Bariatric surgery patients exhibit improved memory function 12 months postoperatively

Changes in Cognitive Function Following Bariatric Surgery: An Updated Systematic Review

Since a previous systematic review published in 2016, there have been further studies investigating the association of changes in cognitive function following bariatric surgery. All studies since the original review that reported at least one element of cognitive function before and after bariatric surgery were eligible. A total of 137 additional studies were identified; 13 were included in addition to the 18 studies previously. Almost all studies reported improvements in at least one domain. Most revealed improvements were limited to a few domains and were not universal. Further findings investigated cognitive function improvement in relation to procedure choice, and mental health or quality of life post-surgery. Further high-powered studies are still necessary, but these findings support the impact of bariatric surgery on cognitive function in obesity.

Bariatric Surgery Improves Cognition Function in the Patients with Obesity: A Meta-Analysis

Obesity and related comorbidities have negative impacts on cognitive function. Weight loss seems to be associated with the improvement of cognitive function and the recovery of brain structure, but the underlying mechanism is not clear. This meta-analysis aimed to explore the status of cognitive function including memory, executive function, attention and language ability in patients with obesity, and to further investigate whether bariatric surgery can improve overall cognitive function in these patients. A total of 11 literatures with 728 subjects were included after retrieval and exclusion. The meta-analysis showed significant improvements in memory, attention and executive function scores after undergoing bariatric surgery in the patients with obesity. However, there was no significant improvement in language ability.

Long-Term Brain Structure and Cognition Following Bariatric Surgery

Importance

Weight loss induced by bariatric surgery (BS) is associated with improved cognition and changed brain structure; however, previous studies on the association have used small cohorts and short follow-up periods, making it difficult to determine long-term neurological outcomes associated with BS.

Objective

To investigate long-term associations of weight loss after BS with cognition and brain structure and perfusion.

Design, Setting, and Participants

This cohort study included participants from the Bariatric Surgery Rijnstate and Radboudumc Neuroimaging and Cognition in Obesity study. Data from participants with severe obesity (body mass index [BMI; calculated as weight in kilograms divided by height in meters squared] >40, or BMI >35 with comorbidities) eligible for Roux-en-Y gastric bypass and aged 35 to 55 years were enrolled from a hospital specialized in BS (Rijnstate Hospital, Arnhem, the Netherlands). Participants were recruited between September 2018 and December 2020 with follow-up till March 2023. Data were collected before BS and at 6 and 24 months after BS. Data were analyzed from March to November 2023.

Exposure

Roux-en-Y gastric bypass.

Main Outcomes and Measures

Primary outcomes included body weight, BMI, waist circumference, blood pressure, medication use, cognitive performance (20% change index of compound z-score), brain volumes, cortical thickness, cerebral blood flow (CBF), and spatial coefficient of variation (sCOV). Secondary outcomes include cytokines, adipokines, depressive symptoms (assessed using the Beck Depression Inventory), and physical activity (assessed using the Baecke Questionnaire).

Results

A total of 133 participants (mean [SD] age, 46.8 [5.7] years; 112 [84.2%] female) were included. Global cognition was at least 20% higher in 52 participants (42.9%) at 24 months after BS. Compared with baseline, at 24 months, inflammatory markers were lower (mean [SD] high-sensitivity C-reactive protein: 4.77 [5.80] μg/mL vs 0.80 [1.09] μg/mL; P < .001), fewer patients used antihypertensives (48 patients [36.1%] vs 22 patients [16.7%]), and patients had lower depressive symptoms (median [IQR] BDI score: 9.0 [5.0-13.0] vs 3.0 [1.0-6.0]; P < .001) and greater physical activity (mean [SD] Baecke score: 7.64 [1.29] vs 8.19 [1.35]; P < .001). After BS, brain structure and perfusion were lower in most brain regions, while hippocampal and white matter volume remained stable. CBF and sCOV did not change in nucleus accumbens and parietal cortex. The temporal cortex showed a greater thickness (mean [SD] thickness: 2.724 [0.101] mm vs 2.761 [0.007] mm; P = .007) and lower sCOV (median [IQR] sCOV: 4.41% [3.83%-5.18%] vs 3.97% [3.71%-4.59%]; P = .02) after BS.

Conclusions and Relevance

These findings suggest that BS was associated with health benefits 2 years after surgery. BS was associated with improved cognition and general health and changed blood vessel efficiency and cortical thickness of the temporal cortex. These results may improve treatment options for patients with obesity and dementia.

Understanding the impact of radical changes in diet and the gut microbiota on brain function and structure: rationale and design of the EMBRACE study

BACKGROUND

Bariatric surgery leads to profound changes in gut microbiota and dietary patterns, both of which may interact to impact gut-brain communication. Though cognitive function improves postsurgery, there is a large variability in outcomes. How bariatric surgery-induced modifications in the gut microbiota and dietary patterns influence the variability in cognitive function is still unclear.

OBJECTIVES

To elucidate the associations between bariatric surgery-induced changes in dietary and gut microbiota patterns with cognition and brain structure.

SETTING

University hospital.

METHODS

A total of 120 adult patients (≥30 years) scheduled to undergo a primary bariatric surgery along with 60 age-, sex-, and body mass index-matched patients on the surgery waitlist will undergo assessments 3-months presurgery and 6- and 12-month postsurgery (or an equivalent time for the waitlist group). Additionally, 60 age-and sex-matched nonbariatric surgery eligible individuals will complete the presurgical assessments only. Evaluations will include sociodemographic and health behavior questionnaires, physiological assessments (anthropometrics, blood-, urine-, and fecal-based measures), neuropsychological cognitive tests, and structural magnetic resonance imaging. Cluster analyses of the dietary and gut microbiota changes will define the various dietary patterns and microbiota profiles, then using repeated measures mixed models, their associations with global cognitive and structural brain alterations will be explored.

RESULTS

The coordinating study site (Centre intégré universitaire de santé et de services sociaux du Nord-de-l'Île-de-Montréal, QC, Canada), provided the primary ethical approval (Research Ethics Board#: MP-32-2022-2412).

CONCLUSIONS

The insights generated from this study can be used to develop individually-targeted neurodegenerative disease prevention strategies, as well as providing critical mechanistic information.

Resting-state network functional connectivity before and after bariatric surgery

BACKGROUND

Bariatric surgery is an increasingly popular treatment for patients with severe obesity and related health issues (e.g., diabetes, cardiovascular disease). Studies have identified alterations in functional connectivity both in obesity and following surgical treatment for severe obesity.

OBJECTIVE

This study aimed to assess brain function via resting-state within-network connectivity in bariatric surgery patients with severe obesity.

SETTING

University hospital.

METHODS

Thirty-four bariatric surgery patients completed functional neuroimaging at baseline and postoperatively (goal, 12 weeks; actual, 16 weeks, on average). They also self-reported health information. Baseline resting-state functional connectivity (RSFC) was predicted by baseline age, body mass index (BMI), continuous positive airway pressure use, and reported history of rheumatoid arthritis and type 2 diabetes. Change in RSFC was assessed using the same predictors. This model was run with and without controlling for baseline RSFC.

RESULTS

Higher baseline BMI predicted lower baseline RSFC in 3 networks. Lower baseline RSFC also was related to rheumatoid arthritis and type 2 diabetes. Difference between baseline and follow-up RSFC was strongly negatively associated with baseline RSFC. Controlling for baseline RSFC, type 2 diabetes negatively predicted RSFC difference.

CONCLUSIONS

RSFC may reflect brain dysfunction in patients with obesity and related diseases. That less connectivity at baseline predicted greater positive change suggests that RSFC may be a biomarker of neurocognitive improvement following bariatric surgery. Diseases more prevalent in patients with obesity (e.g., rheumatoid arthritis and type 2 diabetes) along with elevated BMI negatively affect RSFC likely through inflammatory pathways.

Correlation between improved leptin signaling and cognitive function post bariatric surgery

Determining whether changes in leptin signaling plays a role in the improvement of cognitive function post-bariatric surgery may aid in the understanding and development of novel therapeutic approaches targeting cognitive dysfunction through the greater understanding of processes connecting obesity and brain health. Several studies have explored the effects of cognition post bariatric surgery, and others have studied leptin and its changes post surgery. However the amalgamation of the effects of leptin signaling in relation to cognition post bariatric surgery have yet to be considered as key tools in the understanding of cognitive dysfunction in obese subjects with leptin resistance or insensitivity. This review serves to highlight the potential correlations, to further elucidate the effect of improved leptin signaling on cognition post bariatric surgery, and to propose a direct cause for the improvement of cognitive function via the amelioration of the leptin Janus kinase/Signal transducer and activator of transcription (JAK/STAT) signaling pathway as a result of the reversal of inflammatory processes involved in diseased individuals.

The Effect of Surgical Weight Loss on Cognition in Individuals with Class II/III Obesity

BACKGROUND

Obesity is a global epidemic and is associated with cognitive impairment and dementia. It remains unknown whether weight loss interventions, such as bariatric surgery, can mitigate cognitive impairment.

OBJECTIVES

We aimed to determine the effect of surgical weight loss on cognition in individuals with class II/III obesity.

DESIGN

We performed a prospective cohort study of participants who underwent bariatric surgery. At baseline and two years following surgery, participants completed metabolic risk factor and neuropsychological assessments.

SETTING

Participants were enrolled from an academic suburban bariatric surgery clinic.

PARTICIPANTS

There were 113 participants who completed baseline assessments and 87 completed two-year follow-up assessments (66 in-person and 21 virtual) after bariatric surgery. The mean (SD) age was 46.8 (12.5) years and 64 (73.6%) were female.

INTERVENTION

Bariatric surgery. There were 77 (88.5%) participants that underwent sleeve gastrectomy and 10 (11.5%) that underwent gastric bypass surgery.

MEASUREMENTS

Cognition was assessed using the NIH toolbox cognitive battery (NIHTB-CB) and the Rey Auditory Verbal Learning Test (AVLT). The primary outcome was the change in NIHTB-CB fluid composite score before and after surgery.

RESULTS

The primary outcome, NIHTB-CB composite score, was stable following bariatric surgery (-0.4 (13.9), p=0.81,n=66). Among secondary outcomes, the NIHTB-CB dimensional card sorting test (executive function assessment), improved (+6.5 (19.9),p=0.01,n=66) while the Rey AVLT delayed recall test (memory assessment) declined (-0.24 (0.83),p=0.01,n=87) following surgery. Improvements to metabolic risk factors and diabetes complications were not associated with improvements to NIHTB-CB composite score. The other 4 NIHTB-CB subtests and Rey AVLT assessments of auditory learning and recognition were stable at follow-up.

CONCLUSIONS

Following bariatric surgery, the age-adjusted composite cognitive outcome did not change, but an executive subtest score improved. These results suggest that bariatric surgery may mitigate the natural history of cognitive decline in individuals with obesity, which is expected to be faster than normal aging, but confirmatory randomized controlled trials are needed. The decline in delayed recall also warrants further studies to determine potential differential effects on cognitive subtests.

Effects of Peripheral Neural Blocks in Laparoscopic Sleeve Gastrectomy: a Pilot Study on Cognitive Functions in Severe Obese Patients

BACKGROUND

In addition to the analgesic effect, peripheral neural blocks also prevent cognitive impairment and peripheral inflammation induced by surgery. However, it is unknown if there is collateral impact on cognitive improvement after bariatric surgery.

METHODS

In this pilot study, 75 patients with severe obesity for selective laparoscopic sleeve gastrectomy (LSG) were recruited and randomized into three groups (1:1:1) as general anesthesia (GA) group, transverse abdominis plane block (TAPB) group, and quadratus lumborum block (QLB) group. Bilateral TAPB or QLB was performed (0.33% ropivacaine with dexmedetomidine 1 μg/kg) before the standardized general anesthesia. Cognitive test battery was completed before LSG and in 1-month and 3-month follow-up. The levels of peripheral inflammatory cytokines were determined at equivalent time points.

RESULTS

Patients with LSG exhibited massive cognitive improvement in postoperative 3 month without or with TAPB or QLB (P_time < 0.001). Compared to GA, QLB significantly strengthened performance in MoCA (β = 0.56, 95%CI: 0.08, 1.05). IL-6, IL-8, and high-sensitivity CRP significantly verified among three groups. Changes in IL-6 within postoperative 3 months were negatively correlated with MMSE and MoCA, and positively correlated with AVLT-DR for QLB group. Similar correlation was found in the GA group for changes in IL-6 and AVLT-IR.

CONCLUSION

Laparoscopic sleeve gastrectomy ideally improved memory and attention as early as postoperative 1 month. QLB promoted cognitive improvement in MoCA, which was negatively correlated with changes in IL-6. More precise trials are needed to determine the overall effect of peripheral neural block on cognition following bariatric surgery.

Development of dementia in patients who underwent bariatric surgery

BACKGROUND

Dementia, including Alzheimer's disease, interfere with daily function and are one of the major causes of disability, institutionalization, and death. Obesity is associated with an increased risk of dementia. However, the effect of significant and sustained weight loss following bariatric surgery on dementia is not known. The purpose of this study was to assess the long-term risk of dementia following bariatric surgery.

METHODS

A surgical cohort was identified from the Utah Bariatric Surgery Registry and was linked to the Utah Population Database that includes electronic medical records, death records, and State Facility data. Adult subjects (≥ 18 years old) at time of surgery (1996-2016) were matched with non-surgical subjects. The final sample included 51,078 subjects (1:2 matching); surgery group n = 17,026; non-surgery subjects n = 34,052). Dementia were identified by ICD-9/10 diagnosis codes following surgery year or matched baseline year. Cox proportional hazard model was used to calculate the hazard ratio in the outcome between the groups.

RESULTS

Average (SD) age of the subjects was 42 (12) years old at surgery or matched baseline year, 78% were female and mean follow-up time was 10.5 years. 1.4% of the surgery group and 0.5% of the control group had an incidence of dementia. Controlling the covariates in the Cox regression, the surgery group had a higher risk for dementia incidence than the matched non-surgery subjects (HR = 1.33, p = 0.02).

CONCLUSIONS

The study showed an increased hazard for dementia in individuals who underwent bariatric surgery compared to matched non-surgical subjects. Additional long-term data is needed to verify this association.

Sleeve Gastrectomy Reduces Glycemia but Does Not Affect Cognitive Impairment in Lean 5xFAD Mice

Obesity and hyperglycemia are risk factors for cognitive decline and for the development of Alzheimer’s Disease (AD). Bariatric surgery is an effective treatment for obesity that was shown to improve cognitive decline in obese patients. Bariatric surgery was shown to exert weight loss independent effects on metabolic diseases such as type 2 diabetes. We tested whether sleeve gastrectomy (SG), a common bariatric surgery, can affect the cognitive impairment in lean, normoglycemic female 5xFAD mice, a genetic model for AD. 5xFAD mice and wild-type (WT) littermates underwent SG or sham surgery at the age of 5 months and were tested for metabolic, behavioral, and molecular phenotypes 90 days later. SG led to a reduction in blood glucose levels and total plasma cholesterol levels in 5xFAD mice without inducing weight loss. However, the surgery did not affect the outcomes of long-term spatial memory tests in these mice. Analysis of β-Amyloid plaques corroborated the behavioral studies in showing no effect of surgery on the molecular phenotype of 5xFAD mice. In conclusion, SG leads to an improved metabolic profile in lean female 5xFAD mice without inducing weight loss but does not affect the brain pathology or behavioral phenotype. Our results suggest that the positive effects of bariatric surgery on cognitive decline in obese patients are likely attributed to weight loss and improvement in obesity sequelae, and not to weight loss independent effects of surgery.

Brain effect of bariatric surgery in people with obesity

BACKGROUND/OBJECTIVES

The link between obesity and brain function is a fascinating but still an enigmatic topic. We evaluated the effect of Roux-en-Y gastric bypass (RYGB) on peripheral glucose metabolism, insulin sensitivity, brain glucose utilization and cognitive abilities in people with obesity.

SUBJECTS/METHODS

Thirteen subjects with obesity (F/M 11/2; age 44.4 ± 9.8 years; BMI 46.1 ± 4.9 kg/m²) underwent 75-g OGTT during a [18F]FDG dynamic brain PET/CT study at baseline and 6 months after RYGB. At the same timepoints, cognitive performance was tested with Mini Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Trail making test (TMT) and Token test (TT). Glucose, insulin, C-peptide, GLP-1, GIP, and VIP levels were measured during OGTT. Leptin and BDNF levels were measured before glucose ingestion.

RESULTS

RYGB resulted in significant weight loss (from 46.1 ± 4.9 to 35.3 ± 5.0 kg/m²; p < 0.01 vs baseline). Insulin sensitivity improved (disposition index: from 1.1 ± 0.2 to 2.9 ± 1.1; p = 0.02) and cerebral glucose metabolic rate (CMRg) declined in various brain areas (all p ≤ 0.01). MMSE and MoCA score significantly improved (p = 0.001 and p = 0.002, respectively). TMT and TT scores showed a slight improvement. A positive correlation was found between CMRg change and HOMA-IR change in the caudate nucleus (ρ = 0.65, p = 0.01). Fasting leptin decreased (from 80.4 ± 13.0 to 16.1 ± 2.4 ng/dl; p = 0.001) and correlated with CMRg change in the hippocampus (ρ = 0.50; p = 0.008). CMRg change was correlated with cognitive scores changes on the TMT and TT (all p = 0.04 or less).

CONCLUSIONS

Bariatric surgery improves CMRg directly related to a better cognitive testing result. This study highlights the potential pleiotropic effects of bariatric surgery.

TRIAL REGISTRY NUMBER

NCT03414333.

Changes in Cognition Functions and Depression Severity After Bariatric Surgery: A 3-Month Follow-up Study

Background: Changes in cognitive profile, such as memory and other functions in patients with morbid obesity after bariatric surgery have been reported in the literature with inconsistent results. Objectives: This study aimed to evaluate cognitive changes, executive function and depression severity before and after bariatric surgery in patients with morbid obesity. Methods: In this prospective cohort study, 70 patients with morbid obesity (40 patients undergoing bariatric surgery and 30 patients in the waiting list) referred to the Rasool Akram Medical Complex, obesity clinic, Tehran, Iran, in 2016 entered the study. The two groups were assessed using the Wechsler Memory Scale (WMS) (consists of 7 subscales and assesses memory), the Wisconsin Cart Sorting test (WCST) (includes 64 cards and assesses cognitive skills), the Hamilton Depression Scale (HAM-D) (for measuring depression) and bariatric analysis and reporting outcome system (BAROS) questionnaire (scale to report of the therapeutic results of bariatric surgery and including the three criteria of the weight loss percentage, the change in health state, and the quality of life) at the beginning of the study and three months after the surgery. Moreover, the Bariatric Analysis and reporting outcome system (BAROS) questionnaire was filled three months after surgery. Results: The average changes in WMS score (P = 0.043), working memory (P = 0.002), HAM-A (P = 0.032), weight, and BMI (P = 0.0001) in the surgery group were significantly higher than the control group. There was a significant positive correlation between change in the number of preservative errors in WCST within the surgery group with BAROS score (P = 0.004). Moreover, there was a significant correlation between changes in the score of WMS and those in BMI in the surgery group. Conclusions: Bariatric surgery is associated with improvements in some cognitive functions and worsening of depressive scores in patients with morbid obesity.

Memory and eating: A bidirectional relationship implicated in obesity

This paper reviews evidence demonstrating a bidirectional relationship between memory and eating in humans and rodents. In humans, amnesia is associated with impaired processing of hunger and satiety cues, disrupted memory of recent meals, and overconsumption. In healthy participants, meal-related memory limits subsequent ingestive behavior and obesity is associated with impaired memory and disturbances in the hippocampus. Evidence from rodents suggests that dorsal hippocampal neural activity contributes to the ability of meal-related memory to control future intake, that endocrine and neuropeptide systems act in the ventral hippocampus to provide cues regarding energy status and regulate learned aspects of eating, and that consumption of hypercaloric diets and obesity disrupt these processes. Collectively, this evidence indicates that diet-induced obesity may be caused and/or maintained, at least in part, by a vicious cycle wherein excess intake disrupts hippocampal functioning, which further increases intake. This perspective may advance our understanding of how the brain controls eating, the neural mechanisms that contribute to eating-related disorders, and identify how to treat diet-induced obesity.

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.

PART 3 Bypassing TBI: Metabolic Surgery and the Link Between Obesity and Traumatic Brain Injury-a Review

Obesity is a common outcome of traumatic brain injury (TBI) that exacerbates principal TBI symptom domains identified as common areas of post-TBI long-term dysfunction. Obesity is also associated with increased risk of later-life dementia and Alzheimer's disease. Patients with obesity and chronic TBI may be more vulnerable to long-term mental abnormalities. This review explores the question of whether weight loss induced by bariatric surgery could delay or perhaps even reverse the progression of mental deterioration. Bariatric surgery, with its induction of weight loss, remission of type 2 diabetes, and other expressions of the metabolic syndrome, improves metabolic efficiency, leads to reversal of brain lesions seen on imaging studies, and improves function. These observations suggest that metabolic/bariatric surgery may be a most effective therapy for TBI.

Visual, Verbal and Everyday Memory 2 Years After Bariatric Surgery: Poorer Memory Performance at 1-Year Follow-Up

Severe obesity has been associated with reduced performance on tests of verbal memory in bariatric surgery candidates. There is also some evidence that bariatric surgery leads to improved verbal memory, yet these findings need further elucidation. Little is known regarding postoperative memory changes in the visual domain and how patients subjectively experience their everyday memory after surgery. The aim of the current study was to repeat and extend prior findings on postoperative memory by investigating visual, verbal, and self-reported everyday memory following surgery, and to examine whether weight loss and somatic comorbidity predict memory performance. The study was a prospective, observational study in which participants (n = 48) underwent cognitive testing at baseline, 1 and 2 years after bariatric surgery. Repeated measures analyses of variance revealed significantly poorer visual and verbal memory performance at the 1-year follow-up, with performance subsequently returning to baseline levels after 2 years. Verbal learning and self-reported everyday memory did not show significant postoperative changes. Memory performance at 1 year was not significantly predicted by weight loss, changes in C-reactive protein levels or postoperative somatic comorbidity (Type 2 diabetes, sleep apnea, and hypertension). The study demonstrated poorer visual and verbal memory performance at 1-year follow-up that returned to baseline levels after 2 years. These findings are in contrast to most previous studies and require further replication, however, the results indicate that postoperative memory improvements following bariatric surgery are not universal. Findings suggest that treatment providers should also be aware of patients potentially having poorer memory at 1 year following surgery.

Part 2: Bypassing TBI-Metabolic Surgery and the Link Between Obesity and Traumatic Brain Injury-A Review

Obesity is a common outcome of traumatic brain injury (TBI) that exacerbates principal TBI symptom domains identified as common areas of post-TBI long-term dysfunction. Obesity is also associated with increased risk of later-life dementia and Alzheimer's disease. Patients with obesity and chronic TBI may be more vulnerable to long-term mental abnormalities. This review explores the question of whether weight loss induced by bariatric surgery could delay or perhaps even reverse the progression of mental deterioration. Bariatric surgery, with its induction of weight loss, remission of type 2 diabetes, and other expressions of the metabolic syndrome, improves metabolic efficiency, leads to reversal of brain lesions seen on imaging studies, and improves function. These observations suggest that metabolic/bariatric surgery may be the most effective therapy for TBI.

Western diet, obesity and bariatric surgery sequentially modulated anxiety, eating patterns and brain responses to sucrose in adult Yucatan minipigs

Palatable sweet/fatty foods overconsumption is a major risk factor for obesity and eating disorders, also having an impact on neuro-behavioural hedonic and cognitive components comparable to what is described for substance abuse. We hypothesized that Yucatan minipigs would show hedonic, cognitive, and affective neuro-behavioral shifts when subjected to western diet (WD) exposure without weight gain, after the onset of obesity, and finally after weight loss induced by caloric restriction with (RYGB) or without (Sham) gastric bypass. Eating behavior, cognitive and affective abilities were assessed with a spatial discrimination task (holeboard test) and two-choice feed tests. Brain responses to oral sucrose were mapped using 18F-FDG positron emission tomography. WD exposure impaired working memory and led to an “addiction-type” neuronal pattern involving hippocampal and cortical brain areas. Obesity induced anxiety-like behavior, loss of motivation, and snacking-type eating behavior. Weight loss interventions normalized the motivational and affective states but not eating behavior patterns. Brain glucose metabolism increased in gustatory (insula) and executive control (aPFC) areas after weight loss, but RYGB showed higher responses in inhibition-related areas (dorsal striatum). These results showed that diet quality, weight loss, and the type of weight loss intervention differently impacted brain responses to sucrose in the Yucatan minipig model.

(-)-Epicatechin and the comorbidities of obesity

Obesity has major adverse consequences on human health contributing to the development of, among others, insulin resistance and type 2 diabetes, cardiovascular disease, non-alcoholic fatty liver disease, altered behavior and cognition, and cancer. Changes in dietary habits and lifestyle could contribute to mitigate the development and/or progression of these pathologies. This review will discuss current evidence on the beneficial actions of the flavan-3-ol (-)-epicatechin (EC) on obesity-associated comorbidities. These benefits can be in part explained through EC's capacity to mitigate several common events underlying the development of these pathologies, including: i) high circulating levels of glucose, lipids and endotoxins; ii) chronic systemic inflammation; iii) tissue endoplasmic reticulum and oxidative stress; iv) insulin resistance; v) mitochondria dysfunction and vi) dysbiosis. The currently known underlying mechanisms and cellular targets of EC's beneficial effects are discussed. While, there is limited evidence from human studies supplementing with pure EC, other studies involving cocoa supplementation in humans, pure EC in rodents and in vitro studies, support a potential beneficial action of EC on obesity-associated comorbidities. This evidence also stresses the need of further research in the field, which would contribute to the development of human dietary strategies to mitigate the adverse consequences of obesity.

Analysis of Functional and Cognitive Impairment in Institutionalized Individuals with Movement Disorders

BACKGROUND

Many neurological disorders lead to institutionalization and can be accompanied in their advanced stages by functional impairment, and progressive loss of mobility, and cognitive alterations.

OBJECTIVE

We analyzed the relationship between functional impairment and cognitive performance and its related subdomains in individuals with Parkinson's disease, Alzheimer's disease accompanied by motor dysfunction, and with other neurological disorders characterized by both motor and cognitive problems.

METHODS

All participants lived in nursing homes (Valencia, Spain) and underwent cognitive evaluation with the Mini-Mental State Examination; functional assessment of independence in activities of daily living using the Barthel score and Katz index; and assessment of mobility with the elderly mobility scale.

RESULTS

The mean age of the subjects was 82.8 ± 0.6 years, 47% of the sample included individuals with Parkinson's disease, and 48 % of the sample presented severe cognitive impairment. Direct significant relationships were found between the level of cognitive impairment and functional capacity (p < 0.01) and mobility (p < 0.05). Among the different domains, memory impairment was not associated with altered activities of daily living or mobility. The functional impairment and the risk of severe cognitive impairment were significantly (p<0.05) higher in female compared to male patients. Among comorbidities, overweight/obesity and diabetes were significantly (p < 0.05) associated with poor cognitive performance in those individuals with mild/moderate cognitive impairment.

CONCLUSION

In institutionalized individuals with movement disorders there is an association between functional and cognitive impairment. Reduction of over-weight and proper control of diabetes may represent novel targets for improving cognitive function at such early stages.

Impact of bariatric surgery on cerebral vascular reactivity and cognitive function: a non-randomized pilot study

Background

Bariatric surgery is an effective long-term weight loss strategy yielding improvements in neurocognitive function; however, the mechanism(s) responsible for these improvements remains unclear. Here, we assessed the feasibility of using magnetic resonance imaging (MRI) to evaluate whether cerebral vascular reactivity (CVR) is impaired in severely obese bariatric surgery candidates compared with normal weight healthy controls and whether CVR improves following bariatric surgery. We also investigated whether changes in CVR were associated with changes in cognitive function.

Methods

Bariatric surgery candidates (n = 6) were compared with normal weight healthy controls of a similar age (n = 10) at baseline, and then reassessed 2 weeks and 14 weeks following sleeve gastrectomy bariatric surgery. Young reference controls (n = 7) were also studied at baseline to establish the range of normal for each outcome measure. Microvascular and macrovascular CVR to hypercapnia (5% CO₂) were assessed using blood-oxygen-level-dependent (BOLD) MRI, and changes in the middle cerebral artery (MCA) cross-sectional area, respectively. Cognitive function was assessed using a validated neurocognitive software.

Results

Compliance with the CVR protocol was high. Both macro- and micro-cerebrovascular function were highest in the young reference controls. Cognitive function was lower in obese bariatric surgery candidates compared with normal weight controls, and improved by 17% at 2 weeks and 21% by 14 weeks following bariatric surgery. To our surprise, whole-brain CVR BOLD did not differ between obese bariatric surgery candidates and normal weight controls of similar age (0.184 ± 0.101 vs. 0.192 ± 0.034 %BOLD/mmHgCO₂), and did not change after bariatric surgery. In contrast, we observed vasoconstriction of the MCA during hypercapnia in 60% of the obese patients prior to surgery, which appeared to be abolished following bariatric surgery. Improvements in cognitive function were not associated with improvements in either CVR BOLD or MCA vasodilation after bariatric surgery.

Conclusions

Assessing CVR responses to a hypercapnic challenge with MRI was feasible in severely obese bariatric patients. However, no changes in whole-brain BOLD CVR were observed following bariatric surgery despite improvements in cognitive function. We recommend that future large trials assess CVR responses to cognitive tasks (rather than hypercapnia) to better define the mechanisms responsible for cognitive function improvements following bariatric surgery.

Mental health, loss of control eating, and cognitive functioning in adolescents undergoing bariatric surgery

Bariatric surgery is an effective treatment for severe obesity in adolescence. Nevertheless, much remains to be understood regarding the impact of surgery on mental health, eating behaviors, and cognition. We review the findings related to mental health both before and after surgery as well as long-term changes in psychopathology, including suicide risk. Overall, adolescents with and without a history of psychopathology lose weight at similar rates. At the same time, there is an increased risk for suicide that requires further study. Regarding alcohol and substance use, this population reports lower rates of consumption than age related non-obese cohorts. Nevertheless the impact of altered anatomy and metabolism on alcohol ingestion in a population at risk for substance use is concerning. Eating behaviors, specifically loss of control eating, are discussed. Finally, we include discussion of the cognitive changes occurring perioperatively and considerations for adolescents with cognitive impairments. Clinical recommendations and suggestions for future research are discussed.

Bariatric Surgery and Brain Health-A Longitudinal Observational Study Investigating the Effect of Surgery on Cognitive Function and Gray Matter Volume

Dietary modifications leading to weight loss have been suggested as a means to improve brain health. In morbid obesity, bariatric surgery (BARS)-including different procedures, such as vertical sleeve gastrectomy (VSG), gastric banding (GB), or Roux-en-Y gastric bypass (RYGB) surgery-is performed to induce rapid weight loss. Combining reduced food intake and malabsorption of nutrients, RYGB might be most effective, but requires life-long follow-up treatment. Here, we tested 40 patients before and six months after surgery (BARS group) using a neuropsychological test battery and compared them with a waiting list control group. Subsamples of both groups underwent structural MRI and were examined for differences between surgical procedures. No substantial differences between BARS and control group emerged with regard to cognition. However, larger gray matter volume in fronto-temporal brain areas accompanied by smaller volume in the ventral striatum was seen in the BARS group compared to controls. RYGB patients compared to patients with restrictive treatment alone (VSG/GB) had higher weight loss, but did not benefit more in cognitive outcomes. In sum, the data of our study suggest that BARS might lead to brain structure reorganization at long-term follow-up, while the type of surgical procedure does not differentially modulate cognitive performance.

Obesity-related cognitive impairment: The role of endothelial dysfunction

Obesity is a global pandemic associated with macro- and microvascular endothelial dysfunction. Microvascular endothelial dysfunction has recently emerged as a significant risk factor for the development of cognitive impairment. In this review, we present evidence from clinical and preclinical studies supporting a role for obesity in cognitive impairment. Next, we discuss how obesity-related hyperinsulinemia/insulin resistance, systemic inflammation, and gut dysbiosis lead to cognitive impairment through induction of endothelial dysfunction and disruption of the blood brain barrier. Finally, we outline the potential clinical utility of dietary interventions, exercise, and bariatric surgery in circumventing the impacts of obesity on cognitive function.

Cognitive Performance as Predictor and Outcome of Adolescent Bariatric Surgery: A Nonrandomized Pilot Study

Objectives

Evidence in adults suggests that improvements in cognitive performance may follow weight loss resulting from bariatric surgery, and baseline cognitive performance may be associated with weight loss following surgery. This has not been evaluated in adolescents.

Method

Participants were 38 adolescents of age 14-21 years composed of three groups: (1) 12 adolescents with severe obesity who received vertical sleeve gastrectomy during the study (VSG); (2) 14 adolescents with severe obesity who were wait-listed for VSG (WL); and (3) 12 healthy weight controls (HC). Participants completed testing of visual memory, verbal memory, and executive functioning at baseline (T1), which occurred presurgery for the VSG group, and approximately 4 months after baseline (T2). Body mass index (BMI) was assessed at T1, T2, and additionally at 6 months following VSG for the adolescents who received surgery.

Results

Although there was evidence of greater improvement for the VSG as compared with WL and HC groups in visual and verbal memory, group differences did not reach significance and effect sizes were small (η2 < 0.01). There was a significant positive association between indices of baseline executive functioning and excess BMI loss at 6 months postsurgery.

Conclusions

This small pilot study showed no significant differences by group in cognitive performance post-VSG. There was a significant association of baseline cognitive performance with weight loss outcomes. Given the very preliminary nature of these results in a small sample, future research should examine these relationships in a larger sample and evaluate mechanisms of these associations (e.g., insulin resistance, sleep, physical activity).

Neuroimaging correlates of cognitive changes after bariatric surgery

BACKGROUND

Obesity has been associated with cognitive deficits and increased risk for developing dementia. Bariatric surgery may result in improved cognitive function; however, the underlying structural and functional brain correlates are unclear.

OBJECTIVES

This longitudinal study explores the hypothesis that specific brain regions and networks underlie cognitive changes after bariatric surgery.

SETTING

University Hospital, United States.

METHODS

Seventeen patients were recruited for this prospective cohort study, including 9 patients undergoing bariatric surgery, and 8 age-, sex-, and education level-matched healthy, nonobese control patients. Bariatric patients underwent longitudinal neuropsychologic tests and magnetic resonance imaging (MRI) scans both before and 6 months after surgery. One patient was lost to follow-up. The same neuropsychologic tests and MRI scans were performed for control patients. Differences in MRI and neuropsychologic testing between bariatric patients and control patients, and longitudinal changes within bariatric patients were assessed.

RESULTS

At baseline, bariatric patients demonstrated deficits in cognitive function relative to control patients, including pattern comparison (P = .009) and picture sequence memory (P = .004), which improved after significant weight loss. Baseline cognitive deficits in bariatric patients were accompanied by significantly lower left executive control network connectivity on resting-state functional MRI relative to control patients (P = .028), but differences resolved or diminished after bariatric surgery. Longitudinal improvements in pattern comparison performance correlated significantly with increases in left executive control network connectivity (r = .819; P = .013). No significant group or longitudinal differences were found in brain perfusion or brain white matter lesions.

CONCLUSIONS

Individuals with obesity undergoing bariatric surgery exhibit deficits in cognitive function and specific alterations of brain networks; however, cognitive performance can improve, and executive control network connectivity can increase after weight loss from bariatric surgery.

Neurocognitive Deficits in a Cohort With Class 2 and Class 3 Obesity: Contributions of Type 2 Diabetes and Other Comorbidities

OBJECTIVE

This study examined the relationship between specific metabolic and vascular risk factors and cognition in adults with severe obesity.

METHODS

A total of 129 adults (with BMI ≥ 35 kg/m² ) underwent a baseline clinical evaluation and neuropsychological assessment. Regression analyses examined the relationship between cognition and medical factors (BMI, hemoglobin A1c, diabetes, hypertension, continuous positive airway pressure use, obstructive sleep apnea [OSA], and osteoarthritis).

RESULTS

Diabetes was associated with deficits in overall cognitive performance and with deficits in the executive processing speed and verbal fluency domains. Hemoglobin A1c was inversely related to overall cognitive performance and deficits in the attention domain. Participants using continuous positive airway pressure to treat OSA had stronger learning and memory performance, whereas OSA was associated with reduced total learning. Elevated BMI together with diabetes diagnosis was associated with reduced verbal fluency and greater variability in sustained attention.

CONCLUSIONS

Obesity-associated comorbidities most notably appeared to have a greater relative influence on cognitive performance than BMI itself in adults with severe obesity. This likely reflects the fact that a very elevated BMI was ubiquitous and thereby probably exerted a similar influence among all adults in the cohort. Accordingly, in the context of severe obesity, diabetes and other comorbidities may have greater sensitivity to cognitive deficits than BMI alone.

Neuropsychological Functioning in Older Adults with Obesity: Implications for Bariatric Surgery

Bariatric surgery is the most effective approach to treating morbid obesity, resulting in decreased morbidity, mortality, and improved quality of life. Research on outcomes has generally been restricted to young and middle-aged adults, despite a growing epidemic of obesity in older adults. The use of bariatric surgery has been limited in older individuals, in part due to concerns that preexisting cognitive dysfunction increases the risk of poor post-surgical outcomes, including cognitive decline. The literature on the relationship between obesity and cognition in older adults is emerging, but fraught by several methodological limitations. While there is insufficient research to determine the nature of cognitive outcomes following bariatric surgery in older adults, the aim of this paper is to review the existing evidence and make the case for further study.

The Gut⁻Brain Axis in the Neuropsychological Disease Model of Obesity: A Classical Movie Revised by the Emerging Director "Microbiome"

The worldwide epidemic of obesity has become an important public health issue, with serious psychological and social consequences. Obesity is a multifactorial disorder in which various elements (genetic, host, and environment), play a definite role, even if none of them satisfactorily explains its etiology. A number of neurological comorbidities, such as anxiety and depression, charges the global obesity burden, and evidence suggests the hypothesis that the brain could be the seat of the initial malfunction leading to obesity. The gut microbiome plays an important role in energy homeostasis regulating energy harvesting, fat deposition, as well as feeding behavior and appetite. Dietary patterns, like the Western diet, are known to be a major cause of the obesity epidemic, probably promoting a dysbiotic drift in the gut microbiota. Moreover, the existence of a "gut⁻brain axis" suggests a role for microbiome on hosts' behavior according to different modalities, including interaction through the nervous system, and mutual crosstalk with the immune and the endocrine systems. In the perspective of obesity as a real neuropsychological disease and in light of the discussed considerations, this review focuses on the microbiome role as an emerging director in the development of obesity.

To What Extent Memory Could Contribute to Impaired Food Valuation and Choices in Obesity?

Obesity is associated with a diverse array of cognitive and affective deficits, among which impairments in food valuation and choices have received increasing attention. The neural underpinnings of such impairments, however, remain poorly understood, partly because a complete understanding of these processes under normal conditions has yet to be achieved. A rapidly growing literature on the interaction between memory and decision-making has begun to highlight the integral role of memory in decision making especially in the real world, as well as the role of the hippocampus in supporting flexible decision making. Perhaps not coincidentally, altered memory performances in obesity have been well documented, and the underlying neurobiological bases of these memory alterations have also started to be better described, involving pathologies at the biochemical, cellular, and circuit levels. Despite such correspondence, the link between memory impairments and food valuation/choice deficits in obesity has received little attention. In this article, we first summarize the growing empirical support for the relevance of memory for decision making, focusing on flexible value-based decisions. We then describe converging evidence on different forms of memory impairments accompanying obesity. Building on these findings, we formulate a general neuropsychological framework and discuss how dysfunctions in the formation and retrieval of memory may interfere with adaptive decision making for food. Finally, we stress the important practical implications of this framework, arguing that memory deficits are likely a significant contributor to suboptimal food purchase and eating behavior exhibited by obese individuals.

Central Modulation of Energy Homeostasis and Cognitive Performance After Bariatric Surgery

In moderately or morbidly obese patients, bariatric surgery has been proven to be an effective therapeutic approach to control body weight and comorbidities. Surgery-mediated modulation of brain function via modified postoperative secretion of gut peptides and vagal nerve stimulation was identified as an underlying mechanism in weight loss and improvement of weight-related diseases. Increased basal and postprandial plasma levels of gastrointestinal hormones like glucagon-like peptide 1 and peptide YY that act on specific areas of the hypothalamus to reduce food intake, either directly or mediated by the vagus nerve, are observed after surgery while suppression of meal-induced ghrelin release is increased. Hormones released from the adipose tissue like leptin and adiponectin are also affected and leptin plasma levels are reduced in treated patients. Besides homeostatic control of body weight, surgery also changes hedonistic behavior in regard to food intake and cognitive performance involving the limbic system and prefrontal areas.

Obesity and episodic memory function

Obesity-related lifestyle factors, such as physical activity behavior and dietary intake, have been shown to be associated with episodic memory function. From animal work, there is considerable biological plausibility linking obesity with worse memory function. There are no published systematic reviews evaluating the effects of obesity on episodic memory function among humans, and examining whether physical activity and diet influences this obesity-memory link. Thus, the purpose of this systematic review was to evaluate the totality of research examining whether obesity is associated with episodic memory function, and whether physical activity and dietary behavior confounds this relationship. A review approach was employed, using PubMed, PsychInfo, and Sports Discus databases. Fourteen studies met our criteria. Among these 14 reviewed studies, eight were cross-sectional, four were prospective, and two employed a randomized controlled experimental design. Twelve of the 14 studies did not take into consideration dietary behavior in their analysis, and similarly, nine of the 14 studies did not take into consideration participant physical activity behavior. Among the 14 studies, ten found an inverse association of weight status on memory function, but for one of these studies, this association was attenuated after controlling for physical activity. Among the 14 evaluated studies, four did not find a direct effect of weight status on memory. Among the four null studies, one, however, found an indirect effect of BMI on episodic memory and another found a moderation effect of BMI and age on memory function. It appears that obesity may be associated with worse memory function, with the underlying mechanisms discussed herein. At this point, it is uncertain whether adiposity, itself, is influencing memory changes, or rather, whether adiposity-related lifestyle behaviors (e.g., physical inactivity and diet) are driving the obesity-memory relationship.

An overview of complications affecting the Central Nervous System following bariatric surgery

Bariatric surgery has been considered as an effective treatment for morbid obesity. Apart from procedures related complications, a broad spectrum of neurological disorders affecting any part of neuraxis has been reported following BS. Central nervous system complications, although less common than peripheral nervous system complications, carry significant morbidity and potential mortality. Encephalopathy, behavioral and psychiatric disorders, myelopathy and optic neuropathy are the most frequently reported CNS complications. Early detection and prompt management may improve or completely reverse these neurological complications. It is essential that the treating physicians must be aware of their clinical manifestations and management, so early diagnosis and treatment can prevent patients from suffering significant neurological deficits and even death. This review discusses the clinical manifestations of these complications in detail which will help concerned physician in earlier recognition and hence prevent the delay in specific treatment.

Obesity and neurological disorders: Dietary perspective of a global menace

Obesity is considered a major public health concern throughout the world among children, adolescents, as well as adults and several therapeutic, preventive and dietary interventions are available. In addition to life style changes and medical interventions, significant milestones have been achieved in the past decades in the development of several functional foods and dietary regimens to reduce this menace. Being a multifactorial phenomenon and related to increased fat mass that adversely affects health, obesity has been associated with the development of several other co-morbidities. A great body of research and strong scientific evidence identifies obesity as an important risk factor for onset and progression of several neurological disorders. Obesity induced dyslipidaemia, metabolic dysfunction, and inflammation are attributable to the development of a variety of effects on central nervous system (CNS). Evidence suggests that neurological diseases such as Parkinson's disease and Alzheimer's disease could be initiated by various metabolic changes, related to CNS damage, caused by obesity. These metabolic changes could alter the synaptic plasticity of the neurons and lead to neural death, affecting the normal physiology of CNS. Dietary intervention in combination with exercise can affect the molecular events involved in energy metabolism and synaptic plasticity and are considered effective non-invasive strategy to counteract cognitive and neurological disorders. The present review gives an overview of the obesity and related neurological disorders and the possible dietary interventions.

Changes in Cognitive Function Following Bariatric Surgery: a Systematic Review

Increased body mass is directly associated with reduced cognitive function. The aim of this study was to systematically review the effect of bariatric weight loss surgery on cognitive function. A comprehensive and unrestricted literature search was conducted using the following databases: MEDLINE, EMBASE, PubMed, Scopus, Web of Sciences, and the Cochrane Library. A total of 414 publications were identified, of which 18 were included in the final review. Cognitive function as measured by a number of different assessment tools was shown to improve following surgically induced weight loss in most studies. Significant and rapid weight loss resulting from bariatric surgery is associated with prompt and sustained improvements in cognitive function including memory, executive function, and cognitive control.

Physical Activity, Decision-Making Abilities, and Eating Disturbances in Pre- and Postbariatric Surgery Patients

BACKGROUND

Physical activity (PA) is considered to have a beneficial influence on executive functioning, including decision-making. Enhanced decision-making after bariatric surgery may strengthen patients' ability to delay gratification, helping to establish appropriate eating behavior. The objectives of this study were to (1) compare a preoperative group with a postoperative group with regard to daily PA, decision-making, and eating disturbances; and (2) investigate the relationship between these variables.

METHODS

The study included 71 bariatric surgery candidates (78 % women, BMI [kg/m²] M = 46.9, SD = 6.0) and 73 postoperative patients (78 % women, BMI M = 32.0, SD = 4.1; 89 % Roux-en-Y gastric bypass, 11 % sleeve gastrectomy; months postoperative M = 8.2, SD = 3.5; total weight loss [%] M = 33.2, SD = 8.9) who completed SenseWear Pro₂ activity monitoring. Decision-making was assessed using a computerized version of the Iowa Gambling Task and eating disorder psychopathology using the Eating Disorder Examination-Questionnaire.

RESULTS

The number of patients who were classified as physically inactive was similarly high in the pre- and postoperative groups. No group differences emerged with regard to decision-making, but the postoperative group exhibited less eating disturbances than the preoperative group. No significant associations were found between PA, decision-making, and eating behavior.

CONCLUSIONS

Patients after bariatric surgery were not more physically active than bariatric surgery candidates, which should be considered in care programs. Additionally, future research is needed to explore the possible link between PA, patients' decision-making abilities, and eating disturbances concerning dose-response questions.

Neurological consequences of obesity

The high prevalence of obesity is associated with an enormous medical, social, and economic burden. The metabolic dysfunction, dyslipidaemia, and inflammation caused by obesity contribute to the development of a wide variety of disorders and effects on the nervous system. In the CNS, mild cognitive impairment can be attributed to obesity-induced alterations in hippocampal structure and function in some patients. Likewise, compromised hypothalamic function and subsequent defects in maintaining whole-body energy balance might be early events that contribute to weight gain and obesity development. In the peripheral nervous system, obesity-driven alterations in the autonomic nervous system prompt imbalances in sympathetic-parasympathetic activity, while alterations in the sensory-somatic nervous system underlie peripheral polyneuropathy, a common complication of diabetes. Pharmacotherapy and bariatric surgery are promising interventions for people with obesity that can improve neurological function. However, lifestyle interventions via dietary changes and exercise are the preferred approach to combat obesity and reduce its associated health risks.

Adverse effects of consuming high fat–sugar diets on cognition: implications for understanding obesity

There is increasing evidence for important roles of key cognitive processes, including attention, memory and learning, in the short-term decision making about eating. There is parallel evidence that people who are overweight or obese tend to perform worse on a variety of cognitive tasks. In this review, the evidence for these two ideas is summarised and then the idea that overconsumption of Western-style high-fat (HF)–high-sugar diets may underlie the association between obesity and poorer cognitive performance is explored. In particular, evidence in animals and human subjects that repeated consumption of HF or HF and sugar (HFS) diets leads to specific impairments in the functioning of the hippocampus, which underpin the consequent changes in cognition is summarised. These findings lead into the vicious cycle model (VCM), which suggests that these cognitive changes have knock-on negative effects for future appetite control, and evidence that altered hippocampal function is also associated with impaired appetite control is explored. The review concludes that there is consistent evidence in the animal literature and emerging evidence from human studies that supports this VCM. It is also noted, however, that to date studies lack the nutritional specificity needed to be able to translate these basic research findings into clear nutritional effects, and concludes that there is an urgent need for additional research to clarify the precise nature of the apparent effects of consuming HFS diets on cognition.

Attention Deficit Hyperactivity Disorder Prevalence and Correlates Pre- and Post-Bariatric Surgery: A Comparative Cross-Sectional Study

OBJECTIVE

Previous research shows an association between obesity and attention deficit hyperactivity disorder (ADHD). The present study compares pre- and post-bariatric surgery patients using the internationally used Conners' Adult ADHD Rating Scale (CAARS™) to screen for ADHD.

METHODS

Matched samples pre- (N = 120) and post-bariatric surgery (N = 128) were compared using self-rating instruments to assess ADHD-relevant symptomatology, depression, eating-related psychopathology, and BMI.

RESULTS

Prevalence of probable ADHD did not differ between groups using the CAARS Index Scale T-scores; however, CAARS subscales Inattention/Memory and Self-Concept showed significantly lower scores in post-surgery patients. All CAARS subscales correlated significantly with each other, with depression and eating-related psychopathology. There was no correlation between ADHD and excess BMI loss in post-surgery patients.

CONCLUSION

The findings suggest that a considerable number of patients before and after bariatric surgery screened positive for ADHD. It can be hypothesized that some core ADHD symptoms improve after surgery. Future studies are warranted to investigate the influence of ADHD on long-term surgery outcomes.

Weight loss is associated with improvements in cognitive function among overweight and obese people: A systematic review and meta-analysis

Whilst obesity is associated with a higher risk of cognitive impairment, the influence of weight loss on cognitive function in obese/overweight people is equivocal. We conducted a meta-analysis of randomized controlled trials (RCTs) and longitudinal studies evaluating the influence of voluntary weight loss on cognitive function in obese/overweight individuals. Articles were acquired from a systematic search of major databases from inception till 01/2016. A random effect meta-analysis of weight loss interventions (diet, physical activity, bariatric surgery) on different cognitive domains (memory, attention, executive functions, language and motor speed) was conducted. Twenty studies (13 longitudinal studies=551 participants; 7 RCTs=328 treated vs. 140 controls) were included. Weight loss was associated with a significant improvement in attention and memory in both longitudinal studies and RCTs, whereas executive function and language improved in longitudinal and RCT studies, respectively. In conclusion, intentional weight loss in obese/overweight people is associated with improvements in performance across various cognitive domains. Future adequately powered RCTs are required to confirm/refute these findings.

Cognitive dysfunction predicts poorer emotion recognition in bariatric surgery candidates

OBJECTIVE

Deficits in traditional cognitive domains (e.g. executive function and memory) are common in persons with severe obesity, but it is unclear if this pattern of dysfunction extends to social cognition. The present study examined whether cognitive impairment was associated with poorer emotion recognition in bariatric surgery candidates.

METHODS

One hundred sixteen bariatric surgery candidates (mean age = 43.62 ± 11.03; 81% female) completed the computerized Integneuro test battery as part of a larger study visit. In addition to assessing traditional cognitive domains, the Integneuro also includes an emotion recognition measure. This task presents 48 faces (eight different individuals depicting neutral, happiness, fear, sadness, anger and disgust), and participants must choose the correct verbal label from six expression options. Number of correct responses and average reaction time for correct responses served as primary dependent variables.

RESULTS

Stepwise multiple regression analyses revealed that older age, more maze errors, and history of hypertension predicted less accuracy in emotion recognition (adjusted R² = .22, F[3, 111] = 11.86, p < .001) and that slower switching of attention-digits, worse long-delay recall, and older age predicted speed of responses (adjusted R² = .26, F[3, 111] = 13.00, p < .001).

DISCUSSION

Results show that cognitive dysfunction is associated with poorer performance on a computerized test of emotion recognition, consistent with those in persons with a range of psychiatric and neurological disorders. Additional work is needed to clarify the mechanisms and functional impact of these impairments, especially in relation to weight loss following bariatric surgery.

Sex and Race Differences in the Relationship between Obesity and C-Reactive Protein

C-reactive protein (CRP) is a risk factor for cardiovascular disease and mortality; it is known to be positively associated with obesity but there is some evidence that this association differs by race or sex. We used nationally representative data of adults aged >50 years to investigate sex and race modifiers of the associations between obesity and CRP in non-Hispanic White males (n=3,517) and females (n=4,658), and non-Hispanic Black males (n=464) and females (n=826). Using multiple linear regression models with the natural logarithm of CRP as the dependent variable, we sequentially included body mass index (BMI), a body shape index (ABSI), and socioeconomic, health and health behavior covariates in the model. The association between BMI and CRP was significantly stronger in females than males. Obese White females had mean CRP values slightly above 3 mg/liter (vs 2 for White males) and Black females had mean CRP values >4 mg/liter (vs 3 for Black males). More than 50% of Black females in the United States have obesity. Continued research into racial and sex differences in the relationship between obesity, inflammation, and health risks may ultimately lead to more personalized weight loss recommendations.

Characterization of Executive Functioning in a Portuguese Sample of Candidates for Bariatric Surgery

Aim

The prevalence of obesity has been steadily increasing and is a major worldwide public health problem. It is associated with multiple medical and psychological conditions and recent research supports a link to several cognitive deficit domains, including executive functioning. The aim of this article is to describe socio-demographic, clinical and neuropsychological characteristics of a sample of candidates for bariatric surgery (BS) and to compare their performance with normative values.

Method

Between May 2012 and May 2013 we evaluated the neuropsychological performance of 42 patient candidates for BS at the Morbid Obesity Consultation at Centro Hospitalar Lisboa Norte (CHLN).

Results

The population was predominantly female and education was equally distributed between basic, secondary and tertiary levels. The neuropsychological results showed a significant decrease on Recall (p < .01), Learning (p < .10), Nonverbal Memory (p < .001), Cognitive Flexibility (p < .01) and Resistance to Interference (p < .05).

Conclusion

Despite the limitations inherent to a small sample, the results obtained in the Portuguese population coincide with those of earlier studies; namely that obesity differentially effects instrumental functions.