Cognitive Impairment, Obesity, and the Effects of Bariatric Surgery

December 3, 2025 updated by: University of California, Davis
Study is designed to screen psychological cognitive baseline and retention/improvement after weight loss surgery.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Detailed Description

Patients with morbid obesity have shown to be at increased risk for memory loss and cognitive decline. Obesity and high-fat diets have been associated with deficits in learning, memory, and executive functioning. Bariatric surgery results in significant weight loss for patients and helps resolve obesity-related comorbidities such as diabetes and high blood pressure. Interestingly, bariatric surgery has shown promise in improving some aspects of cognitive function and improved memory. (3-1) Obesity affects brain structure, more specifically the grey and white matter, likely in part by reducing oxygen flow to the various regions in the brain. Studies have shown a correlation between BMI and cerebral blood flow velocity (CBFV), where higher BMI is associated with lower CBFV. Although it is not clear how exactly obesity plays a role in the brain's structural and functional changes, observations revealed compromised grey and white matter integrity, its fiber connectivity or cortical atrophy and metabolic alterations. (2)

Few studies exist on the impact of bariatric surgery on cognition. Some studies have shown that patients with obesity who underwent bariatric surgery had memory and cognitive improvement compared to those who had not undergone surgery. (4) Thus, the investigators hope to add to our understanding of how bariatric surgery can improve cognitive decline and to potentially offer surgery to more patients with baseline cognitive impairment and to improve cognitive function overall for patients with obesity. More longitudinal studies need to be done to connect bariatric surgery effects with cognitive decline, specifically memory.

Study Type

Observational

Enrollment (Estimated)

9500

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Sacramento, California, United States, 95817
        • University of California Davis Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Subjects seeking weight loss surgery or with a history of weight loss surgery at University of California Davis Medical Center 18 years of age or older

Description

Inclusion Criteria:

  • Cognitive impairment/decline, memory impairment/loss, or Alzheimer's disease or dementia and bariatric surgery • Cognitive impairment/decline, memory impairment/loss, or Alzheimer's disease or dementia and obesity, and no bariatric surgery history

Exclusion Criteria:

  • Patients without a history of memory impairment/loss, bariatric surgery, or obesity

    • Patients outside of University of California Davis Health System
    • Patients unable to provide consent

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Surgery
Patients scheduled for or have already completed Weight Loss Surgery at UC Davis Medical Center
Behavioral: Surgery
Study subjects scheduled for or have already completed weight loss surgery and have already completed psychological screening as part of their pre-surgery work up

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
California Verbal Learning Test-3rd Edition (CVLT-3)
Time Frame: Pre-operatively
Measures episodic verbal learning including Verbal Learning, immediate memory, and delayed memory
Pre-operatively
California Verbal Learning Test-3rd Edition (CVLT-3)
Time Frame: 12 Months after index screening/date of surgery
Measures episodic verbal learning including Verbal Learning, immediate memory, and delayed memory
12 Months after index screening/date of surgery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Brief Visuospatial Memory Test
Time Frame: Pre-operatively and 12 months after index screening/date of surgery
Measures visuospatial learning and memory, including visual learning, immediate memory, and delayed memory.
Pre-operatively and 12 months after index screening/date of surgery
Brief Visuospatial Memory Test
Time Frame: Pre-operatively
Measures visuospatial learning and memory, including visual learning, immediate memory, and delayed memory.
Pre-operatively
Trial Making Test, A & B
Time Frame: 12 months after index screening/date of surgery
Measures visual spatial attention, motor speed and cognitive flexibility
12 months after index screening/date of surgery
WAIS-IV Digit Span Forward & Backward
Time Frame: Pre-Operatively
Measures auditory Attention (Forward), and Auditory attention and working memory (Backward)
Pre-Operatively
WAIS-IV Digit Span Forward & Backward
Time Frame: 12 months after Index screening/date of surgery
Measures auditory Attention (Forward), and Auditory attention and working memory (Backward)
12 months after Index screening/date of surgery
Verbal Fluency, Phonemic & Semantic
Time Frame: Pre-operatively
Measures verbal fluency by a word generation task based on letter & category (executive functioning)
Pre-operatively
Verbal Fluency, Phonemic & Semantic
Time Frame: 12 months after index screening/date of surgery
Measures verbal fluency by a word generation task based on letter & category (executive functioning)
12 months after index screening/date of surgery
Stroop Color and Word Test; Word, Color & Word-Color
Time Frame: Pre-Operatively
Measures reading speed (word), naming speed (processing) and selective attention and inhibition (attention/executive functioning)
Pre-Operatively
Stroop Color and Word Test; Word, Color & Word-Color
Time Frame: 12 months after index screening/date of surgery
Measures reading speed (word), naming speed (processing) and selective attention and inhibition (attention/executive functioning)
12 months after index screening/date of surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of California, Davis

Investigators

  • Principal Investigator: Victoria Lyo, MD, University of California, Davis

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2022

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2028

Study Registration Dates

First Submitted

January 18, 2022

First Submitted That Met QC Criteria

January 18, 2022

First Posted (Actual)

January 31, 2022

Study Record Updates

Last Update Posted (Actual)

December 5, 2025

Last Update Submitted That Met QC Criteria

December 3, 2025

Last Verified

December 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1812245

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

No plan in place (yet) for data sharing

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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