Forensic Handwriting Examination of Motor Disorders

Forensic document examination in handwriting and signature cases can be complicated by writers with motor disorder conditions such as Parkinson's disease and essential tremor. These conditions are more prevalent among the elderly and legal issues arise in probate and elder abuse fraud cases where parkinsonian patients sign their signatures to checks, estate, title, and financial documents that are frequently contested. Because writers with motor disorders produce distorted, tremulous handwriting, distinguishing between genuine movement disorder signatures and forgeries can be problematic for handwriting experts. To address the problem, the author conducts original research using innovative digital tablet technology that allows for objective, quantifiable measurement of dynamic handwriting factors such as duration, velocity, pressure, and frequency spectrum analysis of writing tremor. The results have implications not only for handwriting experts working with ink writing and online biometric signatures, but also the elderly, motor disorder patients, legal professionals, investigators, law enforcement, and the justice system.