Total power normalization reduces posterior alpha contrast between Alzheimer disease and control groups in ds004504 version 1.0.9 under a linear age and gender model

Relative EEG power divides band power by total power. We measured both terms in OpenNeuro ds004504 version 1.0.9. The study used 200 seconds from each of 88 people. The groups had 36 people with Alzheimer disease, 29 controls, and 23 people with frontotemporal dementia. We fit the same linear age and supplied gender model to posterior absolute power, total power, and relative power. The adjusted Alzheimer to control ratios were 0.504 for absolute alpha, 0.933 for total power, and 0.540 for relative alpha. Total power normalization therefore reduced the alpha contrast. The theta ratios were 1.038 for absolute power and 1.112 for relative power. The absolute theta interval included 1. Early and late blocks both retained the lower relative alpha contrast. We used 10,000 bootstrap samples of people. An independent FFT calculation matched three fixed source recordings. All eight analysis outputs reproduced exactly. These results apply to this cohort, the supplied preprocessing, and the tested linear model. The package preserves the features, source hashes, code, results, and retrieval instructions. The decomposition is an accounting identity. It does not identify a neural cause.

EEG · relative power · absolute power · Alzheimer disease · frontotemporal dementia · alpha band · theta band · total power · normalization · bootstrap