MindMap: ML-Based Mapping of the Progression of Alzheimer's Disease Using Human Expression as a Behavioral Biomarker

A third of America's elderly die of Alzheimer's or dementia every year. Treatments like MRI scans and injections can cost thousands of dollars and fail to accommodate individual patient needs. Moreover, prior literature has prioritized disease detection instead of its spread, making treatment less effective over time. While Alzheimer's produces physical changes in the brain, it also causes behavioral changes such as increased repetitiveness or irritability. These changes manifest themselves in writings, a form of emotional expression. The researcher harnessed this phenomenon to develop MindMap, the first webbased tool that maps the progression of Alzheimer's disease in the brain based on the psychological features exhibited in diary entries of early-stage patients. The researcher assessed around 1000 diary entries across a set of patients (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{n} \boldsymbol{=} \mathbf{1 0}$</tex>) and evaluated the presence of various psychological features such as positivity and sensitivity over time. These behavioral biomarkers were used to develop personalized forecasting models to map the progression of the features within each patient. Numerous models (ARIMA, SARIMAX, and ExponentialSmoothing) were trained and hyperparameter-tuned for this task. The best performing models achieved average MAE, RMSE, and MAPE of about 0.609, 0.775, and 25.4 % respectively on patient test data, indicating high predictive accuracy for each psychological feature. Moreover, the Mann-Whitney U test revealed a high average correlation between forecasts and true progression (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{p = 0. 8 8 1}$</tex>).