Introduction Since the passage of the Individuals with Disabilities Education Act (IDEA), schools are required to serve all students regardless of their disability in a least restrictive environment. Due to the increase in the number of students identified and placed in general education classrooms, educators can expect to serve students with disabilities. It is important to understand the different types of disabilities, the characteristics of these disabilities and the causes; to ensure student success. This document will define severe disabilities, mental retardation, traumatic brain injury, autism and deafblindness. Additionally, this document will address the characteristics and causes of each disability. Definition of Severe Disability There are many different definitions used to define the meaning of severe disability, a general definition for severe disability is any disability that significantly limits physical, mental ability or emotional performance and requires extensive ongoing support in more than one of major life activities in order to participate fully in education, community settings or work. According to Heward (2009), severe disabilities include “students with significant disabilities in intellectual, physical and/or social functioning, students with multiple disabilities or deafblindness, students with severe mental retardation, severe emotional disturbances and serious disabilities or health problems are included in the term” (p.453). Characteristics of Severe Disabilities Depending on the combination and severity of disabilities and the age of the person with severe disabilities, they may present a wide range of characteristics, however, “ a distinctive feature… in the center of the sheet… a person who has one or more disabilities. By having a better understanding of the definition, characteristics, and causes of these disabilities, educators can be better prepared to educate their students. By gaining a better understanding of these students and how they learn, educators can use effective strategies to ensure the success of all students. Works Cited Heward, W. L. (2009). Exceptional children: An introduction to special education (9th ed.). Upper Saddle River, NJ: Merrill National Extension Center for Children with Disabilities. (2004). Information sheet on disabilities. Retrieved January 8, 2011, from http://www.nichcy.org/InformationResources/Documents/NICHCY%20PUBS/fs10.pdfNational Institute of Neurological Disorders and Stroke. (n.d.). Traumatic brain injury information page. Retrieved January 8, 2011, from http://www.ninds.nih.gov/disorders/tbi/tbi.htm