“Actions speak louder than words.” Although clinician’s behavioral evaluations of dementia most often include assessing episodic memory, declarative memories (e.g., naming and calculating), and executive functions (working memory, letter–word fluency), one of the most important functions of the brain is programing actions, including “how” to move and “when” to move. Patients with Alzheimer’s disease, vascular dementia, and other forms of dementia often have impairments in the systems that mediate these how-apraxic and when-intentional behaviors. Although the presence of these apraxic and action-intentional disorders may help with diagnosis and help doctors gain a better understand these patients’ disability, these functions are rarely tested and are often not well understood. The goal of this chapter is to describe the signs of the various types of apraxic disorders (limb-kinetic, ideomotor, conceptual, ideational, and dissociation) and well as action-intentional disorders (akinesia-hypokinesia, impersistence, perseveration, and defective response inhibition), how to test for these disorders, and their pathophysiology.
