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P3‐145: Diagnostic Methods for Normal Pressure Hydrocephalus in a National Reference Neurological Center in Mexico City: A Case Series
Author(s) -
Bayliss Leo,
Sosa-Ortiz Ana Luisa
Publication year - 2016
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2016.06.1805
Subject(s) - normal pressure hydrocephalus , medicine , lumbar puncture , lumbar , medical diagnosis , shunting , pediatrics , surgery , physical therapy , radiology , dementia , cerebrospinal fluid , disease
ease Neuroimaging Initiative (ADNI, n1⁄4376), the German Dementia Competence Network (DCN, n1⁄4521), and the University of California San Francisco Memory Clinic (UCSF, n1⁄4589). The composition of neuropsychological test batteries differed between cohorts, but all covered the different cognitive domains. After imputation, normalisation, and scaling to include only positive values (0-1), we clustered neuropsychological test results for each cohort using the R package nonnegative matrix factorisation (NMF). This resulted in a clustering of neuropsychological tests (dimensionality reduction) and subjects (cognitive subtypes). Number of clusters was determined based on the highest cophenetic correlation. We compared identified cognitive clusters in terms of demographics, Apolipoprotein E [APOE] genotype, cerebrospinal fluid AD biomarkers, and cortical atrophy ratings. Results: In all four cohorts, neuropsychological tests were clustered into two components (all cophenetic correlations >.8): One including mostly memory tests, and one largely including non-memory tests. Two clusters of patients were identified: One associated with low scores on the memory component (memory-impaired clusters, including 52-71% of patients) and one associated with low scores on the non-memory component (memory-spared clusters, including 2948% of patients). Memory-spared clusters were younger, more often APOE e4 negative, had more severe parietal and frontal atrophy, and had lower MMSE scores than the memory-impaired clusters. Conclusions:Using dual-clustering approach NMF we robustly identified two cognitive AD subtypes in four independent large cohorts; one memory-impaired and one relatively memory-spared. The memory-spared subtypes included about one third of patients, and were characterized by younger age, APOE e4 negative genotype, more severe parietal or frontal atrophy, and lower MMSE scores compared to the memory-impaired clusters.