title: MEG analysis in Alzheimer's disease computing approximate entropy for different frequency bands.
abstract: The goal of this study was to analyze the magnetoencephalogram (MEG) background activity in patients with Alzheimer's disease (AD) using a regularity measure: approximate entropy (ApEn). This measure was computed for a broad band (0.5-40 Hz) as well as typical frequency bands (delta, theta, alpha, beta and gamma). Five minutes of recording were acquired with a 148-channel whole-head magnetometer in 15 patients with probable AD and 15 elderly control subjects. Our results showed that AD patients' MEGs were more regular than controls' recordings at all frequency bands, with the exception of beta. Additionally, there were statistically significant differences (p 〈 0.01, Student's t-test) at the broad and delta bands. Using receiver operating characteristic curves, the highest accuracy (83.33%) was reached at delta band. These results suggest the usefulness of ApEn to gain a better understanding of dynamical processes underlying the MEG recording.
authors.affiliation: Biomedical Engineering Group at Department of Signal Theory and Communications, E.T.S. Ingenieros de Telecomunicación, University of Valladolid, Campus Miguel Delibes, 47011, Spain. cargom@tel.uva.es
authors.forename: Carlos
authors.initials: C
authors.lastname: Gomez
authors.forename: Daniel
authors.initials: D
authors.lastname: Abasolo
authors.forename: Jesus
authors.initials: J
authors.lastname: Poza
authors.forename: Alberto
authors.initials: A
authors.lastname: Fernandez
authors.forename: Roberto
authors.initials: R
authors.lastname: Hornero
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000513:Alpha Rhythm; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology*; D001611:Beta Rhythm; D003700:Delta Rhythm; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013826:Theta Rhythm