Executive Functioning in Extreme Obesity: Contributions from Metabolic Status, Medical Comorbidities, and Psychiatric Factors.

PURPOSE: Extreme obesity has been associated with cognitive deficits across the lifespan and may be a risk factor for dementia in later life. However, the relationship between obesity and domain-specific cognitive deficits is complicated by a body of literature that often fails to adequately account for medical and psychiatric conditions frequently co-occurring with extreme obesity. MATERIALS AND METHODS: The present study included a cross-sectional evaluation of adults with extreme obesity (n=117) compared to lean control (n=46) participants on a brief cognitive battery using the NIH Toolbox and Rey Auditory Verbal Learning Test. Specifically, this study evaluated measures of executive functioning, attention, processing speed, learning, and memory while accounting for many common obesity-related medical and psychiatric comorbidities with known cognitive effects. RESULTS: Results revealed group differences with lower performances on measures of executive functioning, processing speed, and learning (ps<0.01) for participants with obesity. Reduced executive functioning was associated with abdominal obesity and medication use (ps<0.01) and together contributed significantly to overall modeling of cognition in individuals with obesity. CONCLUSION: Individuals with extreme obesity in this sample showed lower cognitive performance on measures of executive functioning, processing speed, and learning compared to lean controls. Abdominal obesity was associated with executive functioning deficits independent of many common medical and psychiatric factors.

Capacity to consent to research participation in adults with metastatic cancer: comparisons of brain metastasis, non-CNS metastasis, and healthy controls.

BACKGROUND: To evaluate the ability of individuals with metastatic cancer to provide informed consent to research participation, we used a structured vignette-based interview to measure 4 consenting standards across 3 participant groups. METHODS: Participants included 61 individuals diagnosed with brain metastasis, 41 individuals diagnosed with non-CNS metastasis, and 17 cognitively intact healthy controls. All groups were evaluated using the Capacity to Consent to Research Instrument (CCRI), a performance-based measure of research consent capacity. The ability to provide informed consent to participate in research was evaluated across 4 consent standards: expressing choice, appreciation, reasoning, and understanding. Capacity performance ratings (intact, mild/moderate impairment, severe impairment) were identified based on control group performance. RESULTS: Results revealed that the brain metastasis group performed significantly lower than healthy controls on the consent standard of understanding, while both metastatic cancer groups performed below controls on the consent standard of reasoning. Both metastatic cancer groups performed similar to controls on the standards of appreciation and expressing choice. Approximately 60% of the brain metastasis group, 54% of the non-CNS metastasis group, and 18% of healthy controls showed impaired research consent capacity. CONCLUSIONS: Our findings, using a performance-based assessment, are consistent with other research indicating that the research consent process may be overly cumbersome and confusing. This, in turn, may lead to research consent impairment not only in patient groups but also in some healthy adults with intact cognitive ability.

Clinical correlates of the ability to consent to research participation in brain metastasis.

OBJECTIVE: Impairment in the ability to provide informed consent is common in persons with brain metastasis. However, little is known about what factors contribute to this impairment in the patient group. Our objective is to determine if the associations between demographic, cognitive, and clinical variables correlate with the ability to provide informed consent in persons with brain metastasis. METHODS: We administered a comprehensive neuropsychological battery to a group of 61 persons with brain metastasis. Demographic and clinical information was also collected. All diagnoses were made by board-certified oncologists and were verified histologically. Statistical analyses included Pearson's product-moment correlations, point biserial correlations, and linear regression. RESULTS: Results indicated that combinations of education, verbal memory, executive function, whole brain radiation therapy, and chemotherapy affected various aspects of the ability to provide informed consent. Subsequent regression models demonstrated that these variables contributed a significant amount of shared variance to the ability to provide informed consent. CONCLUSION: We found that the ability of persons with brain metastasis to provide informed consent is a cognitively complex ability that is also affected by education and treatment variables. This information can help clinical researchers in identifying persons with brain metastasis at risk of an impaired ability to provide informed consent and aid in the consenting process.

Using cognition to predict the ability to understand medical treatment in brain and metastatic cancer.

OBJECTIVE: To determine if cognition can be used to identify persons with cancer at high risk for the impaired ability to understand treatment decisions. METHODS: The association between understanding treatment decisions and cognition was examined using data from 181 participants across four groups: 67 with brain metastasis, 41 with metastatic cancer that has not spread to the brain, 27 with malignant glioma, and 46 healthy controls. All diagnoses were made by board-certified oncologists and were verified histologically. RESULTS: Results indicated that numerous cognitive functions were associated with the ability to understand treatment decisions in persons with cancer. The following proportion of participants demonstrated impaired understanding of treatment decisions in our three patient groups: approximately 51% malignant glioma, approximately 46% brain metastasis, and approximately 24% metastatic cancer. In a combined brain cancer group, we were able to use cognitive performance to predict the impaired ability to understand treatment decisions. CONCLUSIONS: An impaired ability to understand treatment decisions is prevalent in persons with brain cancer and persons with metastatic cancer. Performance on a brief cognitive battery can be used to help clinicians identify patients at particular risk for impaired medical decision making.