Exercise as it relates to Disease/How exercise can improve the quality of life of those who suffer from cognitive impairment

This is an analysis of the Meta analysis:The Effects of Exercise Training on Elderly Persons With Cognitive Impairment and Dementia by Heyn et al (2004)



What is the background to this research?
Dementia is a general term referring to a decline in mental ability, that when severe enough can interfere with daily life. This can include memory disorders, personality changes and impaired reasoning. Dementia can be in many forms such as Alzheimer's disease, Vascular dementia, Parkinson's disease, Frontal Temporal Lobar Degeneration (FTLD), Huntington's disease, Alcohol related dementia (Korsakoff's syndrome) and Creutzfeldt-Jacob disease. Whereas each type of dementia comes with its own specific symptoms, at least two of the following core mental functions must be significantly impaired to be considered dementia;
 * Memory
 * Communication and language
 * Ability to focus and pay attention
 * Reasoning and judgement
 * Visual perception

It is estimated around 46.8 million people worldwide suffer from some form of dementia as of 2015. This number is set to double every 20 years, reaching 74.7 million in 2030 and 131.5 million in 2050. For a disease that is affecting so many people worldwide with no cure close to being discovered, it is important to establish preventative methods that have the potential to improve these individuals quality of life.

Where is the research from?
This research was conducted over three locations in Galveston, Texas, USA
 * School of Allied Health Sciences, Division of Rehabilitation Sciences, Galveston, TX, USA
 * Sealy Center on Aging, University of Texas Medical Branch, Galveston, TX, USA
 * Department of Occupational Therapy, Transitional Learning Center, Galveston, TX, USA

What kind of research was this?
This article was a Meta-Analysis, which is a statistical technique for combining the findings of independent studies to come to an overall conclusion. For this Meta-Analysis a total of 30 studies with with an overall 2020 subjects were identified (1023 Treatment group & 997 control group)

What did the research involve?
The research involved collectively bringing together as many studies on the topic of exercise and the effects it has on individuals suffering from cognitive impairment for further analyses. To identify which articles to choose, a search was conducted on all published articles and non published manuscripts from 1970 to 2003. An extensive Manual search along with a computer aided search was conducted using the following databases; PubMed, CINAHL, MEDLINE, Dissertation Abstracts International, Ageline, Sport Discuss (SIR/CDC), PsycINFO, Cochrane Register, PEDro, Educational Resources Information Centre, PsycLIT.

Studies were identified using key search words electronically and through manual searches. Key search words included; physical activity, physical therapy, exercise, fitness, rehabilitation, aerobic, strength, flexibility, functional performance, activities of daily living, behaviour, and cognition. These key words were combined with the following words: aged, ageing, older, elderly, adult, nursing home residents, geriatric, psychiatric, mental, dementia, Alzheimer’s disease, cognitive impairment, memory impairment, mild cognitive impairment, and organic brain disorder.

This method gathered a mass of studies so a criteria for exclusion was developed, no study was used if;
 * It was not published in English
 * Did not contain enough statistical information to compute an effect size (ES)
 * The outcomes did not involve physical fitness, function, behaviour or cognitive function
 * Studies with small sample size, 5< were excluded

This method yielded over 300 articles and it wasn't until individually reading each article and applying the *criteria for inclusion that they managed to find 30 eligible studies.

Criteria for inclusion, Page No. 1695

What were the basic results?
The results concluded that exercise does have positive treatment effects in older patients with cognitive impairment. The result suggest a large to medium treatment effect for health related physical fitness components, such as; Cardiovascular Fitness, Body Composition, Flexibility, Muscular strength and Muscular endurance. The study also identified a medium treatment effect for combined physical, cognitive, functional and behavioural outcomes.

How did the researchers interpret the results?
To identify how efficient one study was they chose a quantitative method of review proposed by Glass that involves an estimation of a populations effect size (ES) that is generated from individual studies. A summary effect size (SES) is then calculated from individual ES values, to decide whether a SES was statistically significant a fixed effects model was used. Using Hedges equation each individual studies ES was calculated by dividing the difference between the experimental and control groups by the estimated pooled standard deviation (SD) of the base line outcome measure in the treatment and control groups. The researches then coded the ES values so the positive numbers always reflected improvements in performance whereas negative numbers reflected deteriorations in performance.

The overall approach to ES calculations and moderator variables analyses were conducted using computer programs Excel 2002 software and SPSS software, version 11.0.b. The ES values were calculated using a statistical program called the Effect Size Determination Program. This computer program computes standardised mean difference ES and the correlation coefficients from summary statistics, such as means and Standard Deviations, t tests, F tests, and frequencies. Additional analyses were conducted and SES statistics were computed through the Comprehensive meta-analysis software package, using Hedge’s formula.

What conclusions should be taken away from this research?
This study identifies the positive effects exercise training can have on this specific population. By comparing over 30 studies they identified that exercise not only has huge physical fitness development attributes though can also improve physical, cognitive, functional, and behavioural outcomes. The take home message from this article would be; If you are or know of someone suffering from dementia i would advise going to your local GP to get cleared for exercise, who can then refer you further on to an exercise physiologist.

What are the implications of this research?
Because this was a Meta-Analysis there were a lot of variables the researches were unaware of in individual studies, for example;
 * Most of the studies included focused on the short-term effects of exercise and physical activity.
 * Whether subjects maintained the intensity throughout the exercise session or If there was any external motivation used
 * Very few studies reported the qualifications of the exercise leader.
 * The literature search was limited to articles published in English as they lacked the resources to translate articles written in other languages

Further support and research needs to be allocated to a follow-up study looking at the long term effects within this population.

This study has highlighted just how important exercise is and the role it plays on brain function and development on those suffering with a cognitive impairment, this is definitely an area that requires a much more in detail research.