Investigating Metabolic, Brain, and Cognitive Alterations Through Bariatric Surgery

Difference between MRI-predicted brain age and chronological age based (delta age, years) derived from a validated machine learning model based on MRI modalities.

Composite z-score derived from the Stroop Color-Word Interference test, Trail Making Test Part B and Digit Span Test ( z-score change).

Composite z-score derived from the Digit Symbol Substitution Test, Trail Making Test Part A, Stroop Color-Word Interference (z-score change).

Composite z-score derived from the Rey Auditory Verbal Learning Test (z-score change).

Montreal Cognitive Assessment (MoCA) score (0-30), with higher scores indicating better cognitive performance.

Mean fractional anisotropy (FA) derived from diffusion tensor imaging (dimensionless, 0-1); Higher FA values generally reflect greater white matter microstructural organization and fiber tract integrity.

Mean diffusivity (MD; mm²/s) derived from diffusion tensor imaging. Higher MD values generally reflect reduced white matter microstructural integrity and increased water diffusion within tissue.

Grey matter density measured using voxel-based morphometry derived from T1-weighted structural MRI (arbitrary units).

Mean cortical thickness (mm) and total surface area (mm²) derived from T1-weighted MRI.

Total white matter hyperintensity volume (mm3) segmented from 3D FLAIR MRI.

Mean arterial lumen diameter (mm) measured in predefined cerebral arteries using TOF-MRA.

Total cerebral arterial volume (mm³) measured from TOF-MRA using automated vessel segmentation.

Regional and whole-brain cerebral blood flow (mL/100g/min) derived from ASL sequences.

Magnetic susceptibility derived from quantitative susceptibility mapping (QSM), a surrogate marker of cerebral iron content (seconds).

Quantitative MRI estimate of brain Water content (%).

Myelin quantitative MRI measure (myelin water fraction, %).

BMI (kg/m2)

Excess weight loss (%)

Total weight (kg), Fat mass (kg) measured by bioimpedance or DXA.

Waist, Hip and Neck circumference (cm).

Fasting glucose (mmol/L)

HbA1c (%)

Fasting Insulin (pmol/L)

HOMA-IR index (fasting glucose (mmol/L) x fasting insulin (pmol/L) / 135)

Fasting Total Cholesterol (mmol/L), High Density Lipoprotein (HDL) cholesterol (mmol/L), Low Density Lipoprotein (LDL) cholesterol (mmol/L), Triglycerides (mmol/L), Apolipoprotein-B (g/L).

Systolic and diastolic blood pressure (mmHg).

CRP (mg/L), IL-6 (pg/mL), LBP (g/mL), BDNF (pg/mL)

Postprandial GLP-1 (pg/mL) and fasting total ghrelin (pmol/L).

Fasting Leptin concentration (ng/mL)

Healthy Eating Index (HEI) Score; Minimum: 0, Maximum: 100.

The Three-Factor Eating Questionnaire (TFEQ) will be used to assess three dimensions of eating behavior: cognitive restraint of eating, uncontrolled/disinhibited eating, and susceptibility to hunger. The questionnaire generates subscale scores for each dimension, with higher scores indicating greater levels of the respective eating behavior construct.

To assess the presence of certain binge eating behaviors that may be indicative of an eating disorder. The higher the score, the more binge eating behaviors is observed. The minimum score is 0 while the maximum score is 46. The final result allows to determine if the person has an absent (less than 17), moderate (between 18 and 26) or severe (more than 27) binging level.

Laval questionnaire evaluating quality of life on 6 aspects on a scale from 0 to 7, higher scores indicate better quality of life.

Beck Depression Inventory. Evaluates severity of depressive symptoms using a validated questionnaire. Minimum score : 0; Maximum score : 63; Higher scores mean a worse outcome.

General Anxiety Disorder questionnaire (GAD-7). Total score ranges from 0 to 21, with an increasing score on the scale is indicating a worse anxiety state.

Pittsburgh Sleep Quality Index questionnaire (PSQI) (19 self-assessment questions grouped into seven components). The scores for the seven components are summed to give an overall score that ranges from 0 to 21, with "0" indicating no difficulty and "21" indicating severe difficulty in all components. A score higher than 5 indicates problematic sleep in one or more components.

Physical activity measured using accelerometry. Outcomes include daily moderate-to-vigorous physical activity (minutes/day) and sedentary time (minutes/day).