As the population ages, health and social care services will come under pressure to provide services for older people with dementia as well as individuals with a wider range of other chronic diseases that are accompanied with physical impairments. In older adults with a neurodegenerative form of dementia, the on-going degeneration of brain tissue eventually leads to a loss of cognitive and physical functions (Telenius et al., 2015).
Growing evidence suggests that lifestyle factors have a significant impact on how well non-demented people age, and physical activity is one of the most important protective factors against cognitive decline. However, only a few studies have looked at the effect of physical activity in patients already suffering from Alzheimer’s dementia. Several small studies were able to demonstrate significant cognitive benefits for patients with Alzheimer’s dementia and also on quality of life and depression. Study limitations included sample size, lack of information on the use of psychotropic medication, nursing home setting, and discrepancies in contact time. Physical activity may induce neuroplastic changes in elders and thus exert a protective effect against cognitive decline; this may also occur in patients already suffering Alzheimer’s dementia, thus inducing improvement of clinical symptoms (Holthoff et al., 2015).
Physical activity is the movement of skeletal muscles, resulting in energy expenditure beyond the resting state. Physical activity, which includes exercise, is different from physical fitness. A person can be physically active without necessarily having good physical or aerobic fitness (Blondell et al., 2014).
Animal studies have demonstrated physical exercise effects on brain function over the lifespan. Activity in an enriched environment stimulates the brain on a physical and cognitive level and has the potential to affect brain plasticity. In humans, growing evidence suggests that lifestyle factors have a significant impact on how well non-demented people age, and physical activity is one of the most important protective factors against cognitive decline (Holthoff et al., 2015).
In older adults with mild cognitive impairment, emerging evidence suggests that exercise training has cognitive benefits. For example, a 24-week, home-based physical activity program improved performance on the Alzheimer Disease Assessment Scale-Cognitive Subscale in seniors with probable mild cognitive impairment. Additionally, a six-month aerobic training program improved selective attention and conflict resolution, processing speed, and verbal fluency in senior women with amnestic mild cognitive impairment (Nagamatsu et al., 2013).
Preventing Loss of Independence Through Exercise (PLIÉ)
Currently available dementia medications are associated with small improvements in cognitive and physical function but have many adverse effects and do not stop or slow the disease course. In addition, several new medications that initially appeared promising have recently failed in Phase III clinical trials. Therefore, it is critically important to study alternative approaches that allow individuals with dementia to maintain physical function, cognitive function, and quality of life to the greatest degree possible throughout the disease process (Barnes et al., 2015).
A growing body of evidence suggests that “conventional” exercise programs such as walking, resistance training, and seated exercises that focus on improving aerobic endurance, strength, balance, and flexibility have beneficial effects on physical function in individuals with cognitive impairment and dementia. A recent meta-analysis identified 16 randomized, controlled trials of conventional exercise interventions in 937 individuals with dementia, finding evidence that exercise improves the ability to perform basic activities of daily living such as eating, dressing, bathing, using the toilet, and transferring from bed to chair. However, the effects of conventional exercise on other important outcomes such as cognitive function, mood, behaviors, and quality of life were less consistent (Barnes et al., 2015).
A handful of recent studies suggest that “complementary/alternative” forms of exercise such as tai chi, yoga, and dance may be effective for improving these other outcomes. For example, studies have found that tai chi and yoga are associated with improvements in cognitive function and quality of life as well as physical function in older adults with and without cognitive impairment. In addition, dance-based exercise programs are associated with reductions in problematic behaviors and greater enjoyment in individuals with dementia. Taken together, these studies suggest that different types of exercise may offer different benefits, and that a program that combines different approaches may result in greater improvements across multiple domains. In addition, it may be important to incorporate recent evidence from physical and occupational therapy studies, which suggest that a personalized, goal-oriented approach can lead to better outcomes in other settings (Barnes et al., 2015).
At the University of California, San Francisco, a recent pilot study developed an integrative group exercise program for individuals with mild to moderate dementia. The program, called Preventing Loss of Independence through Exercise (PLIÉ), focused on training procedural memory* for basic functional movements (eg, sit-to-stand) while increasing mindful body awareness and facilitating social connection (Barnes et al., 2015).
*Procedural memory: a type of long-term memory that is responsible for storing information related to motor tasks such as walking, talking, cooking, and other learned tasks.
The results suggest that PLIÉ may be associated with improvements in physical performance, cognitive function, and quality of life in individuals with mild to moderate dementia, as well as reduced caregiver burden when compared with a usual care program that involved daily chair-based exercises. The magnitude of improvement observed with PLIÉ was substantially larger than what has been observed with currently approved dementia medications such as cholinesterase inhibitors and memantine and affects a broader range of outcomes (Barnes et al., 2015).
How Dementia Affects Balance and Gait
Balance is the ability to automatically and accurately maintain your center of mass or center of gravity over your base of support. This happens because multiple systems interact flawlessly and automatically—coordinating, weighing, and modulating information from both the environment and the central nervous system. The onset of dementia leads to changes in sensory and motor systems, affecting their ability to coordinate input.
Balance is a central function in most ADLs. Reduced balance increases the risk of falling, and falls and fractures are common among residents with dementia. People with dementia have a two-fold increased risk of falls compared with non-demented older adults. In nursing homes, one-third of all falls result in injuries, and people with dementia are more often injured compared to non-demented residents. Acute trauma with soft tissue damage or fractures, hospitalizations, and immobilization can lead to pressure sores, pneumonia, and fear of falling. Fear of falling itself is a risk factor for inactivity and can create a vicious circle. Improvements in balance may potentially reduce the risk of falling and increase mobility through increased confidence (Telenius et al., 2015).
Dementia impairs judgment, alters visual-spatial perception, and decreases the ability to recognize and avoid hazards. Dementia aggravates age-related changes in sensory perceptions, which adversely affects a person’s ability to adapt to changing environmental conditions (Eshkoor et al., 2014).
When cognitive impairment is mild, studies indicate that lower attention/executive function or memory function may lead to a decline in gait speed. Slow gait speed may indicate deficits in the cognitive-processing speed or in executive and memory functions. Cognitive processes related to prefrontal lobe function, such as attention and executive function, are associated with slower gait and gait instability. The decline in cognitive function in people with mild cognitive impairment is not uniform, but rather depends on the type of cognitive impairment (Doi et al., 2014).
Walking involves complex processes that require the ongoing integration of visual, proprioceptive, and vestibular sensory information. Joint positions must be controlled, the terrain a person is walking on has to be considered, and the environment the person is moving in needs to be observed. Walking often must be integrated with another activity, such as watching for traffic or using a mobile phone—this is referred to as dual-task walking (Beurskens & Bock, 2012).
As we age, walking speed and stride length decrease, while lateral sway increases. Some of these changes are compensatory and act to stabilize posture, while others are dysfunctional and increase the risk of falls. Changes in gait have been attributed to cognitive decline—the critical role of cognition is supported by the fact that age-related gait changes are more pronounced in people with cognitive impairment and that they are accentuated under dual-task conditions (Beurskens & Bock, 2012).
Age-related deficits in walking can be partly compensated for using cognitive workaround strategies, replacing automated sensorimotor processing with conscious effort. This is a good example of neural plasticity, as it shows that deficits arising in one part of the nervous system can be overcome by engaging another part of that system. Those with reduced cognitive capacity have only limited ability to compensate in this way; they are more likely to walk unsteadily and their risk of falling is higher (Beurskens & Bock, 2012).Back Next