Distinguishing Normal Aging from Pathological and Situational Changes in Handwriting: A Differential Approach for Geriatric Practice

Introduction: Handwriting integrates motor, cognitive, visuospatial, and linguistic functions and may be altered by physiological aging, neurodegenerative disease, and psychological stress. Because many changes are nonspecific, differential interpretation requires comparison of characteristic feature patterns.

Aims: To compare handwriting changes associated with four conditions: dementia, Parkinson’s disease (PD), normal aging, and psychological stress. The Alzheimer’s Disease Index (ADI) was developed to distinguish dementia-related handwriting deterioration from healthy writing, whereas the Parkinson’s Disease Index (PDI) is intended mainly to quantify PD-related impairment and evaluate its relationship to Hoehn and Yahr stage.

Methods: The ADI study included 98 participants with dementia aged 36–90 years (mean 68) and over 300 healthy controls from the research database aged 19–86 years (mean 51). Forty-five predefined handwriting and linguistic variables were combined into a normalized ADI score. The PDI study includes 41 participants with PD aged 43–95 years (mean 69) and assesses micrographia, stroke quality, rigidity, rhythm, pressure, and spatial organization. Features associated with normal aging and psychological stress were additionally derived from forensic publications.

Results: ADI values were substantially higher in dementia than in controls (0.47±0.12 vs. 0.22±0.08; Mann–Whitney Z=13.095; Vargha–Delaney A=0.945; ROC AUC=0.95). Multiple regression showed that ADI was independent of age, whereas dementia-group membership was a strong predictor of the index. PDI showed a strong positive association with disease severity according to Hoehn–Yahr stage (Spearman’s ρ≈0.60).

Conclusions: All four conditions may involve slowing, reduced fluency, variability, rhythm disturbance, and pressure changes. Dementia shows a broader graphomotor, spatial, cognitive, and linguistic pattern; PD is dominated by motor abnormalities, particularly micrographia, tremor, and rigidity. Normal aging produces milder changes with relative preservation of individual writing organization, whereas stress-related alterations are more variable, context-dependent, and potentially reversible. Differential interpretation should therefore rely on combinations of features rather than isolated signs.