RT Book, Section A1 McGinnis, Scott M. A2 Silbersweig, David A. A2 Safar, Laura T. A2 Daffner, Kirk R. SR Print(0) ID 1178762987 T1 Approach to Neurocognitive Disorders T2 Neuropsychiatry and Behavioral Neurology: Principles and Practice YR 2021 FD 2021 PB McGraw Hill PP New York, NY SN 9781260117103 LK neurology.mhmedical.com/content.aspx?aid=1178762987 RD 2024/03/29 AB The purpose of this chapter is to provide a framework for approaching cognitive disorders based on anatomical localization and time course. In so doing we will review key clinical considerations in the diagnosis and management of conditions with acute/subacute onset versus those with insidious onset (Figure 20-1). In each case, it is important to know the cardinal features of the more common conditions as well as atypical features that should prompt consideration of alternative, less common conditions. For conditions with acute/subacute onset this involves understanding core aspects of delirium (exceedingly common) and features that might alternatively suggest conditions in the differential diagnosis of rapidly progressive dementia (RPD; relatively less common). For conditions with insidious onset, the chapter reviews a basic workup and considers a high-level distinction between two categories of presentations: nonprogressive disorders, and gradually progressive neurodegenerative (±vascular) diseases. Within the category of neurodegenerative disorders, we will explore the utility of a comprehensive diagnostic formulation encompassing syndrome, severity, and suspected underlying neuropathology. The chapter concludes by examining key elements of relatively more common conditions—late-onset, amnesic, and dysexecutive syndromes associated with underlying Alzheimer’s disease (AD) and Lewy body disease (LBD) neuropathology—and atypical features that might suggest relatively less common conditions such as non-amnesic presentations of AD and syndromes within the spectrum of frontotemporal lobar degeneration (FTLD) neuropathology.