Establishing diagnostic thresholds for Alzheimer's disease in adults with Down syndrome: the Cambridge Examination for Mental Disorders of Older People with Down's Syndrome and Others with Intellectual Disabilities (CAMDEX-DS). Issue 3 (13th April 2021)

• Record Type: Journal Article
• Authors: Beresford-Webb, Jessica A.; Mak, Elijah; Grigorova, Monika; Daffern, Samuel J.; Holland, Anthony J.; Zaman, Shahid H.
• Is Part Of: BJPsych open. Volume 7:Issue 3(2021)
• Publication Date: 2021-04-13
• Subjects: Dementia, -- intellectual disability, -- imaging, -- CAMDEX-DS, -- Alzheimer's disease; Psychiatry -- Periodicals; Mental health -- Periodicals; 616.89005
• DOI: 10.1192/bjo.2021.36
• Languages: English
• ISSNs: 2056-4724

Abstract

Abstract : Background: Diagnosis of prodromal Alzheimer's disease and Alzheimer's disease dementia in people with Down syndrome is a major challenge. The Cambridge Examination for Mental Disorders of Older People with Down's Syndrome and Others with Intellectual Disabilities (CAMDEX-DS) has been validated for diagnosing prodromal Alzheimer's disease and Alzheimer's disease dementia, but the diagnostic process lacks guidance. Aims: To derive CAMDEX-DS informant interview threshold scores to enable accurate diagnosis of prodromal Alzheimer's disease and Alzheimer's disease dementia in adults with Down syndrome. Method: Psychiatrists classified participants with Down syndrome into no dementia, prodromal Alzheimer's disease and Alzheimer's disease dementia groups. Receiver operating characteristic analyses assessed the diagnostic accuracy of CAMDEX-DS informant interview-derived scores. Spearman partial correlations investigated associations between CAMDEX-DS scores, regional Aβ binding (positron emission tomography) and regional cortical thickness (magnetic resonance imaging). Results: Diagnostic performance of CAMDEX-DS total scores were high for Alzheimer's disease dementia (area under the curve (AUC), 0.998; 95% CI 0.953–0.999) and prodromal Alzheimer's disease (AUC = 0.954; 95% CI 0.887–0.982) when compared with healthy adults with Down syndrome. When compared with those with mental health conditions but no Alzheimer's disease, CAMDEX-DS Section B scores, denoting memory and orientation ability, accurately diagnosed Alzheimer's disease dementia (AUC = 0.958; 95% CI 0.892–0.984), but were unable to diagnose prodromal Alzheimer's disease. CAMDEX-DS total scores exhibited moderate correlations with cortical Aβ ( r ~ 0.4 to 0.6, P ≤ 0.05) and thickness ( r ~ −0.4 to −0.44, P ≤ 0.05) in specific regions. Conclusions: CAMDEX-DS total score accurately diagnoses Alzheimer's disease dementia and prodromal Alzheimer's disease in healthy adults with Down syndrome.