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Association between reduced chewing-induced brain blood flow and cognitive performance in mandibular prognathism patients in a pilot study
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  • Published: 16 January 2026

Association between reduced chewing-induced brain blood flow and cognitive performance in mandibular prognathism patients in a pilot study

  • Yuri Inagawa1,
  • Hiroyuki Kanzaki1,2,
  • Chihiro Kariya1,
  • Saki Tanaka1,
  • Masao Kumazawa1 &
  • …
  • Hiroshi Tomonari1 

Scientific Reports , Article number:  (2026) Cite this article

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We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.

Subjects

  • Biomarkers
  • Medical research
  • Neurology
  • Neuroscience

Abstract

Despite established links between masticatory dysfunction and cognitive impairment, cognitive function in dentofacial deformity patients remains unexplored. This study represents the first comprehensive cognitive assessment in mandibular prognathism (MP) patients. Brain blood flow (BBF) during chewing was measured using functional near-infrared spectroscopy in MP patients versus normal occlusion controls (NORM, n = 17). Cognitive function using eye-tracking technology (Mirudake) in MP patients (n = 44) was compared to healthy controls (HC, n = 59), with assessing six cognitive domains. MP patients demonstrated significantly reduced chewing-induced BBF in bilateral inferior frontal gyrus compared to NORM. Global cognitive performance showed no significant difference between MP and HC groups (p = 0.48). However, positive correlations existed between BBF and cognitive performance domains including global performance and memory. ROC analysis using pooled bilateral BBF data (n = 88) revealed modest diagnostic potential for cognitive assessment (AUC = 0.657, 95% CI 0.431–0.865). The optimal threshold yielded 62.5% sensitivity, 73.8% specificity, and 72.7% overall accuracy for detecting cognitive impairment. This first systematic cognitive evaluation of MP patients revealed no significant global cognitive impairment despite confirmed reductions in masticatory-induced brain activation. The observed BBF-cognition correlations suggest BBF measurements may have potential utility as an adjunct measure in cognitive screening, warranting further investigation through longitudinal studies examining orthognathic surgery’s potential cognitive effects.

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Data availability

The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the corresponding author upon reasonable request.

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Acknowledgements

The authors thank Ai-BrainScience Inc. (Osaka, Japan) for generously providing cognitive function data from healthy control participants. This work was supported in part by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (23K09449 and 24K13186).

Funding

This work was supported in part by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (23K09449 and 24K13186).

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Authors and Affiliations

  1. Department of Orthodontics, School of Dental Medicine, Tsurumi University, Yokohama, 230-8501, Japan

    Yuri Inagawa, Hiroyuki Kanzaki, Chihiro Kariya, Saki Tanaka, Masao Kumazawa & Hiroshi Tomonari

  2. Department of Orthodontics, Tohoku University Hospital, Sendai, 980-8574, Japan

    Hiroyuki Kanzaki

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Contributions

Y.I.: Acquisition and analysis of data. Revised the manuscript. H.K.: Conception and design of this work. Interpretation of data. Have drafted the manuscript. C.K.: Design of this work. Acquisition and analysis of data. Revised the manuscript. S.T.: Acquisition of data. Revised the manuscript. M.K.: Conception and design of this work. Revised the manuscript. H.T.: Revised the manuscript.

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Correspondence to Hiroyuki Kanzaki.

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Inagawa, Y., Kanzaki, H., Kariya, C. et al. Association between reduced chewing-induced brain blood flow and cognitive performance in mandibular prognathism patients in a pilot study. Sci Rep (2026). https://doi.org/10.1038/s41598-026-35964-x

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  • Received: 07 October 2025

  • Accepted: 09 January 2026

  • Published: 16 January 2026

  • DOI: https://doi.org/10.1038/s41598-026-35964-x

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