Obesity, MorbidNCT05215886
Cognitive Impairment, Obesity, and the Effects of Bariatric Surgery
An observational study of Obesity, Morbid and Bariatric Surgery Candidate, run by University of California, Davis at 1 site in United States.
Trial summary
Study is designed to screen psychological cognitive baseline and retention/improvement after weight loss surgery. Read more about this study
- Who is it for?
- Ages 18 to 75 years
- Conditions the study is for
- Obesity, Morbid, Bariatric Surgery Candidate
- What is being tested?
- Surgery
- Type of treatment
- Lifestyle or therapy programme
- How many people
- 9,500 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Jan 2022to 31 Dec 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
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
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
University of California Davis Medical Center
Sacramento, California, 95817
About this study
Study is designed to screen psychological cognitive baseline and retention/improvement after weight loss surgery.
Read the 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.
- Conditions
- Obesity, Morbid, Bariatric Surgery Candidate
- Being tested
- Surgery
- Keywords
- Obesity, Bariatric Surgery, Cognitive Screening
- Medical subject headings
- Obesity, Morbid, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SurgeryBehavioural
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
| Study group | Role | What they receive |
|---|---|---|
| Surgery | Patients scheduled for or have already completed Weight Loss Surgery at UC Davis Medical Center Receives: Behavioral: Surgery |
What is being measured
The primary outcome is the main question the study is designed to answer.
California Verbal Learning Test-3rd Edition (CVLT-3)
Measures episodic verbal learning including Verbal Learning, immediate memory, and delayed memory
Measured: Pre-operatively
California Verbal Learning Test-3rd Edition (CVLT-3)
Measures episodic verbal learning including Verbal Learning, immediate memory, and delayed memory
Measured: 12 Months after index screening/date of surgery
Secondary outcomes (9)
Brief Visuospatial Memory Test
Measures visuospatial learning and memory, including visual learning, immediate memory, and delayed memory.
Measured: Pre-operatively and 12 months after index screening/date of surgery
Brief Visuospatial Memory Test
Measures visuospatial learning and memory, including visual learning, immediate memory, and delayed memory.
Measured: Pre-operatively
Trial Making Test, A & B
Measures visual spatial attention, motor speed and cognitive flexibility
Measured: 12 months after index screening/date of surgery
WAIS-IV Digit Span Forward & Backward
Measures auditory Attention (Forward), and Auditory attention and working memory (Backward)
Measured: Pre-Operatively
WAIS-IV Digit Span Forward & Backward
Measures auditory Attention (Forward), and Auditory attention and working memory (Backward)
Measured: 12 months after Index screening/date of surgery
Verbal Fluency, Phonemic & Semantic
Measures verbal fluency by a word generation task based on letter \& category (executive functioning)
Measured: Pre-operatively
Verbal Fluency, Phonemic & Semantic
Measures verbal fluency by a word generation task based on letter \& category (executive functioning)
Measured: 12 months after index screening/date of surgery
Stroop Color and Word Test; Word, Color & Word-Color
Measures reading speed (word), naming speed (processing) and selective attention and inhibition (attention/executive functioning)
Measured: Pre-Operatively
Stroop Color and Word Test; Word, Color & Word-Color
Measures reading speed (word), naming speed (processing) and selective attention and inhibition (attention/executive functioning)
Measured: 12 months after index screening/date of surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Jan 2022
- Study start1 Jan 2022
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Obesity, MorbidStudies of the same condition, open and under way.
- More trials run by University of California, DavisThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Cross-sectional
- Enrolment
- 9,500 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Davis
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Victoria Lyo, MD, Principal investigator, University of California, Davis
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05215886
- Sponsor's protocol ID
- 1812245
- Status last verified
- Dec 2025
- First submitted
- 18 Jan 2022
- Last updated
- 5 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: No plan in place (yet) for data sharing
Publications
Alosco ML, Spitznagel MB, Strain G, Devlin M, Cohen R, Paul R, Crosby RD, Mitchell JE, Gunstad J. Improved memory function two years after bariatric surgery. Obesity (Silver Spring). 2014 Jan;22(1):32-8. doi: 10.1002/oby.20494. Epub 2013 Oct 15.
PubMed 23625587Nota MHC, Vreeken D, Wiesmann M, Aarts EO, Hazebroek EJ, Kiliaan AJ. Obesity affects brain structure and function- rescue by bariatric surgery? Neurosci Biobehav Rev. 2020 Jan;108:646-657. doi: 10.1016/j.neubiorev.2019.11.025. Epub 2019 Nov 30.
PubMed 31794778Miller AA, Spencer SJ. Obesity and neuroinflammation: a pathway to cognitive impairment. Brain Behav Immun. 2014 Nov;42:10-21. doi: 10.1016/j.bbi.2014.04.001. Epub 2014 Apr 12.
PubMed 24727365Stanek KM, Gunstad J. Can bariatric surgery reduce risk of Alzheimer's disease? Prog Neuropsychopharmacol Biol Psychiatry. 2013 Dec 2;47:135-9. doi: 10.1016/j.pnpbp.2012.06.021. Epub 2012 Jul 4.
PubMed 22771689
Study at a glance
From the registry record, last updated by the sponsor on 5 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cognitive Impairment, Obesity, and the Effects of Bariatric Surgery
- ClinicalTrials.gov ID
- NCT05215886
- Acronym / sponsor ID
- 1812245
- Conditions
- Obesity, Morbid, Bariatric Surgery Candidate
- Keywords
- Obesity, Bariatric Surgery, Cognitive Screening
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 9,500 participants (estimated)
- Lead sponsor
- University of California, DavisUniversity, hospital or other
- Study start
- 1 Jan 2022 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2028 (estimated)
- First posted
- 31 Jan 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Study is designed to screen psychological cognitive baseline and retention/improvement after weight loss surgery.
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 design
- Observational model
- Case only
- Time perspective
- Cross-sectional
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Surgery | – | Behavioral: SurgeryPatients scheduled for or have already completed Weight Loss Surgery at UC Davis Medical Center |
Who may qualify
- Ages
- 18 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- 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
Key inclusion criteria (1 listed)
- 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
Key exclusion criteria (3 listed)
- Patients without a history of memory impairment/loss, bariatric surgery, or obesity
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SurgeryStudy subjects scheduled for or have already completed weight loss surgery and have already completed psychological screening as part of their pre-surgery work up | Behavioural | Surgery |
Primary outcome
California Verbal Learning Test-3rd Edition (CVLT-3)
Time frame: Pre-operatively
Measures episodic verbal learning including Verbal Learning, immediate memory, and delayed memory
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
9 secondary outcomes
Brief Visuospatial Memory Test
Time frame: Pre-operatively and 12 months after index screening/date of surgery
Brief Visuospatial Memory Test
Time frame: Pre-operatively
Trial Making Test, A & B
Time frame: 12 months after index screening/date of surgery
WAIS-IV Digit Span Forward & Backward
Time frame: Pre-Operatively
WAIS-IV Digit Span Forward & Backward
Time frame: 12 months after Index screening/date of surgery
Verbal Fluency, Phonemic & Semantic
Time frame: Pre-operatively
Verbal Fluency, Phonemic & Semantic
Time frame: 12 months after index screening/date of surgery
Stroop Color and Word Test; Word, Color & Word-Color
Time frame: Pre-Operatively
Stroop Color and Word Test; Word, Color & Word-Color
Time frame: 12 months after index screening/date of surgery
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Dec 2025.
- Results publication: PubMed 23625587Alosco ML, Spitznagel MB, Strain G, Devlin M, Cohen R, Paul R, Crosby RD, Mitchell JE, Gunstad J. Improved memory function two years after bariatric surgery. Obesity (Silver Spring). 2014 Jan;22(1):32-8. doi: 10.1002/oby.20494. Epub 2013 Oct 15.
- Results publication: PubMed 31794778Nota MHC, Vreeken D, Wiesmann M, Aarts EO, Hazebroek EJ, Kiliaan AJ. Obesity affects brain structure and function- rescue by bariatric surgery? Neurosci Biobehav Rev. 2020 Jan;108:646-657. doi: 10.1016/j.neubiorev.2019.11.025. Epub 2019 Nov 30.
- Results publication: PubMed 24727365Miller AA, Spencer SJ. Obesity and neuroinflammation: a pathway to cognitive impairment. Brain Behav Immun. 2014 Nov;42:10-21. doi: 10.1016/j.bbi.2014.04.001. Epub 2014 Apr 12.
- Results publication: PubMed 22771689Stanek KM, Gunstad J. Can bariatric surgery reduce risk of Alzheimer's disease? Prog Neuropsychopharmacol Biol Psychiatry. 2013 Dec 2;47:135-9. doi: 10.1016/j.pnpbp.2012.06.021. Epub 2012 Jul 4.
- Individual participant dataSharing planned: Undecided. No plan in place (yet) for data sharing
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Victoria Lyo, MD principal investigator
University of California, Davis
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Obesity, Morbid and Bariatric Surgery Candidate, run by University of California, Davis at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 5 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
California Verbal Learning Test-3rd Edition (CVLT-3) (time frame: Pre-operatively). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05215886, which also lists 4 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Dec 2025.