Papa EV1, Hassan M2, Patterson R3, Bugnariu N4
1Idaho State University Health Science Center, Physical & Occupational Therapy, Meridian, United States, 2University of Nebraska Omaha, Biomechanics, Omaha, United States, 3University of North Texas Health Science Center, Family Medicine, Fort Worth, United States, 4University of North Texas Health Science Center, Physical Therapy, Fort Worth, United States
Background: Thirty-eight to 87% of persons with Parkinson's disease (PD) fall each year, and two-thirds of these persons fall recurrently. The economic burden of falls in PD is costly; the direct medical costs of PD fallers is estimated to double the costs of nonfallers. Nearly half of PD patients self-report fatigue as a factor in their fall history but it is unknown whether this self-reported fatigue refers to a sensation of tiredness (perceptions of fatigue) or a reduction in muscle force production (performance fatigability).
Purpose: The purpose of this investigation was to characterize the effects of performance fatigability on postural control and mobility in persons with mild-to-moderate PD.
Methods: Clinical balance assessments were performed on 14 persons with PD (62.7+8.9) (H&Y1.8+0.79). Participants performed the Timed Up and Go (TUG) and Functional Reach (FR) tests prior to- and immediately following a bout of lower-extremity fatiguing exercise on an eccentric ergometer. The duration of the fatigue effects were assessed following 15 and 30 minutes of rest, respectively. Differences were analyzed using a one-way repeated measures ANOVA, with Bonferroni corrections on the time factor. All statistical analyses were conducted with SPSS version 21.0.
Results: The assumption of sphericity was violated as assessed by Mauchly´s test of sphericity. Therefore, a Greenhouse-Geisser correction was applied for both clinical tests. The exercise intervention elicited statistically significant changes in mobility (TUG) and postural stability (FR) over time. The fatiguing exercise prompted statistically significant changes in TUG scores F(1.25, 16.26) = 9.37, p=0.005, partial η2 = 0.419. Post hoc analysis with Bonferroni adjustment revealed that TUG times significantly increased from pre-fatigue to post-fatigue (1.33s; p=0.03) and remained elevated until after 30 minutes of rest (p=0.03). The exercise intervention also induced statistically significant changes in FR scores over time F(2.05, 26.69) = 22.19, p 0.005, partial η2 = 0.631. Post hoc analysis revealed that FR distances significantly decreased from pre-fatigue to post-fatigue (2.75in; p=0.00) and remained decreased until 30 minutes of rest (p=0.008).
Conclusion(s): Performance fatigability has a measurable effect on mobility and postural stability in persons with PD. These alterations appear to resolve within 30 min of recovery. The above deficits, coupled with a predisposition for rigidity and decreased postural control, may help explain the increased fall risk in PD.
Implications: Performance fatigability has negative consequences on maintenance of postural control and mobility during functional tasks in individuals with PD. These results should serve to heighten awareness of the consequences of muscle fatigue on fall risk.
Keywords: Parkinson disease, fatigue, performance fatigability
Funding acknowledgements: Research reported was supported by the National Center for Advancing Translational Sciences, National Institutes of Health under award Number KL2TR001103.
Purpose: The purpose of this investigation was to characterize the effects of performance fatigability on postural control and mobility in persons with mild-to-moderate PD.
Methods: Clinical balance assessments were performed on 14 persons with PD (62.7+8.9) (H&Y1.8+0.79). Participants performed the Timed Up and Go (TUG) and Functional Reach (FR) tests prior to- and immediately following a bout of lower-extremity fatiguing exercise on an eccentric ergometer. The duration of the fatigue effects were assessed following 15 and 30 minutes of rest, respectively. Differences were analyzed using a one-way repeated measures ANOVA, with Bonferroni corrections on the time factor. All statistical analyses were conducted with SPSS version 21.0.
Results: The assumption of sphericity was violated as assessed by Mauchly´s test of sphericity. Therefore, a Greenhouse-Geisser correction was applied for both clinical tests. The exercise intervention elicited statistically significant changes in mobility (TUG) and postural stability (FR) over time. The fatiguing exercise prompted statistically significant changes in TUG scores F(1.25, 16.26) = 9.37, p=0.005, partial η2 = 0.419. Post hoc analysis with Bonferroni adjustment revealed that TUG times significantly increased from pre-fatigue to post-fatigue (1.33s; p=0.03) and remained elevated until after 30 minutes of rest (p=0.03). The exercise intervention also induced statistically significant changes in FR scores over time F(2.05, 26.69) = 22.19, p 0.005, partial η2 = 0.631. Post hoc analysis revealed that FR distances significantly decreased from pre-fatigue to post-fatigue (2.75in; p=0.00) and remained decreased until 30 minutes of rest (p=0.008).
Conclusion(s): Performance fatigability has a measurable effect on mobility and postural stability in persons with PD. These alterations appear to resolve within 30 min of recovery. The above deficits, coupled with a predisposition for rigidity and decreased postural control, may help explain the increased fall risk in PD.
Implications: Performance fatigability has negative consequences on maintenance of postural control and mobility during functional tasks in individuals with PD. These results should serve to heighten awareness of the consequences of muscle fatigue on fall risk.
Keywords: Parkinson disease, fatigue, performance fatigability
Funding acknowledgements: Research reported was supported by the National Center for Advancing Translational Sciences, National Institutes of Health under award Number KL2TR001103.
Topic: Neurology: Parkinson's disease
Ethics approval required: Yes
Institution: University of North Texas Health Science Center
Ethics committee: Institutional Review Board
Ethics number: 2015-074
All authors, affiliations and abstracts have been published as submitted.
