{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,10]],"date-time":"2026-03-10T01:39:48Z","timestamp":1773106788044,"version":"3.50.1"},"reference-count":31,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2024,12,28]],"date-time":"2024-12-28T00:00:00Z","timestamp":1735344000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Encompass Health\/Washington University grant program for Central Nervous System Recovery and Restoration (CNSRR)","award":["TL1TR002344"],"award-info":[{"award-number":["TL1TR002344"]}]},{"name":"National Center For Advancing Translational Sciences of the National Institutes of Health","award":["TL1TR002344"],"award-info":[{"award-number":["TL1TR002344"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Freezing of gait (FOG) is a debilitating symptom of Parkinson disease (PD). It is episodic and variable in nature, making assessment difficult. Wearable sensors used in conjunction with specialized algorithms, such as our group\u2019s pFOG algorithm, provide objective data to better understand this phenomenon. While these methods are effective at detecting FOG retrospectively, more work is needed. The purpose of this paper is to explore how the existing pFOG algorithm can be refined to improve the detection and prediction of FOG. To accomplish this goal, previously collected data were utilized to assess the prediction ability of the current algorithm, the potency of each FOG assessment task(s) for eliciting FOG, and the maintenance of detection accuracy when modifying the sampling rate. Results illustrate that the algorithm was able to predict upcoming FOG episodes, but false positive rates were high. The Go Out and Turn-Dual Task was most potent for eliciting FOG, and the 360-Dual Task elicited the longest duration of FOG. The detection accuracy of the pFOG algorithm was maintained at a sampling rate of 60 Hz but significantly worse at 30 Hz. This work is an important step in refining the pFOG algorithm for improved clinical utility.<\/jats:p>","DOI":"10.3390\/s25010124","type":"journal-article","created":{"date-parts":[[2024,12,31]],"date-time":"2024-12-31T07:00:37Z","timestamp":1735628437000},"page":"124","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Refinement of an Algorithm to Detect and Predict Freezing of Gait in Parkinson Disease Using Wearable Sensors"],"prefix":"10.3390","volume":"25","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2695-238X","authenticated-orcid":false,"given":"Allison M.","family":"Haussler","sequence":"first","affiliation":[{"name":"Program in Physical Therapy, School of Medicine, Washington University in St. Louis, St. Louis, MO 63108, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0661-5340","authenticated-orcid":false,"given":"Lauren E.","family":"Tueth","sequence":"additional","affiliation":[{"name":"Program in Physical Therapy, School of Medicine, Washington University in St. Louis, St. Louis, MO 63108, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David S.","family":"May","sequence":"additional","affiliation":[{"name":"Program in Physical Therapy, School of Medicine, Washington University in St. Louis, St. Louis, MO 63108, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9639-6051","authenticated-orcid":false,"given":"Gammon M.","family":"Earhart","sequence":"additional","affiliation":[{"name":"Program in Physical Therapy, School of Medicine, Washington University in St. Louis, St. Louis, MO 63108, USA"},{"name":"Department of Neurology, School of Medicine, Washington University in St. Louis, St. Louis, MO 63108, USA"},{"name":"Department of Neuroscience, School of Medicine, Washington University in St. Louis, St. Louis, MO 63108, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pietro","family":"Mazzoni","sequence":"additional","affiliation":[{"name":"Department of Neurology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,12,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"368","DOI":"10.1136\/jnnp.2007.131045","article-title":"Parkinson\u2019s disease: Clinical features and diagnosis","volume":"79","author":"Jankovic","year":"2008","journal-title":"J. Neurol. Neurosurg. Psychiatry"},{"key":"ref_2","first-page":"S3","article-title":"The Emerging Evidence of the Parkinson Pandemic","volume":"8","author":"Dorsey","year":"2018","journal-title":"J. Park. Dis."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"12","DOI":"10.1186\/s40035-020-00191-5","article-title":"Freezing of gait in Parkinson\u2019s disease: Pathophysiology, risk factors and treatments","volume":"9","author":"Gao","year":"2020","journal-title":"Transl. Neurodegener."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"734","DOI":"10.1016\/S1474-4422(11)70143-0","article-title":"Freezing of gait: Moving forward on a mysterious clinical phenomenon","volume":"10","author":"Nutt","year":"2011","journal-title":"Lancet Neurol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"S423","DOI":"10.1002\/mds.21927","article-title":"Understanding and treating freezing of gait in parkinsonism, proposed working definition, and setting the stage","volume":"23","author":"Giladi","year":"2008","journal-title":"Mov. Disord. Off. J. Mov. Disord. Soc."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"199","DOI":"10.1002\/mdc3.12893","article-title":"The New Freezing of Gait Questionnaire: Unsuitable as an Outcome in Clinical Trials?","volume":"7","author":"Hulzinga","year":"2020","journal-title":"Mov. Disord. Clin. Pract."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.parkreldis.2011.08.002","article-title":"Assessing the utility of Freezing of Gait Questionnaires in Parkinson\u2019s Disease","volume":"18","author":"Shine","year":"2012","journal-title":"Park. Relat. Disord."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s12984-020-00774-3","article-title":"Measuring freezing of gait during daily life: An open-source, wearable sensors approach","volume":"18","author":"Mancini","year":"2021","journal-title":"J. NeuroEngineering Rehabil."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1155\/2011\/274539","article-title":"On the nature of fear of falling in Parkinson\u2019s disease","volume":"24","author":"Rahman","year":"2011","journal-title":"Behav. Neurol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"884","DOI":"10.1001\/jamaneurol.2014.753","article-title":"Prevalence, determinants, and effect on quality of life of freezing of gait in Parkinson disease","volume":"71","author":"Damier","year":"2014","journal-title":"JAMA Neurol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"871","DOI":"10.1002\/mds.20115","article-title":"Falls and freezing of gait in Parkinson\u2019s disease: A review of two interconnected, episodic phenomena","volume":"19","author":"Bloem","year":"2004","journal-title":"Mov. Disord. Off. J. Mov. Disord. Soc."},{"key":"ref_12","first-page":"699","article-title":"Risk factors for frequent falls in people with Parkinson\u2019s disease","volume":"4","author":"Paul","year":"2014","journal-title":"J. Park. Dis."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"253","DOI":"10.1002\/mds.28883","article-title":"Discussion of Research Priorities for Gait Disorders in Parkinson\u2019s Disease","volume":"37","author":"Bohnen","year":"2022","journal-title":"Mov. Disord. Off. J. Mov. Disord. Soc."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"111480","DOI":"10.1016\/j.isci.2024.111480","article-title":"Continuous tremor monitoring in Parkinson\u2019s disease: A wristwatch-inspired triboelectric sensor approach","volume":"27","author":"Ukasi","year":"2024","journal-title":"iScience"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/j.jns.2019.04.011","article-title":"Smartwatch for the analysis of rest tremor in patients with Parkinson\u2019s disease","volume":"401","author":"Velasco","year":"2019","journal-title":"J. Neurol. Sci."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Antonini, A., Reichmann, H., Gentile, G., Garon, M., Tedesco, C., Frank, A., Falkenburger, B., Konitsiotis, S., Tsamis, K., and Rigas, G. (2023). Toward objective monitoring of Parkinson\u2019s disease motor symptoms using a wearable device: Wearability and performance evaluation of PDMonitor\u00ae. Front. Neurol., 14.","DOI":"10.3389\/fneur.2023.1080752"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"May, D.S., Tueth, L.E., Earhart, G.M., and Mazzoni, P. (2023). Using Wearable Sensors to Assess Freezing of Gait in the Real World. Bioengineering, 10.","DOI":"10.3390\/bioengineering10030289"},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Suppa, A., Kita, A., Leodori, G., Zampogna, A., Nicolini, E., Lorenzi, P., Rao, R., and Irrera, F. (2017). l-DOPA and Freezing of Gait in Parkinson\u2019s Disease: Objective Assessment through a Wearable Wireless System. Front. Neurol., 8.","DOI":"10.3389\/fneur.2017.00406"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2152","DOI":"10.1109\/TBME.2017.2785625","article-title":"Modeling, detecting, and tracking freezing of gait in Parkinson disease using inertial sensors","volume":"65","author":"Prateek","year":"2018","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1362","DOI":"10.1016\/j.parkreldis.2015.09.051","article-title":"Identifying freezing of gait in Parkinson\u2019s disease during freezing provoking tasks using waist-mounted accelerometry","volume":"21","author":"Zach","year":"2015","journal-title":"Park. Relat. Disord."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Giannakopoulou, K.-M., Roussaki, I., and Demestichas, K. (2022). Internet of Things Technologies and Machine Learning Methods for Parkinson\u2019s Disease Diagnosis, Monitoring and Management: A Systematic Review. Sensors, 22.","DOI":"10.3390\/s22051799"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Pardoel, S., Kofman, J., Nantel, J., and Lemaire, E.D. (2019). Wearable-Sensor-Based Detection and Prediction of Freezing of Gait in Parkinson\u2019s Disease: A Review. Sensors, 19.","DOI":"10.3390\/s19235141"},{"key":"ref_23","unstructured":"R Core Team (2024, November 26). R: A Language and Environment for Statistical Computing [Internet]. Available online: https:\/\/www.R-project.org\/."},{"key":"ref_24","unstructured":"Van Rossum, G., and Drake, F.L. (2009). Python 3 Reference Manual, CreateSpace."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.parkreldis.2011.09.006","article-title":"Freezer or non-freezer: Clinical assessment of freezing of gait","volume":"18","author":"Snijders","year":"2012","journal-title":"Park. Relat. Disord."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Handojoseno, A.M.A., Gilat, M., Ly, Q.T., Chamtie, H., Shine, J.M., Nguyen, T.N., Tran, Y., Lewis, S.J.G., and Nguyen, H.T. (2015, January 25\u201329). An EEG study of turning freeze in Parkinson\u2019s disease patients: The alteration of brain dynamic on the motor and visual cortex. Proceedings of the 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Milan, Italy.","DOI":"10.1109\/EMBC.2015.7319910"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Ly, Q.T., Ardi Handojoseno, A.M., Gilat, M., Chai, R., Martens, K.A.E., Georgiades, M., Naik, G.R., Tran, Y., Lewis, S.J.G., and Nguyen, H.T. (2017, January 11\u201315). Detection of turning freeze in Parkinson\u2019s disease based on S-transform decomposition of EEG signals. Proceedings of the 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Jeju, Republic of Korea.","DOI":"10.1109\/EMBC.2017.8037499"},{"key":"ref_28","first-page":"124","article-title":"Nguyen HT Prediction of Freezing of Gait in Patients with Parkinson\u2019s Disease Using EEG Signals","volume":"246","author":"Handojoseno","year":"2018","journal-title":"Stud. Health Technol. Inform."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Jovanov, E., Wang, E., Verhagen, L., Fredrickson, M., and Fratangelo, R. (2009, January 3\u20136). deFOG\u2014A real time system for detection and unfreezing of gait of Parkinson\u2019s patients. Proceedings of the 2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Minneapolis, MN, USA.","DOI":"10.1109\/IEMBS.2009.5334257"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2394","DOI":"10.1109\/TBME.2017.2655344","article-title":"Smart Gait-Aid Glasses for Parkinson\u2019s Disease Patients","volume":"64","author":"Ahn","year":"2017","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Punin, C., Barzallo, B., Clotet, R., Bermeo, A., Bravo, M., Bermeo, J.P., and Llumiguano, C. (2019). A Non-Invasive Medical Device for Parkinson\u2019s Patients with Episodes of Freezing of Gait. Sensors, 19.","DOI":"10.3390\/s19030737"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/25\/1\/124\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:55:09Z","timestamp":1760115309000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/25\/1\/124"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,12,28]]},"references-count":31,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2025,1]]}},"alternative-id":["s25010124"],"URL":"https:\/\/doi.org\/10.3390\/s25010124","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,12,28]]}}}