"Comorbidity" refers to the presence of two or more disorders in the same person. These disorders can occur individually or link together. For example, a person who wears glasses and uses a hearing aid may have a visual impairment and hearing loss that are completely separate from each other. Yet, another person who wears glasses and uses a hearing aid may have an underlying medical condition that affects both their vision and hearing.
How do you know if your child's DLD is a condition by itself or is part of another disorder?
When we study large groups we can see the more common comorbidities. Developmental language disorder (DLD) can occur by itself or it can occur along with other disorders. There are also subtypes of DLD. When a person with DLD has an average or above IQ, the condition is sometimes termed "specific language impairment" (SLI). SLI is the most common type of DLD.
DLD can also happen with other disorders. Studies of children with DLD suggest some disorders co-occur more often. These include emotional problems, ADHD, dyslexia, and autism. When DLD symptoms co-occur in children with autism, this situation is referred to as language disorder associated with autism. We are still learning why this happens. It might be that DLD makes it hard to express yourself and understand other people. If it is hard to communicate, this can lead to problems with friends, family, or teachers. This could lead to frustration and emotional problems. Genes might play a role. We know that DLD and autism happen in families at higher rates than expected. It can also be hard to tell where one disorder ends and another begins. Some children with DLD have problems following directions because they don't understand the words and sentences adults are using. From the teacher's view, children with DLD look like they have ADHD. But that's because DLD can sometimes mimic ADHD. When the verbal challenges are lower these children can pay attention. It takes a team of specialists to figure out if a person has DLD by itself or has additional disorders. Comorbidity research helps us watch for areas where people with DLD might need extra help.
To gain a better understanding if you or your child may have a co-occurring condition, contact your primary care provider.
Bishop, D. V., McDonald, D., Bird, S., & Hayiou-Thomas, M. E. (2009). Children who read words accurately despite language impairment: Who are they and how do they do it? Child Development, 80(2), 593–605
Catts, H. W., Adlof, S. M., Hogan, T. P., & Weismer, S. E. (2005). Are specific language impairment and dyslexia distinct disorders? Journal of Speech Language and Hearing Research, 48, 1378-1396.
Catts, H. W., Adlof, S. M., & Weismer, S. E. (2006). Language deficits in poor comprehenders: A case for the simple view of reading. Journal of Speech, Language, and Hearing Research, 49, 278-293.
Redmond, S.M. (2016). Language impairment in the ADHD context. Journal of Speech, Language, and Hearing Research. 59, 133-142.
Redmond, S.M., Ash, A.C., & Hogan, T.P. (2015). Consequences of co-occurring attention deficit/hyperactivity disorder on children’s language impairments. Language, Speech, and Hearing Services in Schools, 46, 68-80.