Balance, executive functions and falls in elderly with Alzheimer's disease (AD): A longitudinal study
Highlights
► The present study presents a numerical convection and dynamo model for the full sphere using a finite element method in the absence of the tangent cylinder without imposing any boundary conditions at the centre. ► It is found that sustaining the full sphere dynamo without the effect of tangent cylinder is more difficult than that in spherical shells. ► We show that the morphology of the magnetic field generated by the full sphere dynamo is largely dominated by non-dipolar components, suggesting the ancient geomagnetic field prior to the onset of inner-core crystallization would be quite different from the current field.
Introduction
AD is a progressive neurodegenerative process characterized by the decline of cognitive functions and functional activities, as well as behavioral alterations. Initially, the patient presents greater impairment of the recent memory and attention deficits (Stella, 2006, Yaari and Corey-Bloom, 2007). As the clinical condition evolves, we can observe the impairment of cognitive functions associated with the frontal lobe, mainly the executive functions, which regard the cognitive abilities involved in task planning, initiation, sequencing and organization, and also working memory and abstraction (Magila and Caramelli, 2000, Sjöbeck et al., 2010).
The decline of executive functions can make difficult simple tasks as those involved in personal hygiene, cooking, shopping, analyzing a situation, and even starting a certain action, directly affecting daily life activities (Sheridan and Hausdorff, 2007). It has also been widely reported in the literature that executive dysfunctions contribute to instability in gait and balance, and therefore to the increase in the number of falls in those patients (Sheridan and Hausdorff, 2007, Piermartiri et al., 2009).
Up to the present moment, there has been no consensus on the incidence of falls in the elderly with AD. It may range from 60% to 80% (Carvalho and Coutinho, 2002), being considered twice as high as the rate in the general population, which is 30% (Tinetti et al., 1988, Perracini and Ramos, 2002). Moreover, according to Imamura et al. (2000), elderly with AD are three times more prone to falls when compared with elderly without dementia.
Falls in the elderly population constitute one of the main clinical and public health issues due to the resulting general health complications; the increased risk of institutionalization, and the high care costs (Carvalho and Coutinho, 2002, Perracini and Ramos, 2002).
Consequently, it is necessary that strategies be created which might reduce the deterioration of the executive functions and the components of functional capacity in the elderly with AD. Some researches showed that physical activity can indeed reduce the decline of executive functions and the loss of functional capacity components, such as balance, in elderly patients with AD, thus helping reduce the fall risk in those individuals (Sheridan and Hausdorff, 2007, Arcoverde et al., 2008).
In a systematic review of the literature, Coelho et al. (2009) found eight studies that addressed systematized physical activity for the elderly with AD. Those studies pointed to improvement in some cognitive domains, such as executive functions, language and attention. The mechanisms through which physical activity provides benefits to cognitive functions might be explained, according to some authors (Antunes et al., 2006, Kashihara et al., 2009), by the increase in the supply of oxygen and other energy substrates during the regular practice of physical activity, which enhances the use of neurotransmitters and also provides the release of brain-derived neurotrophic factor (BNDF), a substance responsible for the process of neural regeneration.
Other authors, as Teri et al. (2003), observed improvement in the motor function of AD patients after three months of aerobic exercise and training of strength, balance and flexibility. The objective of this study was to analyze the possible effects of a program of physical activity with cognitive task on the executive functions, balance and frequency of falls in patients with AD. We also aimed at assessing whether there is a relation between executive functions, falls and balance.
Section snippets
The sample
The sample comprised 21 patients with a clinical diagnosis of AD, allocated to two groups, the TG and the CG. In the TG, 10 patients were submitted to a program of dual task physical activity. Their mean age was 78.3 ± 7.4 years and they had a mean score of 20.1 ± 4.6 points in the Mini-Mental State Examination (MMSE). In the CG, 11 patients with a mean age of 77.45 ± 6.9 years and a mean score of 19 ± 3.2 points in the MMSE did not participate in this program or in any other program of systematized
Results
As regards the evaluation of global cognitive functions by means of the MMSE, the ANOVA detected a significant interaction between groups and moments (p = 0.000479), confirming the effects of training on global cognitive functions. The TG presented a significantly better performance in the MMSE (p = 0.019) after participating in the intervention program (Fig. 1A).
We used two tests to evaluate executive functions: the FAB and CDT.
The ANOVA detected a significant interaction between groups and
Discussion
The patients who participated in a program of physical activity with cognitive task had a reduction in the number of falls. Even though this reduction was not significant, it is relevant, since elderly individuals with dementia tend to fall three times more often than their healthy counterparts (Imamura et al., 2000, Eriksson et al., 2008).
According to Tinetti et al. (1988), falls are events that might be related to an increase in the number of fractures; loss of mobility; being bedridden;
Conclusion
The elderly who participated in the program of physical activity achieved significant improvement in balance and executive functions, clearly showing the beneficial effects of physical activity on the decline of those variables. Even though the frequency of falls did not present a significant reduction, we observed a reduction in the number of falls in the patients who practiced physical activity.
Conflict of interests statement
None.
Acknowledgements
This study was sponsored by the PROEX–UNESP and Fundunesp. It was carried out at the Laboratory of Physical Activity and Aging (Laboratório de Atividade Física e Envelhecimento – LAFE), a research facility at the Universidade Estadual Paulista (UNESP), Rio Claro, São Paulo, Brazil.
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