Skip to main content Accessibility help

We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.

Close cookie message
×
Hostname: page-component-848d4c4894-xm8r8 Total loading time: 0 Render date: 2024-06-20T13:06:23.550Z Has data issue: false hasContentIssue false

38 - Mobility and Cognitive Decline in Older Adults with Cognitive Impairment

from Part V - Later Life and Interventions

Published online by Cambridge University Press:  28 May 2020

By
Caroline Ward ,
Emily Touchet ,
Elizabeth Marfeo  and
Nathan Ward
Edited by
Ayanna K. Thomas  and
Angela Gutchess
Ayanna K. Thomas
Affiliation:
Tufts University, Massachusetts
Angela Gutchess
Affiliation:
Brandeis University, Massachusetts
Get access

Summary

Physical and cognitive abilities are important for safe and successful participation in daily life, and much research has been done on how to preserve function in both kinds of ability throughout the aging process. Over the past twenty years these concepts were mostly studied separately; more recent research has led to new paradigms focused on the overlap in those brain mechanisms responsible for impairments in both mobility and cognition. A deeper understanding of this overlap could result in better interventions for maintaining the cognitive and physical health of older adults and a more comprehensive theoretical framework for understanding these complex, often integrated functions. This chapter (1) defines and describes cognitive and motor changes as part of the aging process, with a focus on individuals with dementia and mild cognitive impairment, (2) identifies methodologies used to understand the interrelationship between cognition and mobility, (3) describes what has been observed about this interrelationship, and (4) discusses research to date on potential interventions with suggestions for future interdisciplinary research.

Keywords

mild cognitive impairment (MCI)cognitive declinemobilitysingle taskdual taskmotoric cognitive risk syndromecapacity sharing modelcross-domain modelgaitpostural controlstatic postural controldynamic postural control
Type
Chapter
Information
The Cambridge Handbook of Cognitive Aging
A Life Course Perspective
 , pp. 701 - 716
Publisher: Cambridge University Press
Print publication year: 2020

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Agmon, M., Belza, B., Nguyen, H. Q., Logsdon, R. G., & Kelly, V. E. (2014). A systematic review of interventions conducted in clinical or community settings to improve dual-task postural control in older adults. Clinical Interventions in Aging, 9, 477–492. https://doi.org/10.2147/CIA.S54978Google Scholar
Al-Yahya, E., Dawes, H., Smith, L., et al. (2011). Cognitive motor interference when walking: A systematic review and meta-analysis. Neuroscience and Biobehavioral Reviews, 35(3), 715–728. https://doi.org/10.1016/j.neubiorev.2010.08.008Google Scholar
Allali, G., Ayers, E. I., & Verghese, J. (2016). Motoric cognitive risk syndrome subtypes and cognitive profiles. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 71(3), 378–384. https://doi.org/10.1093/gerona/glv092Google Scholar
Atkinson, H. H., Rosano, C., Simonsick, E. M., et al. (2007). Cognitive function, gait speed decline, and comorbidities: The health, aging and body composition study. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 62(8), 844–850. https://doi.org/10.1093/gerona/62.8.844CrossRefGoogle ScholarPubMed
Bandinelli, S., Pozzi, M., Lauretani, F., et al. (2006). Adding challenge to performance-based tests of walking: The Walking InCHIANTI Toolkit (WIT). American Journal of Physical Medicine and Rehabilitation, 85(12), 986–991. https://doi.org/10.1097/01.phm.0000233210.69400.d4Google Scholar
Blazer, D. G., Yaffe, K., & Liverman, C. T. (Eds.) (2015). Cognitive aging: Progress in understanding and opportunities for action. Washington: The National Academies Press.Google Scholar
Blondell, S. J., Hammersley-Mather, R., & Veerman, J. L. (2014). Does physical activity prevent cognitive decline and dementia? A systematic review and meta-analysis of longitudinal studies. BMC Public Health, 14(510). https://doi.org/10.1186/1471-2458-14-510Google Scholar
Buracchio, T., Dodge, H. H., Howieson, D., Wasserman, D., & Kaye, J. (2010). The trajectory of gait speed preceding mild cognitive impairment. Archives of Neurology, 67(8), 980–986. https://doi.org/10.1001/archneurol.2010.159Google Scholar
Camicioli, R., Howieson, D., Oken, B, Sexton, G., & Kaye, J. (1998). Motor slowing precedes cognitive impairment in the oldest old. Neurology, 50(5), 1496–1498. https://doi.org/10.1212/WNL.50.5.1496CrossRefGoogle ScholarPubMed
Centers for Disease Control and Prevention (2017). Healthy brain initiative. www.cdc.gov/aging/healthybrain/index.htmGoogle Scholar
Chertkow, H., Feldman, H. H., Jacova, C., & Massoud, F. (2013). Definitions of dementia and predementia states in Alzheimer’s disease and vascular cognitive impairment: Consensus from the Canadian conference on diagnosis of dementia. Alzheimer’s Research and Therapy, 5(Suppl. 1), S2. https://doi.org/10.1186/alzrt198CrossRefGoogle ScholarPubMed
Chhetri, J. K., Chan, P., Vellas, B., & Cesari, M. (2017). Motoric cognitive risk syndrome: Predictor of dementia and age-related negative outcomes. Frontiers in Medicine, 4, 166. https://doi.org/10.3389/fmed.2017.00166Google Scholar
Cohen, J. A., Verghese, J., & Zwerling, J. L. (2016). Cognition and gait in older people. Maturitas, 93, 73–77. https://doi.org/10.1016/j.maturitas.2016.05.005Google Scholar
de Andrade, L. P., Gobbi, L. T. B., Coelho, F. G. M., et al. (2013). Benefits of multimodal exercise intervention for postural control and frontal cognitive functions in individuals with Alzheimer’s disease: A controlled trial. Journal of the American Geriatrics Society, 61(11), 1919–1926. https://doi.org/10.1111/jgs.12531CrossRefGoogle ScholarPubMed
de Melo Borges, S., Radanovic, M., & Forlenza, O. V. (2012). Dual tasking and functional mobility in Alzheimer’s disease, mild cognitive impairment and normal aging: Correlation with executive function. Alzheimer’s and Dementia, 8(4), P131. https://doi.org/10.1016/j.jalz.2012.05.348Google Scholar
de Melo Borges, S., Radanovic, M., & Forlenza, O. V. (2015). Functional mobility in a divided attention task in older adults with cognitive impairment. Journal of Motor Behavior, 47(5), 378–385. https://doi.org/10.1080/00222895.2014.998331Google Scholar
de Melo Borges, S., Radanovic, M., & Forlenza, O. V. (2018). Correlation between functional mobility and cognitive performance in older adults with cognitive impairment. Aging, Neuropsychology, and Cognition, 25(1), 23–32. https://doi.org/10.1080/13825585.2016.1258035Google Scholar
Demnitz, N., Esser, P., Dawes, H., et al. (2016). A systematic review and meta-analysis of cross-sectional studies examining the relationship between mobility and cognition in healthy older adults. Gait and Posture, 50, 164–174. https://doi.org/10.1016/j.gaitpost.2016.08.028Google Scholar
Demnitz, N., Zsoldos, E., Mahmood, A., et al. (2017). Associations between mobility, cognition, and brain structure in healthy older adults. Frontiers in Aging Neuroscience, 9, 155. https://doi.org/10.3389/fnagi.2017.00155Google Scholar
Forte, R., Boreham, C. A. G., Leite, J. C., et al. (2013). Enhancing cognitive functioning in the elderly: Multicomponent vs resistance training. Clinical Interventions in Aging, 2013(8), 19–27. https://doi.org/10.2147/CIA.S36514CrossRefGoogle Scholar
Fritz, N., Cheek, F., & Nichols-Larsen, D. (2015). Motor-cognitive dual-task training in neurologic disorders: A systematic review. Journal of Neurologic Physical Therapy, 39(3), 142–153. https://doi.org/10.1097/NPT.0000000000000090CrossRefGoogle ScholarPubMed
Gandolfi, M., Geroin, C., Picelli, A., Smania, N., & Bartolo, M. (2018). Assessment of balance disorders. In Sandrini, G., Smania, N., Homberg, V., Pedrocchi, A., & Saltuari, L. (Eds.), Advanced technologies for the rehabilitation of gait and balance disorders (pp. 47–68). Cham, Switzerland: Springer.Google Scholar
Global Council on Brain Health (2016). The brain-body connection: GCBH recommendations on physical activity and brain health. https://doi.org/10.26419/pia.00013.001CrossRefGoogle Scholar
Hackett, R. A., Davies-Kershaw, H., Cadar, D., Orrell, M., & Steptoe, A. (2018). Walking speed, cognitive function, and dementia risk in the English longitudinal study of ageing. Journal of the American Geriatrics Society, 66(9), 1670–1675. https://doi.org/10.1111/jgs.15312Google Scholar
Harada, C. N., Natelson Love, M. C., & Triebel, K. L. (2013). Normal cognitive aging. Clinics in Geriatric Medicine, 29(4), 737–752. https://doi.org/10.1016/j.cger.2013.07.002CrossRefGoogle ScholarPubMed
Härlein, J., Dassen, T., Halfens, R. J. G., & Heinze, C. (2009). Fall risk factors in older people with dementia or cognitive impairment: A systematic review. Journal of Advanced Nursing, 65(5), 922–933. https://doi.org/10.1111/j.1365-2648.2008.04950.xGoogle Scholar
Hausdorff, J. M., Schweiger, A., Herman, T., Yogev-Seligmann, G., & Giladi, N. (2008). Dual-task decrements in gait: Contributing factors among healthy older adults. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 63(12), 1335–1343. https://doi.org/10.1093/gerona/63.12.1335Google Scholar
Hausdorff, J. M., Yogev, G., Springer, S., Simon, E. Y., & Giladi, N. (2005). Walking is more like catching than tapping: Gait in the elderly as a complex task. Experimental Brain Research, 164(4), 541–548. https://doi.org/10.1007/s00221-005-2280-3Google Scholar
Hollman, J. H., Kovash, F. M., Kubik, J. J., & Linbo, R. A. (2006). Age-related differences in spatio-temporal markers of gait stability during dual task walking. Gait and Posture, 26(1), 113–119. https://doi.org/10.1016/j.gaitpost.2006.08.005CrossRefGoogle Scholar
Holtzer, R., Verghese, J., Xue, X., & Lipton, R. B. (2006). Cognitive processes related to gait velocity: Results from the Einstein aging study. Neuropsychology, 20(2), 215–223. https://doi.org/10.1037/0894-4105.20.2.215CrossRefGoogle ScholarPubMed
Inzitari, M., Baldereschi, M., Di Carlo, A., et al. (2007). Impaired attention predicts motor performance decline in older community-dwellers with normal baseline mobility: Results from the Italian longitudinal study on aging (ILSA). Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 62(8), 837–843. https://doi.org/10.1093/gerona/62.8.837CrossRefGoogle ScholarPubMed
Jehu, D., Paquet, N., & Lajoie, Y. (2017). Balance and mobility training with or without concurrent cognitive training does not improve posture, but improve reaction time in healthy older adults. Gait and Posture, 52, 227–232. https://doi.org/10.1016/j.gaitpost.2016.12.006Google Scholar
Kao, C. C., Chiu, H. L., Liu, D., et al. (2018). Effect of interactive cognitive motor training on gait and balance among older adults: A randomized controlled trial. International Journal of Nursing Studies, 82, 121–128. https://doi.org/10.1016/J.IJNURSTU.2018.03.015Google Scholar
Knopman, D. S., & Petersen, R. C. (2014). Mild cognitive impairment and mild dementia: A clinical perspective. Mayo Clinic Proceedings, 89(10), 1452–1459. https://doi.org/10.1016/j.mayocp.2014.06.019Google Scholar
Laatar, R., Kachouri, H., Borji, R., Rebai, H., & Sahli, S. (2018). Combined physical-cognitive training enhances postural performances during daily life tasks in older adults. Experimental Gerontology, 107, 91–97. https://doi.org/10.1016/J.EXGER.2017.09.004Google Scholar
Lee, Y., Kim, J. H, Lee, K. J., Han, G., & Kim, J. L. (2006). Association of cognitive status with functional limitation and disability in older adults. Aging Clinical and Experimental Research, 17(1), 20–28. https://doi.org/10.1007/BF03337716Google Scholar
Maquet, D., Lekeu, F., Warzee, E., et al. (2010). Gait analysis in elderly adult patients with mild cognitive impairment and patients with mild Alzheimer’s disease: Simple versus dual task: A preliminary report. Clinical Physiology and Functional Imaging, 30(1), 51–56. https://doi.org/10.1111/j.1475-097X.2009.00903.xCrossRefGoogle ScholarPubMed
Marquis, S., Moore, M. M., Howieson, D. B., et al. (2002). Independent predictors of cognitive decline in healthy elderly persons. Neurology, 58(4), 601–606. https://doi.org/10.1001/archneur.59.4.601Google Scholar
McGuire, L. C., Ford, E. S., & Ajani, U. A. (2006). Cognitive functioning as a predictor of functional disability in later life. American Journal of Geriatric Psychiatry, 14(1), 36–42. https://doi.org/10.1097/01.JGP.0000192502.10692.D6CrossRefGoogle ScholarPubMed
Mielke, M. M., Roberts, R. O., Savica, R., et al. (2012). Assessing the temporal relationship between cognition and gait: Slow gait predicts cognitive decline in the Mayo Clinic study of aging. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 68(8), 929–937. https://doi.org/10.1093/gerona/gls256CrossRefGoogle ScholarPubMed
Montero-Odasso, M., Almeida, Q. J., Bherer, L., et al. (2018). Consensus on shared measures of mobility and cognition: From the Canadian Consortium on Neurodegeneration in Aging (CCNA). Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 74(6), 897–909. https://doi.org/10.1093/gerona/gly148Google Scholar
Montero-Odasso, M., Bherer, L., Studenski, S., et al. (2015). Mobility and cognition in seniors. Report from the 2008 Institute of Aging (CIHR) mobility and cognition workshop. Canadian Geriatrics Journal, 18(3), 159–167. https://doi.org/10.5770/cgj.18.188Google Scholar
Montero-Odasso, M., Islam, A., Anton-Rodrigo, I., et al. (2015). Cognition predicts frailty status: Results from the “Gait & Brain Study.” Gerontologist, 55(S2), 570. https://doi.org/10.1093/geront/gnv281.04Google Scholar
Montero-Odasso, M., & Speechley, M. (2018). Falls in cognitively impaired older adults: Implications for risk assessment and prevention. Journal of the American Geriatrics Society, 66(2), 367–375. https://doi.org/10.1111/jgs.15219Google Scholar
Montero-Odasso, M., Verghese, J., Beauchet, O., & Hausdorrf, J. M. (2012). Gait and cognition: A complementary approach to understanding brain function and the risk of falling. Journal of the American Geriatrics Society, 60(11), 2127–2136. https://doi.org/10.1111/j.1532-5415.2012.04209.xGoogle Scholar
Morris, R., Lord, S., Bunce, J., Burn, D., & Rochester, L. (2016). Gait and cognition: Mapping the global and discrete relationships in ageing and neurodegenerative disease. Neuroscience and Behavioral Reviews, 64, 326–345. https://doi.org/10.1016/j.neubiorev.2016.02.012Google Scholar
Musich, S., Wang, S. S., Ruiz, J., Hawkins, K., & Wicker, E. (2018). The impact of mobility limitations on health outcomes among older adults. Geriatric Nursing, 39(2), 162–169. https://doi.org/10.1016/j.gerinurse.2017.08.002Google Scholar
Nardone, A., & Turcato, A. M. (2018). An overview of the physiology and pathophysiology of postural control. In Sandrini, G., Homberg, V., Saltuari, L., Smania, N., & Pedrocchi, A. (Eds.), Advanced technologies for the rehabilitation of gait and balance disorders (pp. 3–28). Cham, Switzerland: Springer International Publishing.Google Scholar
National Institute on Aging (2017). What is mild cognitive impairment? www.nia.nih.gov/health/what-mild-cognitive-impairmentGoogle Scholar
Panzer, V. P., Wakefield, D. B., Hall, C. B., & Wolfson, L. I. (2011). Mobility assessment: Sensitivity and specificity of measurement sets in older adults. Archives of Physical Medicine and Rehabilitation, 92(6), 905–912. https://doi.org/10.1016/j.apmr.2011.01.004Google Scholar
Persad, C. C., Jones, J. L., Ashton-Miller, J. A., Alexander, N. B., & Giordani, B. (2008). Executive function and gait in older adults with cognitive impairment. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 63(12), 1350–1355. https://doi.org/10.1093/gerona/63.12.1350Google Scholar
Powell, L. E., & Myers, A. M. (1995). The Activities-Specific Balance Confidence (ABC) Scale. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 50(1), M28–M34. https://doi.org/10.1093/gerona/50A.1.M28Google Scholar
Rankin, J. K., Woollacott, M. H., Shumway-Cook, A., & Brown, L. A. (2000). Cognitive influence on postural stability: A neuromuscular analysis in young and older adults. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 55(3), M112–M119. https://doi.org/10.1093/gerona/55.3.M112Google Scholar
Rantakokko, M., Portegijs, E., Viljanen, A., Iwarsson, S., & Rantanen, T. (2013). Life-space mobility and quality of life in community-dwelling older people. Journal of the American Geriatrics Society, 61(10), 1830–1832. https://doi.org/10.1111/jgs.12473Google Scholar
Ross, L. A., Schmidt, E. L., & Ball, K. (2013). Interventions to maintain mobility: What works? Accident Analysis and Prevention, 61, 167–196. https://doi.org/10.1016/j.aap.2012.09.027Google Scholar
Royall, D. R., Palmer, R., Chiodo, L. K., & Polk, M. J. (2004). Declining executive control in normal aging predicts change in functional status: the Freedom House Study. Journal of the American Geriatrics Society, 52(3), 346–352. https://doi.org/10.1111/j.1532-5415.2004.52104.xGoogle Scholar
Salzman, B. (2010). Gait and balance disorders in older adults. American Family Physician, 82(1), 61–68. www.aafp.org/afp/2010/0701/p61.htmlGoogle ScholarPubMed
Satariano, W. A., Guralnik, J. M., Jackson, R. J., et al. (2012). Mobility and aging: New directions for public health action. American Journal of Public Health, 102(8), 1508–1515. https://doi.org/10.2105/AJPH.2011.300631Google Scholar
Sherrington, C., Whitney, J. C., Lord, S. R., et al. (2008). Effective exercise for the prevention of falls: A systematic review and meta-analysis. Journal of the American Geriatrics Society, 56(12), 2234–2243. https://doi.org/10.1111/j.1532-5415.2008.02014.xCrossRefGoogle Scholar
Shumway-Cook, A., & Woollacott, M. (2000). Attentional demands and postural control: The effect of sensory context. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 55(1), M10–M16. https://doi.org/10.1093/gerona/55.1.M10Google Scholar
Smith-Ray, R. L., Hughes, S. L., Prohaska, T. R., et al. (2013). Impact of cognitive training on balance and gait in older adults. Journals of Gerontology, Series B: Psychological Sciences and Social Sciences, 70(3), 357–366. https://doi.org/10.1093/geronb/gbt097Google Scholar
Springer, S., Giladi, N., Peretz, C., et al. (2006). Dual-tasking effects on gait variability: The role of aging, falls, and executive function. Movement Disorders, 21(7), 950–957. https://doi.org/10.1002/mds.20848Google Scholar
Srygley, J. M., Mirelman, A., Herman, T., Giladi, N., & Hausdorff, J. M. (2009). When does walking alter thinking? Age and task related findings. Brain Research, 1253, 92–99. https://doi.org/10.1016/j.brainres.2008.11.067Google Scholar
Steinmetz, J., & Federspiel, C. (2014). The effects of cognitive training on gait speed and stride variability in older adults: Findings from a pilot study. Aging Clinical and Experimental Research, 26(6), 635–643. https://doi.org/10.1007/s40520-014-0228-9Google Scholar
Sudarsky, L. (2001). Neurologic disorders of gait. Current Neurology and Neuroscience Reports, 1(4), 350–356. https://doi.org/10.1007/s11910-001-0089-4Google Scholar
Valkanova, V., & Ebmeier, K. P. (2017). What can gait tell us about dementia? Review of epidemiological and neuropsychological evidence. Gait and Posture, 53, 215–223. https://doi.org/10.1016/j.gaitpost.2017.01.024Google Scholar
Verbrugge, L. M., & Jette, A. M. (1994). The disablement process. Social Science and Medicine, 38(1), 1–14. https://doi.org/10.1016/0277-9536(94)90294-1Google Scholar
Verghese, J., Lipton, R. B., Hall, C. B., et al. (2002). Abnormality of gait as a predictor of non-Alzheimer’s dementia. New England Journal of Medicine, 347(22), 1761–1768. https://doi.org/10.1056/NEJMoa020441Google Scholar
Verghese, J., Mahoney, J., Ambrose, A. F., Wang, C., & Holtzer, R. (2010). Effect of cognitive remediation on gait in sedentary seniors. Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 65(12), 1338–1343. http://dx.doi.org/10.1093/gerona/glq127Google Scholar
Verghese, J., Wang, C., Lipton, R. B., Holtzer, R., & Xue, X. (2007). Quantitative gait dysfunction and risk of cognitive decline and dementia. Journal of Neurology, Neuroscience, and Psychiatry, 78, 929–935. http://doi.org/10.1136/jnnp.2006.106914Google Scholar
Verghese, J., Wang, C., Lipton, R. B., Holtzer, R. (2013). Motoric cognitive risk syndrome and the risk of dementia. (2013). Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 68(4), 412–418. https://doi.org/10.1093/gerona/gls191CrossRefGoogle ScholarPubMed
Waite, L. M., Grayson, D. A., Piguest, O., et al. (2005). Gait slowing as a predictor of incident dementia: 6-year longitudinal data from the Sydney Older Persons Study. Journal of the Neurological Sciences, 229, 89–93. https://doi.org/10.1016/j.jns.2004.11.009Google Scholar
Webber, S. C., Porter, M. M., & Menec, V. H. (2010). Mobility in older adults: A comprehensive framework. Gerontologist, 50(4), 443–450. https://doi.org/10.1093/geront/gnq013Google Scholar
Wollesen, B., Voelcker-Rehage, C., Regenbrecht, T., & Mattes, K. (2016). Influence of a visual–verbal Stroop test on standing and walking performance of older adults. Neuroscience, 318(24), 166–177. https://doi.org/10.1016/j.neuroscience.2016.01.031Google Scholar
Woollacott, M., & Shumway-Cook, A. (2002). Attention and the control of posture and gait: A review of an emerging area of research. Gait and Posture, 16(1), 1–14. https://doi.org/10.1016/S0966-6362(01)00156-4Google Scholar
Yogev-Seligmann, G., Hausdorff, J. M., & Giladi, N. (2008). The role of executive function and attention in gait. Movement Disorders, 23(3), 329–342. https://doi.org/10.1002/mds.21720Google Scholar

Save book to Kindle

To save this book to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

Available formats
×

Save book to Dropbox

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.

Available formats
×

Save book to Google Drive

To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.

Available formats
×