Relationship Between Diabetes and Cognitive Impairment Based on Olfactory Function Assessment and Functional MRI

Study Overview
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Brief Summary
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The purpose of this study is to explore the relationship between diabetes and cognitive impairment by olfactory function assessment and functional MRI.

Detailed Description
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Previous research has shown both obesity and diabetes are associated with an increased risk of cognitive impairment. Meanwhile, olfactory impairment is associated with incident (amnestic mild cognitive impairment) aMCI and progression from aMCI to (Alzheimer disease) AD dementia. On one hand, in the cross-sectional study, biometric measurements, cognitive assessment, olfactory function and fMRI results are analysed to explore the differences among T1DM patients, T2DM patients and non-diabetic people . One the other hand, in the longitudinal study, changes in olfactory function and fMRI results in diabetic and non-diabetic obese patients both at baseline and 6 months after their bariatric surgery are collected to investigate whether better glucose and weight control benefit brain function.

Official Title
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The Cross-sectional and Longitudinal Study of Relationship Between Diabetes and Cognitive Impairment by Olfactory Function Assessment and Functional MRI in Obese and Normal Weight Diabetic Patients

Conditions
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Diabetes Mellitus, Cognitive Impairment, Obesity

Intervention / Treatment
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* Behavioral: Cognitive assessment
* Other: functional magnetic resonance imaging
* Other: olfactory function measurement
* Procedure: bariatric surgery


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Have a certain level of education (at least 6 years), able to complete the cognitive assessment; Disease duration >1 year. Exclusion Criteria: Control participants would be excluded if they had a fasting blood glucose level >7.0 mmol/L; glucose level> 7.8 mmol/L after oral glucose tolerance test (OGTT); Montreal Cognitive Assessment (MoCA,Beijing edition) score of < 20; History of neurologic or psychological illness; History of cardiovascular or cerebrovascular disease; Abnormal results of thyroid hormones, vitamin B12, and folate. Metal implants, unable to complete the MR examinations or evidence of cortical infarcts, hemorrhage, or structural brain disease other than atrophy, lacunes, or white matter lesions; Left-handed; Partial or complete olfactory dysfunction associated with sinusitis,allergic rhinitis, and deviated nasal septum.

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Type 1 Diabetes Mellitus<br>These T1DM patients have late diabetes onset.(latent autoimmune diabetes in adult, LADA) | Behavioral: Cognitive assessment<br> <br> Other: functional magnetic resonance imaging<br> <br> * Other names: fMRI;Other: olfactory function measurement<br> <br> |
| Type 2 Diabetes Mellitus<br>A subgroup of these T2DM patients are obesity patients who will have the bariatric surgery. These obese T2DM subjects will undergo a physical exam, cognitive and olfactory test as well as structural and functional brain MRI at baseline and 6 months after their surgery. | Behavioral: Cognitive assessment<br> <br> Other: functional magnetic resonance imaging<br> <br> * Other names: fMRI;Other: olfactory function measurement<br> <br> Procedure: bariatric surgery<br>* Only a subgroup of the subjects will have the bariatric surgery.<br>|
| Control<br>A subgroup of these non-diabetic people are obesity patients who will have the bariatric surgery. These obese subjects will undergo a physical exam, cognitive and olfactory test as well as structural and functional brain fMRI at baseline and 6 months after their surgery. | Behavioral: Cognitive assessment<br> <br> Other: functional magnetic resonance imaging<br> <br> * Other names: fMRI;Other: olfactory function measurement<br> <br> Procedure: bariatric surgery<br>* Only a subgroup of the subjects will have the bariatric surgery.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Participants' personal information | Self-reported information(education in years) | 1 day | 
| Glycaemic control measured by blood test. | HbA1c | 1 day | 
| Physical assessments. | BMI(body mess index) in kg/m^2 | 1 Day | 
| Olfactory threshold test | Olfactory threshold test: The same odor with 2 different concentrations are given to the participant each time to find out which one is more intense. (Olfactory software will analyse and give threshold score depending on participant's choice.) | 1 day | 
| Olfactory memory test: | PART A: Participants are shown 4 pictures for each odor(10 odors in total). They select what they sniffed. 10 minutes break. PART B: Participants sniff 20 different odors , 10 of which are same odors in PART A. They select the picture and figure out whether the odor is old or new. | 1 day | 
| Montreal Cognitive Assessment (MoCA) | The MoCA is a cognitive screening test designed to assist Health Professionals in detection of mild cognitive impairment. | 1 Day | 
| Functional MRI of the brain tracking testing. |  | 1day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change form baseline Glycaemic control measured by blood test. | HbA1c | 6 months after the bariatric surgery (for diabetic and non-diabetic obese patients) | 
| Change from baseline Functional magnetic resonance imagine |  | 6 months after the bariatric surgery (for diabetic and non-diabetic obese patients) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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functional MRI, olfactory function, bariatric surgery