The Neuroscience of Handwriting Applications for Forensic Document Examination

The Daubert trilogy of U.S. Supreme Court cases has established that scientific expert testimony must be based on science grounded in empirical research. As such, greater scrutiny is being placed on questioned document examination generally, and handwriting comparison in particular. Bridging the gap between theory and practice, The Neuroscience of Handwriting: Applications in Forensic Document Examination examines the essential neuroscientific principles underlying normal and pathological hand motor control and handwriting. Topics discussed include: Fundamental principles in the neuroanatomy and neurochemistry of hand motor control and their application to research in handwriting The epidemiology, pathophysiology, and motor characteristics of neurogenerative diseases such as Parkinson’s, Huntington’s, Alzheimer’s, multiple sclerosis, essential tremor, and motor neuron disease and their effects on handwriting Psychotropic medications prescribed for depression, bipolar disorder, and psychosis; their mechanisms of action; and their effect on motor behavior and handwriting The impact of substance abuse on handwriting An overview of the aging process and its effects on motor control and handwriting The kinematic approach and new findings on the kinematic analyses of genuine, disguised, and forged signatures The authors’ laboratory research on authentic and forged signatures An essential resource for professionals and researchers in the forensic documentation examination and legal communities, this volume provides a window on the scientific process of signature and handwriting authentication, integrating the extensive research on neural processes and exploring how disease, medication, and advanced age alter these processes.

FUNDAMENTAL ASPECTS OF MOTOR CONTROL AND HANDWRITING Neuroanatomical and Neurochemical Bases of Motor Control Historical Perspective on Brain Function for Hand Motor Control Neuroanatomical Bases of Hand Motor ControlBasal Ganglia Neurochemistry Frontal-Subcortical Neural Circuits and Motor Function The Cerebellum and Brain Stem Neuroanatomical Bases of Handwriting Movements Lesion Studies Functional Neuroimaging StudiesModels of Handwriting Motor Control Handwriting as a Motor Program Hierarchical Models of Handwriting Motor Control Cost Minimization Models Equilibrium Point Model Neurological Disease and Motor Control Parkinson’s Disease Progressive Supranuclear Palsy and Corticobasal Degeneration Essential Tremor Multiple System Atrophy Multiple Sclerosis Huntington’s DiseaseLower Motoneuron Disease Alzheimer’s Disease and Dementia with Lewy Bodies Psychotropic Medications: Effects on Motor Control An Overview of Psychotropic Medications Neurobiology of Psychotropic-Induced Movement Disorders Aging and Motor Control Neurotransmitter Mechanisms of Motor Aging Aging Effects on Motor Behavior KINEMATICS OF SIGNATURE AUTHENTICATION A Kinematic Approach to Signature Authentication The Kinematic ApproachIsochrony in Genuine, Autosimulated, and Forged Signatures Methods: Writers and Procedures Results Discussion Kinematic Analyses of Stroke Direction in Genuine and Forged Signatures Methods: Writers and Procedures Results Upstroke/Downstroke Ratio Scores NEUROLOGIC DISEASE, DRUGS, AND AGING AND THEIR EFFECTS ON HANDWRITING Neurological Disease and Handwriting Handwriting in Specific Neurological Diseases Effects of Psychotropic Medications on HandwritingEmpirical Research on Effects of Psychotropics on Handwriting KinematicsSubstance Abuse and Handwriting MethamphetamineCannabis Alcohol Aging and Handwriting Empirical Research on Effects of Aging on HandwritingConclusions Bibliography

Michael P. Caligiuri, PhD, is a professor in the Department of Psychiatry at the University of California, San Diego. His research over the past two decades has focused on understanding how drugs and disease affect motor control and fine hand movements. He has served as the lead scientist on several federally and industry-sponsored studies on identifying treatment response in psychiatric patients and has authored over 100 peer-reviewed articles in medical journals and book chapters on movement disorders, brain imaging, and biomedical instrument development. His current research interest focuses on kinematic studies of impaired handwriting and understanding writer-based sources of variability in signature authentication.Linton A. Mohammed, MFS, D-ABFDE, has been a forensic document examiner for 25 years. He has testified as an expert witness over 100 times in the United States, England, and the Caribbean. He is currently in private practice with Rile, Hicks, & Mohammed with offices in Long Beach, California, and San Bruno, California. He is certified by the American Board of Forensic Document Examiners and holds a Diploma in Document Examination from the Forensic Science Society in England. He is the current president of the American Society of Questioned Document Examiners, is a fellow in the Questioned Document Section of the American Academy of Forensic Sciences, and is currently completing work for a PhD in Human Biosciences at La Trobe University, Melbourne, Australia.