Power of Ensemble Techniques for Brain Age Prediction Using Machine Learning Models
Bibliographic record
Abstract
Abstract Aging has a profound impact on brain structure and function, resulting in cognitive decline and an increased susceptibility to neurodegenerative diseases. The brain age gap is defined as the difference between an individual's estimated brain age and their actual age, which is considered a potential marker of overall brain health and may indicate structural abnormalities. Considering this work, machine learning models are used to estimate the brain age based on brain imaging data from four prominent repositories namely IXI dataset, Calgary Campinas, Sparse Linear Method, and Sign Agnostic Learning with Derivatives respectively This work is done based on five regression models such as XGBoost (Extreme Gradient Boosting), Support Vector Regression (SVR), Gradient Boosting Regression (GBR), Random Forest Regression (RFR), and K-Nearest Neighbors (KNN) regression, and also considering ensemble models such as Stacking, Bagging, and Boosting. The dataset contains T1-weighted Magnetic resonance imaging (MRI) images from over 1800 patients, and approximately 143 features were extracted using the reliable tool FreeSurfer (6.0). In this study, a major analysis was performed using grid search and cross-validation to train the models and optimize the hyperparameters to prevent overfitting. The results exhibit that a stacked ensemble model of SVR and XGBoost outperformed the other models, with a mean absolute error (MAE) of 4.65 and R2 value of 0.92 on the training dataset while 6.62 and 0.85 on the test set respectively. The validation results indicated that regression models and ensemble techniques for brain age prediction provide a powerful combination of interpretability, accuracy, and robustness.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.006 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".