Exercise as it relates to Disease/Affecting cognition and quality of life via aerobic exercise in Alzheimer’s disease

/Affecting cognition and quality of life via aerobic exercise in Alzheimer’s disease/

This is a review of the article 'Affecting Cognition and Quality of Life via Aerobic Exercise in Alzheimer’s Disease' ; A pilot study conducted by Fang Yu, Nathaniel W. Nelson, Kay Savik, Jean F. Wyman, Maurice Dysken, Ulf G. Bronas

What is the Background to this research?
Alzheimer's disease (AD) is the world's leading cause of dementia and affects up to 25 million people world-wide. AD can be characterised by a progressive decline in cognitive function, which typically begins with deterioration in memory. Due to AD 's primary feature being an impairment of cognitive function, daily-living activities become quite limited also resulting in poor quality of life (QOL), psychological and behavioural symptoms and escalating health care costs. The global prevalence of AD continues to grow exponentially, hence, developing interventions that could potentially improve cognitive impairment is critical for altering AD trajectory and improving health care outcomes in this population. In the article; 'Affecting Cognition and Quality of Life via Aerobic Exercise in Alzheimer’s Disease' they examine the effect of 6-month aerobic exercise on the change in executive function, global cognition, QOL, and depression in older adults with mild to moderate AD.

Where is the Research From?
This study was conducted in a retirement community in Saint Paul, Minnesota, USA between July 2008 and December 2009 and published in the Western Journal of Nursing Research in 2013. The corresponding author is Fang Yu of The University of Minnesota School of Nursing, Minneapolis. Yu's main research revolves around how to prevent and treat AD non-pharmacological interventions. Yu is involved in 49 completed publications, with 29 of these focusing on AD.

What kind of research was this?
Researchers performed a cross-sectional pilot study with a small sample size of 11 participants, including females and males, with only 8 of those completing the study. The final 8 participants were made up of both males and females, aged 81.4±3.6, who all had probable AD diagnosis. Four recruitment strategies were used to enrol participants for the study. These strategies included advertisements at senior newspapers, referral by senior housing managers, flyer distributions at senior housing and community events, and seminars delivered by author F.Y. at AD support groups. This particular study differs to other studies surrounding aerobic exercise and AD as it investigates the impact of aerobic exercise on cognition in AD whereas many studies show the positive impact of aerobic exercise on behavioural therapy for AD.

Eligibility Criteria

 * Have a probable AD diagnosis
 * Live in the community such as home or residence where skilled nursing services are not provided
 * Understand and speak English
 * Age 60 years or above
 * Have medical clearance from the primary physician for aerobic exercise

Exclusion Criteria

 * Mini-mental State Examination (MMSE) score was <12 during screening
 * Has contraindications to exercise such as uncontrolled hypertension
 * Displayed signs and symptoms that need to be evaluated by a physician
 * Cannot cycle
 * Has a recent history of unstable medical conditions

Summary of the Research Design and Methods

 * Once the participants were deemed eligible, all study activities were conducted at a retirement community in Saint Paul, Minnesota.
 * Participants who lived outside the retirement community were transported to and from the retirement community by research staff.
 * Participants completed individualised, moderate intensity cycling on Precor™ recumbent stationary cycles 3 times a week for 6 months.
 * Cycling was conducted for 10 to 45 minutes per session under the supervision of a certified exercise therapist
 * At baseline and when participants completed 3 and 6 months of cycling, outcomes were collected using specific tests on following:
 * Executive function
 * The Executive Interview (EXIT-25)
 * The Stroop Colour-Word Test
 * The Trail Making Test (TMT)
 * The Controlled Oral Word Association (COWA-FAS) Test
 * Global cognition
 * The MMSE
 * The AD Assessment Scale–Cognitive Subscale (ADAS-cog)
 * QOL
 * The QOL in AD
 * Depression.
 * The Geriatric Depression Scale–Short Form (GDS-SF)

What were the basic results?
Results from the present research portray potential changes over time within the participants. Scores on three of the executive function measures show a trend towards improvement from baseline to 3 and 6 months. EXIT-25: Baseline - 13.3, month 3 - 11.6, month 6 11.6. Stroop Colour-Word Test: Baseline - 17.6, month 3 - 28.0, month 6 20.1. COWA-FAS: Baseline - 20.6, month 3 - 26.9, month 6 - 27.3. Although these results look promising, they are statically insignificant according to Friedman’s Test of Significance as they are all a level of significance >0.5. The only measure that showed a statistically significant improvement was significant linear decrease in depression scores over time (p = .026. At month 3 participants reported significantly less depressive symptoms compared to baseline and at month 6 compared with month 3. Baseline: 2.8 ± 4.3, month 3: 2.0 ± 1.9, month 6: 0.9 ± 1.7 . The authors emphasised on the suggestion that the executive function measures could be positively impacted by the intervention along with the significant decline of depressive symptoms in this time frame.

What conclusions can we take from this research?
As this is just a small pilot study, it is not powered to detect significant differences. The overall results were not statistically significant, although they do suggest that there is possibility that aerobic exercise can have positive impacts on executive function, QOL, and depression in older adults with AD. Aerobic exercise can be seen to be a positive intervention for AD.

A 26-week randomised control trial in 2017 came to a similar conclusion. It showed that participants with AD who performed regular aerobic exercise had benefits associated with functional ability.

Practical Advice
Emerging study suggest that older adults with AD were significantly less physically active than those without AD. This could lead to all the negative health consequences associated with physical inactivity. Individuals with AD are likely to achieve many of the same health benefits resulting from aerobic exercise participation irregardless of the factors correlating directly to AD.

The results of this pilot study can be beneficial for future studies to help plan randomised controlled studies with sufficient numbers or participants to test these hypotheses.

Further Information and Resources
For further information regarding Alzheimer’s Disease:
 * About Dementia - Alzheimer's Disease
 * Healthline - Alzheimer's Disease
 * Alz.org - What is Alzheimer’s Disease?

Further readings and studies on Alzheimers' Disease and Aerobic Exercise
 * Improving Cognition and Function Through Exercise Intervention in Alzheimer's Disease
 * Aerobic exercise for Alzheimer's disease