Linkedin version of systematic review
- 1. Physical activity on improving cognitive function in Alzheimer’s disease: A Systematic Review (Attempt) Chiew Keong John, Ng Jun Quan Last update: 16 July 2019 Introduction Alzheimer’s disease (AD) is a neurodegenerative brain disorder that progressively decreases cognitive function, with symptoms including memory difficulties, language dysfunction, disorientation, and mood swings. It is the leading cause of dementia among older adults in the world. (1) Severe AD often causes complications such as immobility, malnutrition and even death, with pneumonia identified as the most common cause of death among elderly patients with AD. (2) With life expectancy trends on the rise, this not only puts the increasing numbers of elderly people in ageing populations risk of developing dementia, but the long duration of illness before death contributes significantly to the public health impact because much of that time is spent in a state of disability and dependence. With the worldwide economic cost estimated to be US$818 billion in 2015, and projected to increase to become more than a trillion dollars within the decade, dementia is far from a small issue. (3) The current underlying principle behind pharmacologic treatment of AD is the management of symptoms and is unable to effectively halt or slow down the deterioration of neurons and cognitive function, largely due to the gaps of knowledge about the precise bio- molecular pathophysiology of AD. (4) In recent years, non-pharmacologic therapies have often been used in adjunct with medication to treat patients with AD, with the aim of improving physical ability, cognitive behavioural symptoms and overall quality of life. Research into employing exercise programs to increase physical activity as a form of non- pharmacologic therapy seems to have promising results. Multiple studies encompassing various types and intensities of physical activity suggest that exercise can have beneficial effects on cognitive function, physical ability and ability to perform activities of daily living (ADLs). (5)(6)(7) Aerobic exercise refers to the type of moderate intensity physical activity that can be sustained for more than just a few minutes, and differs from anaerobic exercise that is performed at an intensity sustained for only a few moments. (8) Previous reviews have focused on physical activity as a form of non-pharmacological therapy, but did not specifically focus on aerobic exercise as an exercise modality. Further research is thus required to determine the efficacy of aerobic exercise on improving cognitive function in patients with AD. Significance to local context Locally, according to a study led by the Institute of Mental Health in 2015, one in 10 people aged 60 and above may have dementia. This translates to almost 82,000 people in 2018, with the number expected to continue rising. In terms of economical costs, an
- 2. estimated S$2.8 billion was spent in 2015, with this figure expected to rise above S$6 billion by 2030. (9) Thus great emphasis has to be placed on improving methods of diagnosis, interventions and holistic support of AD. As such, this systematic review aims to assess the effectiveness of physical exercise as a form of intervention in improving cognitive function in patients with AD. ResearchQuestion This review seeks to establish, through the available literature, what is best practice for smoking cessation. The specific review question to be addressed are: 1) How effective is aerobic exercise in improving cognitive function in existing AD patients? Inclusion Criteria Type of Participants: This review will consider all studies that involve human subjects of ages 50 and older who are clinically diagnosis with Alzheimer’s Disease and have the physical capability to engage in moderate levels of physical activity. Types of Interventions: Interventions of interest included those that performed specifically aerobic training for a period of 3 weeks or more. Types of Outcome Measures: The primary outcome measure of interest is cognitive function encompassing any improvements in reasoning, memory, attention and language. Types of Studies: The review considered all studies evaluating the effectiveness or efficacy of interventions relating to improvement of cognitive function through aerobic exercises. In the absence of this type of studies, those that evaluate a combination of aerobic exercises with flexibility and balance will also be considered. Search Strategy The search strategy will be designed to access published materials and comprises of three stages: 1) A limited search of Web of Science and PubMed to identify relevant keywords contained in the title, abstract and subject descriptors. 2) Terms identified in this way, and the synonyms used by respective databases, will be used in an extensive search of the literature. 3) Reference lists and bibliographies of the articles collected from those identified in stage two above will be searched. The initial search terms will be ‘exercise’, ‘cognitive’ and ‘Alzheimer’. Full copies of articles identified by the search, and considered to meet the inclusion criteria, based on their title, abstract and subject descriptors, will be obtained for data synthesis. Articles identified through reference list and bibliographic searches will also be considered for data collection based on their title. Results of the Review Table 1 outlines the selected characteristics of the 13 studies included in the review. They were divided into 3 categories based on the type of exercises performed: (a) aerobic exercise, (b) aerobic exercise accompanied with flexibility or balance training, (c) walking program. 9 studies introduced aerobic exercises to improve cognitive function in Alzheimer patients. These studies engaged their patients in a moderate to high intensity cardiovascular aerobic exercise that aimed to
- 3. reach 65-80% of their maximal heart rate. These exercise sessions were performed 3 times a week for a period between 12-16 weeks. Hernandaz et al., unlike the other studies which used treadmill, bicycles or cross trainers, performed aerobic exercise through dance routines, circuit training as well as motor developmental exercises. These studies used the Mini Mental State Exam (MMSE) to evaluate cognitive function and all 9 studies in this review showed improvements in their MMSE scores after the intervention of aerobic exercise. Aerobic exercise coupled with flexibility and balance training was the second type of aerobic exercise intervention used to improve cognitive function in Alzheimer patients. These sessions comprise respiratory exercises, static and dynamic balance training, gait circuits with and without obstacles, and stimulation of activities of daily living and of fine motor coordination and balance. There are also sessions of cognitive stimulation which include reminiscence sessions, and exercises to improve attention, verbal fluency, and general recognition. Patients from Arcoverde et al. showed that physical and cognitive stimulation in patients with AD may contribute to a less aggressive progression of the cognitive and functional status as compared to sedentary AD patients. Two studies introduced therapeutic interventions using a walking program. The study done by Venturelli et al. showed that cognitive levels, evaluated by the MMSE test, remained unchanged during the walking program with no significant differences for the Walking Group, while the control group showed a significant decrease in cognitive functions after 6 months. The temporary stabilization of progressive cognitive dysfunctions shown in the Walking Group could be attributed to improvements in blood circulation in the brain and changes in neurotransmitter synthesis stimulated by the exercise sessions. In terms of target groups, all our studies (13) focused on general adults 50 years and older that were clinically diagnosed with Alzheimer’s and can perform moderate to high intensity physical activity. 6 out of the 12 studies used a Randomized Control Trial to perform their experiments whilst the rest did a Cross Sectional Study or Single Group Repeated Measure Design. The most popular (7) cognitive measurement test was the Mini Mental State Examination (MMSE) but other measures include Symbol Digit Modalities Test (SDMT), Number Sequencing, Verbal Test and MOC
- 5. Moving forward from this research Further research into biomolecular mechanisms of dementia, methods of diagnosis and intervention to improve outcomes. Further research into intensity of aerobic exercise needed o Moderate to higher intensity aerobic exercise suggest more promising results in improving cognitive function, as compared to walking program Smart homes – equipped with sensors, video cameras and other ambient assisted living technologies o Gathering data on night-time wandering, falls, physical activity o Monitor progression of dementia and helps clinician evaluate changing needs of patient o Types of sensors in development include: leak and spill detectors, glass break detectors, door and window sensors, voice activation sensors, gait monitors, fall detectors, caregiver alarms Orthotics – to aid with cognitive, functional or physiological deficits o Memory aids devices in the from of glasses, clothing badges o Navigation devices based on standard routes, and corrects navigational errors and visuospatial deficits
- 6. Bibliography 1. https://www.who.int/en/news-room/fact-sheets/detail/dementia 2. https://www.ncbi.nlm.nih.gov/pubmed/19170740 3. https://www.alz.co.uk/research/WorldAlzheimerReport2015.pdf 4. https://www.alz.org/media/Documents/alzheimers-facts-and-figures-2019-r.pdf 5. Palleschi L, Vetta F, Gennaro ED, Idone G, SottosantiG, Gianni W, et al. Effect of aerobic training on the cognitive performance of elderly patients with senile dementia of alzheimer type. Archives of Gerontology and Geriatrics 1996;22:47–50. doi:10.1016/0167-4943(96)86912-3. 6. Venturelli M, Scarsini R, Schena F. Six-Month Walking Program Changes Cognitive and ADL Performance in Patients With Alzheimer. American Journal of Alzheimers Disease & Other Dementias 2011;26:381–8. doi:10.1177/1533317511418956. 7. Borges-Machado F, Ribeiro Ó, Sampaio A, Marques-Aleixo I, Meireles J, Carvalho J. Feasibility and Impact of a Multicomponent Exercise Intervention in Patients With Alzheimer’s Disease: A Pilot Study. American Journal of Alzheimers Disease & Other Dementias® 2018;34:95–103. doi:10.1177/1533317518813555. 8. https://www.emedicinehealth.com/aerobic_exercise/article_em.htm 9. https://alz.org.sg/dementia/singapore/