Evidence map›Paper›PMID 25467638›Full record

ArticleNeurobiology of aging2015

Increased free water in the substantia nigra of Parkinson's disease: a single-site and multi-site study.

Edward Ofori, Ofer Pasternak, Peggy J Planetta, Roxana Burciu, Amy Snyder, Marcelo Febo, Todd E Golde, Michael S Okun, David E Vaillancourt

Open access · greenAbstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Neurobiology of aging, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 117 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
117citing papers in PubMed, 1 pooled it
7.5field-weighted citation impact, top 2% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

117 citing papers in PubMed, 1 synthesis or guideline pooled it, 163 citations in OpenAlex.

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  19. Early diagnosis of Parkinson's disease: biomarker study.Frontiers in aging neuroscience · 2025
    Review
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57 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

9 authors at 2 institutions in 1 country.

Edward OforiDepartment of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
Ofer PasternakDepartment of Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Peggy J PlanettaDepartment of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
Roxana BurciuDepartment of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
Amy SnyderDepartment of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA.
Marcelo FeboDepartment of Neuroscience, Center for Translational Research in Neurodegenerative Disease, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
Todd E GoldeDepartment of Psychiatry, University of Florida, Gainesville, FL, USA.
Michael S OkunDepartment of Neurology, Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, FL, USA.
David E VaillancourtDepartment of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, USA; Department of Neurology, Center for Movement Disorders and Neurorestoration, University of Florida, Gainesville, FL, USA; Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA. Electronic address: vcourt@ufl.edu.
University of Florida · USBrigham and Women's Hospital · US

Funding

Scaling and Sequencing Motor Output in Humans: fMRI StudyR01NS052318 · NINDS · UNIVERSITY OF ILLINOIS AT CHICAGO · PI VAILLANCOURT, DAVID E · 2005 to 2020
$6.0M
Non-Invasive Markers of Neurodegeneration in Movement DisordersR01NS075012 · NINDS · UNIVERSITY OF FLORIDA · PI LI, YUQING, VAILLANCOURT, DAVID E · 2012 to 2022
$4.1M
NINDS NIH HHS R01 NS052318NINDS NIH HHS R01 NS075012NINDS NIH HHS R01NS075012
6 · The paper itself

Abstract

Measures from diffusion magnetic resonance imaging reflect changes in the substantia nigra of Parkinson's disease. It is the case, however, that partial volume effects from free water can bias diffusion measurements. The bi-tensor diffusion model was introduced to quantify the contribution of free water and eliminates its bias on estimations of tissue microstructure. Here, we test the hypothesis that free water is elevated in the substantia nigra for Parkinson's disease compared with control subjects. This hypothesis was tested between large cohorts of Parkinson's disease and control participants in a single-site study and validated against a multisite study using multiple scanners. The fractional volume of free water was increased in the posterior region of the substantia nigra in Parkinson's disease compared with control subjects in both the single-site and multi-site studies. We did not observe changes in either cohort for free-water-corrected fractional anisotropy or free-water-corrected mean diffusivity. Our findings provide new evidence that the free-water index reflects alteration of the substantia nigra in Parkinson's disease, and this was evidenced across both single-site and multi-site cohorts.

Indexed as

AgedAnisotropyBody WaterCohort StudiesDiffusion Magnetic Resonance ImagingFemaleHumansMaleMiddle AgedParkinson DiseaseSubstantia NigraDiffusion MRIFree-water mappingParkinson's diseaseSubstantia nigra

Identifiers

PMID25467638
PMCPMC4315708
OpenAlexW2090789182

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.