2019 Research Forum

Increased Spatiotemporal Gait Asymmetry in Older Adults is related to Fall Risk and Falls Andrew Rosales, Jagjeet Gill, Oscar Obregon and Brian D. Street Department of Kinesiology, California State University Bakersfield, Bakersfield, CA, USA

Results

Introduction Abstract Increased fall risk and declining mobility threaten the health and independence of older adults. Falling is a multifactorial problem, but often falls occur during walking, suggesting that walking patterns may contribute to falls. Gait asymmetry has been shown to increase with age and be an independent factor related to falling in older adults. The purpose of this study was to investigate the relationship between spatiotemporal gait asymmetry, fall risk and falls in older adults. Twenty-two healthy older adults (79.6 years; SD 7.9) walked at comfortable (108.8 steps/min; SD 14.4) and fast (129.2 steps/min; SD 21.1) speeds to calculate asymmetry ratios for step length, stance time, and swing time. Falls (total number reported in the previous 12-months), as well as fall risk measures of function mobility (Timed-up to Go Test) and balance confidence (Activities-specific balance confidence scale) were also collected from each participant. Correlational analyses determined the relationships between gait asymmetry, number of falls and fall risk measures. At comfortable and fast walking speeds, numbers of falls were significantly correlated with step length and swing time asymmetries (r = 0.50-0.84). Functional mobility times were significantly correlated with step length and swing time asymmetries (r = 0.36-0.53). Balance confidence scoring was significantly correlated with step length, swing and stance time asymmetries (r = - 0.68 - -0.57). Spatiotemporal gait asymmetry was more closely related to falls and fall risk at fast walking speeds, suggesting that gait asymmetry and the consequence of a fall may be more likely when older adults are forced to deviate away from their comfortable walking patterns. Knowing that gait asymmetry is correlated with specific risk factors for falling, further study should be made to investigate if interventions can be implemented, targeting these risk factors and specifically during altered gait patterns, to reduce gait asymmetry and ultimately reduce the number of falls for older adults. • Falls and the consequences of falls significantly impact the health, independence and overall well-being of older adults [1]. • Gait cycle patterns, such as gait asymmetry, have been linked to falling rates of older adults [2] and increased age and walking speed have been shown to affect dynamic stability when walking [3]. • Gait asymmetry has also been shown to increase with age and be an independent factor related to falling in older adults [2]. • The purpose of this study was to investigate the relationship between spatiotemporal gait asymmetry, fall risk and falls in older adults. Methods Participants Table 1. Participant characteristics. Mean and (± SD). A convenience sample of 22 participants who, after providing informed consent, were included in this study. TUG = Timed Up and Go test, ABC = Activities-Specific Balance Confidence scale. Number of falls was self-reported from the previous 12-months. Research Sample Size (n) 22 Age (years) 79.6±7.9 Height (cm) 161.6±10.6 Weight (kg) 68.8±11.7 Body Mass Index (kg/m 2 ) 26.0±4.3 TUG test (s) 12.0±7.1 ABC (/100) 66.6±26.2 Number of Falls 0.8±1.3 Experimental Design • This study consisted of four testing measures: 1) gait assessment, measuring step length, %swing phase, %stance phase time parameters, 2) the Timed Up and Go (TUG) test, measured functional mobility, 3) the Activities-specific balance confidence (ABC) scale measured balance confidence, and 4) the total number of self-reported falls in the previous 12-months. • In the gait assessment, participants walked across a 4.27m long GAITRite mat. Three full strides was completed prior to and at the end of each walking trial (beyond the mat) to have steady-state gait within the data collection area. Participants were asked to walk under two conditions: preferred gait speed (PGS), with a cadence of 109 ±14 steps/min , and fast gait speed (FGS), with a cadence of 129 ±21 steps/min . Participants walked across the mat 5 times per condition for a total of 10 trials. • Gait asymmetry for step length, %stance phase, and %swing phase was calculated by creating symmetry ratios for the left and right lower extremities. All symmetry ratios that were below 1.00 were inverted, therefore a value of 1.00 represented perfect symmetry and any value which was greater than 1.00 indicated asymmetry. [4]

Table 2. Quantitative gait data for the two gait conditions, preferred and fast gait speed. Mean and (±SD).

Preferred Gait Speed

Fast Gait Speed

Step Length

Percent Stance

Percent Swing

Step Length

Percent Stance

Percent Swing

1.08±0.10

1.03±0.04

1.06±0.10

1.07±0.09

1.03±0.04

1.06±0.09

Correlations Between Measures of Balance and of Spatiotemporal Gait Asymmetry Ratios Table 3. TUG = Timed Up and Go test, ABC = Activities-Specific Balance Confidence scale. Number of falls was self- reported from the previous 12-months. SLA: Step Leg Asymmetry; PStA: Percent Stance Asymmetry; PSwA: Percent Swing Asymmetry. Bolded values repres nt a significant correlatio .

Preferred Gait Speed

Fast Gait Speed

Correlations TUG & SLA TUG & PStA TUG & PSwA ABC & SLA ABC & PStA ABC & PSwA

P = .047 P = .099 P = .049 P = .001 P = .005 P = .004 P = .017 P = .000 P = .000

r = .427 r = .361 r = .428 r = -.661 r = -.575 r = -.585 r = .502 r = .733 r = .769

P = .011 P = .043 P = .014 P = .001 P = .001 P = .000 P = .004 P = .000 P = .000

r = .530 r = .435 r = .515 r = -.669 r = -.660 r = -.685 r = .588 r = .795 r = .847

Num. of Falls & SLA Num. of Falls & PStA Num. of Falls & PSwA

Discussion • Approximately one-third of all community-dwelling older adults fall each year and these falls can lead to injury, detrimental psychological effects, and add additional health costs. • Because falls suffered by community-dwelling older adults often occur during walking, walking parameters, like gait asymmetry, have been hypothesized to contribute to falls and the risk of falling. • From this current study, as an individual’s functional mobility and balance confidence decreased there was a correlated increase in asymmetry, and inversely, with an increase in the number of reported falls in the previous 12-months there was an increase in asymmetry. This observation was observed across gait conditions. • LaRoche et al. [5] reported that there is a link between asymmetrical limb strength and asymmetrical gait patterns, and importantly, this correlation strengthens with age. • Therefore, the maintenance of strength symmetry, or development of symmetry through unilateral exercise, may be beneficial in reducing gait asymmetry and fall risk in older adults [1] Collerton et al., (2012). The Personal and Health Service Impact of Falls in 85 Year Olds: Cross-Sectional Findings from the Newcastle 85+ Cohort Study. PLoS ONE , 7 (3), e33078. http://doi.org/10.1371/journal.pone.0033078 [2] Pirker, W., & Katzenschlager, R. (2017). Gait disorders in adults and the elderly: A clinical guide. Wiener Klinische Wochenschrift , 129 (3), 81–95. http://doi.org/10.1007/s00508-016-1096-4 [3] Kang HG, Dingwell JB. Effects of walking speed, strength and range of motion on gait stability in healthy older adults. J Biomech. 2008 Oct 20;41(14):2899-905. [4] Lewek, M.D., Bradley, C., Wutzke, C.J., & Zinder, S.M. (2014). The relationship between spatiotemporal gait asymmetry and balance in individuals with chronic stroke. Journal of applied biomechanics, 30 1 , 31-6.[5] LaRoche et al. (2012). Med Sci Sports Exerc. 2012 Nov; 44(11): 2172–2181. References Acknowledgments • We would like to acknowledge the funding agency that supported this work; GRaSP and California State University, Bakersfield. • We would like to acknowledge the Sundale Country Club and its staff for their support in providing us with enthusiastic participants to participate in this study. • We would like to acknowledge Dr. Brian Street for his guidance and mentoring through this project and throughout our undergraduate degree.

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