TY - JOUR
T1 - Anticipatory postural responses prior to protective steps are not different in people with PD who do and do not freeze
AU - Peterson, Daniel
AU - Lohse, K. R.
AU - Mancini, M.
N1 - Funding Information:
This work was supported directly by: The United States Department of Veteran’s Affairs Rehabilitation Research and Development Service (Career Development Award-1: #I01BX007080; PI: DSP) and the Medical Research Foundation of Oregon (Early Investigator Award; PI: DSP). Over the past 12 months, authors have also been funded by: the Canadian Institutes of Health Research ( PTJ 153330 ; CoI: KRL), Auburn University Internal Grants Program (IGP Project #: 170,138; PI: KRL), Federal Aviation Administration – Center for Excellence for Teaching Training and Human Performance (FAA 16-C-TTHP-AU; CoI: KRL), and the NIH: Career Development Award R00 HD078492 (PI, MM) and SBIR 1R43AG056012-01 (CoI: MM). The contents do not represent the views of the U.S. Department of Veterans Affairs or the United States Government.
Publisher Copyright:
© 2018
PY - 2018/7
Y1 - 2018/7
N2 - Background: Protective stepping after a loss of balance is related to falls. Anticipatory postural responses (APAs) prior to protective stepping can impact step performance, may be larger in people with PD, and have been suggested to be related to freezing of gait (FOG). However, whether people with PD and FOG (PD + FOG) exhibit larger APAs than people with PD and no FOG (PD-FOG) is unknown. Research Question: Determine the impact of freezing status on APAs prior to protective steps, thus providing a better understanding of the link between FOG and APAs. Methods: Twenty-eight people with PD (13 PD + FOG) were exposed to 50 support surface translations (25 forward, 25 backward, random order) resulting in protective steps. The size of medio-lateral weight shifts prior to the protective step (i.e. APAs), and the percentage of trials with an APA were calculated via force-plates. FOG status was assessed at the time of testing as well as 3.25(+/-0.43) years later. Participants without FOG at testing, but with FOG at follow-up were identified as “converters”. Results and significance: For both forward and backward protective stepping, size and percentage trials with an APA were not statistically different between PD + FOG and PD-FOG, even after excluding converters from the PD-FOG group (p > 0.27 for all). No group by direction interactions were observed. These data suggest that, in mild to moderate PD, an inability to couple APAs with stepping, rather than an inappropriately sized APA, may be most related to freezing of gait.
AB - Background: Protective stepping after a loss of balance is related to falls. Anticipatory postural responses (APAs) prior to protective stepping can impact step performance, may be larger in people with PD, and have been suggested to be related to freezing of gait (FOG). However, whether people with PD and FOG (PD + FOG) exhibit larger APAs than people with PD and no FOG (PD-FOG) is unknown. Research Question: Determine the impact of freezing status on APAs prior to protective steps, thus providing a better understanding of the link between FOG and APAs. Methods: Twenty-eight people with PD (13 PD + FOG) were exposed to 50 support surface translations (25 forward, 25 backward, random order) resulting in protective steps. The size of medio-lateral weight shifts prior to the protective step (i.e. APAs), and the percentage of trials with an APA were calculated via force-plates. FOG status was assessed at the time of testing as well as 3.25(+/-0.43) years later. Participants without FOG at testing, but with FOG at follow-up were identified as “converters”. Results and significance: For both forward and backward protective stepping, size and percentage trials with an APA were not statistically different between PD + FOG and PD-FOG, even after excluding converters from the PD-FOG group (p > 0.27 for all). No group by direction interactions were observed. These data suggest that, in mild to moderate PD, an inability to couple APAs with stepping, rather than an inappropriately sized APA, may be most related to freezing of gait.
KW - Anticipatory postural responses
KW - Freezing of gait
KW - Protective stepping
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U2 - 10.1016/j.gaitpost.2018.06.006
DO - 10.1016/j.gaitpost.2018.06.006
M3 - Article
C2 - 29902715
AN - SCOPUS:85048214669
SN - 0966-6362
VL - 64
SP - 126
EP - 129
JO - Gait and Posture
JF - Gait and Posture
ER -