was stronger in patients younger than 50 years than those ≥50 years old. CONCLUSIONS: In US patients undergoing primary THA for ONFH, malnutrition increases the risk of unfavorable in-hospital outcomes. This patient subgroup may require special attention and better strategies to improve perioperative care.

Sensorimotor and Frontoparietal Network Connectivity Are Associated With Subsequent Maintenance of Gait Speed and Episodic Memory in Older Adults.

BACKGROUND: Slow gait is predictive of functional impairments in older adults, while concomitant slow gait and cognitive complaints are associated with a greater risk for cognitive decline and dementia. However, functional neural correlates for gait speed maintenance are unclear. As the sensorimotor network (SMN) and frontoparietal network (FPN) are integral components of these functions, this study investigated differences in SMN and FPN in older adults with/without gait speed decline over 24 months; and whether these networks were associated with the maintenance of cognitive function. METHODS: We included 42 community-dwelling older adults aged >70 years from the MOBILIZE Boston Study. Resting-state fMRI was performed at the study baseline. Participant characteristics, gait speed, Mini-Mental State Examination, and Hopkins Verbal Learning Test (HVLT) were assessed at baseline and at 24-month follow-up. Decliners were identified as individuals with >0.05 meters/second decline in gait speed from baseline to 24 months. Of the 26 decliners and 16 maintainers, decliners exhibited a significant decline in delayed-recall performance on the HVLT over 24 months. RESULTS: Controlling for baseline age and multiple comparisons, contrary to initial hypothesis, maintainers exhibited lower baseline primary motor and premotor connectivity (p = .01) within the SMN, and greater baseline ventral visual-supramarginal gyrus connectivity within the FPN (p = .02) compared to decliners. Lower primary motor-premotor connectivity was correlated with maintenance of delayed-recall performance on the HVLT (p = .04). CONCLUSION: These findings demonstrated a potential compensatory mechanism involved in the link between the decline in gait speed and episodic memory, whereby baseline connectivity of the SMN and FPN may underlie subsequent maintenance of gait speed and cognitive function in old age.

Precise joint preserving surgery by using Three-Dimensional Printing Technology for metastatic periacetabular bone tumor: A technique note and preliminary report.

BACKGROUND/PURPOSE: Complex arthroplasties for periacetabular metastatic lesions can result in complications including infection and prosthesis loosening owing to poor bone quality. A new surgical protocol has been developed as a joint-sparing surgery to avoid complications after arthroplasties. The main surgical steps are: (a) conservative and accurate tumor resection with aid of 3D printing model-assisted preoperative resection simulation and preparation of pre-contour plate, (b) reconstruction with structural bone graft through the sandwich technique for augmentation of subchondral bone. METHODS: This retrospective study consisted of 6 patients (5 with metastatic bone tumors and one with multiple myeloma). The pelvic bone resection as defined by Enneking and Dunham were typed I + II in 2 patients and type II in 4 patients. The medical records, images, musculoskeletal tumor society (MSTS) score and visual analogue scale (VAS) were used for evaluation. RESULTS: The mean operative time was 234 minutes, and the average surgical blood loss was 1408 mL. The mean follow-up period was 21 months. The mean VAS significantly decreased at postoperative 1-week and 1-year follow-up. There were no intraoperative or early postoperative complications. The median MSTS score during the final follow-up was 26 points (range, 14-28 points). Except for one case who experienced severe joint destruction, all the other five cases were classified as excellent or good (>15). CONCLUSION: With precise tumor resection and reconstruction with sandwich procedure, the joint-sparing surgery can be performed in selected patients with metastatic periacetabular tumors.

Six month lower-leg mechanical tactile sensory stimulation alters functional network connectivity associated with improved gait in older adults with peripheral neuropathy - A pilot study.

Foot sole somatosensory impairment associated with peripheral neuropathy (PN) is prevalent and a strong independent risk factor for gait disturbance and falls in older adults. Walkasins, a lower-limb sensory prosthesis, has been shown to improve gait and mobility in people with PN by providing afferent input related to foot sole pressure distributions via lower-leg mechanical tactile stimulation. Given that gait and mobility are regulated by sensorimotor and cognitive brain networks, it is plausible improvements in gait and mobility from wearing the Walkasins may be associated with elicited neuroplastic changes in the brain. As such, this study aimed to examine changes in brain network connectivity after 26 weeks of daily use of the prosthesis among individuals with diagnosed PN and balance problems. In this exploratory investigation, assessments of participant characteristics, Functional Gait Assessment (FGA), and resting-state functional magnetic resonance imaging were completed at study baseline and 26 weeks follow-up. We found that among those who have completed the study (N = 8; mean age 73.7 years) we observed a five-point improvement in FGA performance as well as significant changes in network connectivity over the 26 weeks that were correlated with improved FGA performance. Specifically, greater improvement in FGA score over 26 weeks was associated with increased connectivity within the Default Mode Network (DMN; p < 0.01), the Somatosensory Network (SMN; p < 0.01), and the Frontoparietal Network (FPN; p < 0.01). FGA improvement was also correlated with increased connectivity between the DMN and the FPN (p < 0.01), and decreased connectivity between the SMN and both the FPN (p < 0.01) and cerebellum (p < 0.01). These findings suggest that 26 weeks of daily use of the Walkasins device may provide beneficial neural modulatory changes in brain network connectivity via the sensory replacement stimulation that are relevant to gait improvements among older adults with PN.

Propofol-based total intravenous anesthesia is associated with better survival than desflurane anesthesia in limb-salvage surgery for osteosarcoma: A retrospective analysis.

Previous studies have demonstrated that anesthetic techniques can affect the outcomes of cancer surgery. We investigated the association between anesthetic techniques and patient outcomes after elective limb-salvage surgery for osteosarcoma (OS). This was a retrospective cohort study of patients who underwent elective limb-salvage surgery for OS between January 2007 and December 2018. Patients were grouped according to the administration of propofol-based total intravenous anesthesia (TIVA) or desflurane (DES) anesthesia. Kaplan-Meier analysis was performed, and survival curves were constructed from the date of surgery to death. Univariate and multivariate Cox regression models were applied to compare the hazard ratios (HRs) for death after propensity matching. Subgroup analyses were done for postoperative recurrence, metastasis, and tumor-node-metastasis (TNM) staging. A total of 30 patients (17 deaths, 56.7%) who received DES anesthesia and 26 (4 deaths, 15.4%) who received TIVA were eligible for analysis. After propensity matching, 22 patients were included in each group. In the matched analysis, patients who received TIVA had better survival with a HR of 0.30 (95% confidence interval [CI], 0.11-0.81; P = .018). Subgroup analyses also showed significantly better survival in the presence of postoperative metastasis (HR, 0.24; 95% CI, 0.06-0.87; P = .030) and with TNM stage II to III (HR, 0.26; 95% CI, 0.09-0.73; P = .011) in the matched TIVA group. In addition, patients administered with TIVA had lower risks of postoperative recurrence and metastasis than those administered with DES anesthesia in the matched analyses. Propofol-based TIVA was associated with better survival in patients who underwent elective limb-salvage surgery for OS than DES anesthesia. Prospective studies are needed to assess the effects of TIVA on oncological outcomes in patients with OS.

Weight for It: Resistance Training Mitigates White Matter Hyperintensity-Related Disruption to Functional Networks in Older Females.

BACKGROUND: White matter hyperintensities (WMH) are associated with impaired cognition and increased falls risk. Resistance training (RT) is a promising intervention to reduce WMH progression, improve executive functions, and reduce falls. However, the underlying neurobiological process by which RT improves executive functions and falls risk remain unclear. We hypothesized that: 1) RT reduces the level of WMH-related disruption to functional networks; and 2) reduced disruption to the sensorimotor and attention networks will be associated with improved executive function and reduced falls risk. OBJECTIVE: Investigate the impact of 52 weeks of RT on WMH-related disruption to functional networks. METHODS: Thirty-two older females (65-75 years) were included in this exploratory analysis of a 52-week randomized controlled trial. Participants received either twice-weekly RT or balance and tone training (control). We used lesion network mapping to assess changes in WMH-related disruption to the sensorimotor, dorsal attention, and ventral attention networks. Executive function was measured using the Stroop Colour-Word Test. Falls risk was assessed using the Physiological Profile Assessment (PPA) and the foam sway test. RESULTS: RT significantly reduced the level of WMH-related disruption to the sensorimotor network (p = 0.012). Reduced disruption to the dorsal attention network was associated with improvements in Stroop performance (r = 0.527, p = 0.030). Reduced disruption to the ventral attention network was associated with reduced PPA score (r = 0.485, p = 0.049)Conclusion:RT may be a promising intervention to mitigate WMH-related disruption to the sensorimotor network. Additionally, reducing disruption to the dorsal and ventral attention networks may contribute to improved executive function and reduced falls risk respectively.

Reshaping the path of mild cognitive impairment by refining exercise prescription: a study protocol of a randomized controlled trial to understand the "what," "for whom," and "how" of exercise to promote cognitive function.

BACKGROUND: Targeted exercise training is a promising strategy for promoting cognitive function and preventing dementia in older age. Despite the utility of exercise as an intervention, variation still exists in exercise-induced cognitive gains and questions remain regarding the type of training (i.e., what), as well as moderators (i.e., for whom) and mechanisms (i.e., how) of benefit. Both aerobic training (AT) and resistance training (RT) enhance cognitive function in older adults without cognitive impairment; however, the vast majority of trials have focused exclusively on AT. Thus, more research is needed on RT, as well as on the combination of AT and RT, in older adults with mild cognitive impairment (MCI), a prodromal stage of dementia. Therefore, we aim to conduct a 6-month, 2 × 2 factorial randomized controlled trial in older adults with MCI to assess the individual effects of AT and RT, and the combined effect of AT and RT on cognitive function and to determine the possible underlying biological mechanisms. METHODS: Two hundred and sixteen community-dwelling adults, aged 65 to 85 years, with MCI from metropolitan Vancouver will be recruited to participate in this study. Randomization will be stratified by biological sex and participants will be randomly allocated to one of the four experimental groups: (1) 4×/week balance and tone (BAT; i.e., active control); (2) combined 2×/week AT + 2×/week RT; (3) 2×/week AT + 2×/week BAT; or (4) 2×/week RT + 2×/week BAT. The primary outcome is cognitive function as measured by the Alzheimer's Disease Assessment Scale-Cognitive-Plus. Secondary outcomes include cognitive function, health-related quality of life, physical function, actigraphy measures, questionnaires, and falls. Outcomes will be measured at baseline, 6 months (i.e., trial completion), and 18 months (i.e., 12-month follow-up). DISCUSSION: Establishing the efficacy of different types and combinations of exercise training to minimize cognitive decline will advance our ability to prescribe exercise as "medicine" to treat MCI and delay the onset and progression of dementia. This trial is extremely timely as cognitive impairment and dementia pose a growing threat to global public health. TRIAL REGISTRATION: ClinicalTrials.gov NCT02737878 . Registered on April 14, 2016.

Objective Sleep Quality and the Underlying Functional Neural Correlates Among Older Adults with Possible Mild Cognitive Impairment.

BACKGROUND: Poor sleep quality is common among older individuals with mild cognitive impairment (MCI) and may be a consequence of functional alterations in the brain; yet few studies have investigated the underlying neural correlates of actigraphy-measured sleep quality in this cohort. OBJECTIVE: The objective of this study was to examine the relationship between brain networks and sleep quality measured by actigraphy. METHODS: In this cross-sectional analysis, sleep efficiency and sleep fragmentation were estimated using Motionwatch8 (MW8) over a period of 14 days in 36 community-dwelling older adults with possible MCI aged 65-85 years. All 36 participants underwent resting-state functional magnetic resonance imaging (fMRI) scanning. Independent associations between network connectivity and MW8 measures of sleep quality were determined using general linear modeling via FSL. Networks examined included the somatosensory network (SMN), frontoparietal network (FPN), and default mode network (DMN). RESULTS: Across the 36 participants (mean age 71.8 years; SD = 5.2 years), mean Montreal Cognitive Assessment score was 22.5 (SD = 2.7) and Mini-Mental State Examination score was 28.3 (SD = 1.5). Mean sleep efficiency and fragmentation index was 80.1% (SD = 10.0) and 31.8 (SD = 10.4) respectively. Higher sleep fragmentation was significantly correlated with increased connectivity between the SMN and insula, the SMN and posterior cingulate, as well as FPN and primary motor area (FDR-corrected, p < 0.004). CONCLUSION: Functional connectivity between brain regions involved in attentional and somatosensory processes may be associated with disrupted sleep in older adults with MCI.

Myelin Content and Gait Impairment in Older Adults with Cerebral Small Vessel Disease and Mild Cognitive Impairment.

We investigated whether myelin is associated with gait parameters in older adults with cerebral small vessel disease (cSVD). Cross-sectional data from sixty-four participants with cSVD and mild cognitive impairment were analyzed. Myelin was assessed via MRI multi-echo gradient and spin echo T2 relaxation sequence, indexed as myelin water fraction (MWF). Gait was assessed using an electronic walkway. Hierarchical regression models adjusting for total intracranial volume, age, sex, Mini-Mental State Examination, and body mass index were conducted to determine associations between MWF and gait parameters. Significant models were further adjusted for white matter hyperintensities. Sixty-four participants were included (mean [SD], age = 75.2y [5.4], 62.5% female). In adjusted models, lower MWF in the cingulum (p = 0.015), superior longitudinal fasciculus (p = 0.034), posterior corona radiata (p = 0.039), and body of the corpus callosum (p = 0.040) was associated with higher cycle time variability. White matter hyperintensities weakened these associations. Lower myelin in specific white matter tracts may contribute to higher gait variability, increasing the overall risk of mobility impairment.

Risk Factors Associated with Cartilage Defects after Anterior Cruciate Ligament Rupture in Military Draftees.

This study aimed to evaluate the different clinical results and factors associated with cartilage defects in military draftees who underwent different treatments after anterior cruciate ligament (ACL) rupture. Overall, 105 patients who had sustained ACL rupture were military draftees who underwent a conscription examination for physical status assessment from January 2012 to December 2020. Patients were divided into three groups: conservative treatment after ACL rupture, status post-anterior cruciate ligament reconstruction (ACLR), but graft rupture, and status post-ACLR with graft intact. Inter-group comparisons and statistical analyses were performed for age, body mass index (BMI), thigh circumference difference, side-to-side difference in anterior knee translation by KT-2000, meniscus tear, and cartilage defect. Multivariate logistic regression analysis was used to determine the factors associated with cartilage defects. The multivariable regression model showed that BMI (odds ratio OR: 1.303; 95% CI: 1.016-1.672; p = 0.037), thigh circumference difference (OR: 1.403; 95% CI: 1.003-1.084; p = 0.034), tear of lateral meniscus (LM) and medial meniscus (MM) (OR: 13.773; 95% CI: 1.354-140.09; p = 0.027), and graft rupture group (OR: 5.191; 95% CI: 1.388-19.419; p = 0.014) increased the risk of cartilage defects. There was no correlation between cartilage defects and age, KT-2000 difference, tear of LM or MM, or graft intact group. Progression of osteoarthritis was concerned after ACL rupture, and this study identified several factors of post-ACLR graft rupture, greater thigh circumference difference, BMI, and meniscus tear of both LM and MM affecting cartilage defects, which represent early degenerative osteoarthritis changes of the knee. The results of this study should be customized for rehabilitation and military training, especially in military draftees with ACL injuries.

The independent associations of physical activity and sleep with neural activity during an inhibitory task: cross-sectional results from the MONITOR-OA study.

Sleep and physical activity (PA) are important for the maintenance of executive functions. Whether these lifestyle factors independently contribute to associated neural correlates of executive functions is unknown. We therefore investigated the independent associations of PA and sleep with neural activity during executive performance using task-based functional magnetic resonance imaging (fMRI). Baseline data from a subset of participants (n = 29) enrolled in a randomised trial were used for this cross-sectional analysis. We measured PA, sleep duration and efficiency for 7 days using the SenseWear Mini and examined neural activity underlying response inhibition using the Go/NoGo executive performance task. Brain activation patterns during the NoGo condition were contrasted to activation patterns during the Go condition (i.e., NoGo-Go). We constructed two separate models (controlling for age, sex, and education) to examine the independent associations of (i) PA and sleep duration; and (ii) PA and sleep efficiency with brain activation. Significant clusters were corrected for multiple comparisons (p < 0.05) to determine region-specific activation patterns. The mean (SD) participant age was 61 (9) years, and 79% were female. PA was independently associated with greater task-related blood-oxygen-level dependent (BOLD) signal activity in the left cingulate gyrus; longer sleep duration was independently associated with greater BOLD signal activity in the left putamen. Higher sleep efficiency was independently associated with increased BOLD signal activity in the left hippocampus. PA, sleep duration, and efficiency are each independently associated with greater neural activity underlying response inhibition, which further illustrates that PA and sleep are each uniquely important for brain health.

Baseline health-related quality of life predicts falls: a secondary analysis of a randomized controlled trial.

PURPOSE: Among older adults, health-related quality of life (HRQoL) and falls are associated. Generic patient-reported outcomes measures (PROMs) assess individual's HRQoL. The role for PROMs, a potential tool for predicting subsequent falls, remains under-explored. Our primary aim was to determine whether a baseline PROMs assessment of HRQoL may be a useful tool for predicting future falls. METHODS: A secondary analysis of a 12-month randomized clinical trial (RCT) of a home-based exercise program among 344 adults (67% female), aged ≥ 70 years, with ≥ 1 falls in the prior year who were randomized (1:1) to either a home-based exercise program (n = 172) or usual care (n = 172). A negative binomial regression model with total falls count as the dependent variable evaluated the main effect of the independent variable-baseline HRQoL (measured by the Short-Form-6D)-controlling for total exposure time and experiment group (i.e., exercise or usual care) for the total sample. For the usual care group alone, the model controlled for total exposure time. RESULTS: For the total sample, the rate of subsequent total falls was significantly predicted by baseline HRQoL (IRR = 0.044; 95% CI [0.005-0.037]; p = .004). For the usual care group, findings were confirmed with wider confidence intervals and the rate of prospective total falls was significantly predicted by baseline HRQoL (IRR = 0.025; 95% CI [0.001-0.909]; p = .044). CONCLUSION: These findings suggest the ShortForm-6D should be considered as part of falls prevention screening strategies within a Falls Prevention Clinic setting. Trial Registrations ClinicalTrials.gov Protocol Registration System. Identifier: NCT01029171; URL: https://clinicaltrials.gov/ct2/show/NCT01029171 . Identifier: NCT00323596; URL: https://clinicaltrials.gov/ct2/show/NCT00323596 .

Comparing the cost-effectiveness of the Otago Exercise Programme among older women and men: A secondary analysis of a randomized controlled trial.

OBJECTIVE: Using stratified analyses, we examined the cost-effectiveness of the Otago Exercise Programme (OEP), from a health care system perspective, among older women and men who have previously fallen. METHODS: This study was a secondary stratified analysis (by women and men), of a 12-month prospective economic evaluation of a randomized clinical trial (OEP compared with usual care). Three hundred and forty four community-dwelling older adults (≥70; 172 OEP (110 women; 62 men), 172 usual care (119 women; 53 men)) who sustained a fall in the past 12 months and received a baseline assessment at the Vancouver Falls Prevention Clinic, Canada were included. A gender by OEP/usual care interaction was examined for the falls incidence rate ratio (IRR). Outcome measures stratified by gender included: falls IRR, incremental cost-per fall prevented (ICER), incremental cost per quality adjusted life year (QALY, ICUR) gained, and mean total health care resource utilization costs. RESULTS: Men were frailer than women at baseline. Men incurred higher mean total healthcare costs $6794 (SD: $11906)). There was no significant gender by OEP/usual care interaction on falls IRR. The efficacy of the OEP did not vary by gender. The adjusted IRR for the OEP group demonstrated a 39% (IRR: 0.61, CI: 0.40-0.93) significant reduction in falls among men but not women (32% reduction (IRR: 0.69, CI: 0.47-1.02)). The ICER showed the OEP was effective in preventing falls and less costly for men, while it was costlier for women by $42. The ICUR showed the OEP did not impact quality of life. CONCLUSION: Future studies should explore gender factors (i.e., health seeking behaviours, gender related frailty) that may explain observed variation in the cost-effectiveness of the OEP as a secondary falls prevention strategy. TRIAL REGISTRATIONS: ClinicalTrials.gov Protocol Registration System Identifier: NCT01029171; URL: https://clinicaltrials.gov/ct2/show/NCT01029171 Identifier: NCT00323596; URL: https://clinicaltrials.gov/ct2/show/NCT00323596.

Mind the gaps: functional networks disrupted by white matter hyperintensities are associated with greater falls risk.

White matter hyperintensities (WMH) are associated with greater falls risk and slow gait speed. Whether these deficits are caused by the disruption of large-scale functional networks remains inconclusive. Further, physical activity moderates the association between WMHs and falls, but whether this extends to the disruption of functional networks remains unknown. One hundred and sixty-four adults (>55 years old) were included in this study. Using lesion network mapping, we identified significant correlations between the percentage of WMH-related disruption of the dorsal attention network and Physiological Profile Assessment (PPA) score (r = 0.24, p < 0.01); and between disruption of both the sensorimotor (r = 0.23, p < 0.01) and ventral attention networks (r = 0.21, p = 0.01) with foam sway. There were no significant associations with floor sway or gait speed. Physical activity moderated the association between the dorsal attention network and PPA score (p = 0.045). Thus, future research should investigate whether physical activity should be recommended in the clinical management of older adults with cerebral small vessel disease.

Sweat the Fall Stuff: Physical Activity Moderates the Association of White Matter Hyperintensities With Falls Risk in Older Adults.

Background: Falls in older adults are a major public health problem. White matter hyperintensities (WMHs) are highly prevalent in older adults and are a risk factor for falls. In the absence of a cure for WMHs, identifying potential strategies to counteract the risk of WMHs on falls are of great importance. Physical activity (PA) is a promising countermeasure to reduce both WMHs and falls risk. However, no study has yet investigated whether PA attenuates the association of WMHs with falls risk. We hypothesized that PA moderates the association between WMHs and falls risk. Methods: Seventy-six community-dwelling older adults aged 70-80 years old were included in this cross-sectional study. We indexed PA using the Physical Activity Score for the Elderly (PASE) Questionnaire. Falls risk was assessed using the Physiological Profile Assessment (PPA), and WMH volume (mm3) was determined by an experienced radiologist on T2-weighted and PD-weighted MRI scans. We first examined the independent associations of WMH volume and PASE score with PPA. Subsequently, we examined whether PASE moderated the relationship between WMH volume and PPA. We plotted simple slopes to interpret the interaction effects. Age, sex, and Montreal Cognitive Assessment (MoCA) score were included as covariates in all models. Results: Participants had a mean age of 74 years (SD = 3 years) and 54 (74%) were female. Forty-nine participants (66%) had a Fazekas score of 1, 19 (26%) had a score of 2, and 6 (8%) a score of 3. Both PASE (ß = -0.26 ± 0.11; p = 0.022) and WMH volume (ß = 0.23 ± 0.11; p = 0.043) were each independently associated with PPA score. The interaction model indicated that PASE score moderated the association between WMH volume and PPA (ß = -0.27 ± 0.12; p = 0.030), whereby higher PASE score attenuated the association between WMHs and falls risk. Conclusion: PA is an important moderator of falls risk. Importantly, older adults with WMH can reduce their risk of falls by increasing their PA.

Painting by lesions: White matter hyperintensities disrupt functional networks and global cognition.

White matter hyperintensities (WMH) are a prominent feature of cerebral small vessel disease and are associated with cognitive impairment. These deficits in cognition may be caused by the disruption of large-scale functional networks due to the presence of WMHs. However, knowledge regarding the relevance of these lesions on functional networks remains inconclusive. These inconsistencies may derive from issues with interpreting functional imaging data from clinical populations. Lesion network mapping is a technique that allows the overlaying of lesions from a patient population to the functional connectivity of a human connectome derived from healthy adults. This allows researchers to identify functional networks that would be disrupted in a healthy population should the WMHs seen in cerebral small vessel disease be present. We hypothesized that the extent to which these functional networks are disrupted by WMHs is associated with cognitive performance in older adults with cerebral small vessel disease. This cross-sectional study combined baseline data from four studies to create a total sample of 164 older adults (aged ≥55) from metropolitan Vancouver with cerebral small vessel disease. Using lesion network mapping, we assessed the percentage overlap between voxels functionally connected with both the WMHs (lesion network) and five common functional networks: (1) visual; (2) dorsal attention; (3) ventral attention; (4) sensorimotor; and (5) frontoparietal. Cognition was assessed using: (1) Montreal Cognitive Assessment (MoCA); (2) Stroop Colour Word Test (3-2); (3) Trail Making Tests (Part B-A); and (4) Digit Symbol Substitution Test. A One-Way ANOVA and Tukey post-hoc tests were performed to identify the functional networks with greatest percentage overlap with the lesion network. Partial correlations controlling for age were used to analyse whether the extent of the overlap between the lesion and functional networks was associated with poorer cognition. The visual, ventral attention, and frontoparietal networks had significantly greater overlap with the lesion network. After controlling for multiple comparisons, level of lesion network overlap with both the sensorimotor network (p<.001) and ventral attention network (p <. 001) was significantly correlated with MoCA score. Thus, the greater the disruption to the sensorimotor and ventral attention networks, the poorer the global cognition. Our results reveal that the visual, ventral attention, and frontoparietal networks are most vulnerable to disruptions stemming from WMHs. Additionally, we identified that disruption to the sensorimotor and ventral attention networks, as a result of WMHs, may underlie deficits in global cognition in older adults with cerebral small vessel disease.

Functional Connectivity and Response Inhibition: A Secondary Analysis of an 8-Week Randomized Controlled Trial of Computerized Cognitive Training.

BACKGROUND: Evidence suggests that computerized cognitive training (CCT) can improve cognitive function in older adults, particularly executive functions. However, the underlying mechanisms by which CCT may improve executive functions are not well established. OBJECTIVE: To determine: 1) inter-network functional connectivity correlates of changes in executive functions; and 2) the effect of CCT on these functional connectivity correlates. METHODS: This secondary analysis included a subset of 124 adults aged 65-85 years enrolled in an 8-week randomized controlled trial of CCT. Participants were randomized to either: 1) group-based CCT 3x/week for 1 hour plus 3x/week home-based training; 2) group-based CCT preceded by brisk walking (Ex+CCT) 3x/week for 1 hour plus 3x/week home-based training; or 3) group-based balanced and toned (BAT) classes 3x/week for 1 hour (control). At baseline and trial completion, 65 of the 124 participants completed resting-state functional magnetic resonance imaging and neuropsychological tests of executive functions, specifically the Stroop Colour-Word Test and Flanker Test. RESULTS: Improved performance on the Stroop Colour-Word Test and Flanker Test were associated with decreased correlation between the default mode network (DMN) and the fronto-parietal network (FPN) (p < 0.05). Compared with BAT, CCT alone significantly decreased correlation between the left dorsolateral prefrontal cortex and both the left and right medial temporal gyrus (-0.143, 95%CI [-0.256,-0.030], p = 0.014, and -0.123, 95%CI [-0.242,-0.004], p = 0.043, respectively). CONCLUSION: Decreased correlation between DMN and FPN, indicating less connection between these networks, may be an underlying mechanism by which CCT improves executive functions. Future studies are needed to replicate this finding.

Early fixation failure of locked plating in complex distal femoral fractures: Root causes analysis.

BACKGROUND/PURPOSE: Orthopaedic Trauma Association (OTA) C-type distal femoral fractures can be very challenging to treat effectively. While locked plating is widely used in the complex distal femoral fracture, failure of locked plate fixation is not uncommon. First, we tried to determine the risk factor related to early failure of multiplanar OTA C-type fracture in the distal femur after fixation with lateral locked plate. Second, we tried to provide a strategy for surgeons to prevent pitfalls of early failure in the complex distal femoral fractures treated with lateral locked plating. METHODS: We retrospectively reviewed 44 adults with OTA C-type fractures of the distal femur treated with locked plate fixation between 2010 and 2016 at Tri-Service General Hospital. Average length of follow-up was 27.6 months (range, 12-54 months). Univariate and multivariate logistic regression were used to determine the association of variables on early failure of fixation. A p-value < 0.05 in univariate and multivariate analyses were considered significant. RESULTS: There were six patients experiencing early failure, and the early failure rate was 13.6%. The risk factors associated with early failure of complex distal femoral fracture identified by univariate analysis included sagittal oblique fracture pattern, longer working length and post-operative sagittal malalignment (odds ratio [OR] and 95% confidence intervals [CI]: 90.00 (6.85-1183.33), 0.55 (0.31-0.98) and 8.63 (1.077-69.075) respectively). The multivariate analysis showed only sagittal oblique fracture pattern was associated with early failure [OR: 52.348 (3.06-895.23)]. CONCLUSION: Sagittal oblique fracture was more likely to result in early postoperative failure. Early recognition of the fracture pattern should be considered to avoid catastrophic results.