Autism spectrum disorder (ASD) is complex. Poor social skills, sensory integration difficulties and speech and language problems encompass the typical behavioral signs.
The primary focus of research has been on receptive language skills and behavioral difficulties. In comparison, little attention has been given to the articulatory/phonological aspects of language production in childhood ASD.
Phonological difficulties and autism
According to the most recent diagnostic criteria for ASD, there are two domains of impairments: social communication impairment and repetitive behaviors.
Studies have shown that children with autism can exhibit specific phonological patterns. Some children show atypical phonological patterns that are not typical to normal development. Schoen et al. studied the phonological development in 30 toddlers with ASD. The study showed that all toddlers with ASD demonstrated atypical vocalizations when compared to matched controls.
By using both perceptual and acoustic measures to assess speech sound behavior, prosody and voice behavior, Shriberg and colleagues found an increased rate of speech errors, inappropriate prosody and higher prevalence of speech delay in children with autism.
Using various language tests, Wolk and Brennan studied eight children with ASD who were divided into two groups: a group exhibiting mild-moderate global language delay and a group that had a severe global language delay. Results from this study showed that all children had a phonological impairment, with some showing typical processes reflecting delayed development and some exhibited atypical processes not typical of normal development. Also, two trends occurred: a) There was a significant, positive correlation between language delay and several phonological processes; and b) there was a higher occurrence of both typical and atypical phonological processes in the severely impaired group.
Key Characteristics of Apraxia
Limited consonant and vowel sounds
Strong desire to talk (e.g., the child might “grope” with his or her mouth because they’re trying so hard to speak)
Trouble sequencing sounds and syllables
Stressing the wrong syllable in a word or putting equal emphasis on all syllables
Inconsistent speech patterns (e.g., making different errors when trying to say the same word multiple times)
Apraxia can sometimes get mistaken for another condition such as autism because they can have some of the same symptoms, such as difficulty making eye contact when trying to talk and sensory issues. However, children with apraxia of speech will show better receptive than expressive language skills, while those with autism spectrum disorder will show impairment in both areas. Additionally, kids experiencing apraxia will usually be able to express their needs effectively through non-verbal means.
Apraxia of speech and autism
A recent study conducted by the Penn State Milton S. Hershey Medical Center has found apraxia as a common occurrence in ASD. Apraxia is a speech sound disorder that affects the brain pathways responsible for planning the movement sequences involved in speech production. It results in distorting sounds, making inconsistent errors in speech, tone, stress and rhythm.
Using the Checklist for Autism Spectrum Disorder (CASD), the study found that two-thirds of children who were initially diagnosed with autism also had apraxia.
Some perspectives support the hypothesis that apraxia may be the cause of the absence of speech development in ASD. Extension of findings from praxis studies is that praxis deficit in speech can be the cause of failure in ASD. Apraxia’s neurobehavioral substrates could account for the speech and prosody findings in ASD.
Autism and apraxia and other phonological deficits are highly comorbid. Thus, all children diagnosed with apraxia must be monitored for signs of autism and vice versa. This will allow earlier identification and access to services appropriate for the child’s needs.
Future directions
Continued screening for autism and apraxia, especially non-verbal ones, mean that children have a better chance of receiving appropriate early intervention. Larger data protocols are needed to investigate the phonological/articulatory patterns in children with ASD and expand the underlying models of phonology.
Further correlation studies are needed to understand:
The link between language severity and specific types of phonological deficits
The relationship between the severity of phonological difficulties and behavioral manifestations
Deeper investigation into the speech sound deficits in children with ASD may be vital for designing ultimate rehabilitation programs for these children.
Speech Assessments
There are some things that need to be done to make an adequate assessment:
1. Case history, parent/client interview
2. Hearing assessment
3. Oral mechanism exam, to rule out structural or functional abnormalities
4. Standardized assessment (typically spontaneous production of single words, e.g., GFTA)
5. Dynamic motor speech assessment (informal or formal, e.g., DEMSS) ▪ Including targets with varying sounds, syllable shapes, and stress patterns
6. Conversational speech sample analysis ▪ Phonemic repertoire, PCC, syllable shapes, intelligibility, prosodic features
Multiple sampling methods are recommended for comprehensive speech assessment (McLeod & Baker, 2014, Stoel-Gammon & Williams, 2013)
When doing the assessments:
1. Plan for the assessment to take several sessions
2. Break assessments into discrete tasks, followed by reinforcement (informed by preference assessment)
3. Embed task in play and reference the meaning of words when possible
4. Minimize verbal directions
5. Use visual strategies to facilitate attention
References
Vashdi, E. (2014). The Influence of Initial Phoneme Cue Technique on Word Formation: A Case Study of a Child with Apraxia of Speech and Autism. https://www.questia.com/library/journal/1P3-3498985991/the-influence-of-initial-phoneme-cue-technique-on
Wolk, L., Edwards, M. & Brennan, C. (2016). Phonological difficulties in children with autism: An overview. https://www.tandfonline.com/doi/full/10.1080/2050571X.2015.1133488