Matthew N Petrucci1, Colum D MacKinnon2, Elizabeth T Hsiao-Wecksler3. 1. Neuroscience Program, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, United States; Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 W Green Street, Urbana, IL, 61801, United States. Electronic address: mpetrucc@stanford.edu. 2. Department of Neurology, University of Minnesota, 516 Delaware St SE, Minneapolis, MN, 55455, United States. 3. Neuroscience Program, University of Illinois at Urbana-Champaign, 505 South Goodwin Avenue, Urbana, IL 61801, United States; Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 W Green Street, Urbana, IL, 61801, United States.
Abstract
BACKGROUND: Freezing of gait (FOG) during gait initiation in people with Parkinson's disease (PD) may be related to a diminished ability to generate anticipatory postural adjustments (APAs). Externally applied perturbations that mimic the desired motion of the body during an APA have been demonstrated to shorten and amplify APAs; however, no portable device has been tested. In this study, a portable powered ankle-foot orthosis (PPAFO) testbed was utilized to investigate the effect of mechanical assistance, provided at the ankle joint, on the APAs during gait initiation. RESEARCH QUESTION: Does mechanical assistance provided at the ankle joint improve APAs during gait initiation in people with PD and FOG? METHODS: Thirteen participants with PD and FOG initiated gait across five test conditions: two self-initiated (uncued) conditions in walking shoes [Baseline-Shoes], and the PPAFO in unpowered passive mode [Baseline-PPAFOPassive]; three "go" cued conditions that included an acoustic tone with the PPAFO in unpowered passive mode [Acoustic + PPAFOPassive], the mechanical assistance from the PPAFO [PPAFOActive], and the acoustic tone paired with mechanical assistance [Acoustic + PPAFOActive]. A warning-cue preceded the imperative "go" cue for all the cued trials. Peak amplitudes and timings of the vertical ground reaction forces (GRFs) and center of pressure (COP) shifts from onset to toe-off were compared across conditions. RESULTS: Mechanical assistance significantly increased the peak amplitudes of the GRFs and COP shifts, reduced APA variability, and decreased the time to toe-off relative to the passive conditions. SIGNIFICANCE: These findings demonstrate the potential utility of mechanical assistance at the ankle joint (with or without an acoustic cue) as a method to generate more consistent, shortened, and amplified APAs in people with PD and FOG.
BACKGROUND: Freezing of gait (FOG) during gait initiation in people with Parkinson's disease (PD) may be related to a diminished ability to generate anticipatory postural adjustments (APAs). Externally applied perturbations that mimic the desired motion of the body during an APA have been demonstrated to shorten and amplify APAs; however, no portable device has been tested. In this study, a portable powered ankle-foot orthosis (PPAFO) testbed was utilized to investigate the effect of mechanical assistance, provided at the ankle joint, on the APAs during gait initiation. RESEARCH QUESTION: Does mechanical assistance provided at the ankle joint improve APAs during gait initiation in people with PD and FOG? METHODS: Thirteen participants with PD and FOG initiated gait across five test conditions: two self-initiated (uncued) conditions in walking shoes [Baseline-Shoes], and the PPAFO in unpowered passive mode [Baseline-PPAFOPassive]; three "go" cued conditions that included an acoustic tone with the PPAFO in unpowered passive mode [Acoustic + PPAFOPassive], the mechanical assistance from the PPAFO [PPAFOActive], and the acoustic tone paired with mechanical assistance [Acoustic + PPAFOActive]. A warning-cue preceded the imperative "go" cue for all the cued trials. Peak amplitudes and timings of the vertical ground reaction forces (GRFs) and center of pressure (COP) shifts from onset to toe-off were compared across conditions. RESULTS: Mechanical assistance significantly increased the peak amplitudes of the GRFs and COP shifts, reduced APA variability, and decreased the time to toe-off relative to the passive conditions. SIGNIFICANCE: These findings demonstrate the potential utility of mechanical assistance at the ankle joint (with or without an acoustic cue) as a method to generate more consistent, shortened, and amplified APAs in people with PD and FOG.
Authors: Morgan K Boes; Rachel E Bollaert; Richard M Kesler; Yvonne C Learmonth; Mazharul Islam; Matthew N Petrucci; Robert W Motl; Elizabeth T Hsiao-Wecksler Journal: Arch Phys Med Rehabil Date: 2017-08-02 Impact factor: 3.966
Authors: Ana Claudia de Souza Fortaleza; Martina Mancini; Patty Carlson-Kuhta; Laurie A King; John G Nutt; Eliane Ferrari Chagas; Ismael Forte Freitas; Fay B Horak Journal: Gait Posture Date: 2017-05-10 Impact factor: 2.840
Authors: Chiahao Lu; Sommer L Amundsen Huffmaster; Paul J Tuite; Jacqueline M Vachon; Colum D MacKinnon Journal: Arch Phys Med Rehabil Date: 2017-02-04 Impact factor: 3.966
Authors: John G Nutt; Bastiaan R Bloem; Nir Giladi; Mark Hallett; Fay B Horak; Alice Nieuwboer Journal: Lancet Neurol Date: 2011-08 Impact factor: 44.182