Use of the Higuchi's fractal dimension for the analysis of MEG recordings from Alzheimer's disease patients

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Author list: Gómez, C., Mediavilla, A., Hornero, R., Abásolo, D., Fernández, A.
Publisher: Elsevier: 12 months
Publication year: 2009
Volume number: 31
Issue number: 3
Start page: 306
End page: 313
Number of pages: 8
ISSN: 1350-4533
Languages: English-Great Britain (EN-GB)


Alzheimer's disease (AD) is an irreversible brain disorder of unknown
aetiology that gradually destroys brain cells and represents the most
prevalent form of dementia in western countries. The main aim of this
study was to analyse the magnetoencephalogram (MEG) background activity
from 20 AD patients and 21 elderly control subjects using Higuchi's
fractal dimension (HFD). This non-linear measure can be used to estimate
the dimensional complexity of biomedical time series. Before the
analysis with HFD, the stationarity and the non-linear structure of the
signals were proved. Our results showed that MEG signals from AD
patients had lower HFD values than control subjects' recordings. We
found significant differences between both groups at 71 of the 148 MEG
channels (p < 0.01; Student's t-test with Bonferroni's correction).
Additionally, five brain regions (anterior, central, left lateral,
posterior and right lateral) were analysed by means of receiver
operating characteristic curves, using a leave-one-out cross-validation
procedure. The highest accuracy (87.8%) was achieved when the mean HFD
over all channels was analysed. To sum up, our results suggest that
spontaneous MEG rhythms are less complex in AD patients than in healthy
control subjects, hence indicating an abnormal type of dynamics in AD.


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Last updated on 2019-13-08 at 00:16