Focal brain atrophy in gastric bypass patients with cognitive complaints

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.

A Case of Bariatric Surgery-related Wernicke-Korsakoff Syndrome with Persisting Anterograde Amnesia

Objective

To describe the theoretical and clinical implications of the neuropsychological evaluation of a case of bariatric surgery-related Wernicke-Korsakoff syndrome.

Method

The patient was a 37-year old, female, bilingual, bachelor's degree educated, Mexican American public relations consultant without preexisting psychiatric, neurological, or substance abuse history. Recovery from laparoscopic sleeve gastrectomy surgery for morbid obesity was complicated by intraabdominal abscess, multibacterial infection, and prolonged nausea and vomiting. About 15 weeks post-surgery she was diagnosed with Wernicke's encephalopathy. She had a positive response to thiamine supplement but was left with persisting self-reported memory problems that were confirmed by family members. Multiple neuroimaging studies were all normal.

Results

A neuropsychological evaluation at 14 months post-surgery revealed anterograde amnesia for verbal and visual-perceptual material. There was no clear period of temporally graded retrograde amnesia. Scores on tests of visual-perceptual, language, fine motor, and executive functions were unimpaired. She had awareness of her neurocognitive impairment, but did not exhibit emotional distress. Follow-up neuropsychological evaluation at 17 months showed a similar neurocognitive profile with increased emotional distress.

Conclusions

Her preserved executive functioning is theoretically important as it supports arguments that such impairment in alcohol use-related Korsakoff syndrome derives from the toxic effects of the prolonged misuse of alcohol and not vitamin deficiency. From a clinical perspective, neuropsychological evaluation of thiamine treated, bariatric surgery-related, Wernicke's encephalopathy cases is indicated if there is suspicion of residual memory impairment.

Exploring Postoperative Cognitive Dysfunction and Delirium in Noncardiac Surgery Using MRI: A Systematic Review

Surgical patients are at high risk of developing postoperative cognitive dysfunction (POCD) and postoperative delirium (POD). POCD and POD are associated with increased morbidity and mortality and worsening functional outcomes leading to severe socioeconomic consequences for the patient and the society in general. Magnetic resonance imaging (MRI) offers a unique opportunity to study the anatomy and function of the brain. MRI thus plays an important role in elucidating the neuronal component of POCD and POD. Our aim has been to systematically gather MRI findings that are related to POCD and POD. Systematic searches were conducted in PubMed, EMBASE, and PsycINFO: MRI studies investigating patients with POCD as identified by perioperative cognitive testing or patients with delirium identified postoperatively by the Confusion Assessment Method. A total of ten eligible papers were included with a total of 269 surgical patients, 36 patient controls, and 55 healthy controls who all underwent MRI examination. These studies suggested that reduction of thalamic and hippocampal volumes and reduction of cerebral blood flow may be associated with POCD, while presurgery/preexisting and postoperative white matter pathology may be associated with POD. However, the evidence from these studies is rather weak. Future MRI studies are warranted to verify the current findings.

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.

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.

Neuropsychiatric features associated with nutritional and metabolic status in a gastric bypass patient

Bariatric patients may present for psychiatric evaluation due to exacerbation of preexisting psychiatric disorders, new onset psychiatric disorders and/or neuropsychiatric complications associated with abnormal nutritional and metabolic states following the surgical procedure. These neuropsychiatric complications can be insidious, and clinical manifestations may vary, possibly due to the individual central nervous system (CNS) vulnerability to nutritional decline. Lack of awareness of these complications and their symptoms can result in delays in diagnosis and treatment. Identifying and correcting underlying pathophysiologic processes that lead to such neuropsychiatric syndromes can be challenging. We report a case of a patient who developed a protracted course of mood and cognitive disorder after gastric bypass surgery, which illustrates some of the complexities encountered in diagnosing and managing these patients.

Can bariatric surgery reduce risk of Alzheimer's disease?

Recent studies demonstrate that obesity is independently associated with poor neurocognitive outcomes, including cognitive impairment, increased risk for dementia, and regional alterations in brain structure. Bariatric surgery is an effective treatment for obesity and initial findings suggest that it may result in cognitive improvements. The current paper reviews and integrates recent research in this area, with a focus on potential mediators and moderators of neuropsychological outcome in bariatric surgery patients, including anesthetic and nutritional complications, and proposes novel avenues for continued study in this area.