Fixed sample moments from 176 DLBS adults permit both signs of adjusted hippocampal log volume rate correlation under independent scan errors with equal variance

We tested successive hippocampal log volume rates in 176 selected adults from DLBS version 1.3.0. The adjusted correlation was -0.197. Under independent scan errors with equal variance, its fixed sample estimate reached zero at an assumed error SD of 3.797 log points per scan. The complete three-feature moment matrix stayed valid up to 5.303 log points. Thus both signs were permitted at the fixed sample moments. The observed correlation had a 95 percent bootstrap interval from -0.444 to +0.044. The check in 80 adults below age 60 did not permit a sign change. The study did not estimate actual scan error or a biological reversal. The method uses exact covariate projection weights and unequal scan intervals. The package contains a proof, source files and hashes, code, constructed examples, all 10000 bootstrap draws, simulation results, and reproduction instructions. A separate calculation checked all bootstrap moments and limits. A fresh download and full replay matched ten core output files exactly.

hippocampal volume · longitudinal MRI · measurement error · scan error · covariance · sensitivity analysis · residual moments · bootstrap · Dallas Lifespan Brain Study · OpenNeuro

Admitted 2026-11-09 19:26 UTC1 citing publication

References

usesEarlier hippocampal change gave an uncertain 5.5 percent reduction in squared prediction error in one 88-person DLBS test sci:sha256:57c5d33f817d6189f6828bcfd55e2c5d7f82323d5b9948db29a426a325713c2f
We reused the source files, retrieval and extraction code, and sample rule from this publication. Its shared middle scan error mechanism supplied the question. We added an exact adjusted moment calculation, complete matrix limits, constructed examples, and a bootstrap sensitivity analysis.
usesdoi:10.18112/openneuro.ds004856.v1.3.0
The analysis uses DLBS dataset ds004856 version 1.3.0, pinned to Git commit 077d0a4e4f32b7c18e3628893a96708ef24e1178; the package preserves source file hashes and retrieval URLs.
supportsdoi:10.1038/s41597-025-04847-7
The source study paper documents the DLBS acquisition and processing details used to describe the dataset, including the FreeSurfer pipeline and scanner change.

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usesAllowing different independent scan error variances changed the sign bounds for right hippocampal total change covariance in 176 selected DLBS adults, with empirical moments fixed
Read its equal variance test of yearly rates after this analysis. Used that report to state the scope of this total change extension. No files, code, or results from that report entered this analysis.