Book excerpt: Principles and Practice of Movement Disorders provides the complete, expert guidance you need to diagnose and manage these challenging conditions. Drs. Stanley Fahn, Joseph Jankovic and Mark Hallett explore all facets of these disorders, including the latest rating scales for clinical research, neurochemistry, clinical pharmacology, genetics, clinical trials, and experimental therapeutics. This edition features many new full-color images, additional coverage of pediatric disorders, updated Parkinson information, and many other valuable updates. An accompanying Expert Consult website makes the content fully searchable and contains several hundred video clips that illustrate the manifestations of all the movement disorders in the book along with their differential diagnoses. Get just the information you need for a clinical approach to diagnosis and management, with minimal emphasis on basic science. Find the answers you need quickly and easily thanks to a reader-friendly full-color format, with plentiful diagrams, photographs, and tables. Apply the latest advances to diagnosis and treatment of pediatric movement disorders, Parkinson disease, and much more. View the characteristic presentation of each disorder with a complete collection of professional-quality, narrated videos online. Better visualize every concept with new full-color illustrations throughout. Search the complete text online, follow links to PubMed abstracts, and download all of the illustrations, at www.expertconsult.com.