Complexity analysis of the magnetoencephalogram background activity in Alzheimer's disease patients

Evaluation of spectral ratio measures from spontaneous MEG recordings in patients with Alzheimer's disease

“…Moreover, all spectral ratios were able to retain more than 83% of variance with just PC 1 . These findings are in agreement with those obtained in previous MEG studies, which only analysed PC 1 due to the redundancy of the data [32,33,41].…”

“…However, it should be noticed that some authors point out that there is no ideal solution to the problem of dimensionality in a PCA [39] or that selection rules offer little advantage over simple schemes in most circumstances [38]. In this sense, previous EEG and MEG studies only retained the first principal component (PC 1 ), since the explained variance for the calculated parameters was higher than 72% [32,33,40,41]. In the present work, we applied a similar PCA scheme to summarise the variability of each parameter.…”

Analysis of MEG Background Activity in Alzheimer’s Disease Using Nonlinear Methods and ANFIS

“…EEG/MEG studies demonstrated that AD patients have significantly lower Lempel-Ziv complexity (LZC) values than elderly control subjects. 3,11 The application of neural networks and fuzzy logic techniques to classify AD patients' brain recordings has not received much attention. Besthorn et al 5 employed a neural network to recognize the EEGs from AD patients and controls.…”

“…LZC has been widely applied to EEG/MEG data and other biomedical signals. 3,11,31,41 LZC analysis is based on a coarse-graining of the measurements, so the MEG time series must be transformed into a finite symbol sequence. In this study, we used the simplest way: a binary sequence conversion (zeros and ones), since previous studies suggested that this kind of conversion may keep enough signal information.…”

Brain oscillatory complexity across the life span

“…LZC has been used to analyse EEG and MEG signals in patients with Alzheimer's disease Fernández et al, 2010;Gómez et al, 2006), attention deficit-hyperactivity disorder (ADHD) (Fernández et al, 2009), depression and schizophrenia (Li et al, 2008;Fernández et al, 2011a;Méndez et al, 2011;) as well as to measure the depth of anaesthesia (Zhang et al, 2001), or to study epileptic seizures (Radhakrishnan and Gangadhar, 1998). The increasing clinical use of LZC and other estimates of oscillatory complexity is the main reason to carry out a normative study where the 'normal' behaviour of complexity values is defined according to age and gender influences in a large population.…”