Lindsay A. Miller

Cognitive function predicts weight loss after bariatric surgery.

BACKGROUND Clinically significant cognitive impairment is found in a subset of patients undergoing bariatric surgery. These difficulties could contribute to a reduced adherence to postoperative lifestyle changes and decreased weight loss. The present study is the first to prospectively examine the independent contribution of cognitive function to weight loss after bariatric surgery. Executive function/attention and verbal memory at baseline were expected to negatively predict the percentage of excess weight loss (%EWL) and body mass index (BMI) at follow-up. Three sites of the Longitudinal Assessment of Bariatric Surgery parent project were used: Columbia (New York, NY), Cornell (Princeton, NJ), and the Neuropsychiatric Research Institute (Fargo, ND). METHODS A total of 84 individuals enrolled in the Longitudinal Assessment of Bariatric Surgery project undergoing bariatric surgery completed a cognitive evaluation at baseline. The BMI and %EWL were calculated at the 12-week and 12-month postoperative follow-up visits. RESULTS Clinical impairment in task performance was most prominent in tasks associated with verbal recall and recognition (14.3-15.5% of the sample) and perseverative errors (15.5%). After accounting for demographic and medical variables, the baseline test results of attention/executive function and memory predicted the BMI and %EWL at 12 months but not at 12 weeks. CONCLUSIONS These results have demonstrated that baseline cognition predicts for greater %EWL and lower BMI 12 months after bariatric surgery. Additional work is needed to clarify the degree to which cognition contributes to adherence and the potential mediation of cognition on the relationship between adherence and weight loss in this group.

Depression is associated with reduced physical activity in persons with heart failure.

OBJECTIVE Reduced physical activity is common in persons with heart failure (HF). However, studies of correlates and modifiers of physical activity in this population rarely employ objective measures. Motivational and mood related factors that may exacerbate inactivity in HF patients are also rarely investigated. In this study, we examined the relationship between physical activity as assessed by accelerometry, and depression in older adults with HF. METHODS At baseline, older adults with HF (N = 96; 69.81 ± 8.79) wore an accelerometer for seven days, and completed a brief fitness assessment, neuropsychological testing, and psychosocial measures including the Beck Depression Inventory-II (BDI-II). Medical and demographic history was obtained through record review and self-report. RESULTS Accelerometer measures showed that HF patients averaged 587 minutes of sedentary time and just 0.31 minutes of vigorous activity per day. Lower daily step count was associated with poorer quality of life and reduced cognitive function. A multiple linear regression adjusting for important demographic and medical variables found that greater number of depressive symptoms on the BDI-II independently predicted lower physical activity levels. CONCLUSION Consistent with past work, the current study found that low physical activity is common in older adults with HF. Depression is an independent predictor of physical activity in older adults with HF and reduced physical activity is associated with numerous adverse psychosocial outcomes. Future studies need to determine whether treatment of depression can boost physical activity and thus improve health outcomes in this population.

Both Texting and Eating Are Associated With Impaired Simulated Driving Performance

Objective: Distracted driving is a known contributor to traffic accidents, and many states have banned texting while driving. However, little is known about the potential accident risk of other common activities while driving, such as eating. The objective of the current study was to examine the adverse impact of eating/drinking behavior relative to texting and nondistracted behaviors on a simulated driving task. Methods: A total of 186 participants were recruited from undergraduate psychology courses over 2 semesters at Kent State University. We utilized the Kent Multidimensional Assessment Driving Simulation (K-MADS) to compare simulated driving performance among participants randomly assigned to texting (N = 45), eating (N = 45), and control (N = 96) conditions. Multivariate analyses of variance (MANOVA) were conducted to examine between-group differences on simulated driving indices. Results: MANOVA analyses indicated that groups differed in simulated driving performance, F(14, 366) = 7.70, P < .001. Both texting and eating produced impaired driving performance relative to controls, though these behaviors had approximately equal effect. Specifically, both texting and eating groups had more collisions, pedestrian strikes, and center line crossings than controls. In addition, the texting group had more road edge excursions than either eating or control participants and the eating group missed more stop signs than controls. Conclusions: These findings suggest that both texting and eating are associated with poorer simulated driving performance. Future work is needed to determine whether these findings generalize to real-world driving and the development of strategies to reduce distracted driving.

Road Test and Naturalistic Driving Performance in Healthy and Cognitively Impaired Older Adults: Does Environment Matter?

To relate the standardized road test to video recordings of naturalistic driving in older adults with a range of cognitive impairment.

Neurocognitive Effects of Obesity and Bariatric Surgery.

This review paper will discuss the recent literature examining the relationship between obesity and neurocognitive outcomes, with a particular focus on cognitive changes after bariatric surgery. Obesity is now recognized as an independent risk factor for adverse neurocognitive outcomes, and severely obese persons appear to be at even greater risk. Bariatric surgery is associated with rapid improvements in cognitive function that persist for at least several years, although the mechanisms underlying these improvements are incompletely understood. Assessment of cognitive impairment in bariatric surgery patients is challenging, and improved methods are needed, as poorer performance on neuropsychological tests of memory and executive function leads to poorer clinical weight outcomes. In addition to its clinical importance, further study in this area will provide key insight into obesity-related cognitive dysfunction and clarify the possibility of an obesity paradox for neurological outcomes.

Acute cold exposure and cognitive function: evidence for sustained impairment

Several industries experience periods of cold exposure and rewarming throughout the workday but mental performance under these conditions is unknown. A better understanding of cognition during the rewarming phase after cold exposure may help reduce accidents and improve performance. Ten young men (wearing ∼0.1 clo) underwent three consecutive mornings trials where they were exposed to cold air (10°C) and then subsequently rewarmed (25°C air). A computerised test battery was administered during each stage of the protocol to determine working memory, choice reaction time, executive function and maze navigation. Rectal and skin temperature, oxygen consumption and thermal sensation were also measured throughout and showed a typical response. Relative to baseline performance, working memory, choice reaction time and executive function declined during exposure to 10°C, and these impairments persisted 60 min into the recovery period (i.e. once physiological parameters had returned to baseline). Further work is needed to develop countermeasures to this predicament. Practitioner Summary: This study showed that working memory, choice reaction time and executive function declined during exposure to 10°C air, and these impairments persisted 60 min into the rewarming period (i.e. once measurable physiological parameters had returned to normal). Individuals may be at risk for injury after removal from a cold environment.

Cognitive Profiles in Heart Failure: A Cluster Analytic Approach

Cognitive impairment is common among individuals with heart failure (HF), but the exact nature of these impairments remains unclear. The current study examined 140 older adults with heart failure and sought to determine whether there are distinct cognitive profiles using a cluster analytic approach. Results indicated three unique profiles comprising individuals who were cognitively intact, memory impaired, and globally impaired. Clusters differed on several important demographic and clinical characteristics. These findings suggest that cognitive impairment in persons with HF is more heterogeneous than commonly believed and has important implications for treatment recommendations.

Structured Exercise Does Not Stabilize Cognitive Function in Individuals with Mild Cognitive Impairment Residing in a Structured Living Facility

ABSTRACT Exercise has been shown to have positive effects on the brain and cognition in healthy older adults, though no study has directly examined possible cognitive benefits of formal exercise programs in persons with mild cognitive impairment (MCI) living in structured facilities. Thirty-one participants completed neuropsychological testing and measures of cardiovascular fitness at baseline and after 6 months of a structured exercise program that included aerobic and resistance training. While exercise improved cardiovascular fitness in persons with MCI, there was no improvement in cognitive function. Rather, MCI patients in this sample declined in performance on several tests sensitive to Alzheimers disease. Examined in the context of past work, it appears exercise may be beneficial prior to the onset of MCI, though less helpful after its onset.

Effects of cholinesterase inhibitors on visual attention in drivers with Alzheimer disease

Objective: We conducted a combined observational cohort and case-control study in patients with Alzheimer disease (AD) to assess the effects of acetylcholinesterase inhibitor (ChEI) treatment on cognitive functions important for driving. Methods: Performance of 24 outpatients with newly diagnosed (untreated) early-stage AD was compared before beginning ChEI (pre-ChEI) and after 3 months of therapy (post-ChEI) on a set of computerized tests of visual attention and executive function administered under both single-task and dual-task conditions. To address the limitation of a lack of an untreated control group in this observational cohort study, performance of 35 outpatients with newly diagnosed (untreated) early-stage AD (ChEI nonusers) were also compared with a demographically matched group of AD patients treated with stable doses of a ChEI (ChEI users) on these tasks. Results: Performance was consistently worse under dual-task than single-task conditions regardless of ChEI treatment status. However, ChEI treatment consistently affected specific components of attention within each test across both sets of comparisons: ChEI treatment enhanced simulated driving accuracy and was associated with significantly better visual search target detection accuracy and response time in both pre-ChEI-post-ChEI and users-nonusers treatment comparisons. Cholinesterase inhibitor treatment also improved overall time to complete a set of mazes while not affecting accuracy of completion. Conclusions: Cholinesterase inhibitor treatment was associated with improvements in tests of executive function and visual attention. These findings could have important implications for patients who continue to drive in the early stages of AD.

Greater physical activity is associated with better cognitive function in heart failure.

OBJECTIVE Nearly 6 million Americans have heart failure (HF), up to 80% of which exhibit cognitive deficits on testing. Physical inactivity is common in HF, yet little is known about the possible contribution of physical inactivity to cognitive dysfunction in this population. METHOD Older adults with HF (N = 93; Mage = 68.5 years, 33.7% women) completed neuropsychological testing, as well as cardiac and physical activity assessment as part of a larger protocol. HF severity was measured via impedance cardiography. Physical activity was assessed via an Actigraph accelerometer and operationalized using daily step count and time engaged in moderate-vigorous activity (minutes/day). RESULTS Linear regression analyses controlling for sex, high blood pressure, diabetes, depressive symptomatology, and HF severity showed that greater physical activity (both step count and minutes spent in moderate-vigorous activity) was associated with better executive function/attention, processing speed, and scores on a screening measure of cognition. CONCLUSIONS These findings indicate that physical activity is an independent predictor of cognitive function in persons with HF. Future work is needed to clarify the mechanisms by which physical activity benefits cognitive function in HF and determine whether interventions to promote physical activity can attenuate cognitive decline over time.