Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2005 Dec;48(6):1378-96.
doi: 10.1044/1092-4388(2005/096).

Are specific language impairment and dyslexia distinct disorders?

Hugh W Catts  1 , Suzanne M Adlof, Tiffany P Hogan, Susan Ellis Weismer
Affiliations

Are specific language impairment and dyslexia distinct disorders?

Hugh W Catts et al. J Speech Lang Hear Res. 2005 Dec.

Abstract

Purpose: The purpose of this study was to determine whether specific language impairment (SLI) and dyslexia are distinct developmental disorders.

Method: Study 1 investigated the overlap between SLI identified in kindergarten and dyslexia identified in 2nd, 4th, or 8th grades in a representative sample of 527 children. Study 2 examined phonological processing in a subsample of participants, including 21 children with dyslexia only, 43 children with SLI only, 18 children with SLI and dyslexia, and 165 children with typical language/reading development. Measures of phonological awareness and nonword repetition were considered.

Results: Study 1 showed limited but statistically significant overlap between SLI and dyslexia. Study 2 found that children with dyslexia or a combination of dyslexia and SLI performed significantly less well on measures of phonological processing than did children with SLI only and those with typical development. Children with SLI only showed only mild deficits in phonological processing compared with typical children.

Conclusions: These results support the view that SLI and dyslexia are distinct but potentially comorbid developmental language disorders. A deficit in phonological processing is closely associated with dyslexia but not with SLI when it occurs in the absence of dyslexia.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Models of the relationship between specific language impairment (SLI) and dyslexia.
Figure 2
Figure 2
Phonological awareness performance of subgroups in kindergarten and the second, fourth, and eighth grades.
Figure 3
Figure 3
Nonword repetition performance of subgroups in the second and eighth grades.
See this image and copyright information in PMC

References

    1. Adams CV, Bishop DVM. Genetic influences on verb morphology deficits in 6-year-old twins; Madison, WI. Poster presented at the joint conference of the International Association for the Study of Child Language and the Symposium for Research on Children with Language Disorders.2002. Jul,
    1. Badian N, McAnulty G, Duffy G, Als HS. Prediction of dyslexia in kindergarten boys. Annals of Dyslexia. 1990;41:221–243. - PubMed
    1. Bedore LM, Leonard LB. Specific language impairment and grammatical morphology: A discriminant function analysis. Journal of Speech, Language, and Hearing Research. 1998;41:1185–1192. - PubMed
    1. Berkson J. Limitations of the application of fourfold table analysis to hospital data. Biometrics. 1946;2:47–53. - PubMed
    1. Bishop DVM. Genetic influences on language impairment and literacy problems in children: Same or different? Journal of Child Psychology and Psychiatry. 2001;42:189–198. - PubMed

Publication types

MeSH terms