Single-Domain Amnestic Mild Cognitive Impairment Identified by Cluster Analysis Predicts Alzheimer's Disease in the European Prospective DESCRIPA Study

• Published in: Dementia and geriatric cognitive disorders Vol. 36; no. 1-2; pp. 1 - 19
• Main Authors: Damian, Marinella, Hausner, Lucrezia, Jekel, Katrin, Richter, Melany, Froelich, Lutz, Almkvist, Ove, Boada, Merce, Bullock, Roger, De Deyn, Peter Paul, Frisoni, Giovanni B., Hampel, Harald, Jones, Roy W., Kehoe, Patrick, Lenoir, Hermine, Minthon, Lennart, Olde Rikkert, Marcel G.M., Rodriguez, Guido, Scheltens, Philip, Soininen, Hilkka, Spiru, Luiza, Touchon, Jacques, Tsolaki, Magda, Vellas, Bruno, Verhey, Frans R.J., Winblad, Bengt, Wahlund, Lars-Olof, Wilcock, Gordon, Visser, Pieter Jelle
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland Karger 01.01.2013; S. Karger AG
• Subjects: Aged; Aged, 80 and over; Alzheimer Disease - complications; Alzheimer Disease - epidemiology; Alzheimer Disease - psychology; Alzheimer's disease; Apolipoproteins E - genetics; Biological and medical sciences; Biomarkers; Cardiovascular system; Clinical Medicine; Cluster Analysis; Cognitive Dysfunction - complications; Cognitive Dysfunction - epidemiology; Cognitive Dysfunction - psychology; Cohort Studies; Conversion to Alzheimer's disease; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Disease Progression; Europe - epidemiology; Female; Genotype; Humans; impairment subtypes; Klinisk medicin; Logistic Models; Magnetic Resonance Imaging; Male; Medical and Health Sciences; Medical sciences; Medicin och hälsovetenskap; Mental Recall - physiology; Middle Aged; Mild cognitive; Mild cognitive impairment; mild cognitive impairment subtypes; Neurologi; Neurology; Neuropsychological Tests; Original Research Article; Pharmacology. Drug treatments; Psychology; psykologi; Reproducibility of Results; Tomography, X-Ray Computed; Vasodilator agents. Cerebral vasodilators; Mild cognitive impairment subtypes; Mild cognitive impairment; Alzheimer's disease; Conversion to Alzheimer's disease; Cluster analysis; Drug conversion; Nervous system diseases; Cognitive disorder; Alzheimer disease; Central nervous system disease; mild cognitive impairment; Degenerative disease; Cerebral disorder
• ISSN: 1420-8008; 1421-9824; 1421-9824
• DOI: 10.1159/000348354

Background/Aims: To identify prodromal Alzheimer's disease (AD) subjects using a data-driven approach to determine cognitive profiles in mild cognitive impairment (MCI). Methods: A total of 881 MCI subjects were recruited from 20 memory clinics and followed for up to 5 years. Outcome measures included cognitive variables, conversion to AD, and biomarkers (e.g. CSF, and MRI markers). Two hierarchical cluster analyses (HCA) were performed to identify clusters of subjects with distinct cognitive profiles. The first HCA included all subjects with complete cognitive data, whereas the second one selected subjects with very mild MCI (MMSE ≥28). ANOVAs and ANCOVAs were computed to examine whether the clusters differed with regard to conversion to AD, and to AD-specific biomarkers. Results: The HCAs identified 4-cluster solutions that best reflected the sample structure. One cluster (aMCIsingle) had a significantly higher conversion rate (19%), compared to subjective cognitive impairment (SCI, p < 0.0001), and non-amnestic MCI (naMCI, p = 0.012). This cluster was the only one showing a significantly different biomarker profile (Aβ 42 , t-tau, APOE ε4, and medial temporal atrophy), compared to SCI or naMCI. Conclusion: In subjects with mild MCI, the single-domain amnestic MCI profile was associated with the highest risk of conversion, even if memory impairment did not necessarily cross specific cut-off points. A cognitive profile characterized by isolated memory deficits may be sufficient to warrant applying prevention strategies in MCI, whether or not memory performance lies below specific z-scores. This is supported by our preliminary biomarker analyses. However, further analyses with bigger samples are needed to corroborate these findings.