Classification of Non-Demented Patients Attending a Memory Clinic using the New Diagnostic Criteria for Alzheimer's Disease with Disease-Related Biomarkers
Affiliations: [a] Neurology Department, Saint Luc University Hospital, Université catholique de Louvain, Brussels, Belgium | [b] Nuclear Medicine Department, Saint Luc University Hospital, Université catholique de Louvain, Brussels, Belgium | [c] Radiology Department, Saint Luc University Hospital, Université catholique de Louvain, Brussels, Belgium | [d] Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
Correspondence:
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Correspondence to: Adrian Ivanoiu, MD, PhD, Saint Luc University Hospital/Neurology Department, Av. Hippocrate, 10, Brussels 1200, Belgium. Tel.: +32 2 764 21 46; Fax: +32 2 764 90 46; E-mail: adrian.ivanoiu@uclouvain.be.
Abstract: Background:New diagnostic criteria for predemential Alzheimer's disease (AD) advocate the use of biomarkers. However, the benefit of using biomarkers has not been clearly demonstrated in clinical practice. Objective:To investigate whether a combination of biomarkers may be helpful in classifying a population of non-demented patients attending a Memory Clinic. Methods:Sixty non-demented patients were compared with 31 healthy elderly subjects. All subjects underwent a neuropsychological examination, brain 3T magnetic resonance imaging, [F18]-fluorodeoxyglucose and [F18]-flutemetamol positron emission tomography. According to their performance on memory, language, executive, and visuo-spatial domains, the patients were classified as mild cognitive impairment (amnestic, non-amnestic, single, or multiple domain) or subjective cognitive impairment. Patients were then classified according to the National Institute on Aging-Alzheimer's Association (NIA-AA) criteria, using the normalized mean hippocampal volume (Freesurfer), [F18]-FDG PALZAD, and [F18]-flutemetamol standard uptake value ratio (SUVr) (cut-off at the 10th percentile of controls). The standard of truth was the clinical status at study entry (patient versus control). Results:The sensitivity/specificity of the clinical classification was 65/84%. The NIA-AA criteria were applicable in 85% of patients and 87% of controls. For biomarkers the best sensitivity (72%) at a fixed specificity of 84% was achieved by a combination of the three biomarkers. The clinical diagnosis was reconsidered in more than one third of the patients (42%) as a result of including the biomarker results. Conclusions:Application of the new NIA-AA AD diagnostic criteria based on biomarkers in an unselected sample of non-demented patients attending a Memory Clinic was useful in allowing for a better classification of the subjects.
Keywords: Alzheimer's disease, biological markers, early diagnosis, mild cognitive impairment
