It’s not all about test scores, but …

by Lisa Archibald

DLD Diagnostics Flowcharts

Scenario: As part of an assessment for Developmental Language Disorder, an SLP/T observes a child with low average scores on an omnibus standardized language test. Given the concerns expressed about this child, the SLP/T wonders if the child could still have DLD.

We all know that a language assessment should combine information from multiple sources such as caregiver report, observation, standardized tests, and language learning context. We also know that standardized language tests may not be sensitive to all impairments that affect day-to-day language functioning. It seems possible, then, that a child who scores in the low average range on language tests could still have DLD.

We should be cautious here. Not every child who struggles at school or has weak language skills has DLD. We don’t want to be overzealous in a quest to explain every child’s learning challenges in the context of language. If we do, we’ll end up overapplying the label of DLD, which will reduce the impact and purpose of DLD. Let’s agree that scores in the average range on a standardized language test should provide fairly convincing evidence that language development is not disordered. What, then, might lead you to provide a diagnosis of DLD despite a child scoring in the low average range on a standardized language test?

As the clinician weaves together the multiple sources of information, there might be clues that confirm a DLD diagnosis – or at least favour it. The SLP/T might reflect on the reason for referral and concerns raised by caregivers. These indicators might lead the clinician to administer an additional standardized test designed to address the particular issues of concern. Of course, I’m not suggesting we administer test after test after test until we find one that identifies a deficit. I’m imagining that you identify an area of language concern not fully tested by your omnibus language test, and that an additional test exists perfectly aligned with your identified area of concern. Unlikely, you say? Agreed, but in theory, it’s possible. Another possibility is that you have an excellent parent or student checklist that identifies a child’s language disorder. Just on its own, you say? Remember, it’s multiple sources of information, and the challenge is to figure out how all the evidence adds up. You might also consider results of a dynamic assessment, that is, a direct assessment of the child’s language learning in a test-teach-retest cycle. Typically, dynamic assessments are described in the context of cultural and linguistic differences, but the point is that they provide additional information about a child’s language learning. Finally, evidence of a language disorder could come from examining written language skills. For older children in particular, a language disorder may be most evident in written language tasks.

Now let’s consider evidence that would disconfirm a DLD diagnosis. Here we’re considering other factors that might account for the depressed language scores described in this scenario. In the context of low average standardized test scores, we should be on the look for evidence consistent with our findings. In fact, there are lots of reasons why a child might score low on a language test. The presence of other conditions might interfere with a child’s ability to concentrate on test items, or answer succinctly or clearly. Children who speak a different language or dialect from that of the test might not know the required linguistic forms. And some children may not know the answers because of a lack of opportunity rather than a disorder. The question is whether these reasons fully account for the depressed language test scores, because the trick is - and this is important - each of these reasons can also co-occur with DLD. Of course, making this determination is challenging. It is the work of the knowledgeable expert clinician, the SLP/T. 

Now, we’re not at the end of the list. There are still more considerations that could help or complicate the decision! The properties of the test itself, the child’s characteristics, previous assessments or interventions, and the cognitive and behavioural tells you observe during the assessment – these are all factors that are part of the picture. Overall, you’re trying to determine if there is sufficient evidence to conclude that a child’s language skills are substantially different from their peers. A case like this is challenging and complex. There’s no flowchart that will easily give you the right answer. I only hope that discussions and tools like this will help!