A severe learning disability is any condition that causes significant and profound intellectual impairment and a very low intelligence quotient (IQ). Such disabilities can be present from birth or acquired later in life through either accident or illness. People with severe learning disabilities require a lot of support in their daily lives to perform basic everyday activities, navigate their environments safely, and learn.

It is generally accepted than an IQ below 50 constitutes a severe learning disability. The average IQ is 100, while moderate learning disabilities fall into the 50 to 75 IQ range. It can be very difficult to achieve an accurate IQ score for people with learning disabilities, so these numbers may not be completely accurate for every child or adult. The more important factor is how the individual is able to understand and experience his or her environment, and how much assistance he or she requires.

While there are many factors and conditions that can cause a severe learning disability, most are caused by specific medical diagnoses. One of the most common diagnoses resulting in profound learning disabilities is cerebral palsy. This is a condition in which significant brain injury results from brain damage before, during or after birth. It is often caused by a lack of oxygen during the birthing process. Other diagnoses that can cause a severe learning disability are autism, Down syndrome, Fragile X syndrome, meningitis or traumatic brain injury (TBI).

Symptoms of a severe learning disability vary greatly from person to person and depend largely on the location of brain injury, the time at which the injury occurred, the severity of the condition, and the environment in which the individual is living. Common symptoms include significant difficulty attending to tasks or following directions as well as an inability to communicate verbally or comprehend verbal instructions. Other signs are issues with controlling muscles for fine and gross motor tasks, and a lack of understanding of basic spatial concepts. Individuals may also exhibit challenging or demanding behaviors. These may include tantrums, violent behavior, loud vocalizing, repetitive actions and reduced emotional control.

Most students with severe learning disabilities will attend a specialist school or a mainstream school with special education support. In many cases a one-to-one aid is required to provide support, guidance and safety throughout the day. A number of modifications may be required to provide the best possible learning environment, including visual aids, adaptive equipment, command prompt technology and computer assisted instruction.