The category of pervasive developmental disorders includes children with severe and profound disabilities. These are defined as children who function within the lowest one percent of their age groups. This category also includes children with multiple disabilities—those who show evidence of independent and interdependent deficits in two or more areas of functioning.
With multiple disabilities, innumerable combinations of impairments are possible, although some appear more often than others and some are more difficult to cope with. Individuals may suffer multisensory impairments such as deaf-blindness, or they may have conditions that combine sensory disorders with physical, neurological, or mental disabilities.
Students with multiple disabilities present a range of special educational and psychological needs. To an even greater degree than for children with single disabilities, each child must be considered individually.
Definitions of Severe and Multiple Disabilities
In the area of multiple disabilities, both generic and specific definitions exist. Generic definitions tend to be comprehensive and general, with broad parameters. Because of their broadness, generic definitions have some disadvantages.
Given the disadvantages of generic definitions, many educators prefer definitions that are more categorical and specific. Educators define children as multisensory impaired, multiple dependent handicapped, deaf-blind, and so on. Such specific definitions serve to focus on individual problems and allow access to specialized services.
Classification of Severe and Multiple Disabilities
In Canada, individuals with multiple disabilities are classified according to the primary disability, the agency providing services, and the type of educational program. However, classifying by primary and secondary disability overlooks the cumulative nature of the problems.
Prevalence of Severe and Multiple Disabilities
It is extremely difficult to obtain accurate figures for students with multiple disabilities because Canada does not have a national registry of disabled children; the interpretations of the definitions of certain populations, such as deaf-blind, have recently changed dramatically; and children are often counted in terms of their primary disability (other conditions that arise are known as secondary disabilities). As well, figures are affected by changes in technology and demographic trends.
Etiology of Severe and Multiple Disabilities
A wide variety of etiologies are responsible for multiple disabilities. Many of the causes are also the villains in other childhood disabilities existing alone, such as deafness, blindness, and intellectual disabilities.
Genetics, maternal rubella, birth traumas, and childhood infections such as meningitis and encephalitis are major factors in multiple disabilities. On the whole, chromosomal disorders account for the least number of multiple disabilities. Maternal rubella is most dangerous if contracted by the mother during the first trimester, the time when the organs are developing. Meningitis can cause cerebral palsy, convulsive disorders, and hearing and visual handicaps. Further causes of multiple disabilities include hydrocephalus, central nervous system damage, and complications associated with prematurity.
Usher's syndrome is a genetically determined condition in which a hearing disability is combined with progressive visual impairment resulting from pigment degeneration of the retina (retinitis pigmentosa).
Developmental Consequences of Severe and Multiple Disabilities
The variety of disabilities and combinations of disabilities make generalizations about consequences almost impossible. Each combination of disabilities forms a completely unique child.
Children with severe or multiple disabilities often show uneven development and lags in reaching developmental milestones. Walking, using first words, and toilet training may be quite delayed, and in some children, they never emerge.
Multiple disabilities do not necessarily correlate with intellectual dysfunctions. However, the conditions tend to distort, delay, and interfere with children's perceptions of incoming stimuli. Children find the world irregular and unpredictable.
Children with severe and multiple disabilities have enormous difficulties with speech and language development. Children may be at prelinguistic or minimally linguistic levels.
Learning and educational attainment depends upon the age of onset of the conditions, their nature, the time of intervention, and the quality of educational services provided.
Problem behaviours are the rule rather than the exception in the population of individuals with severe disorders. These children are frequently characterized by self-abusiveness, intense self-stimulation, and repetitive and stereotyped movements and behaviours.
Social and Emotional Development
Social interactions are severely restricted by severe and multiple disabilities.
The play of children with severe and multiple disabilities is often limited.
Assessment of Children with Severe and Multiple Disabilities
The diagnosis and assessment of multiple disabilities require a multi-disciplinary approach employing a battery of measures.
Assessment of Hearing
It is very difficult to assess the auditory acuity and functioning of multiply disabled children, and special techniques have been devised. Hearing acuity may be tested through electrophysiological or behavioural methods. Electrodiagnostic procedures provide information regarding responses to auditory stimuli; behavioural measures give further comparative results that may be used for prognostic purposes.
Assessment of Vision
It is also hard to determine whether multiply disabled children have usable vision. In order to assess the electrical activity of the visual pathway and occipital cortex of the brain, electrophysiological techniques are used. In addition to electro-diagnostic techniques, children should receive thorough eye examinations.
Children with severe and multiple disabilities challenge the ingenuity of even the most experienced assessors. Assessment focuses on intellectual function and other domains, especially language, and explores the child's impairments and abilities. Methods include psychometric tests, learning tests, direct observation, and informal interviews.
Psycho-educational assessments are most successful when they focus on functional areas of competence, are made over a period of time, are taken at regular intervals, are done in surroundings familiar to the child, incorporate tasks and materials familiar to the child, and include observational data and interviews. Informal interviews may be conducted with parents, teachers, and other important people in the child's life.
Arena testing is an observational assessment approach in which people from several disciplines focus on their particular domains within the context of play. Activity-based assessment measures functional skills; collaborative ongoing assessment follows a child through a day's activities.
Intervention with Children who have Severe and Multiple Disabilities
Services provided to individuals who are multiply disabled cover a broad range, and include medical, therapeutic, and educational personnel. Generally, treatment hinges on etiology and the specific combination of the disabling conditions.
A variety of medical procedures are used. Teachers should be aware of these procedures and should keep an emergency protocol for each child.
Children need speech and language therapy, as well as occupational and physical therapy. Physical and occupational therapists work on gross motor development, muscle relaxation, and fine motor control. Speech and language therapists assist in speech and language development and feeding problems.
Students will use a range of adaptive equipment and computer technology.
Education for students with multiple disabilities extends schooling beyond its traditional parameters.
Service Delivery Models
School-age students with severe and multiple disabilities may be served in a range of settings—the regular classroom with support, a self-contained classroom, a residential school, and the hospital-based day school.
Increasingly, children who are deaf-blind or who have other severe or multiple disabilities are being educated in general classes. Defensible reasons for placing children with severe and profound disabilities in general classrooms are access to social relationships with peers and access to normalized learning environments. However, there is still disagreement within the field as to whether students with intensive educational needs belong in general education classrooms.
Approaches include early intervention, team models, systematic procedures, appropriate curricula, program modifications, and support services.
In the training and education of students with severe and multiple disabilities, team approaches have developed in order to eliminate traditional professional boundaries while encouraging communication and information sharing.
Curricula must reflect all areas of development. Educational needs include language development, visual and auditory training, mobility training, and self-care skills. Psychosocial needs include adaptive behaviour, group activities, life skills, and a range of socialization experiences.
The skills taught to students with severe and multiple disabilities should be functional skills, and should include language development, visual and auditory training, mobility training, and self-care skills.
Specialized language training for children who are prelinguistic or minimally linguistic uses two methods—presymbolic training and communication-first methods.
Alternative Methods of Communication
Anything that augments speech or accomplishes communicative function is augmentative communication. Augmentative communication may be aided or unaided. The way in which language is expressed is called a communication mode.
Unaided approaches use signals, codes, gestures, and signs. Signal and code communications include yes-no signals, audio signalling, Morse code, Amerind, and American Sign Language.
Aided approaches often use communication boards with Blissymbolics. Both Blissymbolics and other picture systems are displayed on communication boards. Some current boards are sophisticated; they may have voice outputs that provide prerecorded or programmed speech in the form of words, phrases, or sentences.
Orientation and Mobility Training
Orientation and mobility specialists help the visually impaired child to develop a knowledge of the environment and enhance the ability to find specific locations.