A common belief of many parents and clinicians is that, if a child with ASD has not developed communicative speech by 5 years of age, the prognosis for future development of speech is extremely poor. In 2009 scientists challenged this belief by conducting a comprehensive review of the research literature to search for reports of individuals who were reported to have acquired speech at age 5 or older1. Remarkably, one-hundred sixty-seven such cases were identified, changing the way in which we view language development in individuals with ASD.
Early theories of brain development held that the period before age 5 represents a unique time in development during which language acquisition is possible, a critical period for language. Yet, recent longitudinal neuroimaging research has shown that the brain has a prolonged development, with major changes occurring during adolescence, and we now know that the capacity for neural generation extends even into adulthood. While the field of neuroscience has revised its notions of neuroplasticity and development accordingly, the field of ASD has held onto the notion of an early critical period for language acquisition. This paper published in the Journal of Cognitive and Behavioral Neurology, however, provides a very different perspective.
The authors identified in the published literature 167 individuals with ASD who used speech for the first time after age 5. Many of these children had been offered language intervention based on either traditional or naturalistic applied behavior analysis during the elementary school years, with the intensity of intervention ranging from 30 minutes/week to 30 hour/week. Others had been taught sign language or provided with Picture Exchange Communication System (PECS) training, computer-based training, or speech-language therapy. Children who developed phrase speech were found to have been in treatment longer than those who only achieved single word speech. In virtually all cases, significant time and effort put into treatment was necessary for speech to develop. According to their records, many of these children learned to "use phrases," "answer simple questions," "make spontaneous requests," use "complete sentences," and "speak in spontaneous, complex sentences."
Although the age at which speech developed was variable (ranging from 6-12 years), once the child began speaking, subsequent improvement was often quite rapid. This suggests that achieving initial sound production and words can provide an important springboard for the development of subsequent speech. This important paper offers hope for the many children who have not yet developed speech by age 5, dispelling the belief that older individuals with ASD cannot respond well to speech interventions and providing a much more positive prognosis for individuals with ASD.