{
  "abstract": "Developmental stuttering has been repeatedly linked to decreased white matter integrity and structural connectivity differences in major white matter tracts. Prior diffusion-weighted MRI studies reporting such white matter structural differences involved voxel-averaged tensor measures (e.g., fractional anisotropy (FA)). A well-acknowledged limitation of this approach, however, has been that it cannot resolve distinct fiber populations within crossing-fiber regions. Fixel-based analysis addresses this limitation by quantifying individual fiber populations within a voxel and providing complementary measures of fiber density (FD), fiber-bundle cross-section (FC), and their combined measure (FDC).\n\nHere we applied Fixel-based analysis to diffusion MRI data from 171 children aged 3–13 years, including 84 children who stutter and 87 typically developing controls, to test whether white-matter differences associated with developmental stuttering were expressed as differences in FD, FC, and FDC and whether these measures show group-specific age-related patterns. We evaluated this at both the whole-brain level and within a priori white-matter tracts.\n\nFC, but not FD or FDC, showed significant Group and Group × Age effects, indicating that white-matter differences were primarily expressed in fiber-bundle macrostructure. Tract-of-interest analyses identified developmental differences in bilateral arcuate fasciculus FC that remained significant across tracts, with controls showing greater age-related increases in FC than children who stutter. Additional FC differences were observed across corticospinal and thalamocortical pathways, although these tract-wise effects were less robust to across-tract correction.\n\nThese findings suggest that white-matter differences in developmental stuttering are prominently expressed in fiber-bundle macrostructure rather than fiber density and highlight divergent development of bilateral arcuate pathways. FBA provides fiber-specific information that complements conventional tensor-based diffusion measures and may improve characterization of white-matter development in childhood stuttering.\n\nSignificance Statement: Developmental stuttering has repeatedly been associated with white-matter differences, but conventional diffusion measures cannot readily distinguish changes in individual fiber populations within regions containing crossing fibers. Using Fixel-based analysis in children who stutter, we show that these differences are primarily expressed in fiber-bundle cross-section rather than fiber density, implicating macrostructural differences in white-matter organization. The strongest tract-wise developmental effects were observed bilaterally in the arcuate fasciculus, a major pathway supporting auditory-motor integration, where children who stutter showed divergent age-related trajectories relative to typically developing children. These findings provide a fiber-specific perspective on the neurodevelopmental basis of stuttering and refine the interpretation of white-matter differences previously identified using conventional diffusion imaging.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "name": "Hasini Weerathunge",
      "orcid": "0000-0002-0240-9104"
    },
    {
      "name": "Yanni Liu",
      "orcid": "0000-0003-3826-3626"
    },
    {
      "name": "Fiona Höbler",
      "orcid": "0000-0001-7065-3670"
    },
    {
      "name": "Mike Angstadt",
      "orcid": "0000-0003-4870-7649"
    },
    {
      "name": "Andrew Jahn",
      "orcid": "0000-0001-5286-049X"
    },
    {
      "name": "Ho Ming Chow",
      "orcid": "0000-0001-9333-4840"
    },
    {
      "name": "Soo-Eun Chang",
      "orcid": "0000-0003-4448-9525"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bz7tkq11tngmx.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.29.762844",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.10.29.762844v1.full",
  "id": "bz7tkq11tngmx",
  "issns": [
    "2692-8205"
  ],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.10.29.762844v1",
  "language": "en",
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "neuroscience"
    ],
    [
      "heading",
      "Article"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.10.29.762844v1.full.pdf",
  "pmcid": "PMC13734101",
  "pmid": "42990544",
  "published": "2026-10-29",
  "publisher": "Cold Spring Harbor Laboratory Preprints",
  "ris": "https://research.draconitic.com/paper/bz7tkq11tngmx.ris",
  "sources": [
    {
      "first_seen": "2026-10-31T12:21:12Z",
      "native_id": "10.64898/2026.10.29.762844",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.10.29.762844v1"
    },
    {
      "first_seen": "2026-11-08T12:23:44Z",
      "native_id": "PMC13734101",
      "source": "pmc",
      "url": "https://doi.org/10.64898/2026.10.29.762844"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "biorxiv:neuroscience",
      "subfield": "neuroscience"
    }
  ],
  "title": "Fixel-wise Differences in White Matter Fiber-bundle Cross-section identified in Children who Stutter",
  "title_text": "Fixel-wise Differences in White Matter Fiber-bundle Cross-section identified in Children who Stutter",
  "type": "preprint",
  "updated_at": "2026-11-08T12:23:44Z",
  "url": "https://research.draconitic.com/paper/bz7tkq11tngmx",
  "venue": "bioRxiv",
  "versions": []
}