Stability of language difficulties among a clinical sample of preschoolers

Some data call into question the persistence of developmental language disorders (DLDs) identified during the preschool period. For this reason, speech-language pathologists (SLPs) often reassess children. However, it is unclear if the instability of the profiles documented in community sample studies is present in children referred to specialized clinics. Given the scarcity of SLP resources, is re-evaluating the language skills of these children a good use of clinical time?

To examine the stability of the findings from two SLP assessments in a sample of Canadian preschool children referred to a tertiary clinic between the ages of 2 and 6 years. It was hypothesized that children under the age of 4 years at first assessment and children with less severe initial deficits would show less stability of DLD diagnosis.

The clinical files of children referred to an early childhood psychiatric clinic in Canada were reviewed. For 149 children with two SLPs assessment reports, persistence of language deficits was documented and tested with McNemar's statistics. Differences between preschoolers under the age of 4 versus 4 years and over, as well as between mildly and severely impaired children, were examined.

High level of agreement (94%) and McNemar's test (p = 0.180) supported the stability of initial diagnosis. The stability for children assessed before the age of 4 (n = 64) was 100%, and was significantly different from older children's (n = 85) stability of 89% (Fisher's exact test, p = 0.01; bilateral). The stability for children with mild impairments (n = 18) was 78%, which was significantly lower than the stability (97%) in children with severe impairments (n = 114) (Fisher's exact test, p = 0.007; bilateral).

No instability of language status was observed in children assessed before 4 years of age, which could be related to the significant severity of the difficulties that children in this age group presented and be specific to this type of clinical sample. The great stability of language status observed in preschoolers referred to a specialized clinic suggests that clinicians should limit reassessments to devote available resources to intervention efforts.

What is already known on this subject? Previous research that has demonstrated important instability in the classification of language impairment before 4 years of age gathered data mainly by screening the general population or was not based on a comprehensive clinical assessment. What this paper adds to existing knowledge? This study investigated the classification stability of DLD between two comprehensive SLP assessments in a clinical sample of Canadian preschoolers. The results indicate great stability of language status assessed before 4 years old in this population, suggesting that severity of impairments may trump the age factor in this group. What are the potential or actual clinical implications of this work? In the case of children referred to a specialized clinic, clinicians and policymakers should be aware that DLD diagnosis made before 4 years of age remains stable during preschool age, and that a best practice with this population would be to abandon unnecessary testing in favour of early intervention.