Prosody characteristics of individuals with fragile X syndrome and autism spectrum disorder
In recent years, autism has become more and more prevalent in the public mind of the world. A growing number of children are being diagnosed with autisms, and researchers and laypeople alike struggle to understand the details of the disorder: What exactly causes autism? How can we treat and support those who have autism? How can we better understand the communicative patterns of individuals with autism so as to facilitate their social interactions?
Critical to understanding the communicative patterns of individuals with autism is understanding what exactly makes their speech difficult to understand, or what exactly characterizes their manners of speaking as being “unusual”. A number of studies (Vilkman et al. 1988, Roberts et al. 2005, McCleery et al. 2006, Barnes et al. 2009) have attempted to uncover whether or not individuals diagnosed with fragile X syndrome (FXS) and with autism spectrum disorder (ASD) have a particular speech phenotype; many of these studies (Vilkman et al. 1988, Roberts et al. 2005, Barnes et al. 2009) have had limited success in determining the exact processes that contribute to this phonological unintelligibility, with the general consensus being that the speech phenotype of individuals with FXS and individuals with ASD does not differ substantially from their typically developing (TD) peers. Recent research, then, has focused more on trying to understand the prosody characteristics of individuals with FXS and individuals with ASD. This research is primarily focused on uncovering what exactly causes the speech of those with FXS and with ASD to be considered perceptually abnormal: Studies have examined whether or not those with ASD truly speak faster than those without (e.g. Zajac et al. 2006, Zajac et al. 2009) and have also attempted to uncover how well those with FXS and with ASD respond to meaning that is encoded at the prosodic level. As with studies intent on discovering a speech phenotype for those with FXS and with ASD, results have conflicted and are currently inconclusive.