Identifying dyslexia-consistent reading profiles in mild intellectual disability: cluster-derived severity gradients and severity-calibrated classification rules
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By
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Bartosz M. Radtke
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Paweł Jurek
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Michał Olech
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Ariadna Łada-Maśko
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Urszula Sajewicz-Radtke
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May 29, 2026
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Objective:
To quantify over-identification of dyslexia in individuals with mild intellectual disability (MID) using severity-calibrated classification rules.
Key Findings:
- A two-cluster solution indicated a dominant severity gradient across reading and related markers.
- Broad criteria classified 88% of the sample, including many higher-performing cases.
- Introducing an extreme-severity anchor reduced prevalence to 37%, concentrating classified cases within the lower-performing profile.
- Adding phonological/RAN criteria yielded little further classification gain when very low decoding was required.
Interpretation:
Limitations:
- The study did not formulate a priori hypotheses due to the substantial heterogeneity in reading-related mechanisms in ID.
- Measurement artefacts such as floor effects may mimic reading-specific weaknesses.
Conclusion:
