In a network state of mind

Altered oscillatory brain activity in Alzheimer’s disease (AD) may reflect underlying neuropathological changes, and its characterization might lead to new diagnostic possibilities. The present study using quantitative magnetoencephalography (MEG) was set up to examine power spectrum changes in AD patients, and their diagnostic strength. Whole-head 151-channel MEG was recorded during an eyes-closed resting state. MEG channels were grouped in ten cortical regions, and both global and regional relative power was analyzed for the commonly used frequency bands.18 AD patients (mean age 72.1 years ± 5.6 (SD); 7 females; mean MMSE 19.2, range: 13-25) and 18 healthy controls (mean age 69.1 ± 6.8 (SD), 11 females; mean MMSE 29, range: 27-30) were recruited, controls being mainly spouses of patients. Relative power analysis showed significant differences in most frequency bands, particularly in the temporo-parietal regions, with some relation to MMSE scores. Greatest diagnostic accuracy was found in the beta band, especially in the right occipital area (sensitivity 94%, specificity 78%). Quantitative relative power analysis of MEG recordings is able to show widespread abnormalities in oscillatory brain dynamics in AD patients. By analyzing distinct cortical regions, this study provides a more detailed topographical view of abnormal brain activity in AD. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 Resting-state oscillatory brain dynamics in Alzheimer’s disease 21