Older adults with history of falls are unable to perform walking and prehension movements simultaneously

NSC 16794 No of Pages 12 29 December 2015 Please cite this article in press as: Rinaldi NM, Moraes R Older adults with history of falls are unable to perform walking and prehension movements simultaneously Neuroscience (2015), http://dx.doi.org/10.1016/j.neuroscience.2015.12.037 Neuroscience xxx (2015) xxx–xxx OLDER ADULTS WITH HISTORY OF FALLS ARE UNABLE TO PERFORM WALKING AND PREHENSION MOVEMENTS SIMULTANEOUSLY N M RINALDI a,b* AND R MORAES b,c a b 10 11 et al., 1993; Perracini and Ramos, 2002) Consequently, fall-related injuries are associated with a poorer quality of life due to restricted mobility and functional decline (Tideiksaar, 1996) In addition, one of the major intrinsic risk factors for falls in older adults is deficit in static and dynamic postural control (Verghese et al., 2007) Importantly, more than 50% of falls occur during locomotion (Barak et al., 2006) Older adults with a history of falls (FOA) present some gait impairments (Hausdorff et al., 2001), such as a decrease in stride length and velocity, and an increase in gait variability and double support time (Kirkwood et al., 2011; Toebes et al., 2012) These changes in the walking pattern are even more evident when two motor tasks are combined (Nordin et al., 2010) FOA have a slower swing time and step velocity than older adults without a history of falls in a dual task paradigm (Springer et al., 2006) These results suggest that FOA may have problems switching their attention between two motor tasks due to neuromuscular problems (Hawkes et al., 2012) The changes in the walking behavior during a dual task paradigm can predict falls in older adults (Beauchet et al., 2009) Moreover, the level of difficulty of the secondary task can also influence how dual-task-related changes are associated with a history of falls (Chu et al., 2013) Nordin et al (2010) investigated, in FOA, gait changes during dual task conditions at different levels of difficulty They found that FOA increased their step width in the two most difficult tasks (task 1: carry a saucer with a coffee cup in one hand; task 2: perform serial subtractions by three starting from 50) These results indicated the usage of sensory-motor resources in a flexible manner to decrease the risk of falls (i.e., a protective strategy) Hall et al (2011) investigated the impact of cognitive task level of difficulty on walking of FOA FOA reduced gait speed when cognitive task demand increased, suggesting that the more difficult the secondary task is, the greater the impact on gait performance Furthermore, FOA performed the alphabet and alternate letters tasks more slowly in walking than in the seated condition With an increase in task difficulty, older adults must allocate more attentional resources to walking to compensate for the reduction in sensory-motor control (Stelmach et al., 1990) The combined task of walking and prehension (i.e., reach-to-grasp) is widely performed during activities of daily life Older adults exhibit smaller peak wrist velocity and greater movement times than young adults when reaching for an object (Roy et al., 1996) Furthermore, Ribeirao Preto Medical School, University of Sao Paulo, Brazil Research Support Center on Chronic-Degenerative Diseases, University of Sao Paulo, Brazil c Biomechanics and Motor Control Lab, School of Physical Education and Sport of Ribeirao Preto, University of Sao Paulo, Brazil Abstract—Older adults have a greater incidence of falls, and risk of falls will increase when combining two motor tasks Thus, it is interesting to investigate the effect of fall history on motor performance in older adults when combining walking with another task such as grasping an object The aim of this study was to investigate the combined task of walking and prehension with different levels of manual task difficulty in older adults with and without a history of falls Thirty older adults participated in this study; groups were designated as fallers (n = 15) and non-fallers (n = 15) Participants were asked to reach-to-grasp a dowel during quiet standing and during walking Level of manual task difficulty was manipulated by the type of dowel support and obstacles located at different distances to the sides of the dowel Fall history influenced the performance of this combined task for the most difficult manual conditions Fallers were able to be identified due to differences in the grasping strategies used while walking compared to non-fallers In addition, walking and grasping were mutually modulated due to the level of difficulty of the manual task Ó 2015 Published by Elsevier Ltd on behalf of IBRO Key words: aging, falls, locomotion, prehension, dual task 12 13 INTRODUCTION 14 It is estimated that one-third of community-dwelling people aged 65 and older fall every year (O’loughlin 15 *Correspondence to: N M Rinaldi, Faculdade de Medicina de Ribeira˜o Preto, Programa de Po´s-Graduac¸a˜o em Reabilitac¸a˜o e Desempenho Funcional, Universidade de Sa˜o Paulo, Avenida dos Bandeirantes, 3900 Ribeira˜o Preto, SP 14049-900, Brazil Tel: +5516-3315-0359; fax: +55-16-3315-0551 E-mail address: narinaldi@yahoo.com.br (N M Rinaldi) Abbreviations: ANOVAs, analysis of variances; AP, anterior–posterior; COM, center of mass; FOA, Older adults with a history of falls; HCs, heel contacts; MDS, margin of dynamic stability; ML, medial–lateral; MMSE, Mini Mental State Examination; OA, older adults with no history of falls; SB, stable base; SLD, stable base with obstacles at long; SSD, stable base with obstacles at short; UB, unstable base; WT, walking baseline http://dx.doi.org/10.1016/j.neuroscience.2015.12.037 0306-4522/Ó 2015 Published by Elsevier Ltd on behalf of IBRO 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 NSC 16794 No of Pages 12 29 December 2015 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 N M Rinaldi, R Moraes / Neuroscience xxx (2015) xxx–xxx older adults have reduced tactile sensitivity and, consequently, increase the grip force as a compensatory strategy (Gorniak et al., 2011) During walking aging has been found to affect prehension Diermayr et al (2011) investigated the aging effects on grasp control when walking and transporting an object They found an increase in grip force while walking, indicating a decline in manual dexterity while performing functional tasks Interestingly, Delbaere et al (2004) found that walking and reaching are the most avoided tasks in older adults with fear of falling When reaching for an object in an upright position older adults adopted a hip strategy to perform the task, which is different than that of young adults who preferred an ankle strategy (Delbaere et al., 2004) Additionally, Huang and Brown (2015) found that older adults showed a larger center of pressure excursions compared to young individuals when combining upright stance with reach-to-grasp These different strategies are likely to compensate for constraints in balance-related functions Thus, it becomes interesting to combine these two tasks because they have the potential to challenge dynamic stability due to mechanical constraints and, at the same time, increase cognitive load because this combined task is also a dual task Many studies have investigated the interference of motor/cognitive tasks on walking and the relationship to fall risk in older adults (Menant et al., 2014) However, most of these studies involving dual task paradigms and FOA investigated primarily the main task (i.e., walking) (Beauchet et al., 2009) Recently, we found modifications in walking and prehension when combining these two tasks in young adults (Rinaldi and Moraes, 2015) We suggested that prehension was superimposed on gait, although the adaptations in motor behavior were global because both motor patterns were modified to guarantee the execution of prehension with different levels of difficulty while walking without stopping Then, in this context of dual task and falls, it is important to analyze both tasks to investigate the level of interference between these two motor tasks in FOA Possible changes in the prehension control, such as, reduced movement time, wrist velocity and grip aperture velocity could be related to changes in walking control Changes in gait stability could be part of a compensatory strategy to accommodate the control of upper body movements toward an object in FOA Furthermore, this combined motor task is different from other dual task paradigms in the literature (Yamada et al., 2011), because most studies have older adults perform the secondary task during the entire pathway (e.g., carrying a tray) Thus, they not need to change their motor strategy to perform the secondary task, since they could preprogram their movement from the beginning of the walking task However, to perform daily life activities, older adults are required to change their walking patterns to accommodate other tasks (e.g., prehension) Based on these assumptions, our combined motor task can contribute to investigate the motor strategies used by FOA when they have to disrupt the walking pattern to superimpose a voluntary, discrete task Based on these considerations, this study presents two main research questions: (1) what are the changes in prehension and walking when these tasks are combined in FOA? (2) Do these changes occur as a function of the manual task difficulty? To answer these questions, we analyzed variables based on whole body center of mass (COM) (including stability measures) and spatiotemporal gait parameters to describe the possible changes in walking of the FOA due to manual task difficulty We analyzed two steps before object grasping to investigate the changes in walking during the approach phase In relation to reach-to-grasp, we analyzed the reaching and grasping components, such as reaching duration and velocity, and hand grip aperture and velocity We also investigated prehension variables in the upright stance to identify changes in reach-to-grasp due to the addition of walking Therefore, the aim of this study was to investigate the combined task of walking and prehension with different levels of manual task difficulty in older adults with and without a history of falls 125 EXPERIMENTAL PROCEDURES 143 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 Participants 144 Thirty individuals participated in this study They were distributed in two groups (n = 15): older adults with no history of falls (OA) (15 females); older adults who experienced at least one fall in the 12-month period prior to data collection (FOA) (15 females) Participants were screened before starting the experimental task by filling out a clinical questionnaire to check the history of falls, health status, physical activity level (Baecke) (Voorrips et al., 1991), cognitive function (Mini Mental State Examination, MMSE) (Folstein et al., 1975) and balance performance (Mini-BESTest) (Maia et al., 2013) Participants were excluded if they had cognitive impairment ([...]... conservative walking strategy They also decoupled the combined task when compared to OA, since they need to increase body stability to be able to perform grasping successfully History of falls affected the prehension movement Our combined task allowed for identification of changes in the motor control strategies adopted by FOA for grasping while walking In addition, motor patterns (walking and grasping) of older. .. kinematic analysis of age-related changes in grasping to use and grasping to move common objects Acta Psychol 151:134–142 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 Please cite this article in press as: Rinaldi NM, Moraes R Older adults with history of falls are unable to perform walking and prehension movements simultaneously Neuroscience... T, Tchihaski N (2011) The reliability and preliminary validity of game-based fall risk assessment in community-dwelling older adults Geriatr Nurs 32 (3):188–194 (Accepted 20 December 2015) (Available online xxxx) Please cite this article in press as: Rinaldi NM, Moraes R Older adults with history of falls are unable to perform walking and prehension movements simultaneously Neuroscience (2015), http://dx.doi.org/10.1016/j.neuroscience.2015.12.037... older adults (fallers and non-fallers) were mutually modified due to the level of difficulty of the manual task This study manipulated a combined task that is widely used by older adults during daily life activities The older adults with a history of falls presented important changes in their action strategies probably in order to divide attention between the two motor tasks, which could impair their performance... No of Pages 12 29 December 2015 N M Rinaldi, R Moraes / Neuroscience xxx (2015) xxx–xxx 655 to- peak grip aperture and the time -to- peak grip aperture velocity increased in the presence of obstacles Therefore, level of difficulty influenced the performance of reaching and grasping components in older adults When considering the reaching component, older adults presented differences compared to young adults. .. adults (Rinaldi and Moraes, 2015) Young adults had an increased movement time and an earlier time -to- peak wrist velocity only for the most difficult condition (unstable base with obstacles at short distance) It was observed that the type of base and presence of obstacles influenced reaching movement of older adults, but not young adults The results of the present study are in agreement with studies that... modified the performance of goal-directed movements with a decrease in movement speed (Ren et al., 2013) and increase in movement time (Roy et al., 1996) Changes in reaching control of older adults due to manual task level of difficulty can be thought of as a conservative strategy to achieve the task successfully Grasping is a complex action which requires the involvement of higher level motor control... we are already planning additional experiments were we will manipulate the starting point and the starting limb Moreover, the prehension task represents a challenge for the walking stability, and during the approaching phase, older adults adopted a conservative walking strategy to perform reaching and grasping successfully, based on anticipatory control However, for future studies, we are planning to. .. The walking task was more difficult for older adults, because of the challenge to body stability, leading to the adoption of a conservative strategy for prehension control In addition, time -to- peak grip aperture occurred earlier in the stationary condition than in the walking condition This result indicated that walking changed the control of grasping, thus older adults allocated more attention for dynamic... of elderly people with a history of falls: a dynamic approach Phys Ther 86 (11):1501–1510 Beauchet O, Annweiler C, Dubost V, Allali G, Kressig RW, Bridenbaugh S, Berrut G, Assal F, Herrmann (2009) Stops walking when talking: a predictor of falls in older adults? Eur J Neurol 16:786–795 Beurskens R, Helmich I, Rein R, Bock O (2014) Age-related changes in prefrontal activity during walking in dual-task