Uniting Behind the DLD Diagnosis: What’s the Evidence?
Published in the May 2024 ISHA Voice.
By Carol Szymanski, an invited author by ISHA’s Evidence-based Practice Committee
Treating children with language deficits is a large part of the practice of speech-language pathology. The prevalence rate of language deficits among school-age children in the U.S is approximately 7% (McGregor, 2020; Tomblin, et al, 1997). This puts the number of children with language deficits at more than 5 million.
The sheer number of clients with language deficits must mean that speech-language pathologists are in agreement about what to call the problem and how to provide therapeutic intervention, correct? Incorrect. Over time, there have been many labels for language deficits, including specific language impairment, language delay, language disability, language disorder, and developmental language disorder. After years of using this variety of labels in clinical practice, and the resultant inconsistency, the field is finally moving toward agreement, with the use of the term developmental language disorder (DLD) (Bishop et al, 2016).
Why DLD?
The term developmental language disorder can be used to describe children experiencing difficulty in the development, comprehension, and use of language. The language disorder is considered the primary disability, there is not a known medical etiology, and it is present throughout the lifespan. DLD can be co-morbid with other developmental diagnoses, and symptoms evolve as the child ages (Bishop et al, 2017). When a primary condition has been diagnosed (autism, Down syndrome, traumatic brain injury, etc.) the deficit can be described as a language disorder associated with [condition].
If all speech-language pathologists consistently used the term DLD, we could solve many problematic issues in the diagnosis and treatment of language deficits. In fact, in January of 2023, the then-President of ASHA, Dr. Robert Augustine, wrote to the U.S. Department of Education, Office of Special Education and Rehabilitative Services. His letter asked the Department “for their consideration to encourage states and school districts to review their policies, procedures, and practices to ensure that they do not prohibit the use of the terms such as DLD for evaluation, eligibility, and as part of an individualized education program (IEP).”
You can read the full text of his letter.
McGregor (2020) documents how we are failing children with DLD in her LSHSS article. In this article, McGregor reports that DLD does not draw the research attention that it should based upon the numbers of children diagnosed, that children with DLD are underserved in general, and there are inequalities in access to services. This can be attributed to the fact that DLD is a hidden and unknown disorder to the general public, despite its prevalence and significant impact. In addition, there are outdated policies governing services (e.g., insurance denials for developmental disorders), and inconsistent diagnosis in the schools because there is not an outside medical diagnosis for DLD as there is for other disorders (for example, hearing impairment or ASD). McGregor ends the article with a call to action: SLPs in all settings and our national organization need to work together to advocate for our clients, educate and communicate with families, and develop new diagnostic and treatment tools. By doing so, hopefully we can generate new knowledge and overcome barriers to service.
DLD as a Neurodevelopmental Disorder
The first step is to conceptualize DLD as a neurodevelopmental condition, as we do with other childhood disorders (e.g., ASD, intellectual disability, ADHD, etc.). Why should we do so? DLD fits criteria generally used to describe neurodevelopmental disorders: the child experiences difficulties and differences in the development of basic skills due to a disruption in early brain development, the causes are multifactorial, the disorder is spectral in nature, and it is a lifelong disorder that changes over time (McGregor et al, 2021, 2022). Using criteria aligned with this construct of DLD will provide uniformity in diagnosis and treatment across settings.
If we view DLD as a spectral disorder that changes as the child ages and experiences different and increasingly difficult linguistic, academic, and social situations, we can advocate for continued service delivery over time. Evidence shows that after age 4, language ability relative to same-age peers stabilizes, and that children with DLD have a lower but parallel path as compared to these same-age peers. In other words, children with DLD make progress; but not at a rate fast enough to catch up (Bornstein et al 2014; Tomblin et al, 2003; Norbury et al, 2021). In addition, symptom presentation changes over time. At age 5, we may see what we consider “classic” language disorder symptoms (grammatical errors, low vocabulary). At age 10 we are seeing a language learning impairment that affects communication and literacy. By age 16 this is a complicated disorder with language, learning, and emotional aspects (Brinton et al, 2005). Core language ability is not very malleable after age 10.
Implications
What are the implications of DLD as it changes with a client’s increasing age? Changing or additional diagnoses are likely. DLD imposes risks for learning disabilities and mental health issues. Problems become more broad-based and affect many aspects of life. Acquiring new diagnoses does not mean that the earlier diagnoses were wrong; it just means that the symptoms and communicative and learning environments have evolved and our conceptualization of the disorder must also change.
What are the implications for service delivery? Functional abilities should drive service delivery decisions for children, adolescents, and young adults with DLD. The nature of services will shift over time; a different focus may be required as the client ages and develops. DLD is a lifelong neurodevelopmental disorder, and changing symptom presentation requires the continuation of services. For those clients that were dismissed from services, a return to services may be necessary at various times as clients age. It is NEVER too late to support language learning, teach compensatory strategies, or facilitate development of vocational or functional skills. (McGregor, 2022)
Take Away Message
- Use the included resources and references to learn more about DLD.
- Use assessment tools with high levels of diagnostic accuracy and diagnose DLD as appropriate.
- Be clear to clients and families about what the diagnosis means and the significant, life-long impact of DLD.
- Advocate for your clients with DLD and provide excellent services to them.
- Advocate for research, public awareness, and policy change to advance our understanding of DLD and our service to clients with DLD.
Resources
ASHA Practice Portal Spoken Language Disorders
Raising Awareness of Developmental Language Disorder
Engage with Developmental Language Disorder
References
Bishop, D.V.M., Snowling, M. J., Thompson, P.A., Greenhalgh, T. & CATALISE consortium. (2016). CATALISE: A Multinational and Multidisciplinary Delphi Consensus Study. Identifying Language Impairments in Children. PLoS One 11(7), e0158753.
Bishop, D. V. M., Snowling, M. J., Thompson, P. A., Greenhalgh, T., & the CATALISE-2 consortium. (2017). Phase 2 of CATALISE: A multinational and multidisciplinary Delphi consensus study of problems with language development: Terminology. The Journal of Child Psychology and Psychiatry, 58(10), 1068–1080. https://doi.org/10.1111/jcpp.12721
Bornstein, M. H., Hahn, C. S., Putnick , D. L., & Suwalsky , J. T. (2014). Stability of core language skill from early childhood to adolescence: A latent variable approach. Child development, 85(4), 1346 - 1356.
Brinton, B., Fujiki , M., & Robinson, L. A. (2005). Life on a tricycle: A case study of language impairment from 4 to 19. Topics in Language Disorders, 25(4), 338 - 352 Brownlie , E. B., Beitchman , J. H., Escobar, M., Young, A.,
McGregor, K. K. (2020). How we fail children with developmental language disorder. Language, Speech, and Hearing Services in Schools, 51(4), 981–992. https://doi.org/10.1044/2020_LSHSS-20-00003
McGregor, K. K., Eden, N., Arbisi - Kelm , T., & Oleson, J. (2020). The fast - mapping abilities of adults with developmental language disorder. Journal of Speech, Language, and Hearing Research, 63(9), 3117 - 3129.
McGregor, K.K., Ohlmann , N., Eden, N., Arbisi - Kelm , T., & Young, A. (2022). A mixed - method examination of abilities and disabilities among children with developmental language disorder. Manuscript under review.
McGregor, K.K. (2022). Developmental language disorder in Children, Adolescents, and Young Adults. SpeechPathology.com Webinar, August 1, 2022.
Norbury, C. F., Griffiths, S., Vamvakas , G., Baird, G., Charman , T., Simonoff , E., & Pickles, A. (2021). Socioeconomic disadvantage is associated with prevalence of developmental language disorders, but not rate of language or literacy growth in children from 4 to 11 years: evidence from the Surrey Communication and Language in Education Study (SCALES)
Paul, R., Norbury, C. N. & Gosse, C. (2018). Language Disorders from Infancy through Adolescence 5th Edition, Elsevier: St. Louis, MO.
Tomblin, J. B., Records, N. L., Buckwalter, P., Zhang, X., Smith, E., & O’Brien, M. (1997). Prevalence of specific language impairment in kindergarten children. Journal of Speech, Language, and Hearing Research, 40(6), 1245–1260. https://doi.org/10.1044/jslhr.4006.1245
Tomblin, J. B., Zhang, X., Buckwalter, P., & O'Brien, M. (2003). The stability of primary language disorder: Four years after kindergarten diagnosis. Journal of Speech, Language, and Hearing Research, 46(6), 1283 - 1296.
Carol Szymanski is an Associate Professor in Speech-Language Pathology at Lewis University. She teaches undergraduate and graduate coursework in language development and disorders, and has been a long-time active ISHA member and volunteer.
