Neurodegenerative diseases (NDDs), which involve progressive damage to function and structure neurons, are chronic, progressive, generally incurable, and sometimes fatal. The types and severity of impairments, as well as their impact on daily living, vary greatly from person to person. As a result, people with NDD often face long-term, changing levels of disability and must learn to cope with and manage disability over time. This Practice Guideline discusses the etiology, epidemiology, and incidence of multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease, and transverse myelitis to provide background information for readers to understand how each disease can lead to disability and thus the need for occupational therapy services. Using an evidence-based perspective and key concepts from the Occupational Therapy Practice Framework: Domain and Process, this guideline provides an overview of the occupational therapy process and defines the occupational therapy domain and interventions that occur within the boundaries of acceptable practice, as well as explains the evidence available to support these interventions.