Accelerometry measures of physical activity and sedentary behavior: Associations with cognitive functioning in MS

BACKGROUND

Cognitive dysfunction is a pervasive symptom of multiple sclerosis (MS). Correlational evidence on the relationships between physical activity, sedentary behavior, and cognition has been mixed and limited to a few activity measures. The collinearity of accelerometry-based metrics has precluded an assessment of the full activity spectrum. Here, we aimed to examine the rich set of activity measures using analytic approaches suitable for collinear metrics. We investigated the combination of physical activity, sedentary, and clinicodemographic measures that explain the most variance in composite scores of working memory/processing speed, visual memory, and verbal memory.

METHODS

We analyzed baseline accelerometry and neuropsychological data (n = 80) from a randomized controlled trial of pedometer tracking. Using partial least squares regression (PLSR), we built three models to predict latent scores on the three domains of cognition using 12 activity metrics, sex, education, and Expanded Disability Status Scale (EDSS) scores. Significance was assessed using linear regression models with model component scores as predictors and cognitive composites as outcomes.

RESULTS

The latent component was significant for working memory/processing speed but was not significant for visual memory and verbal memory after Bonferroni correction. Working memory/processing speed was positively associated with average kilocalories, moderate-to-vigorous physical activity (MVPA), steps, and sex (i.e., higher scores in males) and negatively related to duration of long sedentary bouts and EDSS.

CONCLUSIONS

These findings suggest that increasing overall energy expenditure through walking and MVPA, while decreasing prolonged sedentary time may positively benefit working memory/processing speed in people with MS.

TRIAL REGISTRATION

This RCT #NCT03244696 was registered on Clinicaltrials.gov (https://www.

CLINICALTRIALS

gov/ct2/show/NCT03244696).

Protocol for a randomized controlled trial of mindfulness-based stress reduction to improve attentional control in older adults (HealthyAgers trial)

BACKGROUND

Mindfulness meditation is a form of mind-body intervention that has increasing scientific support for its ability to reduce age-related declines in cognitive functioning, improve affective health, and strengthen the neural circuitry supporting improved cognitive and affective health. However, the majority of existent studies have been pilot investigations with small sample sizes, limited follow-up data, and a lack of attention to expectancy effects. Here, we present the study design of a Phase I/II, efficacy trial-HealthyAgers trial-that examines the benefits of a manualized mindfulness-based stress reduction program in improving attentional control and reducing mind-wandering in older adults.

METHODS

One hundred fifty older adults (ages 65-85 years) will be randomized into one of two groups: an eight-week mindfulness program or an eight-week, placebo-controlled, lifestyle education program. Behavioral and neuroimaging assessments are conducted before and after the training. Participants are then invited to booster sessions once every three months for a period of 12 months with post-intervention follow-up assessments conducted at 6-months and 12-months. The primary outcomes for the study are behavioral measures of attentional control and mind-wandering. Additional, secondary outcomes include network strength in an a priori defined neuromarker of attentional control, fluid and everyday cognition, emotion regulation strategy use, and markers of inflammation.

DISCUSSION

This study will establish the efficacy of a group-based, low-cost mind-body intervention for the inter-related facets of attentional control and mind-wandering in older adults. Strengths of this study include a well-designed, placebo-controlled comparison group, use of web/mobile application to track study adherence, and longitudinal follow-up.

TRIAL REGISTRATION

Clinicaltrials.gov (# NCT03626532 ). Registered August 4, 2018.

Time-Varying Functional Connectivity Decreases as a Function of Acute Nicotine Abstinence

BACKGROUND

The nicotine withdrawal syndrome (NWS) includes affective and cognitive disruptions whose incidence and severity vary across time during acute abstinence. However, most network-level neuroimaging uses static measures of resting-state functional connectivity and assumes time-invariance and is thus unable to capture dynamic brain-behavior relationships. Recent advances in resting-state functional connectivity signal processing allow characterization of time-varying functional connectivity (TVFC), which characterizes network communication between networks that reconfigure over the course of data collection. Therefore, TVFC may more fully describe network dysfunction related to the NWS.

METHODS

To isolate alterations in the frequency and diversity of communication across network boundaries during acute nicotine abstinence, we scanned 25 cigarette smokers in the nicotine-sated and abstinent states and applied a previously validated method to characterize TVFC at a network and a nodal level within the brain.

RESULTS

During abstinence, we found brain-wide decreases in the frequency of interactions between network nodes in different modular communities (i.e., temporal flexibility). In addition, within a subset of the networks examined, the variability of these interactions across community boundaries (i.e., spatiotemporal diversity) also decreased. Finally, within 2 of these networks, the decrease in spatiotemporal diversity was significantly related to NWS clinical symptoms.

CONCLUSIONS

Using multiple measures of TVFC in a within-subjects design, we characterized a novel set of changes in network communication and linked these changes to specific behavioral symptoms of the NWS. These reductions in TVFC provide a meso-scale network description of the relative inflexibility of specific large-scale brain networks during acute abstinence.

Nicotine Abstinence Influences the Calculation of Salience in Discrete Insular Circuits

BACKGROUND

Insular subdivisions show distinct patterns of resting-state functional connectivity (rsFC) with specific brain regions, each with different functional significance. Seeds in these subdivisions are employed to characterize the effects of acute nicotine abstinence on rsFC between insula subdivisions and brain networks implicated in addiction and attentional control.

METHODS

In a within-subjects design, resting-state blood oxygen level-dependent data were collected from treatment-seeking smokers (N= 20) following smoking satiety and again following 48 hours of nicotine abstinence. Three right hemisphere insular regions of interest (dorsal, ventral, and posterior) served as seeds for analyses. Indices of both static and dynamic rsFC were obtained and correlated with indices of subjective withdrawal and behavioral performance.

RESULTS

Abstinence-induced physiological, subjective, and cognitive differences were observed. Overall dynamic rsFC was reduced during abstinence, and circuits containing each insular seed showed changes in rsFC as a function of nicotine abstinence. Specifically, dorsal and posterior insular connections to the default mode and salience networks were enhanced, while a previously undescribed ventral insular connection to the executive control network was reduced. Further, static rsFC was significantly correlated with subjective ratings of aversive affect and withdrawal in the modified ventral and posterior insular-seeded circuits.

CONCLUSIONS

As predicted, divergent connections between insula subdivisions and anticorrelated resting brain networks were observed during abstinence. These changes reflect an attentional bias toward aversive affective processing and not directly away from exogenous cognitive processing, suggesting a coordinated modulation of circuits associated with interoceptive and affective processing that instantiates an aversive state during nicotine abstinence.

Melanoma and non-Melanoma Skin Cancer in Inflammatory Bowel Disease Patients following Tumor Necrosis Factor-α Inhibitor Monotherapy and in Combination with Thiopurines: Analysis of the Food and Drug Administration Adverse Event Reporting System

Background & Aims: Reports have shown an increased risk of melanoma skin cancer (MSC) with exposure to tumor necrosis factor alpha (TNF-α) inhibitors and non-melanoma skin cancer (NMSC) with thiopurine exposure in inflammatory bowel disease (IBD) patients. Using the Food and Drug Administration Adverse Event Reporting System (FAERS) we sought to evaluate the odds of developing MSC and NMSC for patients on TNF-α inhibitors as monotherapy and in combination therapy with thiopurines and/or steroids.Methods: The FAERS was queried for reports between January 2003 and June 2012. A proportional reporting ratio (PRR) metric analyses was performed on the data to determine the odds of developing MSC and NMSC.Results: The PRR analysis showed increased odds of developing MSC and NMSC for patients on a TNF-α inhibitor (p-value = 0.035 and p-value = 0.03, respectively) and those on a TNF-α inhibitor in combination with a thiopurine (p-value < 0.001 and p-value < 0.001).Conclusion: TNF-α inhibitor monotherapy or use with concomitant thiopurines in patients with IBD is associated with higher odds of developing MSC and NMSC.