Background and Purpose: Flexed truncal posture is common in people with Parkinson disease (PD); however, little is known about the mechanisms responsible or its effect on physical performance. This cross-sectional study aimed to establish the reliability of a truncal posture measurement and explore relationships between PD impairments and truncal posture, as well as truncal posture and balance and mobility.
Methods: A total of 82 people with PD participated. Truncal posture was measured in standing as the distance between vertebra C7 and a wall. Univariate and multivariate regression analyses were performed with truncal posture and impairments, including global axial symptoms, tremor, bradykinesia, rigidity, freezing of gait (FOG), reactive stepping and executive function, as well as truncal posture with balance and mobility measures.
Results: The truncal posture measure had excellent test-retest reliability (ICC3,1 0.79, 95% CI 0.60-0.89, P < 0.001). Global axial symptoms had the strongest association with truncal posture (adjusted R2 = 0.08, P = 0.01), although the majority of the variance remains unexplained. Post hoc analysis revealed that several impairments were associated with truncal posture only in those who did not report FOG. Flexed truncal posture was associated with poorer performance of most balance and mobility tasks after adjustment for age, gender, disease severity, and duration (adjusted R2 = 0.24-0.33, P < 0.001-0.03).
Discussion and Conclusions: The C7 to wall measurement is highly reliable in people with PD. Global axial symptoms were independently associated with truncal posture. Greater flexed truncal posture was associated with poorer balance and mobility. Further studies are required to elucidate the mechanisms responsible for flexed truncal posture and the impact on activity.
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Faculty of Health Sciences, The University of Sydney, Sydney, Australia (A.L.F., S.S.P., N.E.A., C.G.C.); Musculoskeletal Division, The George Institute for Global Health, Sydney Medical School, The University of Sydney, Sydney, Australia (S.S.P., C.S.); Movement Disorders Unit, Department of Neurology, Westmead Hospital, Sydney, Australia (V.S.C.F.); Sydney Medical School, The University of Sydney, Sydney, Australia (V.S.C.F.); and Department of Physical Therapy, University of Utah, Salt Lake City, United States of America (S.S.P.).
Correspondence: Colleen G. Canning, PhD, MA, BPhty, Faculty of Health Sciences, The University of Sydney, PO Box 170, Lidcombe, NSW 1825, Australia (firstname.lastname@example.org).
Catherine Sherrington's research has been funded by the Australian National Health and Medical Research Council, Parkinson's NSW, Consortium national de formation en santé (Canada), the University of Sydney, Arthritis NSW, Canadian Institute of Health Research, NSW Ministry for Health and her salary is funded by an Australian National Health and Medical Research Council Fellowship and the George Institute for Global Health. She has received travel expenses from the Australian Physiotherapy Association and the Fragility Fracture Network.
Victor Fung is on advisory boards and/or has received travel grants from Abbott, Allergan, Boehringer-Ingelheim, Hospira, Ipsen, Lundbeck, Novartis, Parkinson's KinetiGraph, Solvay and UCB.
Colleen Canning has received travel expenses and honoraria for lectures and educational activities from the Movement Disorders Society and the Postgraduate Allied Health Institute, Singapore.
This research was supported by a seeding grant from the Physiotherapy Research Foundation of Australia (ID: S10-012).
Aimi Forsyth, Serene Paul, and Natalie Allen declare no conflicts of interest.
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