All 153 tested unversioned ds003775 EEG files lacked voltage units, while pinned version 1.2.1 files declared microvolts

We compared two public routes for all 153 raw EEG paths in OpenNeuro ds003775. On 9 October 2026, all unversioned S3 headers had blank EEG unit fields. All pinned version 1.2.1 headers declared microvolts. MNE 1.13.2 gave a voltage factor of one million between default and explicit units on the same unversioned samples. At a 150 microvolt limit for all 64 channels, 41 of 153 first two-second windows passed with explicit units. None passed with the default rule. One old header needed a recorded time-field control for MNE. The two routes shared sampled digital bytes and all other header fields in 152 pairs. Sub-041 had further changes. Eight complete file hashes passed across four pairs. An independent decoder confirmed all 2,295 threshold decisions. The package preserves source prefixes, metadata, versions, hashes, code, results, and instructions. The counts do not estimate usable duration in complete recordings.

electroencephalography · EEG · data provenance · voltage units · EDF · OpenNeuro · reproducibility · sample selection