Brain Energy for Amyloid Transformation in Alzheimer's Disease Study

Aβ40 is a peptide biomarker primarily used in the evaluation and diagnosis of Alzheimer's disease and other neurodegenerative conditions

total tau is a general indicator of neuronal degeneration and injury

ptau181 (phosphorylated tau 181) biomarker is a specialized protein used as a primary diagnostic indicator for Alzheimer's disease

NfL (Neurofilament Light Chain) biomarker is a tool for diagnosing, monitoring, and predicting the progression of various neurodegenerative and neurological diseases

Aβ42 is a a key Alzheimer's disease biomarker that reflects pathological aggregation of amyloid in the brain.

Aβ40 is a peptide biomarker primarily used in the evaluation and diagnosis of Alzheimer's disease and other neurodegenerative conditions

p-tau217 (phosphorylated tau at threonine 217) is a biomarker used to detect and predict the brain changes associated with Alzheimer's disease

pTau181 (phosphorylated tau 181) is a biomarker that serves as a primary diagnostic indicator for Alzheimer's disease

NfL (Neurofilament Light Chain) biomarker is a tool for diagnosing, monitoring, and predicting the progression of various neurodegenerative and neurological diseases

Hemoglobin A1c measures your average blood sugar levels over the past 2 to 3 months. Below 5.7% is normal, 5.7-6.4% indicates prediabetes, 6.5% or higher indicates diabetes.

The level of triglycerides (a type of fat) in blood with less than 150 mg/dL being normal.

LDL (low-density lipoprotein) is the amount of "bad" cholesterol in the blood. The optimal level is less than 100 mg/dL.

HDL (High-Density Lipoprotein) blood test measures the amount of "good" cholesterol in the blood. Optimal level is ≥ 60 mg/dL. Low HDL (<40 mg/dL for men, <50 mg/dL for women) indicates a higher risk for cardiovascular disease.

Measure of overall amount of cholesterol in the blood, which includes both "bad" (LDL) and "good" (HDL) cholesterol. Desirable level is less than 200 mg/dL with higher levels indicating greater risk for heart attack and stroke.

A blood ketone test specifically measures beta-hydroxybutyrate, the primary ketone in your blood. Under 0.6 mmol/L normal or negative. 0.6 to 1.5 mmol/L slightly elevated, body is in ketosis (burning fat for fuel). 1.6 to 3.0 mmol/L elevated, risk for diabetic ketoacidosis. Over 3.0 mmol/L high, indicates potentially dangerous levels that require emergency medical attention.

Level of blood glucose with normal being less than 100 mg/dL while fasting. Fasting levels of 100 to 125 mg/dL indicate prediabetes. Fasting levels of 126 mg/dL or higher (on more than one occasion) indicate diabetes.

Cerebral blood flow will be measured with pseudo continuous arterial spin labeling MRI and voxel based analyses will be conducted to determine diet-induced changes and their relationship to cognitive and biomarker outcomes. Healthy adult gray matter typically ranges between 50 to 70 ml/100g/min. Lower than typical range indicates reduced cerebral blood flow.

Pseudo Continuous Arterial Spin Labeling measures regional cerebral blood flow. Meta-Region of Interest combines data from multiple predefined brain regions into a single composite uptake score. Higher values in mL/100g/min indicate greater tissue perfusion, while lower values reflect reduced blood flow. Normal gray matter perfusion in a healthy adult typically ranges between 50 and 60 mL/100g/min, while white matter generally measures around 20 mL/100g/min.

NODDI-NDI measures the packing and density of neurites (axons and dendrites) in the hippocampal region of the brain. NDI values drop in the hippocampus as neurites degenerate during Alzheimer's disease or normal aging. NDI is expressed as a decimal value typically falling between 0 and 1. A value of 0 represents an area with no neurites (e.g., pure cerebrospinal fluid), while a value closer to 1 indicates a highly dense network of axons or dendrites.

NODDI-NDI measures the packing and density of neurites in the region of interest in the brain. NDI values drop as neurites degenerate during Alzheimer's disease or normal aging. NDI is expressed as a decimal value typically falling between 0 and 1. A value of 0 represents an area with no neurites (e.g., pure cerebrospinal fluid), while a value closer to 1 indicates a highly dense network of axons or dendrites.

ISOVF measures the proportion of water molecules that are diffusing freely and isotropically in the hippocampal region of the brain. Elevated ISOVF is frequently observed in Alzheimer's disease, cognitive decline, aging, and infection burdens, reflecting a breakdown of tissue structure. Expressed as a value between 0 and 1 with a higher number indicating a higher level of free, isotropic water.

ISOVF Meta-ROI measures the proportion of water molecules that are diffusing freely and isotropically within a region of interests in the brain. Elevated ISOVF is frequently observed in Alzheimer's disease, cognitive decline, aging, and infection burdens, reflecting a breakdown of tissue structure. Expressed as a value between 0 and 1 with a higher number indicating a higher level of free, isotropic water.

NODDI ODI (Orientation Dispersion Index) is used to quantify the spatial configuration and branching of neurites (axons and dendrites) in hippocampal region of the brain. It measures how widely the orientations of neurites spread out in space within a voxel. Low ODI indicates highly aligned or parallel fibers, typical of coherent white matter tracts. High ODI indicates highly dispersed or fanned-out fibers, typical of gray matter or areas with complex fiber crossings. ODI ranges from 0 to 1, where values closer to 0 represent fibers pointing in nearly the same direction (low dispersion).

NODDI ODI (Orientation Dispersion Index) is used to quantify the spatial configuration and branching of neurites (axons and dendrites) in the region of interest in the brain. It measures how widely the orientations of neurites spread out in space within a voxel. Low ODI indicates highly aligned or parallel fibers, typical of coherent white matter tracts. High ODI indicates highly dispersed or fanned-out fibers, typical of gray matter or areas with complex fiber crossings. ODI ranges from 0 to 1, where values closer to 0 represent fibers pointing in nearly the same direction (low dispersion).

The modified Preclinical Alzheimer Cognitive Composite 5 (mPACC5) measures cognitive changes associated with Alzheimer's-related brain pathology. It aggregates z-scores from five specific cognitive tests across four domains: episodic memory (delayed recall tests), timed executive function (speed and processing tasks), semantic memory (verbal fluency tests), global cognition (overall mental status exams). Total Z-score range: healthy /unimpaired baseline -0.50 to +1.00, mild cognitive impairment -2.50 to -0.50, dementia -3.50 to -2.50. The central value of the mPACC5 is 0.

The ADAS-Cog 12 is a psychometric instrument that evaluates memory, attention, reasoning, language, orientation, and praxis. A higher score indicates more impairment. Scores range from 0-85 with higher scores indicating greater cognitive impairment.

The NPI-Q is widely used to assess the presence of mood disorders in geriatric populations. The NPI-Q measures 12 symptom categories and is scored on a scale of 0-36. A higher score indicates a higher burden of neuropsychiatric symptoms. A score of 0 indicates no symptoms are present.

The Geriatric Depression Scale is a well-validated self-report questionnaire used frequently in clinical and research settings to assess mood in older adults. Total score range is 0-15 with 0-4 normal range (no risk of depression indicated), 5-8 mild depressive symptoms, 9-11 moderate depressive symptoms, 12-15 severe depressive symptoms.