IHP Researcher Marc Maffei Uncovers Data Showing Mouth Skills Can Help Differentiate Which Children Are Verbal, And Which Children Are Not
With April being Autism Awareness Month, we’re focusing some of the IHP’s researchers who are making a difference in the field. Earlier this week, we shared the story of Karen Chenausky, who is lead author on a paper aimed at providing best practices for collecting and analyzing speech data from minimally verbal autistic speakers.
Today in The IHP Interview, we sit down with Marc Maffei, MGH IHP Instructor, researcher in the IHP’s Speech and Feeding Disorders Lab, and PhD candidate who will earn his degree this summer. Maffei recently had his paper, “Oromotor skills in autism spectrum disorder: A scoping review” accepted for publication in Autism Research, without any need for revisions, a rarity in the world of academic research.
The paper offers an exhaustive review of almost three decades of autism research – more than 16,000 studies were sifted through. The 107 studies that met the stiff criteria Maffei and his collaborators were looking for were thoroughly examined. Maffei’s findings may help pave the way for future research.
There are well documented differences in the motor skills of autistic individuals but not a lot of research has looked at oromotor skills (mouth movements). What is significant about what you’ve reviewed?
Researchers, clinicians, and families are always on the lookout for predictors of language outcomes in ASD. We don't currently have a reliable way to predict which children diagnosed with autism spectrum disorder (ASD) are going to develop functional verbal language, and which kids are going to be what we refer to as minimally verbal, or in some cases, nonverbal. Being able to predict that would allow for earlier access to intervention including speech and language therapy or alternative modes of communication like tablets and other technologies.
If we could predict earlier who is less likely to develop spoken language, then we can get in earlier and provide support for those who would need it most. Prior research has shown that motor skills are promising as a potential predictor of language outcomes and other cognitive outcomes in ASD. It makes sense to me that oromotor skills might also be associate with language outcomes, since the most common method for expressing language is through the mouth and related structures.
Did your research uncover any trend lines, or areas that would point to a predictor of which children with autism might be able to speak and which children might not?
This review paper revealed that abnormalities in the accuracy, consistency, rate, and coordination of oromotor movements are commonly reported in ASD, but the correlation between these skills and language functioning has only been addressed in a small subset of studies. However, these limited findings are compelling, showing that oromotor skills – whether it’s the way a child speaks, eats, or performs nonspeech actions like moving the tongue, blowing a kiss, or smiling – can differentiate children who are verbal from children who are not verbal. These skills have also been found to correlate with standardized measures of language, with learning rates during language intervention, and with parent reports of a child’s language abilities. Ultimately, it will take additional research to identify exactly what the best skills to measure for this purpose are.
How long did it take you?
This paper took over two years. I was working on other project during that time, but I never put this one down. In fact, it took so long that I conducted a second search because I got the sense that so much was being published as I was writing. We ended up with over 16,000 citations that we needed to assess. Working with the MGH IHP library to design a good search strategy was invaluable in this process.
So, when you went through your material, what was the biggest takeaway or surprise that you came away with?
I'd say the biggest surprise was the overwhelming percentage of studies – 81% of the studies in the review – that reported that autistic individuals have significant abnormalities in their oromotor skills.
Isn’t a number like that to be expected? Why is that significant if most people assume children with autism have verbal limitations or abnormalities?
It's a really good question. As we know, many autistic individuals have overt problems communicating. In fact, deficits in social communication are one of the diagnostic criteria for ASD. However, what is much less clear is whether speech problems are common in this population. I’m a speech-language pathologist and take this distinction for granted, but there is an important difference between speech and language. There's a lot of ways to express language. You can speak, you can write, you can sign, you can type. You can use an assistive device if you have difficulty speaking. Speech specifically refers to the use of the lungs, throat, mouth, and nose to manipulate sound to express language.
And so, while it's well understood that autistic individuals have problems communicating, whether or not that is related to a difference in the way that their mouths move has not been widely recognized despite all of this evidence. It has not been collected and summarized in this way so far.
Talk about the development of kids who have autism, and how that that correlates to the adult population.
That is an important question, and there are indeed adults included in many of these studies. The main thing to think about in the dichotomy between children and adults is that as children develop speech and language skills, it's all embedded in the context of their developing bodies and in the dynamic process of learning. Children's mouths, throats, and brains – their whole bodies – are undergoing radical changes in the first 10-15 years of life and beyond. On the other hand, when adults have a speech or language disorder, their patterns of speaking and using language are usually settled at that point.
When children have speech or language disorders, they often miss out on critical social, cognitive, linguistic, and academic opportunities because of their limited communication skills. That's one of the reasons to press for earlier intervention, which is difficult at the moment for autistic children since we don't have many ways to predict how language skills will develop over time.
What kind of feedback have you got received from fellow researchers on this?
My colleagues in the ASD and language fields have expressed that this is an important piece of work because of its potential to motivate future research. In the study I provide not only what we found among the 107 studies, but also suggestions based on my experience as a clinician and researcher on how we can improve this research going forward. This includes what kind of information is missing, what kinds of methods could improve our findings, and what would help us synthesize the findings we already have. One of my main points in the review is that it's hard to summarize exactly what is known about oromotor skills in ASD because so many different methods have been used, so we tried our best to provide advice for future researchers on what is needed to complete the story.
What would you say is a misconception that people have when it comes to speech and autistic children?
One thing I've learned as an autism researcher is that as exciting as these findings are, just as in other areas of ASD research like behavioral issues, non-verbal IQ, expressive language, and receptive language, we're not going to be able to draw major conclusions about the population as a whole but that autistic individuals are really defined by their heterogeneity. A very important avenue for this research going forward will be to look at subgroups of autistic individuals to see what different kinds of clusters of oromotor abnormalities exist in this population. There are clearly autistic individuals with no detectable oromotor abnormalities, and some with severe deficits. This review will help clinicians and researchers understand the present landscape of what's known about this topic, identify trends, and use that information as a springboard to better characterize these deficits.
How would you characterize this contribution to autism research?
There appears to be significant oromotor abnormalities among autistic individuals. There also appears to be significant potential for those abnormalities to serve as a predictor of outcomes, which are sorely needed for this population. Whether that means developing new motor-based language and speech interventions or measuring these skills as early as possible to predict outcomes and enact existing speech and language interventions earlier, there are multiple avenues for these findings to be extremely valuable.
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