Posterior EEG ratios had rest-light concordance of 0.187 in 72 selected people with equal sample time and fixed source processing

We tested a fixed posterior theta/alpha EEG score in paired rest and light protocol records. The selected sample has 30 Alzheimer disease cases, 29 controls, and 13 frontotemporal dementia cases. Each main score used 40 seconds. The primary Alzheimer-control AUC change was +0.052, with a paired bootstrap 95 percent interval of -0.115 to +0.218. This does not establish equal AUC. Individual score concordance was 0.187 (-0.022 to 0.390). Planned equal-duration controls gave concordance of 0.588 between rest blocks, versus 0.253 and 0.141 across protocols. Paired difference intervals were above zero. The gap also remained after removal of diagnosis means. All planned score checks are preserved. Independent arithmetic checks and an offline rerun passed. Six source recordings were rebuilt independently. The package preserves code, source hashes, metadata, participant scores, bootstrap draws, figures, and instructions. The result is conditional on selection, one site, fixed record order, and supplied source processing. It does not identify a causal effect of light or test new patients.

electroencephalography · EEG · theta/alpha ratio · Alzheimer disease · frontotemporal dementia · protocol agreement · concordance · paired analysis