Postural stability in older adults with mild to moderate cognitive impairment and Alzheimer’s disease
Older adults with Alzheimer’s disease are at high risk of experiencing falls; their risk is double that of their healthy peers. The guidelines for achieving a fall risk reduction via an exercise-based intervention, for this population group, are unclear. Therefore, this thesis primarily aimed to develop, and to proof a concept of, an exercise-based intervention to improve postural stability as one means of reducing falls risk in older adults with mild to moderate cognitive impairment due to Alzheimer’s disease. A mixed methods study design was employed to achieve the study aim, via the following objectives: 1) to explore postural stability and the factors contributing to, or impacting on, postural instability in older adults with mild to moderate Alzheimer’s disease; 2) to identify and evaluate the psychometric properties of two commonly used clinical measures of postural stability (the Physiological Profile Approach and the Timed Up and Go test) for use in a proof of concept study of an exercise-based intervention; 3) to explore what older adults, with mild to moderate cognitive impairment due to Alzheimer’s disease, and their significant others, considered important to include in a sustainable and engaging exercise-based intervention; and 4) to proof a concept of the exercise-based intervention. The systematic review (n = 18 studies) suggested that older adults with mild to moderate Alzheimer’s disease have reduced static and dynamic postural stability compared to their peers without cognitive impairment. The instability was mostly associated with activities that require attentional demand; for instance, dual task activities and when visual input is reduced (for example, activities with eyes closed). A preliminary psychometric properties study (n = 13) suggested that falls risk screening, by the Physiological Profile Approach (moderate to good correlations rs = 0.604-0.745, p < 0.05; 33% sensitivity and 89% specificity) and the Timed Up and Go test (moderate to good correlations rs = 0.548-0.719, p < 0.05; 75% sensitivity and 67% specificity), might be appropriate to measure postural instability and predict falls risk in older adults with cognitive impairment for both research and clinical purposes. Both tests are feasible to be used in a community setting. Qualitative semi-structured interviews, conducted with 10 older adults with cognitive impairment and 7 support people, suggested that factors that might optimise delivery and engagement in exercise were: 1) having the choice of an individual- or a group-based exercise programme; 2) that exercise should be enjoyed and be pleasurable; 3) that exercises should stimulate brain activity; 4) that a support system is necessary; 5) that the programme should be of short duration; and 6) that the programme should include complex activities (e.g. dual task) that challenge their postural stability. These factors are however contingent of the understanding that while people living with cognitive impairment perceive that exercise is beneficial, as their cognition declines, a cyclic process of 1) awareness; 2) denial; 3) acceptance; and 4) coping strategies, influences decisions and degree of exercise engagement. Based on these three preliminary studies, “Balance Wise”, an exercise-based intervention, was designed and tested among older adults with memory loss (group-based n = 9, individual-based n = 1) in a feasibility case series. It was conducted for 30 minutes once a week. To measure falls risk and postural stability, the Physiological Profile Approach, the Timed Up and Go test [basic], the Timed Up and Go test [cognitive] and the Step Test were used. The Timed Up and Go test [cognitive] and the Step Test were added to test attentional demand in dual task activity and postural stability in standing respectively. “Balance Wise” was found to be feasible, accepted, practical and safe to be conducted among older adults with memory loss. Most participants chose to join the group-based option. Improvements in functional postural stability performance and dynamic stability, measured by the Timed Up and Go test [basic] (turning to non-dominant side p < 0.05, r = -0.79; turning to dominant side p < 0.05, r = -0.82 and the Step Test (p < 0.05, r = -0.81), respectively, were demonstrated. Dropout was 5 out of 15 participants. Adherence was from 10% to 100% of 10 sessions of interventions. Findings from systematic reviews (Chapter 4, study 1) found strong evidence for justifications of the need of an intervention study to improve postural stability and risks of falling. The findings derived from study 2 to 4 (Chapter 6 to 7) should be interpreted with caution because of their limitations such as small sample size and heterogeneous of the population being studied. Therefore it limits the applicability of the findings to be transferred for practise. The recruitment was challenging. This difficulty may be related to the cyclical process of denial and level of acceptance identified in the qualitative study. Even though, the thesis began by targeting older adults with mild to moderate cognitive impairment due to Alzheimer’s disease, participation by adults categorised in this way was found to be almost impossible to achieve. So, during the thesis, the target group evolved to become older adults with self-declared memory loss (with or without diagnostic evidence). The data synthesising and integration of the findings highlighted a few considerations for an intervention targeting older adults with memory loss: 1) support systems are required, not only for older adults with memory loss, but also for their support person; 2) the higher the complexity of the activity, the more difficulty older adults, with cognitive impairment, have to execute it; those who have more severe cognitive impairment need supported one-to-one based exercise; and 3) supported and uninfluenced decision making is required to protect the autonomy of older adult with cognitive impairment. Therefore, this thesis suggests the need for further exploration in the recruitment strategies of this vulnerable group of the population. For those who need one-to-one based exercise, the cost effectiveness of such an intervention will need to be evaluated in future studies. It is also recommended that physicians should use standardised tools to diagnose Alzheimer’s disease especially in the early phase of declining of cognitive function. Until these strategies are in place, researching postural stability to reduce risks of falling among older adults with Alzheimer’s disease in New Zealand is impossible due to the lack of specificity with such a broad terminology and spectrum of diseases presentation.
Advisor: Hale, Leigh; Perry, Meredith
Degree Name: Doctor of Philosophy
Degree Discipline: Physiotherapy
Publisher: University of Otago
Keywords: postural stability; older adults; cognitive impairment; cognitive decline; mild to moderate cognitive impairment; Alzheimer's disease; falls
Research Type: Thesis