Smartphone-Based Behavioural Profiling for Distinguishing Dementia with Lewy Bodies from Alzheimer’s Disease

BACKGROUND AND OBJECTIVE: Dementia with Lewy bodies (DLB) is frequently misdiagnosed as Alzheimer’s disease (AD) due to overlapping clinical presentations. In this study, we evaluated a smartphone-based digital platform that leverages behavioral markers to accurately differentiate between DLB and AD. METHODS: We conducted a cross-sectional study on 81 participants (Healthy controls = 40, AD = 21, DLB = 20), administering the MMSE and a smartphone-based noise pareidolia test (NPT) with integrated eye-tracking and speech inputs. Ground truth for patients was established using nuclear imaging (DAT-SPECT, IMP-SPECT, and/or MIBG). Core behavioral features such as response efficiency, gaze parameters (fixation count, saccadic patterns, surface area coverage), and acoustic features (latency, spectral properties) were extracted. A two-tiered classification system involving a deep learning and a support vector machine model was used. Based on the behavioral output, probability scores were generated with a focus on explainability to differentiate DLB from AD. RESULTS AND INTERPRETATION: The DLB group showed more pareidolias than the AD group on the digital app. DLB patients exhibited several short saccades, inconsistent scanning behavior, and smaller fixation dispersion, suggesting impaired top-down modulation of visual attention. However, fixation duration did not differ between AD and DLB. Vocal responses (latency, spectral properties) lacked specificity for DLB classification. Response fluctuation analysis revealed lower variability in AD patients compared to DLB. The app outperformed paper-based methods with 87% sensitivity and 93% specificity, and an overall accuracy of 90% for AD–DLB classification. Two AD patients were classified as healthy controls (probability scores: 15%, 45%), likely due to the early disease stage or unmeasured neurocognitive factors. CONCLUSIONS: By effectively capturing core symptoms, our smartphone-based modality provides a reliable, scalable, and non-invasive tool for the classification of DLB from AD. The integration of machine learning enabled precise quantification of behavioral microfluctuations between AD and DLB subtypes, underscoring its significant diagnostic potential. Future research is needed to refine classifiers to address early-stage cases and for disease staging.