{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,14]],"date-time":"2026-08-14T05:26:39Z","timestamp":1786685199592,"version":"build-2736575974"},"reference-count":32,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T00:00:00Z","timestamp":1786492800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NIH"},{"DOI":"10.13039\/100000065","name":"NINDS","doi-asserted-by":"publisher","award":["K23NS124688"],"award-info":[{"award-number":["K23NS124688"]}],"id":[{"id":"10.13039\/100000065","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000065","name":"NINDS","doi-asserted-by":"publisher","award":["R01NS089757"],"award-info":[{"award-number":["R01NS089757"]}],"id":[{"id":"10.13039\/100000065","id-type":"DOI","asserted-by":"publisher"}]},{"award":["K23NS124688"],"award-info":[{"award-number":["K23NS124688"]}],"id":[{"id":"https:\/\/ror.org\/01s5ya894","id-type":"ROR","asserted-by":"publisher"}]},{"award":["R01NS089757"],"award-info":[{"award-number":["R01NS089757"]}],"id":[{"id":"https:\/\/ror.org\/01s5ya894","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Wearable inertial measurement units (IMUs) offer an accessible alternative to optical motion capture (MoCap) gait analysis, but their performance in Progressive Supranuclear Palsy (PSP) requires validation. We assessed the concurrent validity of IMU-derived versus MoCap-derived gait metrics and static postural sway in 30 patients with PSP using Bland\u2013Altman analysis, Intraclass Correlation Coefficients (ICC), and Spearman rank correlations. Finally, we assessed equivalence using the Two one-sided tests (TOST) procedure. Multivariable linear regression was used to determine whether clinical severity, as measured by the PSP Rating Scale (PSPRS), independently predicted absolute IMU measurement error while controlling for patient age and gait velocity. IMUs demonstrated excellent between-system agreement for parameters such as cadence (100.76 \u00b1 11.42 vs. 100.52 \u00b1 11.59) and cycle time (1.21 \u00b1 0.15 vs. 1.22 \u00b1 0.15; ICC &gt; 0.98), despite a systematic underestimation of gait velocity (p &lt; 0.05). Agreement significantly diminished for micro-phases (e.g., single\/double support times) and spatial asymmetry. Interestingly, the TOST procedure revealed that only sagittal and transverse trunk kinematics were equivalent between systems, with all other measures failing to find equivalency. For static sway, the IMU demonstrated strong rank-order correspondence for tracking relative postural instability (\u03c1 = 0.82, p &lt; 0.05). Multivariable analysis revealed that higher PSPRS scores are independently associated with greater between-system discrepancies in support phases and pelvic and trunk kinematics (p &lt; 0.05), irrespective of reduced gait speed. These findings highlight the need to develop disease-specific algorithms, rather than relying on normative commercial models, to establish reliable digital biomarkers for monitoring progressive motor decline.<\/jats:p>","DOI":"10.3390\/s26165105","type":"journal-article","created":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T09:11:36Z","timestamp":1786525896000},"page":"5105","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Concurrent Validity and Between-System Agreement of a Commercial Wearable Inertial Sensor System for Gait and Postural Sway Assessment in Progressive Supranuclear Palsy"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3484-4514","authenticated-orcid":false,"given":"Ryan E.","family":"Novotny","sequence":"first","affiliation":[{"name":"Neurology, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2144-9523","authenticated-orcid":false,"given":"Victor S.","family":"You","sequence":"additional","affiliation":[{"name":"Neurology, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cecilia A.","family":"Hogen","sequence":"additional","affiliation":[{"name":"Motion Analysis Laboratory, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6914-1563","authenticated-orcid":false,"given":"Jennifer L.","family":"Whitwell","sequence":"additional","affiliation":[{"name":"Radiology, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2930-8634","authenticated-orcid":false,"given":"Keith A.","family":"Josephs","sequence":"additional","affiliation":[{"name":"Neurology, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7311-3781","authenticated-orcid":false,"given":"Kenton R.","family":"Kaufman","sequence":"additional","affiliation":[{"name":"Motion Analysis Laboratory, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6060-3995","authenticated-orcid":false,"given":"Farwa","family":"Ali","sequence":"additional","affiliation":[{"name":"Neurology, Mayo Clinic, Rochester, MN 55905, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,12]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1789","DOI":"10.1016\/S0140-6736(18)32279-7","article-title":"Global, Regional, and National Incidence, Prevalence, and Years Lived with Disability for 354 Diseases and Injuries for 195 Countries and Territories, 1990\u20132017: A Systematic Analysis for the Global Burden of Disease Study 2017","volume":"392","author":"James","year":"2018","journal-title":"Lancet"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1093\/gerona\/glv126","article-title":"Gait Speed Predicts Incident Disability: A Pooled Analysis","volume":"71","author":"Perera","year":"2016","journal-title":"J. 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