title: Infrared spectroscopy: a new diagnostic tool in Alzheimer disease.
abstract: Biological markers play an evolving role in the diagnosis of Alzheimer disease (AD). We compare conventional measurements of cerebrospinal fluid (CSF) tau and beta-amyloid(1-42) proteins to a novel approach - Fourier transformed infrared (FT-IR) spectroscopy - a simple technique derived from chemical and physical sciences that characterizes intramolecular bonds. For automatic diagnostic analysis, we developed an artificial neural network (ANN). We examined 71 patients with a clinical diagnosis of AD and 66 controls. beta-Amyloid(1-42) was decreased (sensitivity 80% and specificity 78%); tau was elevated (sensitivity 76% and specificity 88%) in CSF of AD patients. The combined tau/beta-amyloid(1-42) quotient was able to distinguish healthy from diseased subjects with 99% sensitivity and 86% specificity. The ANN could separate FT-IR spectroscopy data with 88.5% sensitivity and 80% specificity. FT-IR spectroscopy proved to be cost-effective and simple to perform. Diagnostic sensitivity and specificity is in the range of CSF tau and beta-amyloid(1-42) protein analysis. Larger sample numbers for ANN training and validation could increase diagnostic accuracy and thus prove to be a useful screening tool.
authors.affiliation: Department of Neurology, Universitaetsklinikum Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68135 Mannheim, Germany. griebe@neuro.ma.uni-heidelberg.de
authors.forename: Martin
authors.initials: M
authors.lastname: Griebe
authors.forename: Michael
authors.initials: M
authors.lastname: Daffertshofer
authors.forename: Mark
authors.initials: M
authors.lastname: Stroick
authors.forename: Magdalena
authors.initials: M
authors.lastname: Syren
authors.forename: Parviz
authors.initials: P
authors.lastname: Ahmad-Nejad
authors.forename: Michael
authors.initials: M
authors.lastname: Neumaier
authors.forename: Juergen
authors.initials: J
authors.lastname: Backhaus
authors.forename: Michael G
authors.initials: MG
authors.lastname: Hennerici
authors.forename: Marc
authors.initials: M
authors.lastname: Fatar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis*; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D000704:Analysis of Variance; D015415:Biomarkers; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016571:Neural Networks, Computer; D009483:Neuropsychological Tests; D010446:Peptide Fragments / Q000134:cerebrospinal fluid; D013055:Spectrophotometry, Infrared; D017550:Spectroscopy, Fourier Transform Infrared; D055815:Young Adult; D016875:tau Proteins / Q000134:cerebrospinal fluid
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D016875:tau Proteins