Unlocking the silent signals: Motor kinematics as a new frontier in early detection of mild cognitive impairment

Abstract

The increasing global prevalence of mild cognitive impairment (MCI) necessitates a paradigm shift in early detection strategies. Conventional neuropsychological assessment methods, predominantly paper-and-pencil tests such as the Mini-Mental State Examination and the Montreal Cognitive Assessment, exhibit inherent limitations with respect to accessibility, administration burden, and sensitivity to subtle cognitive decline, particularly among diverse populations. This commentary critically examines a recent study that champions a novel approach: The integration of gait and handwriting kinematic parameters analyzed via machine learning for MCI screening. The present study positions itself within the broader landscape of MCI detection, with a view to comparing its advantages against established neuropsychological batteries, advanced neuroimaging (e.g., positron emission tomography, magnetic resonance imaging), and emerging fluid biomarkers (e.g., cerebrospinal fluid, blood-based assays). While the study demonstrates promising accuracy (74.44% area under the curve 0.74 with gait and graphic handwriting) and addresses key unmet needs in accessibility and objectivity, we highlight its cross-sectional nature, limited sample diversity, and lack of dual-task assessment as areas for future refinement. This commentary posits that kinematic biomarkers offer a distinctive, scalable, and ecologically valid approach to widespread MCI screening, thereby complementing existing methods by providing real-world functional insights. Future research should prioritize longitudinal validation, expansion to diverse cohorts, integration with multimodal data including dual-tasking, and the development of highly portable, artificial intelligence-driven solutions to achieve the democratization of early MCI detection and enable timely interventions.

Keywords: Mild cognitive impairment; Early detection; Motor kinematics; Gait analysis; Handwriting analysis; Digital biomarkers; Machine learning

Core Tip: This study proposes a paradigm shift in mild cognitive impairment screening, moving from subjective cognitive tests to objective, quantifiable measures of gait and handwriting kinematics. This novel approach uses readily observable behaviors and non-invasive technology (like digital pens) to circumvent barriers of traditional neuropsychological assessments, such as language dependency and cultural bias. By measuring motor kinematics, which capture the real-world effect of cognitive-motor changes, the method offers ecological validity and reflects functional status, distinguishing it from biomarkers focused only on pathology. The integration of gross and fine motor abilities provides a scalable and accessible foundation for early, proactive mild cognitive impairment detection, paving the way for better intervention.