Discrepancies in assessing intellectual disability levels in adults with Down syndrome: Implications for dementia diagnosis

Topic: Risk, prevention and care in population studies

Inter-rater agreement for ID level classification was 95% within sites but 60% between sites. While CAMCOG-DS score distributions in the whole cohort were similar across sites, ID classification discrepancies caused higher cut-offs in Barcelona for mild and moderate ID compared to Munich. Applying site-specific cut-offs to another cohort reduced sensitivity and specificity. Standardizing ID classification is critical for generalizable cut-offs to accurately diagnose AD dementia based on neuropsychological assessments in DS. HIGHLIGHTS: CAMCOG-DS cut-offs by intellectual disability level classify dementia in Down syndrome. ID classification discrepancies between sites impact CAMCOG-DS diagnostic cut-offs. Applying site-specific cut-offs to other cohorts reduces sensitivity and specificity. Standardized ID classification is essential for generalizable cognitive cut-offs. Use site-specific cut-offs until ID classification is standardized.

Key findings

• Inter-rater agreement for ID level classification was 95% within sites but 60% between sites.
• While CAMCOG-DS score distributions in the whole cohort were similar across sites, ID classification discrepancies caused higher cut-offs in Barcelona for mild and moderate ID compared to Munich.
• Applying site-specific cut-offs to another cohort reduced sensitivity and specificity.
• Standardizing ID classification is critical for generalizable cut-offs to accurately diagnose AD dementia based on neuropsychological assessments in DS.
• HIGHLIGHTS: CAMCOG-DS cut-offs by intellectual disability level classify dementia in Down syndrome.

Why it matters

This study found that discrepancies in classifying intellectual disability levels between sites affect the cut-offs used to diagnose dementia in adults with Down syndrome. It highlights the need for standardized classification to improve diagnostic accuracy, but it does not report any treatment, cure, or prevention.

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Study details

• Study designcohort study
• Participants673
• Evidence strengthModerate

Read the original

• DOI: 10.1002/alz.70307
• PubMed: 40528393
• Original source →
• Free full text: Alzheimer s & Dementia →

Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).

@article{soriano2025-40528393,
  author  = {Soriano, Laura del Hoyo and Sandkühler, Katja and Videla, Laura and Benejam, Bessy and Carmona‐Iragui, María and Wlasich, Elisabeth and Kustermann, Julia and Barroeta, Isabel and others},
  title   = {{Discrepancies in assessing intellectual disability levels in adults with Down syndrome: Implications for dementia diagnosis}},
  journal = {Alzheimer s \& Dementia},
  year    = {2025},
  doi     = {10.1002/alz.70307},
  pmid    = {40528393},
  url     = {https://doi.org/10.1002/alz.70307}
}

Studies this one cites

Referenced by this study and also in the alzhub library, so you can read them here.

• Longitudinal Clinical and Cognitive Changes Along the Alzheimer Disease Continuum in Down Syndrome JAMA network open · 2022-08-01 · usefulness score 66/100 · Down syndrome and Alzheimer's
• Alzheimer's disease associated with Down syndrome: a genetic form of dementia The Lancet. Neurology · 2021-11-01 · usefulness score 59/100 · Prevention and risk
• Down syndrome Nature reviews. Disease primers · 2020-02-06 · usefulness score 56/100 · How common it is

Later studies that cite this one

2 studies in the alzhub library list this one in their references.

• The Down Alzheimer Barcelona Neuroimaging Initiative (DABNI) and its contributions to understanding Alzheimer's disease in Down syndrome: A decade of discovery Alzheimer's & dementia : the journal of the Alzheimer's Association · 2025-06-01 · usefulness score 67/100 · Down syndrome and Alzheimer's
• Changes in serum β-synuclein precede blood biomarkers of Alzheimer pathology in Down syndrome Alzheimer's & dementia : the journal of the Alzheimer's Association · 2026-09-01 · usefulness score 47/100 · Down syndrome and Alzheimer's

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• Cognitive deficits and associated neurological complications in individuals with Down's syndrome The Lancet. Neurology · 2010-06-01 · usefulness score 53/100
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• Assessing Cognition Remotely: Expanding the Reach of Cognitive Testing for Older Adults at Risk for Dementia in a Randomized Controlled Trial Canadian Geriatrics Journal · 2025-03-05 · usefulness score 46/100
• Cardiovascular-kidney-metabolic syndrome and incidence of dementia among older adults The Journal of Prevention of Alzheimer s Disease · 2025-03-04 · usefulness score 59/100

Also tagged “down”

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• Change in plasma Aß peptides and onset of dementia in adults with Down syndrome Neurology · 2010-11-01 · usefulness score 54/100 · Down syndrome and Alzheimer's
• Down syndrome and Alzheimer's disease: Oxidative stress in the neurodegenerative process Journal of Alzheimer's disease : JAD · 2025-04-03 · usefulness score 39/100 · Down syndrome and Alzheimer's
• Nardilysin in human brain diseases: both friend and foe Amino acids · 2013-04-19 · usefulness score 32/100 · Down syndrome and Alzheimer's

Similar studies

• Sequence of cognitive decline in dementia in adults with Down's syndrome 2000 · Down syndrome and Alzheimer's
• [Alzheimer's dementia in people with Down syndrome : Results of guideline-assisted expert interviews on healthcare deficits in the diagnostics and treatment as well as solution approaches] 2025 · Down syndrome and Alzheimer's
• [Diagnosing Alzheimer Dementia in People with Down Syndrome in Accordance with ICD, DSM V and A/T/N System] 2022 · Down syndrome and Alzheimer's
• Prevalence of dementia in adults with and without Down syndrome 1996 · Down syndrome and Alzheimer's
• Prevalence of dementia and impact on intellectual disability services 2000 · Down syndrome and Alzheimer's
• Symptoms of dementia among adults with Down's syndrome: a qualitative study 2007 · Digital health tools

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