Mary Beth Spitznagel

Relationship Between Body Mass Index and Brain Volume in Healthy Adults

There is a growing evidence that elevated body mass index (BMI) is associated with adverse neurocognitive outcome, though no study has examined whether morphometric differences are found in persons across the adult life span. We compared 201 healthy individuals in normal weight, overweight, and obese groups (aged 17–79). After correcting for demographic differences, obese individuals showed smaller whole brain and total gray matter volume than normal weight and overweight individuals. These findings support an independent relationship between BMI and brain structure and demonstrate that these differences are not limited to older adults.

Exposure to early life trauma is associated with adult obesity

Exposure to traumatic events during childhood is associated with an elevated risk of adult obesity. It has been hypothesized that the psychological sequelae from childhood trauma account for this risk, though no study has examined whether an increased risk of obesity is found in persons without psychological disorders. We examined exposure to early life stressors and body mass index (BMI) in 696 adults without significant medical or psychiatric history. Bivariate correlation showed that the total number of early life stressors (r=0.08), age (r=0.19), and sex (r=0.16) were significantly related to adult BMI. Given the relationship between sex and BMI, we examined the contribution of early life stressors to adult obesity separately for men and women. In men, hierarchical regression showed that exposure to early life stressors predicted adult obesity. Specifically, history of being bullied/rejected (Obese 31%, Normal weight, 9%) and emotional abuse (Obese, 17%; Normal weight, 2%) predicted adult obesity after controlling for the effects of age. In women, no relationship between early life stressors and adult obesity was found. These findings suggest that multiple processes mediate the relationship between early life stress and adult obesity and that their relative contributions may differ between men and women.

BDNF Val66Met Polymorphism Is Associated with Body Mass Index in Healthy Adults

Although recent studies suggest a possible relationship between the brain-derived neurotrophic factor Val66Met polymorphism and eating disorders, no study has examined the possibility that the Met-Met genotype is associated with a lower body mass index (BMI) in healthy individuals. We examined this possibility in 481 adults (age range 18–82 years) without significant medical or psychiatric history. After adjusting for gender, analysis of covariance showed that persons with the Met-Met genotype had a lower BMI than those with the Val-Met/Val-Val genotypes (22.28 ± 3.77 vs. 24.72 ± 4.81). A similar, though nonsignificant, trend emerged when comparing all three genotypes separately. These findings suggest a possible relationship between Val66Met polymorphism and BMI in healthy adults. Further work is needed to clarify possible mechanisms for this relationship.

Cerebral Perfusion is Associated With White Matter Hyperintensities in Older Adults With Heart Failure

Cognitive impairment is common in heart failure (HF) and believed to be the result of cerebral hypoperfusion and subsequent brain changes including white matter hyperintensities (WMHs). The current study examined the association between cerebral blood flow and WMHs in patients with HF and the relationship between WMHs and cognitive impairment. Sixty-nine patients with HF completed the Mini-Mental State Examination (MMSE) and underwent echocardiography, transcranial Doppler sonography for cerebral blood flow velocity of the middle cerebral artery, and brain magnetic resonance imaging. Multivariable hierarchical regression analyses controlling for medical and demographic characteristics as well as intracranial volume showed reduced cerebral blood flow velocity of the middle cerebral artery was associated with greater WMHs (β=-0.34, P=.02). Follow-up regression analyses adjusting for the same medical and demographic factors in addition to cerebral perfusion also revealed marginal significance between increased WMHs and poorer performance on the MMSE (β=-0.26, P=.05). This study suggests that reduced cerebral perfusion is associated with greater WMHs in older adults with HF. These findings support the widely proposed mechanism of cognitive impairment in HF patients and prospective studies are needed to confirm these results.

Cognitive function and treatment adherence in older adults with heart failure.

Objective Treatment recommendation and guidelines for patients with heart failure (HF) can be complex, and past work has shown that patients with HF demonstrate low rates of adherence to recommended health behaviors. Although previous work has identified several medical, demographic, and psychosocial predictors of the capacity to adhere to treatment recommendations of persons with HF, little is known about the contribution of cognitive impairment to reported treatment adherence in this population. Methods A total of 149 persons with HF (mean [standard deviation] = 68.08 [10.74] years) completed a brief fitness assessment and neuropsychological testing. Treatment adherence was assessed using the Heart Failure Compliance Questionnaire, a brief measure that asks participants to report their adherence to a variety of recommended health behaviors (i.e., medication management, diet, and exercise, among others). Results The percentage of participants who reported poor overall adherence was 16.1%, with particularly high rates of nonadherence to dietary and exercise recommendations. Hierarchical regression analyses adjusting for possible confounds revealed that reduced performance on attention (&bgr; = .26, p = .01), executive function (&bgr; = .18, p = .04), and language (&bgr; = .22, p = .01) was associated with poorer overall adherence. Follow-up analyses showed that these cognitive domains were associated with behaviors such as keeping doctor appointments, medication management, and dietary recommendations (p < .05 for all). Conclusions The current findings demonstrate that cognitive function is an independent contributor to adherence in older adults with HF. Prospective studies that objectively measure treatment adherence are needed to clarify these findings and identify possible strategies to improve outcomes in this population. Trial Registration: clinicaltrials.gov Identifier: NCT00871897.

Improvements in Cognitive Function Following Cardiac Rehabilitation for Older Adults With Cardiovascular Disease

ABSTRACT Cognitive impairment is common in persons with cardiovascular disease (CVD). Cardiac rehabilitation (CR) improves many aspects of CVD linked to cognitive impairment. The current study explored whether CR may improve cognitive function. Potential mechanisms for cognitive changes were also examined through exploratory analyses, including changes in cardiovascular fitness and cerebral blood flow. Fifty-one older adults with CVD underwent neuropsychological assessment at baseline and discharge from a 12-week CR program. Cardiovascular fitness (i.e., metabolic equivalents [METs]) was estimated from a symptom-limited volitional stress test. Transcranial doppler quantified mean cerebral blood flow velocity and pulsatility indexes for the middle cerebral artery and anterior cerebral artery (ACA). Repeated measures ANOVA showed improvements in global cognition, attention-executive-psychomotor function, and memory. Exploratory analyses revealed improvement in METs and changes in ACA flow velocity, but only improvement in METs was related to improved verbal recall. CVD patients exhibited improvements in multiple cognitive domains following a 12-week CR program, suggesting that cognitive impairment is modifiable in this population. Although other studies are needed to elucidate underlying mechanisms, exploratory analyses suggest that cognitive improvements may be better explained by physiological processes other than improved cardiovascular fitness and cerebral blood flow.

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

OBJECTIVEnReduced 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.nnnMETHODSnAt 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.nnnRESULTSnAccelerometer 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.nnnCONCLUSIONnConsistent 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.

Depression is associated with cognitive dysfunction in older adults with heart failure.

Persons with heart failure (HF) frequently exhibit cognitive impairment with deficits in attention and memory. Depression is common in HF though its possible contribution to cognitive impairment is unknown. Cognitive dysfunction and depression may share common mechanisms in HF, as both are associated with similar abnormalities on neuroimaging. A total of 116 participants with HF (68.53 ± 9.30 years) completed a neuropsychological battery and self-report measures of depression. Regression models showed depression incrementally and independently predicted test performance in all cognitive domains. Follow-up partial correlations revealed that greater depressive symptoms were associated with poorer performance on tests of attention, executive function, psychomotor speed, and language. These results indicate that depressive symptoms are associated with poorer cognitive performance in HF though further work is needed to clarify mechanisms for this association and possible cognitive benefits of treating depression in persons with HF.

Sleep apnea and cognitive function in heart failure

Background. Prior research indicates that heart failure (HF) patients exhibit significant cognitive deficits on neuropsychological testing. Sleep apnea is associated with both HF and reduced cognitive function, but the combined impact of these conditions on cognitive function is unknown. Methods. In the current study, 172 older adults with a dual diagnosis of HF and sleep apnea or HF alone completed a battery of cognitive tests measuring attention, executive functioning, and memory. Results. Relative to patients with HF alone, persons with both HF and sleep apnea performed worse on measures of attention after adjusting for demographic and medical variables. Conclusions. The current findings suggest that HF patients with comorbid sleep apnea may be at greater risk for cognitive impairment relative to HF patient without such history. Further work is needed to clarify mechanisms for these findings and to determine whether the interactive effects on cognitive function lead to poorer patient outcomes.

Handedness and cognition across the healthy lifespan.

The relationship between handedness and cognitive function varies across studies, perhaps partly due to the many medical and psychiatric conditions with known cognitive impact. This study examined cognitive performance in 643 healthy individuals (age 5–82) who were categorized as strongly right-handed, moderately right-handed, or left/mixed-handed. Cognitive differences emerged, as left/mixed-handed individuals demonstrating superior psychomotor speed and cognitive flexibility, and strongly and moderately right-handed individuals exhibiting better time estimation skills. No interaction-among handedness, sex, and age were found. These findings indicate cognitive differences associated with handedness exist independent of medical and psychiatric confounds. Further work is needed to clarify these findings.