Paper Info
Title
Evaluation of spectral ratio measures from spontaneous MEG recordings in patients with Alzheimer's disease.
Abstract
Alzheimer's disease (AD) is the most frequent form of dementia in western countries. The rise in life expectancy will likely increase its prevalence, since ageing is the greatest known risk factor. Although an early and accurate identification is critical, low diagnostic accuracy is currently reached. Hence, the aim of the present study was to analyse the spontaneous magnetoencephalographic (MEG) activity from 148 channels in 20 AD patients and 21 healthy controls to extract discriminating spectral features. Relative power (RP) was calculated in conventional frequency bands and several ratios were defined to emphasise the differences in its distribution. Both RP values and spectral ratios were transformed with a principal component analysis to summarise information with minimal loss of variability. AD patients showed a significant increase of RP(delta) and RP(theta), along with a decrease of RP(beta) and RP(gamma). The most significant differences were reached by spectral ratios using the beta band. Specifically, we obtained 75.0% sensitivity, 90.5% specificity and 82.9% accuracy (linear discriminant analysis with a leave-one-out cross-validation procedure), together with a p-value lower than 0.001 (one-way analysis of variance with age as a covariate) using the [RP(alpha)+RP(beta(1))+RP(beta(2))+RP(gamma)]/[RP(delta)+RP(theta)] ratio. The spectral ratios also showed a higher correlation with the severity of dementia than individual relative power measures. Our results suggest that the spectral ratios could be useful descriptors to help in the AD diagnosis, since they effectively summarise the slowing of the AD patients' MEG rhythms in individual indexes and correlate significantly with the severity of dementia.
Year
DOI
Venue
2008
10.1016/j.cmpb.2007.12.004
Computer Methods and Programs in Biomedicine
Keywords
Field
DocType
ad diagnosis,spectral feature,ad patient,linear discriminant analysis,spectral ratio measure,spectral ratio,individual index,rp value,spontaneous meg recording,meg rhythm,principal component analysis,one-way analysis,risk factors,leave one out cross validation,fourier transform,analysis of variance,life expectancy
Ageing,Covariate,Correlation,Linear discriminant analysis,Statistics,Mathematics,Principal component analysis,Analysis of variance,Dementia
Journal
Volume
Issue
ISSN
90
2
0169-2607
Citations 
PageRank 
References 
2
0.69
1
Authors
5
Name
Order
Citations
PageRank
Jesús Poza15512.29
Roberto Hornero260367.74
Daniel Abásolo325326.22
Alberto Fernández45311.82
Agustín Mayo51528.69