Speech acquisition in older nonverbal individuals with autism: a review of features, methods, and prognosis.

Individuals with autism often fail to develop useful speech. If they have not done so by age 5, the prognosis for future development has been thought to be poor. However, some cases of later development of speech have been reported. To quantify and document the nature of later speech development and the factors that might be important for prognosis, we reviewed the extant literature. We searched both manually and electronically, examining all literature with at least an English-language abstract, through March 2008. The search identified a total of 167 individuals with autism who reportedly acquired speech at age 5 or older. Most of the cases of reported late speech development occurred in the younger age groups; no case older than 13 was reported. Behavioral modification was the most frequently reported training program used, although there was a wide range of interventions reported to be associated with late speech development. Given the underreporting of such cases in the literature, and the likelihood that more intensive and more focused training might be more successful, the prognosis for late development of speech in such individuals may now be better than was historically thought to be the case.