503
NeuroRehabilitation 35 (2014) 503–508 DOI:10.3233/NRE-141143 IOS Press
Six minutes of walking leads to reduced lower limb strength and increased postural sway in people with Multiple Sclerosis J.V. McLoughlina,c,∗ , C.J. Barra , M. Crottya , D.L. Sturnieksb,c and S.R. Lordb,c a Flinders
University, South Australia and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia c School of Public Health and Community Medicine, University of New South Wales, Sydney, Australia b Falls
Abstract. BACKGROUND: Fatigue, lower limb weakness and poor balance can significantly limit safe mobility in people with Multiple Sclerosis (MS). Further research is required to elucidate relationships among these factors. OBJECTIVE: To investigate the effect of walking-induced fatigue on lower limb strength and postural sway in people with moderately disabling MS. METHODS: Thirty-four people (26 female) with moderate MS (mean Expanded Disability Status Scale of 3.7 ± 0.7) underwent assessments of acute fatigue, postural sway and lower limb strength before and after six-minute conditions of seated rest and walking. A matched sample of 10 healthy controls also undertook identical assessments before and after a six-minute walk. RESULTS: Significant time by condition effects for all assessment measures indicated the six-minute walk induced fatigue with associated increases in postural sway and reductions in lower limb strength in people with MS. Increases in sway with eyes closed correlated with increases in acute fatigue and self-reported impact of fatigue on physical and psychological functioning. No changes were observed in healthy controls. CONCLUSION: People with MS show signs of fatigue after 6 minutes of walking, including strength and balance deficits. These findings have implications for both mobility and fall risk in this group. Keywords: Multiple Sclerosis, fatigue, muscle strength, postural balance, mobility limitation, accidental falls
1. Introduction Balance impairments are common in people with Multiple Sclerosis (MS) and are associated with increased fall risk (Cameron & Lord, 2010; Gunn, Newell, Haas, Marsden, & Freeman, 2013). Over 50% of people with MS will fall within a six month period (Gunn et al., 2013) with consequences including injury (Peterson, Cho, von Koch, & Finlayson, 2008), fear, activity restrictions (Peterson, Cho, & Finlayson, ∗ Address for correspondence: James McLoughlin, Department of Rehabilitation, Aged & Extended Care, Flinders University, South Australia, Australia. Tel.: +61 8 82751103; Fax: +61 8 82751130; E-mail: [email protected].
2007) and death (Brønnum-Hansen, Hansen, KochHenriksen, & Stenager, 2006). In people with MS impaired balance is associated with degree of disability (Corporaal et al., 2013), lower limb strength (Yahia, Ghroubi, Mhiri, & Elleuch, 2011), reduced sensation in the feet (Citaker et al., 2011), slower spinal somatosensory conduction (Cameron, Horak, Herndon, & Bourdette, 2008) and lower limb spasticity (Sosnoff, Shin, & Motl, 2010). Further, central nervous system lesions that delay sensory and motor integration can also impair balance control (Diener et al., 1984). Perceived fatigue is a common disabling condition experienced by people with MS and has been shown to be associated with muscle fatigue (Steens et al., 2012).
1053-8135/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved
NeuroRehabilitation 35 (2014) 503–508 DOI:10.3233/NRE-141143 IOS Press
Six minutes of walking leads to reduced lower limb strength and increased postural sway in people with Multiple Sclerosis J.V. McLoughlina,c,∗ , C.J. Barra , M. Crottya , D.L. Sturnieksb,c and S.R. Lordb,c a Flinders
University, South Australia and Balance Research Group, Neuroscience Research Australia, University of New South Wales, Sydney, Australia c School of Public Health and Community Medicine, University of New South Wales, Sydney, Australia b Falls
Abstract. BACKGROUND: Fatigue, lower limb weakness and poor balance can significantly limit safe mobility in people with Multiple Sclerosis (MS). Further research is required to elucidate relationships among these factors. OBJECTIVE: To investigate the effect of walking-induced fatigue on lower limb strength and postural sway in people with moderately disabling MS. METHODS: Thirty-four people (26 female) with moderate MS (mean Expanded Disability Status Scale of 3.7 ± 0.7) underwent assessments of acute fatigue, postural sway and lower limb strength before and after six-minute conditions of seated rest and walking. A matched sample of 10 healthy controls also undertook identical assessments before and after a six-minute walk. RESULTS: Significant time by condition effects for all assessment measures indicated the six-minute walk induced fatigue with associated increases in postural sway and reductions in lower limb strength in people with MS. Increases in sway with eyes closed correlated with increases in acute fatigue and self-reported impact of fatigue on physical and psychological functioning. No changes were observed in healthy controls. CONCLUSION: People with MS show signs of fatigue after 6 minutes of walking, including strength and balance deficits. These findings have implications for both mobility and fall risk in this group. Keywords: Multiple Sclerosis, fatigue, muscle strength, postural balance, mobility limitation, accidental falls
1. Introduction Balance impairments are common in people with Multiple Sclerosis (MS) and are associated with increased fall risk (Cameron & Lord, 2010; Gunn, Newell, Haas, Marsden, & Freeman, 2013). Over 50% of people with MS will fall within a six month period (Gunn et al., 2013) with consequences including injury (Peterson, Cho, von Koch, & Finlayson, 2008), fear, activity restrictions (Peterson, Cho, & Finlayson, ∗ Address for correspondence: James McLoughlin, Department of Rehabilitation, Aged & Extended Care, Flinders University, South Australia, Australia. Tel.: +61 8 82751103; Fax: +61 8 82751130; E-mail: [email protected].
2007) and death (Brønnum-Hansen, Hansen, KochHenriksen, & Stenager, 2006). In people with MS impaired balance is associated with degree of disability (Corporaal et al., 2013), lower limb strength (Yahia, Ghroubi, Mhiri, & Elleuch, 2011), reduced sensation in the feet (Citaker et al., 2011), slower spinal somatosensory conduction (Cameron, Horak, Herndon, & Bourdette, 2008) and lower limb spasticity (Sosnoff, Shin, & Motl, 2010). Further, central nervous system lesions that delay sensory and motor integration can also impair balance control (Diener et al., 1984). Perceived fatigue is a common disabling condition experienced by people with MS and has been shown to be associated with muscle fatigue (Steens et al., 2012).
1053-8135/14/$27.50 © 2014 – IOS Press and the authors. All rights reserved
