Brain-wide slowing of spontaneous alpha rhythms in mild cognitive impairment

Journal article


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Publication Details

Author list: Fernández A
Publisher: Frontiers Media
Publication year: 2013
Volume number: 5
Number of pages: 7
ISSN: 1663-4365
Languages: English-Great Britain (EN-GB)


Abstract

The neurophysiological changes associated with Alzheimer's Disease (AD)
and Mild Cognitive Impairment (MCI) include an increase in low frequency
activity, as measured with electroencephalography or
magnetoencephalography (MEG). A relevant property of spectral measures
is the alpha peak, which corresponds to the dominant alpha rhythm. Here
we studied the spatial distribution of MEG resting state alpha peak
frequency and amplitude values in a sample of 27 MCI patients and 24
age-matched healthy controls. Power spectra were reconstructed in source
space with linearly constrained minimum variance beamformer. Then, 88
Regions of Interest (ROIs) were defined and an alpha peak per ROI and
subject was identified. Statistical analyses were performed at every
ROI, accounting for age, sex and educational level. Peak frequency was
significantly decreased (p < 0.05) in MCIs in many posterior ROIs.
The average peak frequency over all ROIs was 9.68 +/- 0.71 Hz for
controls and 9.05 +/- 0.90 Hz for MCIs and the average normalized
amplitude was (2.57 +/- 0.59).10(-2) for controls and (2.70 +/-
0.49).10(-2) for MCIs. Age and gender were also found to play a role in
the alpha peak, since its frequency was higher in females than in males
in posterior ROIs and correlated negatively with age in frontal ROIs.
Furthermore, we examined the dependence of peak parameters with
hippocampal volume, which is a commonly used marker of early structural
AD-related damage. Peak frequency was positively correlated with
hippocampal volume in many posterior ROIs. Overall, these findings
indicate a pathological alpha slowing in MCI.


Keywords

Neuropsychology, Neuroscience, Psychology


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