Helping the aging move better: Gait and mobility

You know that normal physiology changes as you age. Gait and mobility are altered with aging and changes in gait speed is contributed by impaired balance and stability, lower limb strength, fear of falling  and are related to functional decline and impaired quality of life(1). Multisensory aging is an important concept, as other systems ie., vision, hearing, can contribute to cognitive load and decline(2,3). In a study of gait speeds with women >75 years old, decreased cognitive function is associated with changes in gait speed(4). 

The Canadian Longitudinal Study on Aging showed that all cognitive measures were related to indices of mobility and the relationship often increased with age and brain health(5,6). Mobility limitations are heavily influenced by musculoskeletal mechanisms and higher brain centers especially  the motor control circuit of the dorsal basal ganglia are all involved(7). Since the musculoskeletal and brain systems are involved in mobility and they change with aging, then we should be looking at dual tasking, ie., combines walking with say mental tracking tasks to get a better appreciation of their interactions. In a study comparing young vs old adults dual tasking, it showed that the older group exhibited shorter times during single–leg stance and single-leg stance + cognitive task compared to younger group(8). Another study looked at cognitive function and postural control showed that postural control during visuospatial tasks and dementia may share neural substrates, specifically in memory-related regions(9). Also sex differences such as the effect of aging on the recruitment of muscles may explain overall increased instability and fall risk in older adults(10).

Both gait impairment and cognitive decline have been shown to constitute major fall risk factors. Those are two big domains and it would be beneficial for doctors/therapists working with the aging population to have more specific areas to access. Some results are beginning to show that in the cognitive domain, specifically the cortical executive system and its sub-domains – attention control, is linked with gait performance in the aging with high risks of falls(11).  Attention, sensory integration, and motor planning are the sub-domains of executive function associated with risk of falls through gait dysfunction(12). This information will begin to guide us as we begin the task or improving gait/mobility.

The feet are significant for gait/mobility. Their range of motion, flexibility, co-ordination and strength are all critical for the normal gait cycle. By assessing all the evidence based studies, conclusions can be drawn regarding which maybe the best approach to rehabilitate the gait/mobility cycle. Here are a few pertinent ones. This study evaluated the effects of resistive exercise (RE) with head rotation exercise (RE+HRE) on postural balance, lower limb muscle strength, and gait in older women. This is a dual task study. They are including head rotation exercises which is a powerful means of stimulating the vestibular system and restoring proper proprioceptive sense to the cervical muscles, brain stem and brain(cognitive/motor).Their findings suggest that RE+HRE can improve dynamic postural balance, lower limb strength, gait speed, and cadence in older women(13). 

Another study looking at the effectiveness of exercise intervention to control dynamic postural stability under unstable conditions in old adults(65-80), found that a training program focusing on exercising mechanisms of dynamic stability in unstable conditions ie., dual task, enhanced muscle strength as well as sensory information processing within the motor system during balance tasks, reducing the risk of falls in old adults(14). 

Lack of stability with gait/mobility is caused also by age-related neuromuscular changes in the hip abductor-adductor muscles leading to reduced performance, causing more medio-lateral sway contributing to balance issues and falls. When power training was introduced into the program, ie. strengthening the hip muscles, it was found to be more effective than strength training at eliciting improvements in maximal neuromuscular performance and enhanced medio-lateral balance recovery(15). 

Is there a reliable, easy and cost efficient way to measure body strength in the aging person? By reviewing the studies, stand-alone handgrip strength can be considered an umbrella assessment of the body systems that contribute to strength capacity, and a panoptic measurement of muscle strength that is representative of overall health status(16). Results in older adults found that muscle weakness of the leg extensors and forearm flexors is related to slow gait speed and is suitable for screening for muscle weakness in older adults(17). Handgrip strength can also be used in clinical settings for helping to determine the onset and progression of cognitive impairment(18).

Looking specifically at the musculoskeletal system and how it affects gait/mobility of older adults, recent studies show that tibialis anterior and vastus lateralis muscles deserve attention in physical training for gait. Specifically, tibialis anterior strength helps with obstacle crossing, and vastus lateralis assists knee extensors when aiming at improving gait speed and step length(19). But we should also condition the entire body, because the entire system functions as a unit, muscles affect the brain and visa versa. After a 12 week program of regular resistance exercises, the elderly group showed significant increases in the average upper body strength (58%), lower body strength (68%), and cognitive capacity (19%), these benefits bring enhanced life quality(20). For a complete neuro-musculoskeletal effect, adding plyometric training, which is safe training when done correctly, has potential for improving various performance, functional, and health-related outcomes in older persons(21). 

Balance training over a lifespan can improve vestibular function and decrease postural deterioration. This training effect can contribute to the physical capabilities of the person functioning as been 10 years younger(22). The balance training is inducing structural neuroplasticity in the human brain and to enhance cognitive functions. A 12-week study of balance training involving 19-65 year old subjects, found improved balance performance which correlated with the increase of precentral cortical thickness. This area is involved with visual and vestibular self-motion perception, spatial orienting and memory. Stimulating visual-vestibular pathways during self-motion might mediate beneficial effects of physical exercise on cognition(23).

Dance is multi functional, a great way to have fun and improve brain function. Dance practice integrates brain areas to improve neuroplasticity. In a systematic review, structural changes were found indicating increased hippocampal volume, gray matter volume in the left precentral, parahippocampal gyrus and white matter integrity. Functional changes included alterations in cognitive function such as significant improvement in memory, attention, body balance, psychosocial parameters and altered peripheral neurotrophic factor(24). Dance training promotes mental and physical well-being of senior citizens(25).

Here is the real potential of the dual-task program. A simple approach like walking and simultaneously performing a cognitive task, such as counting backwards from 100 by 3, in older adults, has been shown to effectively improve the normal gait cycle and for complex real world tasks (26, 27). Aging cause declines in executive functions and basic motor skills such as posture control, muscle strength, and balance performance. What would happen if we trained executive functions and exercise – resistance training? In a 12 week program of 68 year old males assessing balance performance and working memory, the results found that dual-task interventions improved both balance performance and working memory, but more so if cognitive performance was specifically trained along with resistance training(28).

The ability to walk and perform cognitive tasks simultaneously is a key aspect of daily life. When they are performance declines in these dual-tasks, it may be associated with early signs of neurodegenerative disease and increased risk of falls. Dual-task aerobic exercise and cognitive training intervention significantly improved cognitive performance during a dual-task walking test in healthy older adults.(29) Aerobic exercise is the next step up in physical demand, so of course we will see improvements.  

What would be the outcome if we added nutrition to aerobic exercise? There is a complex interplay between mobility and cognition in older adults. High-DHA multi-nutrient supplement improves habitual walking speed, verbal memory and psychomotor response latency in older women. Exercise also improves mobility and cognition in older adults, and n-3 fatty acids and exercise share a range of overlapping biological effects. The effects of the high-DHA multi-nutrient supplement and aerobic exercise on mobility and cognition in older women 60-70 years,   found significant improvements in self-reported emotional well-being with multi-nutrient and exercise groups v. placebo. The results suggest that the high-DHA multi-nutrient supplement produces similar improvements in cognitive function to aerobic exercise, offering the intriguing prospect that supplementation may be able to mitigate some of the effects of low physical activity on cognitive function in the elderly.(30 

The aging population needs to be educated that different types of exercise, along with dance, dual-task exercises, balance and cognitive training are all necessary, in addition to taking good supplements and eating properly to enjoy healthy living. 

References

1. Cruz-Jimenez M. Normal Changes in Gait and Mobility Problems in the Elderly. Phys Med Rehabil Clin N Am. 2017 Nov; 28(4): 713-725. 
2. Li K, et al. Cognitive Involvement in Balance, Gait and Dual-Tasking in Aging: A Focused Review From a Neuroscience of Aging Perspective. Neurol , 9, 913  2018. 
3. Morris R, et al. Gait and Cognition: Mapping the Global and Discrete Relationships in Ageing and Neurodegenerative Disease. Neurosci Biobehav Rev. 2016 May; 64: 326-45. 
4. Noh B, et al. Age-specific Differences in Gait Domains and Global Cognitive Function in Older Women: Gait Characteristics Based on Gait Speed Modification. PeerJ. 2020 Mar 16; 8: e8820. 
5. Demnitz N, et al.  Cognition and Mobility Show a Global Association in Middle- And Late-Adulthood: Analyses From the Canadian Longitudinal Study on Aging. Gait Posture . 2018 Jul; 64: 238-243. 
6. Jee L, et al. Association of Neurocognitive and Physical Function With Gait Speed in Midlife. JAMA Netw Open. 2019 Oct 2; 2(10): e1913123. 
7. Clark B, et al. The Aging Brain & the Dorsal Basal Ganglia: Implications for Age-Related Limitations of Mobility. Adv Geriatr Med Res. 2019; 1: e190008.
8. Bonetti L, et al. The Effect of Mental Tracking Task on Spatiotemporal Gait Parameters in Healthy Younger and Middle- And Older Aged Participants During Dual Tasking. Exp Brain Res. 2019 Dec; 237(12): 3123-3132. 
9. Sparto P, et al. Shared Neural Substrates of Cognitive Function and Postural Control in Older Adults. Alzheimers Dement . 2020 Apr; 16(4): 621-629. 
10. Bailey C, et al.  Sex-dependent and Sex-Independent Muscle Activation Patterns in Adult Gait as a Function of Age. Exp Gerontol. 2018 Sep;  110: 18. 
11. Fernandez N, et al. Age-related Changes in Attention Control and Their Relationship With Gait Performance in Older Adults With High Risk of Falls. Neuroimage. 2019 Apr 1; 189: 551-559. 
12. Zhang W, et al. Review of Gait, Cognition, and Fall Risks With Implications for Fall Prevention in Older Adults With Dementia. Dement Geriatr Cogn Disord. 2019; 48(1-2): 17-29. 
13. Choi W, et al. The effects of head rotation exercise on postural balance, muscle strength, and gait in older women. Women Health. 2019 Oct 6:1-14.
14. Haned A, et al. Exercises of Dynamic Stability Under Unstable Conditions Increase Muscle Strength and Balance Ability in the Elderly. Scand J Med Sci Sports . 2018 Mar. 28 (3): 961-971. 
15. Inacio M, et al. Low-dose hip abductor-adductor power training improves neuromechanical weight-transfer control during lateral balance recovery in older adults. Clin Biomech (Bristol, Avon). 2018 Dec;60:127-133. 
16. McGrath R, et al. What Are the Association Patterns Between Handgrip Strength and Adverse Health Conditions? A Topical Review. SAGE Open Med. 2020 Feb 28; 8: 2050312120910358. 
17. Fragala M, et al. Comparison of Handgrip and Leg Extension Strength in Predicting Slow Gait Speed in Older Adults. J Am Geriatr Soc . 2016 Jan; 64(1): 144-50. 
18. Shaughnessy K, et al. A Narrative Review of Handgrip Strength and Cognitive Functioning: Bringing a New Characteristic to Muscle Memory. J Alzheimers Dis. 2020; 73(4): 1265-1278. 
19. Guadagnin E, et al. Correlation Between Lower Limb Isometric Strength and Muscle Structure With Normal and Challenged Gait Performance in Older Adults. Gait Posture. 2019 Sep; 73:101-107. 
20. molarek A, et al. The Effects of Strength Training on Cognitive Performance in Elderly Women. Clin Interv Aging. 2016 Jun 1;11:749-54. 
21. Vetrovsky T, et al. The Efficacy and Safety of Lower-Limb Plyometric Training in Older Adults: A Systematic Review. Sports Med. 2019 Jan; 49(1): 113-131. 
22. Wiesmeier I, et al. Balance Training Enhances Vestibular Function and Reduces Overactive Proprioceptive Feedback in Elderly. Front Aging Neurosci . 2017 Aug 11; 9: 273. 
23. Rogge A, et al. Exercise-induced Neuroplasticity: Balance Training Increases Cortical Thickness in Visual and Vestibular Cortical Regions. Neuroimage. 2018 Oct 1; 179: 471-479. 
24. Teixeira-Machado L, et al. Dance for Neuroplasticity: A Descriptive Systematic Review. Neurosci Biobehav Rev. 2019 Jan; 96: 232-240. 
25. Zilidou V, et al. Functional Re-organization of Cortical Networks of Senior Citizens After a 24-Week Traditional Dance Program. Front Aging Neurosci. 2018 Dec 21; 10: 422.
26. Salazar-González B, et al. A physical-cognitive intervention to enhance gait speed  in older Mexican adults. Am J Health Promot. 2015 Nov-Dec; 30(2) :77-84. 
27. Ehlers D, et al. Effects of Gait Self-Efficacy and Lower-Extremity Physical Function on Dual-Task Performance in Older Adults. Biomed Res Int. 2017; 2017: 8570960. 
28. Norouzi E, et al. Dual-task Training on Cognition and Resistance Training Improved Both Balance and Working Memory in Older People. Phys Sportsmed. 2019 Nov; 47(4): 471-478. 
29. Raichlen D, et al. Effects of Simultaneous Cognitive and Aerobic Exercise Training on Dual-Task Walking Performance in Healthy Older Adults: Results From a Pilot Randomized Controlled Trial. BMC Geriatr. 2020 Mar 2; 20(1): 83. 
30. Fairbairn P, et al. Effects of a high-DHA Multi-Nutrient Supplement and Exercise on Mobility and Cognition in Older Women (MOBILE): A Randomised Semi-Blinded Placebo-Controlled Study. Br J Nutr. 2020 Feb 26; 1-10.

DR. DON FITZ-RITSON is a chiropractor and a rehab specialist. He was an Assistant Professor at CMCC. He published 17 papers and 3 chapters on chiropractic.He co-invented a laser and it received 7 Health Canada Approvals. He is focused on helping the aging population live better lives.