Language versus learning disorder: part 1

 

In this post and in the next post, we will discuss language disorder versus learning disorder, according to the DSM-5 as compared with Flanagan’s definition.

How is language disorder defined according to the DSM-5, and is it an exclusionary factor for learning disorder according to the DSM-5?

How would Flanagan approach language disorder and learning disability/disorder?

Before we begin, a note about the use of terms. The authors of the DSM-5 definition of learning disorder recognize that low performance in reading/writing/arithmetic stems from an impairment in cognitive abilities. They believed that administering a psychological assessment to every child in order to identify the cognitive impairment underlying the child’s difficulties is a very slow and expensive process, and does not always benefit the child compared with diagnosing a learning disorder without examining cognitive abilities. Their goal was to simplify and facilitate the process, and I think they are right.

The authors of the DSM-5 definition never intended to create a situation in which their criteria would be insufficient for determining the existence of a learning disability/disorder. They believed that low performance in reading/writing/arithmetic, which exists despite high-quality academic intervention and is not caused by any exclusionary factor, is sufficient for the child to be defined as having a learning disability/ a specific learning disorder. From their perspective, “learning disorder” = “learning disability.” The word “disorder” appears in the DSM-5 because that is the term used to describe all types of mental difficulties.

In the DSM-5, language disorder appears under communication disorders and is defined as follows:

A. Persistent difficulties in the acquisition and use of language across modalities — for example, spoken language, written language, sign language, or another form — due to deficits in comprehension or production that include:

1. Reduced vocabulary: word knowledge and word use.
2. Limited sentence structure: difficulty forming proper sentences according to the rules of grammar and morphology.
3. Impairments in discourse: difficulty using vocabulary and sentences to explain or describe a topic or a series of events, or difficulty holding a conversation.

B. Language abilities are substantially below those expected for age. This results in impairment in effective communication and/or social participation and/or academic achievement and/or occupational performance.

C. The symptoms begin in the early developmental period.

D. The difficulties are not caused by hearing impairment or another sensory impairment, by motor difficulties, or by another medical or neurological condition, and are not better explained by intellectual disability — intellectual developmental disorder — or global developmental delay.

Is language disorder, as defined in the DSM-5, an exclusionary factor for learning disorder as defined in the DSM-5, in a school-age child with difficulties in reading/writing/arithmetic? In the comorbidity section of the definition of learning disorder, on page 74 of the DSM-5, it is stated that learning disorder often appears together with communication disorders — and, as noted above, language disorder is one of them. Language disorder does not necessarily exclude a diagnosis of learning disorder, but it may make the differential diagnosis more difficult. This is because both learning disorder and language disorder affect learning functions. If there is an indication that language disorder can explain the difficulties in reading/writing/arithmetic, then the child is not diagnosed as having a learning disorder.

In other words, the differential diagnosis depends on the key word “primary.” If language disorder is the primary cause of the child’s difficulties in reading/writing/arithmetic, the child is not defined as having a learning disorder. If language disorder exists, but is not the primary cause of the child’s difficulties in reading/writing/arithmetic, the child may receive both definitions. He or she will be diagnosed with both a learning disorder and a language disorder.

To be convinced that language disorder is not the primary cause of the child’s difficulties in reading/writing/arithmetic, one presumably needs to find another cognitive factor that is the primary cause of these difficulties. But the DSM-5 does not require cognitive abilities to be assessed in order to look for such a factor. In my opinion, this is where there is a problem.

How would Flanagan’s definition address language disorder versus learning disorder, and would a problem of differential diagnosis arise under Flanagan’s definition as well? That will be discussed in the next post.

American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders: DSM-5. American Psychiatric Publishing. 991 pp.