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• Differential Diagnosis: DLD vs. Language Disorder Associated with {biomedical condition}

Differential Diagnosis: DLD vs. Language Disorder Associated with {biomedical condition}

by Lisa Archibald

Scenario: An SLP/T determines that a child meets criteria for a language disorder: the child has a persistent language problem with a significant impact on everyday interactions or educational progress. Does this child have DLD?

According to the CATALISE consensus (Bishop et al., , ), Language Disorder is an overarching term for a persistent language problem with a functional impact. This category is further divided into two subtypes: (1) Language Disorder associated with {biomedical condition} is used when a child has been diagnosed with a biomedical condition known to impact language development; and (2) Developmental Language Disorder (DLD), which refers to a child with a language disorder without a known biomedical condition. 

In order to determine if the child has DLD, the presence of a biomedical condition that could account for the language disorder must be ruled out. A specialized or multidisciplinary team assessment is required to consider the question of a biomedical condition. Access to such assessments could constrain how a SLP/T goes about making the DLD diagnosis.

Ideally, the SLP/T works as part of a multidisciplinary team. The team works together when assessing a child and determines the presence/absence of a language disorder, any associated biomedical conditions, etc. The results of the assessment guides the diagnostic decision regarding language disorder, as well as any other relevant diagnoses. Unfortunately, many SLP/Ts are not part of a multidisciplinary assessment team. In many cases, SLP/Ts work within a region, district, or school board authority with psychologists, occupational therapists, special educators, etc. Together, these colleagues form an informal team when a child is referred for multiple services.

It is quite common, however, for children to be referred to a single service such as SLP/T, which may mean that additional cross-disciplinary assessments to aid in the diagnostic process are unavailable. As well, the extent to which the SLP/T can refer the child for additional assessments may be constrained by a number of factors. For example, there may be a need to manage the number of referrals made for additional assessments. And when referrals are made, long waitlists could preclude timely assessments. As well, professionals may be involved with a child at different times. SLP/Ts are often consulted when a child is very young and showing early signs of difficulty developing language. A psychoeducational assessment, on the other hand, may not be completed until the child has attended school for some time.

It is against this backdrop that many SLP/Ts need to make their diagnostic decisions regarding DLD. When access to multidisciplinary assessments is limited, children for whom there is no concern regarding biomedical conditions might not be referred for additional assessments. SLP/Ts should consult with the child, parent, educators, or other team members in determining that there are no concerns regarding neurocognitive or intellectual development. Under these conditions, it would be reasonable to provide the DLD diagnosis (when relevant) based on the SLP/T assessment alone. In cases where concern regarding a biomedical condition exists, the SLP/T will need to consider the balance between providing a parent or educator with timely information and the availability/timeliness of the additional assessments. If the required additional assessments will be completed within a reasonable timeframe, the SLP/T might wait to determine the child’s diagnosis based on the outcome of those assessments. If not, the SLP/T should consider providing a provisional diagnosis of DLD with the caveat that future assessments may warrant a review of the diagnosis. The flowchart (v.2) available for download tries to capture the decision making based on these various scenarios.

As a final note, it could be argued that many diagnoses are provisional. A diagnosis is made based on the available information at the time of the assessment. Information that comes to the light in the future can and should be considered, and the diagnosis modified as needed.