Young children with autism spectrum disorders (ASD) are noted for a constellation of developmental difficulties that differentiate them from other children.1,2
These early difficulties center primarily on social and communication skills, such as joint attention, imitation, affective sharing, and object play skills. Longitudinal studies document the importance of these early skills to later developmental outcomes and particularly spoken language, a core developmental problem of autism.1,3
Several examples include motor imitation skills at age two led to greater language at age four,4
initiating joint attention at age two was associated with better language outcomes at age five,5
and responding to joint attention at age three to five years predicted better language outcomes a year later3
and eight years later.6
Theoretically, these early skills may affect language outcome because they require a shared focus of attention that enables the child to acquire the types of skills that are socially learned, such as language.7,8
Perhaps the greatest goal of early intervention for children with autism is to gain functional spoken language by entry into school at age five years. Indeed, acquiring spoken language before age five has been heralded as the single most important achievement leading to the best social outcomes of children with autism.9,10,11,12
Thus one approach to improving spoken language outcomes is to target the prelinguistic skills that develop before the onset of spoken words (e.g., gestures used for sharing attention with another about an event or common interest) and that are impaired in children with autism.13,14
These gestures include pointing to share, showing an object, and coordinating looks between people and objects.
There is ample evidence that these early skills are important to later spoken language outcomes in children with autism and that they should be teaching targets for early intervention programs.1,15
Over the past ten years, comprehensive early intervention programs have focused greater effort on improving joint attention, imitation and play skills in young children.16,17
We also have amassed a great deal of evidence of the effectiveness of comprehensive early interventions on the developmental outcomes of children with ASD when interventions are delivered with intensity, at least twenty hours per week for several years.18
However, because early skills in joint attention and play are rarely assessed before and after intervention, we have little information on how they might change with specific interventions, and whether changes in these skills account for improvements in developmental outcomes. In general, greater change is identified in cognitive developmental domains compared to spoken language, with language outcomes requiring longer durations of intervention.18
For example, in two randomized controlled experiments examining outcomes of comprehensive intervention, spoken language standard scores significantly improved only after two years of intensive treatment in one study19
and were non-significant in the other.20
An issue is whether interventions that directly target joint attention might yield better language outcomes.21
Recent studies that have directly taught these early skills have had mixed results. The reasons for these inconsistent findings may relate to the intensity in which the intervention was delivered and/or the method of delivery. For example, two studies implemented a parent education model in which there was only a small amount of direct intervention with children. One study found significant change in children's social communication skills when the intervention was delivered over twelve months22
but neither study found significant main effects on language outcomes for the experimental intervention compared to a no-treatment control group.22,23
Thus, whether 11 sessions of intervention over 3.5 months23
or 18 sessions over one year22
findings were similar and may relate to the minimal direct intervention with children (as opposed to parents), or to the low intensity of the intervention in general. Most children participated in additional community interventions with non-significant differences across groups. Similarly, in a toddler classroom study, overall improvements in cognition and language were noted for children in two classrooms, one in which joint attention and imitation were infused into the curriculum, and one in which this focus was not included.24
Compared to children in the control classroom, the children in the experimental classroom showed significantly better imitation skills at the end of treatment. No other group main effects were noted at the end of treatment or in cognitive and language outcomes six months later.
Changes in language development may come about with a certain level of intensity of intervention, as well as targeted focus on the content of the interventions. For example, significant effects on joint attention skills were found in a study in which focused content on joint attention was delivered by skilled interventionists for 30 minutes daily over an average of 6 weeks and layered into an intensive early intervention program of 30 hours per week.25
This randomized controlled study also included a targeted play intervention and a control group receiving only the standard preschool program. Not only did joint attention skills improve relative to the control group but children also demonstrated significantly greater spoken language scores one year after the end of intervention.26
In this study, children receiving the play intervention also demonstrated significantly improved language scores one year later suggesting that the joint attention and play interventions had a common mechanism of joint engagement between parent and child affecting language. Theoretically, joint engagement serves as a platform for the continued development of social, communication and language skills over time.
These data suggest there are benefits to focused content on joint attention and play skills in early intervention programs of sufficient intensity. Further, language outcomes improved at least one year post intervention. However, to date we have limited data on the long- term effects of children's early intervention experiences. Indeed, most rigorously tested (randomized controlled) early intervention studies report limited or no follow up data.19,20
One example of a long -term follow up of early intervention was reported recently. This seven year follow up study was non –controlled/non-experimental; children received two years of intensive community based early intervention services and assessments prior to enrollment and again at 7 years post intervention.27
Assessments were standardized measures of cognition, language, adaptive behavior and severity of diagnosis. Results indicated great variability in this sample, but time 1 scores on assessments tended to predict scores on the seven year follow up; thus early cognitive abilities predicted later cognitive abilities. This study did not examine early core social communication skills as predictors of later language and cognition.
The current study reports on 5 year follow up data for the original targeted intervention study in which 3-4 year old children were randomized to a joint attention, symbolic play or control group within the same intensive early intervention program.25
We were particularly interested in the long term effect on expressive language outcomes of early interventions that targeted core deficits of joint attention and play skills. Our first aim was to determine the spoken language outcomes of this group of children 5 years post treatment, at age 8 -9 years of age. Second, we examined predictors of language and cognitive development at age 8-9 from early assessments of joint attention and play at ages 3-4. We hypothesized that both joint attention and play abilities would predict more positive developmental outcomes in children with autism spectrum disorder.