[Posted on 7 October, 2019 by Carmela Miniscalco]
The other day a psychologist asked me whether the diagnosis of language disorder always means that the child also has autism? She had read that “pure” language disorder affects 6-8% of all children and wondered if the rest is combined with autism. In her experience, language disorder is indeed sometimes the primary problem, meaning that the interaction difficulties come as a result of language disorder rather than autism. However, her supervisor had told her that language disorder always and automatically causes autism.
My answer was: It is true that the prevalence of “pure” language disorder is usually estimated at 6-8%, but the number of children actually affected depends on several different factors: age of detection, which test instruments are used and which areas – speech, language or communication skills – are being investigated.
But it is not true that everyone with language disorder also has autism! On the other hand, children with language disorder may have major secondary difficulties with communication and interaction (what we speech therapists call pragmatics), but when the speech and language abilities improve, the pragmatic difficulties diminish, meaning that the child can participate in more social-communicative interactions and contexts.
Recently, just over 7,000 5-year-olds were screened in England and it was found that 7.6% had only language disorder and another 2.3% had language disorder in combination with e.g. ASD and/or intellectual disability. Language difficulties were associated with higher levels of social, emotional and behavioural problems and increased risk of school failure (Norbury et al., 2016).
In our Swedish study, nearly 300 children who had been screened positively at the age of 2.5 were examined both for language disorder alone (and were referred to a speech therapist) or for autism (and were referred to the child-neuropsychiatric clinic for team investigation). Five years later, about 40% of the children had – in addition to language disorder and autism – other ESSENCE-related difficulties as well, such as problems with behaviour, attention or motor skills, and many were also in ongoing contact with health services. (Miniscalco et al., 2018).
In another Swedish study, speech and language abilities of children ages 4-6 with ASD without intellectual disability were investigated. The results showed that about 60% of the children had moderate to severe language impairment, and that about 20% of the children also had speech disorder, i.e. difficulties pronouncing speech sounds (Kjellmer et al., 2018). These figures indicate that language and speech difficulties are more common in children with autism than in children without autism.
As early as the 1990’s, Dorothy Bishop wrote that there are many similarities between children with autism and children with language disorder: for example, both groups can have difficulties with non-verbal communication, social interaction and prosody (speech melody).
Several studies have shown that children in clinical groups with autism and/or language disorder weave in and out of their diagnoses when they are followed up over time. Still, language disorder and autism are sometimes claimed to be completely separate disabilities, but research and experience show, on the contrary, that overlap or “comorbidity” is the rule rather than the exception!
So, the answer to the question I got from the psychologist is that children can absolutely have a language disorder without simultaneous autism, but since it is common that the two conditions overlap, an awareness is important in order to give appropriate intervention. Both groups are usually identified because of parents’ concerns, delayed, abnormal or absent language development, or in conjunction with screening at child health care services.
Today, according to DSM-5, children can have parallel diagnoses of language disorder and autism. Symptoms may overlap, diagnostic criteria may be met for more than one diagnosis at time of identification or at follow-up some years later. Therefore, different professions need to cooperate in the assessment of children!