o very well on tests requiring manipulative or visual skills or immediate memory, while they do poorly on tasks demanding symbolic or abstract thought and sequential logic. The process of learning and thinking in these children is impaired, most particularly in the capacity for imitation, comprehension of spoken words and gestures, flexibility, inventiveness, learning and applying rules, and using acquired information. Yet, a small number of children with PDDNOS show excellent rote memories and special skills in music, mechanics, mathematics, and reading. Because many children with PDDNOS are either without functional speech or otherwise untestable, some people question the validity of testing their intelligence. Moreover, it has been observed that a number of these children show major improvements in other developmental areas during the follow-up period without a change in their tested IQ. Follow-up studies have also shown that retardation present at the time of initial diagnosis tends to persist. Those children with a low IQ show more severely impaired social development. They are more likely to display unusual social responses, such as touching or smelling people, ritualistic behavior, or self-injury.Associated FeaturesThe emotional expression of some children with PDDNOS may be flattened, excessive, or inappropriate to the situation. For no obvious reason, they may scream or sob inconsolably one time, yet giggle and laugh hysterically another time. Real dangers, such as moving vehicles or heights, may be ignored, yet the same child might seem frightened of a harmless object, such as a particular stuffed animal....
