However, co-occ urring motor 
and sensory impairments may 
prevent functional use of 
objects. The individual has very limited understanding 
of symbolic communication in speech or ges-
ture. He or she may understand some simple 
instructions or gestures. The individual 
expresses his or her own desires and emotions 
largely through nonverbal, nonsymbolic com-
munication. The individu al enjoys relation-
ships with well-known family members, 
caretakers, and familiar others, and initiates 
and responds to social interactions through 
gestural and emotional  cues. Co-occurring 
sensory and physical impairments may pre-
vent many social activities. The individual is dependent on others for all aspects of 
daily physical care, health, and safety, although he or 
she may be able to participat e in some of these activi-
ties as well. Individuals without severe physical 
impairments may assist with some daily work tasks at 
home, like carrying dishes to the table. Simple actions 
with objects may be the basi s of participation in some 
vocational activities with high levels of ongoing sup-
port. Recreational activities  may involve, for example, 
enjoyment in listening to music, watching movies, 
going out for walks, or part icipating in water activi-
ties, all with the support of others. Co-occurring 
physical and sensory impairments are frequent 
barriers to participation (beyond watching) in home, 
recreational, and vocational activities. Maladaptive 
behavior is present in a significant minority.TABLE 1 Severity levels for intellectual disability (intellectual developmental disorder) (continued)
Severity 
level Conceptual domain Social domain Practical domain