Leisure activity participation and cognitive reserve
Over the past few years, there has been a growing interest in the study of factors that may protect us from developing Alzheimer's disease (AD). Among the list of protective factors, which includes education and diet, lifestyle and activity participation have been examined in several empirical studies. Verghese and his group on the Bronx Aging Study examined the influence of leisure activity participation on risk of developing AD (2003), and more recently on amnestic mild cognitive impairment (aMCI) (2006). A total of 488 cognitively healthy community-dwelling older adults (>75 years-old) were enrolled to the study in the early eighties and followed up over a 21-year span. Leisure activities were broadly classified into cognitive activities such as reading and writing and physical activities such as walking and exercise. The results of the aMCI study suggested that a one-point increase in the cognitive activity scale (i.e., high levels of participation in cognitive leisure activities) was associated with a 5% reduced risk of aMCI. The observed association remained robust after adjusting for potential confounders such as age, education, and baseline cognitive status. Participation in physical activity, however, was not associated with reduced risk of aMCI. Although some studies suggested that participation in physical activity was associated with reduced risk of AD, others reported a null effect (e.g., Fratiglioni et al., 2004).
Another research group of the Taub Institute for Research of Alzheimer's Disease and the Aging Brain extended the study of leisure activity participation to the Cognitive Reserve (CR) hypothesis. According to Stern (2002, 2006), CR suggests that the brain actively attempts to cope with brain damage by using pre-existing cognitive processing approaches or by enlisting compensatory approaches. The study of Scarmeas et al. (2003) examined whether pre-morbid activity participation might provide cognitive reserve in individuals with AD. Regional cerebral blood flow (CBF), as measured by position emission tomography (PET), was used as an indirect index of cerebral pathology in AD. The pre-morbid level of participation in physical, social, and cognitive activities was gauged in 9 subjects with AD and 16 cognitively intact subjects. The results indicated that there was an inverse relationship between activity score and CBF in subjects with AD. This inverse relationship remained significant when education and IQ were controlled as covariates. The findings lent further support to the CR hypothesis that the brain has become more tolerant of neurologically pathological changes in individuals with AD with a higher level of activity participation. Such tolerance allows for a delayed manifestation of AD, which only occurs when CR (compensatory networking) can no longer compensate for pathological neurological changes in AD brains. Although Scarmeas et al.'s study did not examine the individual effects of different types of activities on CR, the message is evident that a higher level of activity participation as a whole does increase our cognitive reserve.
Have you got the message? Quick! Go and develop a balanced lifestyle by including leisure activities in your life and health portfolio.
References
Fratiglioni, L., Paillard-Borg, S., Winblad, B. (2004). An active and socially integrated lifestyle in late life might protect against dementia. Lancet Neurology, 3, 343-353.
Scarmeas, N., Zarahn, E., Anderson, K. E., Habeck, C. G., Hilton, J., Flynn, J. et al. (2003). Association of life activities with cerebral blood flow in Alzheimer disease - Implications for the cognitive reserve hypothesis. Archives of Neurology, 60, 359-365.
Stern, Y. (2002). What is cognitive reserve? Theory and research application of the reserve concept. Journal of the International Neuropsychological Society, 8, 448-460.
Stern, Y. (2006). Cognitive reserve and Alzheimer disease. Alzheimer Diseases & Associate Disorders, 20, 112-117.
Verghese, J., Le Valley, A., Derby, C., Kuslansky, G., Katz, M., Hall, C. et al. (2006). Leisure activities and the risk of amnestic mild cognitive impairment in the elderly. Neurology, 66, 821-827.
Verghese, J., Lipton, R.B., Katz, M., Hall, C., Derby, C., Kuslansky et al. (2003). Leisure activities and the risk of dementia in the elderly. New England Journal of Medicine, 348, 2508-2516.
Issue Author:
Jenny Chung, PhD
Associate Professor, Department of Rehabilitation Sciences, The PolyU
TAG: Issue Jan