The descriptive statistics revealed changes in VRT that corresponded to increasing functional task complexity (Figure 1). The means indicate that sitting and standing VRT were faster than walking VRT for both groups. Voice reaction time for men and women were similar in sitting. Standing VRT was slightly faster than sitting for both groups (10 milliseconds for men versus 2.5 milliseconds for women) and men participants responded a little quicker than women (444.90 milliseconds versus 452.09 milliseconds). When walking, VRT became longer for both groups and men responded faster than women. The results from the 2 (gender) by 3 (task condition) ANOVA revealed a significant main effect for task condition (F2,59 = 16.24, P < .001); the main effect of gender (F1,60 = .190, P = .665) and the interaction of group with task (F2,59 = 0.632, P = .433) were both not statistically significant. Post hoc analysis of the main effects of task revealed that there were no statistically significant differences (P = .833) between sitting (n = 62, mean = 454.68, SD = 116.89 milliseconds) and standing (n = 62, mean = 448.36, SD = 108.37 milliseconds) VRT. However, walking VRT (n = 62, mean = 524.25, SD = 131.71 milliseconds) was significantly longer than both sitting (P < .001) and standing (P < .001) VRT. The pattern of statistically significant differences in VRT for the post hoc analysis of the main effect of task indicated that the attentional requirements of walking was significantly greater than both sitting and standing. There were no statistically significant differences in VRT for any of the task conditions based on gender (Figure 1).
The study results demonstrate that the attentional demands of walking in a closed environment within a laboratory setting are not different for older adult men and women who are independent in community mobility. When sitting in a chair with back support, older men and women had similar response times (Figure 1) for the baseline single-task VRT condition. The transition from sitting to standing can be assumed to provide a greater balance challenge but did not seem to increase the associated attentional demands of task performance on the basis of the observed differences in VRTs. There were no significant task and gender differences in sitting and standing VRTs. Given the participants' functional capacity based on walking velocity, measures of balance, and self-reported independence in community ambulation, the postural challenge posed by standing on a stable surface without challenge was not sufficient to increase the attentional demands of the task. However, the combinations of more challenging standing balance and cognitive tasks have been shown to increase the attentional demands of standing in older adults.62,63
When examining walking, older men, on average, had a faster VRT than older women; however, those differences did not reach the level of statistical significance. This finding indicates a similar capacity for the allocation of attention to the task of walking on a level surface for the study participants who were not disabled and had low fall risk and who reported being independent in community ambulation. Gender differences might be expected if there were significant differences seen in gait performance, balance, and mobility confidence, which could affect attentional allocation. While older men did reached significantly farther on the FRT, other measures of balance were different but not significantly better based on gender. Older men and women with a similar functional level do not differ in how much attention is required to walk on a level surface.
The results from the examination of between-task differences in VRT clearly indicate that walking had an associated cognitive cost for the study participants. When compared with sitting and standing, walking VRT was significantly longer for both older men and women (Figure 1). Thus, confirmation is provided for what has been previously reported in the literature by other authors who have used dual-task reaction time paradigms.64,65 The importance of the finding relates to potential impact of not having sufficient attentional resources to respond to other environmental stimuli that could contribute to a fall. While the current study was conducted in a laboratory setting, walking in a more open environment, such as in the community, is a more complex task that requires the acquisition of information from a variety of sources to guide ongoing motor actions.66,67 Tripping is a frequent source of falls in older adults.28,29,40,68,69 One plausible explanation is the failure to perceive an environmental feature as having the potential for causing instability or even a fall. Relative to younger adults, older adults frequently allocate greater attention to walking tasks that can lead to delays in responding to environmental features that can cause a loss of balance. Chen and colleagues70 suggest that a 50 or 100 milliseconds delay in responding to an obstacle appearing in the path of travel reduces the chance of successful negotiation. The destabilizing effects of having to complete one or more concurrent tasks while walking, such as talking or engaging in a cognitive task, when add to baseline level of attention required only to walk, may explain why tripping is a frequent cause of falls in older adults or the increased difficulty when walking in an environment containing multiple obstacles. A reduced capacity to direct and divide attention to perform multiple concurrent tasks is associated increased fall risk.3,13,71–73
There were no statistically significant differences in gait velocity when comparing men to women and between the single- and dual-task conditions. Older men in the study walked slower than older women. Gait velocity findings indicated that both groups maintained primary task performance, which was walking, when presented with the secondary dual-task stimulus. Altering walking performance to improve reaction time to the auditory stimulus can make the results difficult to interpret because of the switch in attentional focus.46,47,74 Given the single- and dual-task walking velocity findings, it is a reasonable assumption that VRT changes reflect the increased attentional demands of walking. The robustness of the finding underscores the importance the participants may have placed on walking safely. The participants could have adopted “a posture first strategy,” where attentional priority or focus is prudently shifted to walking to ensure stability.63,75
The application of the findings from this study is limited to community-dwelling older adults who are independent in ambulation. Given the expected level of function for someone residing in the community, there may not be significant differences in the attentional requirements of walking based on gender. More substantial differences based on gender may present when either examining groups of older adults with impairments and whose physiological level of function limit access to community or those who are frail or transitioning to frailty. These groups are more likely to fall while walking and physiological gender differences, such as strength, activity levels, body mass, or flexibility, may make the task of walking more difficult and therefore more attentionally demanding.76–78 Among frail older adults, increased attention during gait has been linked to increased fall risk and limitations in mobility.79–82 Recent work has also suggested a link between changes in executive function and attentional allocation for walking and falls in older adults.42,73,83
What merits additional investigation and cannot be ruled out as influencing how attention was allocated for the level walking task implemented in this study are changes in vision, altered somatosensory function, variations in physical activity levels, and possible early changes in executive function in the older adult group. These factors were not explored in the current study but can potentially influence gait performance and the level of attention that must be allocated during walking.42,73,76–78,83 While the participants were all, by self-report, independent in community ambulation, there could have been underlying mild changes in executive function that would have influenced the study outcome.
While dual-task probe reaction time paradigms have been shown to a valid indicator of attentional cost, exploring the effects of the secondary cognitive task on walking performance is also indicated as a future direction of study. A complimentary dual-task approach to what was implemented in this study involves an examination changes in walking performance arising from the concurrent and continuous performance of a cognitive or mental task while walking. The focus of this approach is on changes in walking, such as reductions in gait speed or increasing stride and stance variability, arising out of the concurrent performance of a cognitive task. This line of work has demonstrated that performing a concurrent cognitive task while walking leads to increased gait variability.11,12,84 Typical cognitive tasks include counting or spelling words backwards, and memory, or mental manipulations involving spatial areas of the brain. Older men and women may perform cognitive tasks differently, which could potentially lead to destabilizing gait alterations that are associated with falls and a different study outcome.
The study findings provide insight into age-specific attentional requirements of walking based on gender for nondisabled older adults. On the basis of the dual-task paradigm used, older men and women who are independent in community ambulation demonstrate a similar capacity to allocate attention when walking. The results of the study are consistent with previous reports in the literature indicating that walking is an attentional demanding task for older adults. Additional investigation exploring the capabilities of older adults who are more functionally limited is necessary to see how gender might influence the attentional requirements of walking.
1. Al-Yahya E, Dawes H, Smith L, Dennis A, Howells K, Cockburn J. Cognitive motor interference while walking: a systematic review and meta-analysis. Neurosci Biobehav Rev. 2011;35:715–728.
2. Lord S, Rochester L. Walking in the real world: concepts related to functional gait. N Z J Physiother. 2007;35:126–130.
3. Yogev-Seligmann G, Hausdorff JM, Giladi N. The role of executive function and attention in gait. Mov Disord. 2008;23:329–342; quiz 472.
4. Woollacott M, Shumway-Cook A. Attention and the control of posture and gait: a review of an emerging area of research. Gait Posture. 2002;16:1–14.
5. Stuss DT, Levine B. Adult clinical neuropsychology: lessons from studies of the frontal lobes. Annu Rev Psychol. 2002;53:401–433.
6. Chayer C, Freedman M. Frontal lobe functions. Curr Neurol Neurosci Rep. 2001;1:547–552.
7. Sarter M, Gehring WJ, Kozak R. More attention must be paid: the neurobiology of attentional effort. Brain Res Rev. 2006;51:145–160.
8. Abernethy B. Dual-task methodology and motor skills research: some applications and methodological constraints. J Hum Movem Stud. 1988;14:101–132.
9. Abernethy B, Summers J, Ford S. Issues in the measurement of attention. In: Duda JL, ed. Advances in Sport and Exercise Psychology Measurement. Morgantown, WV: Fitness Information Technology, Inc; 1998:173–193.
10. Wright DL, Kemp TL. The dual-task methodology and assessing the attentional demands of ambulation with walking devices. Phys Ther. 1992;72:306–312; discussion 313–305.
11. Hollman JH, Kovash FM, Kubik JJ, Linbo RA. Age-related differences in spatiotemporal markers of gait stability during dual task walking. Gait Posture. 2007;26:113–119.
12. Priest AW, Salamon KB, Hollman JH. Age-related differences in dual task walking: a cross sectional study. J Neuroeng Rehabil. 2008;5:29.
13. Srygley JM, Mirelman A, Herman T, Giladi N, Hausdorff JM. When does walking alter thinking? Age and task associated findings. Brain Res. 2009;1253:92–99.
14. Dubost V, Kressig RW, Gonthier R, et al. Relationships between dual-task related changes in stride velocity and stride time variability in healthy older adults. Hum Mov Sci. 2006;25:372–382.
15. Wellmon R, Pezzillo K, Eichhorn G, Lockhart W, Morris J. Changes in dual-task voice reaction time among elders who use assistive devices. J Geriatr Phys Ther. 2006;29:74–80.
16. Kemper S, Herman RE, Lian CH. The costs of doing two things at once for young and older adults: talking while walking, finger tapping, and ignoring speech or noise. Psychol Aging. 2003;18:181–192.
17. Montero-Odasso M, Casas A, Hansen KT, et al. Quantitative gait analysis under dual-task in older people with mild cognitive impairment: a reliability study. J Neuroeng Rehabil. 2009;6:35.
18. Barak Y, Wagenaar RC, Holt KG. Gait characteristics of elderly people with a history of falls: a dynamic approach. Phys Ther. 2006;86:1501–1510.
19. Nordin E, Moe-Nilssen R, Ramnemark A, Lundin-Olsson L. Changes in step-width during dual-task walking predicts falls. Gait Posture. 2010;32:92–97.
20. Springer S, Giladi N, Peretz C, Yogev G, Simon ES, Hausdorff JM. Dual-tasking effects on gait variability: the role of aging, falls, and executive function. Mov Disord. 2006;21:950–957.
21. Siu K-C, Chou L-S, Mayr U, Donkelaar Pv, Woollacott MH. Does inability to allocate attention contribute to balance constraints during gait in older adults? J Gerontol A Biol Sci Med Sci. 2008;63:1364–1369.
22. Ojha HA, Kern RW, Lin CH, Winstein CJ. Age affects the attentional demands of stair ambulation: evidence from a dual-task approach. Phys Ther. 2009;89:1080–1088.
23. Lundin-Olsson L, Nyberg L, Gustafson Y. “Stops walking when talking” as a predictor of falls in elderly people. Lancet. 1997;349:617.
24. Sparrow WA, Bradshaw EJ, Lamoureux E, Tirosh O. Ageing effects on the attention demands of walking. Hum Mov Sci. 2002;21:961–972.
25. Chen HC, Schultz AB, Ashton-Miller JA, Giordani B, Alexander NB, Guire KE. Stepping over obstacles: dividing attention impairs performance of old more than young adults. J Gerontol A Biol Sci Med Sci. 1996;51:M116–M122.
26. Talbot LA, Musiol RJ, Witham EK, Metter EJ. Falls in young, middle-aged and older community dwelling adults: perceived cause, environmental factors and injury. BMC Public Health. 2005;5:86.
27. Painter JA, Elliott SJ, Hudson S. Falls in community-dwelling adults aged 50 years and older: prevalence and contributing factors. J All Health. 2009;38: 201–207.
28. Tinetti ME, Speechley M, Ginter SF. Risk factors for falls among elderly persons living in the community. N Engl J Med. 1988;319:1701–1707.
29. Berg WP, Alessio HM, Mills EM, Tong C. Circumstances and consequences of falls in independent community-dwelling older adults. Age Ageing. 1997;26:261–268.
30. Sterling DA, O'Connor JA, Bonadies J. Geriatric falls: injury severity is high and disproportionate to mechanism. J Trauma. 2001;50:116–119.
31. Stalenhoef PA, Crebolder HFJM, Knottnerus JA, Van Der Horst FGEM. Incidence, risk factors and consequences of falls among elderly subjects living in the community. Eur J Public Health. 1997;7:328–334.
32. Stevens JA, Sogolow ED. Gender differences for non-fatal unintentional fall related injuries among older adults. Inj Prev. 2005;11:115–119.
33. Kiel DP, O'Sullivan P, Teno JM, Mor V. Health care utilization and functional status in the aged following a fall. Med Care. 1991;29:221–228.
34. Tinetti ME, Williams CS. Falls, injuries due to falls, and the risk of admission to a nursing home. N Engl J Med. 1997;337:1279–1284.
35. Alexander BH, Rivara FP, Wolf ME. The cost and frequency of hospitalization for fall-related injuries in older adults. Am J Public Health. 1992;82:1020–1023.
36. Schiller JS, Kramarow EA, Dey AN. Fall injury episodes among noninstitutionalized older adults: United States, 2001–2003. Adv Data. 2007:1–16.
37. Tinetti ME, Mendes de Leon CF, Doucette JT, Baker DI. Fear of falling and fall-related efficacy in relationship to functioning among community-living elders. J Gerontol. 1994;49:M140–M147.
38. Tennstedt S, Howland J, Lachman M, Peterson E, Kasten L, Jette A. A randomized, controlled trial of a group intervention to reduce fear of falling and associated activity restriction in older adults. J Gerontol B Psychol Sci Soc Sci. 1998;53:P384–P392.
39. Zijlstra GA, van Haastregt JC, van Eijk JT, van Rossum E, Stalenhoef PA, Kempen GI. Prevalence and correlates of fear of falling, and associated avoidance of activity in the general population of community-living older people. Age Ageing. 2007;36:304–309.
40. Campbell AJ, Borrie MJ, Spears GF, Jackson SL, Brown JS, Fitzgerald JL. Circumstances and consequences of falls experienced by a community population 70 years and over during a prospective study. Age Ageing. 1990;19:136–141.
41. Callisaya ML, Blizzard L, Schmidt MD, McGinley JL, Srikanth VK. Sex modifies the relationship between age and gait: a population-based study of older adults. J Gerontol A Biol Sci Med Sci. 2008;63:165–170.
42. de Bruin ED, Schmidt A. Walking behaviour of healthy elderly: attention should be paid. Behav Brain Funct. 2010;6:59.
43. Callisaya ML, Blizzard L, Schmidt MD, McGinley JL, Lord SR, Srikanth VK. A population-based study of sensorimotor factors affecting gait in older people. Age Ageing. 2009;38:290–295.
44. Lord SR, Ward JA, Williams P, Anstey KJ. Physiological factors associated with falls in older community-dwelling women. J Am Geriatr Soc. 1994;42:1110–1117.
45. Lord SR, Ward JA. Age-associated differences in sensori-motor function and balance in community dwelling women. Age Ageing. 1994;23:452–460.
46. Damos DL. Dual-task methodology: Some common problems. In: Damos DL, ed. Multiple-Task Performance. Bristol, PA: Taylor & Francis Inc; 1991.
47. Fisk AD, Schneider W, Derrick WL. A methodological assessment and evaluation of dual-task paradigms. Curr Psychol Res Rev. 1986–87;5:315–327.
48. Duncan PW, Weiner DK, Chandler J, Studenski S. Functional reach: a new clinical measure of balance. J Gerontol. 1990;45:M192–M197.
49. Weiner DK, Duncan PW, Chandler J, Studenski SA. Functional reach: a marker of physical frailty. J Am Geriatr Soc. 1992;40:203–207.
50. Mathias S, Nayak US, Isaacs B. Balance in elderly patients: the “get-up and go” test. Arch Phys Med Rehabil. 1986;67:387–389.
51. Podsiadlo D, Richardson S. The timed “Up & Go”: a test of basic functional mobility for frail elderly persons. J Am Geriatr Soc. 1991;39:142–148.
52. Myers AM, Powell LE, Maki BE, Holliday PJ, Brawley LR, Sherk W. Psychological indicators of balance confidence: relationship to actual and perceived abilities. J Gerontol A Biol Sci Med Sci. 1996;51:M37–M43.
53. Powell LE, Myers AM. The Activities-specific balance confidence (ABC) scale. J Gerontol A Biol Sci Med Sci. 1995;50A:M28–M34.
54. Salmoni A, Sullivan J, Starkes J. The attentional demands of movements: a critique of the probe technique. J Motor Behav. 1976;8:161–169.
55. Lusardi MM, Pellecchia GL, Schulman M. Functional performance in community living older adults. J Geriatr Phys Ther. 2003;26:14–22.
56. Pondal M, del Ser T. Normative data and determinants for the timed “up and go” test in a population-based sample of elderly individuals without gait disturbances. J Geriatr Phys Ther. 2008;31:57–63.
57. Shumway-Cook A, Brauer S, Woollacott M. Predicting the probability for falls in community-dwelling older adults using the Timed Up & Go Test. Phys Ther. 2000;80:896–903.
58. Lajoie Y, Gallagher SP. Predicting falls within the elderly community: comparison of postural sway, reaction time, the Berg balance scale and the Activities-specific Balance Confidence (ABC) scale for comparing fallers and non-fallers. Arch Gerontol Geriatr. 2004;38:11–26.
59. Myers AM, Fletcher PC, Myers AH, Sherk W. Discriminative and evaluative properties of the activities-specific confidence (ABC) scale. J Gerontol: Med Sci. 1998;53A:M287–M294.
60. Bohannon RW. Population representative gait speed and its determinants. J Geriatr Phys Ther. 2008;31:49–52.
61. Perera S, Mody SH, Woodman RC, Studenski SA. Meaningful change and responsiveness in common physical performance measures in older adults. J Am Geriatr Soc. 2006;54:743–749.
62. Brown LA, Shumway-Cook A, Woollacott MH. Attentional demands and postural recovery: the effects of aging. J Gerontol A Biol Sci Med Sci. 1999;54:M165–M171.
63. Shumway-Cook A, Woollacott M, Kerns KA, Baldwin M. The effects of two types of cognitive tasks on postural stability in older adults with and without a history of falls. J Gerontol A Biol Sci Med Sci. 1997;52:M232–M240.
64. Lajoie Y, Teasdale N, Bard C, Fleury M. Upright standing and gait: are there changes in attentional requirements related to normal aging? Exp Aging Res. 1996;22:185–198.
65. Lajoie Y, Teasdale N, Bard C, Fleury M. Attentional demands for static and dynamic equilibrium. Exp Brain Res. 1993;97:139–144.
66. Shumway-Cook A, Patla AE, Stewart A, Ferrucci L, Ciol MA, Guralnik JM. Environmental demands associated with community mobility in older adults with and without mobility disabilities. Phys Ther. 2002;82:670–681.
67. Patla AE. Mobility in complex environments: implications for clinical assessment and rehabilitation. J Neurol Phys Ther. 2001;25:82–90.
68. Blake AJ, Morgan K, Bendall MJ, et al. Falls by elderly people at home: prevalence and associated factors. Age Ageing. 1988;17:365–372.
69. Lord SR, Ward JA, Williams P, Anstey KJ. An epidemiological study of falls in older community-dwelling women: the Randwick falls and fractures study. Aust J Public Health. 1993;17:240–245.
70. Chen HC, Ashton-Miller JA, Alexander NB, Schultz AB. Effects of age and available response time on ability to step over an obstacle. J Gerontol. 1994;49:M227–M233.
71. Di Fabio RP, Zampieri C, Henke J, Olson K, Rickheim D, Russell M. Influence of elderly executive cognitive function on attention in the lower visual field during step initiation. Gerontology. 2005;51:94–107.
72. Hausdorff JM, Schweiger A, Herman T, Yogev-Seligmann G, Giladi N. Dual-task decrements in gait: contributing factors among healthy older adults. J Gerontol A Biol Sci Med Sci. 2008;63:1335–1343.
73. Herman T, Mirelman A, Giladi N, Schweiger A, Hausdorff JM. Executive control deficits as a prodrome to falls in healthy older adults: a prospective study linking thinking, walking, and falling. J Gerontol A Biol Sci Med Sci. 2010;65:1086–1092.
74. Pashler H, Johnston JC. Attentional limitations in dual-task performance. In: Pashler H, ed. Attention. East Sussex, UK: Psychology Press, Ltd.; 1998:155–189.
75. Bloem BR, Valkenburg VV, Slabbekoorn M, Willemsen MD. The multiple tasks test: development and normal strategies. Gait Posture. 2001;14:191–202.
76. Fone S, Lundgren-Lindquist B. Health status and functional capacity in a group of successfully ageing 65–85-year-olds. Disabil Rehabil. 2003;25:1044–1051.
77. Fiser WM, Hays NP, Rogers SC, et al. Energetics of walking in elderly people: factors related to gait speed. J Gerontol A Biol Sci Med Sci. 2010;65:1332–1337.
78. McKean KA, Landry SC, Hubley-Kozey CL, Dunbar MJ, Stanish WD, Deluzio KJ. Gender differences exist in osteoarthritic gait. Clin Biomech. 2007;22:400–409.
79. Beauchet O, Dubost V, Herrmann F, Rabilloud M, Gonthier R, Kressig RW. Relationship between dual-task related gait changes and intrinsic risk factors for falls among transitional frail older adults. Aging Clin Exp Res. 2005;17:270–275.
80. Beauchet O, Annweiler C, Dubost V, et al. Stops walking when talking: a predictor of falls in older adults? Eur J Neurol. 2009;16:786–795.
81. Lundin-Olsson L, Nyberg L, Gustafson Y. Attention, frailty, and falls: the effect of a manual task on basic mobility. J Am Geriatr Soc. 1998;46:758–761.
82. Beauchet O, Dubost V, Stierlam F, et al. [Influence of a specific cognitive task on spatial-temporal walking parameters in elderly frail individuals]. Presse Med. 2002;31:1117–1122.
83. van Iersel MB, Kessels RPC, Bloem BR, Verbeek ALM, Olde Rikkert MGM. Executive functions are associated with gait and balance in community-living elderly people. J Gerontol A Biol Sci Med Sci. 2008;63:1344–1349.
84. van Iersel MB, Ribbers H, Munneke M, Borm GF, Rikkert MG. The effect of cognitive dual tasks on balance during walking in physically fit elderly people. Arch Phys Med Rehabil. 2007;88:187–191.
aging; attention; dual task; women; men; older adult; walking