Relations Among Canonical Babbling and Volubility in Infants Later Diagnosed with ASD and Other Markers Predictive of Outcome

Background:

 

Onset of canonical babbling is a key milestone for speech development in typically developing infants.  Delays in canonical babbling and decreased volubility (density of vocalizations) are often indicative of poor communication outcomes (Oller, 2000). 

A retrospective study of audio-video samples of 9-12 and 15-18 month old infants later diagnosed with ASD has suggested early potential diagnostic markers. Watson et al. (2013) found that children with autism were less likely to use communicative gestures during both age ranges than typically developing children, and Colgan et al. (2006) found that variety of type of gesture was significantly associated with ASD status.  Poon et al. (2012) evaluated imitation, play and gesture, finding these predicted communication and intellectual functioning at 3-7 years.  A subsequent study by Patten et al. (2013) of overlapping samples showed that vocalization variables (canonical babbling and volubility) also differed in the ASD group. The associations among these variables has not yet been evaluated.

Objectives:

We will present data exploring associations between vocal development and these other key features of development and examine later cognitive outcomes in the ASD children, comparing predictions based on multiple regression models.

 

Methods:

This series of studies is derived from an extant data set that includes home movies recorded during infancy and developmental measures acquired during early childhood.  Vocal behaviors of 37 infants, 23 who were later diagnosed with ASD and 14 who were typically developing were analyzed using a total of 20 minutes of video randomly extracted from home movies at 2 time points (10 minutes at each age-range).  Gesture, imitation, and play behaviors were previously coded for each of the age ranges.  For the vocalization study, a naturalistic real-time listening technique with coding of vocalizations on a single pass for canonical and non-canonical syllables was used.  These data will be analyzed using multiple regression to evaluate associations between independent variables (at least one vocal variable along with at least one other potentially aggregated developmental skills variable) and outcome variables (communication and intellectual functioning).

Results:

 

1. Infants later diagnosed with ASD were less likely than typically developing infants to engage in key gestural, imitative, and play behaviors at both age ranges.

2. Infants later diagnosed with ASD were less likely to have reached the canonical babbling stage, produced significantly lower canonical babbling ratios, and produced significantly lower volubility at both age ranges. 

3. The gestural, imitative and play behaviors significantly predicted later cognitive development in the ASD group.

4. Associations between the vocal development and other features of development are currently being analyzed along with prediction of cognitive outcomes as determined by multiple regression.

Conclusions:

Assessment of vocal patterns and other key developmental features in infants as young as 9-12 months may well provide useful components in diagnosing ASD in infancy.  The current effort will illuminate potential relations among these markers.