Exercise as it relates to Disease/The effects of a multi-component exercise intervention in older adults with mild cognitive impairment

An analysis of the journal article "A Randomised Controlled Trial of Multi-component Exercise in Older Adults with Mild Cognitive Impairment" by Suzuki et. al. 2013

What is the background to this research?
Classification: Mild Cognitive Impairment (MCI) is the stage between the normal process of cognitive changes with ageing and Dementia. Furthermore, Alzheimer's Disease (AD) is diagnosed following the progressive and rapid cognitive decline beginning with slight impairments in memory formation. It ultimately affects mental functions and leads to full dependence on carers for daily activities, a decreased quality of life and can lead to premature death.

Prevalence: The global prevalence of cognitive diseases like AD is estimated to be 24 million and predicted to double every 20 years to 2040, leading to an impending increase in public health costs in future decades. The effects of cognitive decline and AD is placing an increasing burden on patients, caregivers and the general society.

Risk Factors: As AD effects the brain and cognitive function, other risk factors have been linked such as; cerebrovascular disease, diabetes, hypertension, smoking, obesity and normal ageing. There is also increasing research to indicate that genetic patterns can determine the risk of cognitive decline in adults over 65 years of age.

As cognitive decline in older adults is individualised, it is important to identify changes which can lead to Dementia. Therefore, interventions to slow these progressions are essential. Tracking cognitive function can also be used as a preventative measure for those who are not yet symptomatic.

Implementing physical activity or cognitive therapy interventions have been shown to slow the rate of AD progression. However, there are limitations due to the memory defects and impaired cognitive state. Suzuki et.al used a combination of aerobic exercise, strength training, postural balance training and multi-tasking therapies to determine the effects of a multi-component intervention on memory capacity and cognitive function in older adults with MCI.

Where is the research from?
The research is from the National Centre for Geriatrics and Gerontology and the Centre for Development of Advanced Medicine for Dementia, Obu (Aichi) Japan. It was conducted by Suzuki et. al. on urban community-dwelling individuals (living alone in the community) aged 65+ in the city of Obu, Japan.

What kind of research was this?
This was a randomised controlled trial. The main researcher was blind to the aims when randomising participants into groups. Other study personal responsible for recording outcome variables were also blind to the randomisation assignment. To further add to the reliability and validity, health professionals working with groups were blinded to group status.

Randomised control trials can produce the most reliable and valid evidence as subjects are allocated to treatments/interventions randomly, removing the allocation bias shown in other study designs.

What did the research involve?
Methodology: 1543 volunteers who were 65 years or older, were recruited from a database by random sampling or when attending a medical check-up. 528 participants with a clinical dementia rating (CDR) of 0.5 were recruited in the first round. 135 individuals met the requirements of the second round of assessments consisting of neuropsychological tests (language and memory). From this 35 were excluded, leaving 100 participants in the study who all met the definition of MCI based on the Petersen Criteria.

A researcher blind to the aims randomly allocated individuals into an amnestic MCI (aMCI) (n=50) or other MCI group (n=50). The aMCI group had a sub analysis consisting of neuroimaging measures with objective memory impairment based on the Wechsler Memory Scale-Revised (WMS). The subjects were further divided into either a multi-component exercise intervention (n=25) or educational control group (n=25) at a ratio of 1:1 in each group respectively, as shown in the table below. A limitation was that participants knew they were in the aMCI group, as consent was required for the sub-analysis involving MRIs. However, the overall recruitment strategy and eligibility criteria was beneficial for the outcomes of the study.

Interventions: Over the six-month study period, the multi-component exercise program consisted of bi-weekly 90-minute sessions involving aerobic exercise, muscle strength training, postural balance training and dual-task training. The group also focused on promoting exercise and functional behaviour change with two trained geriatric physiotherapists conducting each intervention.

Subjects in the educational control group attended two health promotion classes during the study period designed to inform individuals about health, diet, oral care, urinary incontinence prevention and health checks. To adhere to the aims, this group did not receive any information about physical activity or cognitive health.

What were the basic results?
From the MCI data collected, Suzuki et. al. found that the intervention group showed improved results from Alzheimer’s Disease Assessment Scale-cognitive subscale (ADAS-cog), WMS and Whole Brain Corticies (WBC) atrophy. They all had a p-value of <0.03 indicating statistically significant data. This improvement can be attributed to increased cognitive function as a result of the physical activity and cognitive tasks.

From the aMCI data collected, the intervention group had increased Mini-Mental State Examination (MMSE) and WMS scores. This together with an increase in group-time interaction indicates benefits over time. The control group had a decrease in MMSE score, indicating that cognitive capacity can decline over time. It was also noted that the control group had an increase in WBC atrophy (p=<0.05) following the six-month period

In both the MCI and aMCI group, individuals with the multi-component intervention had increased cognitive function compared to baseline results. The control group, however, had little improvement with some results lower than baseline as shown through the WBC atrophy data. This suggests that cognitive capacity can decline at a faster rate bringing about the more serious effects of Dementia and AD without any intervention. It is important to note that eight participants did not complete the full study possibly skewing results and outcomes, however, this effect was not significant.

What conclusions can we take from this research?
Multi-component interventions consisting of physical activity, strength training, postural balance exercises and dual-task training can be effective in slowing the progression of cognitive decline in older adults. Previous studies have found a positive relationship between exercise and progression of AD. In particular, there is a link between cognitive intervention and delayed onset of cognitive impairments like Dementia and AD. This study shows that multi-component interventions addressing physical and cognitive issues associated with ageing can be effective in treating older adults with MCI. Improving the cognitive capacity of individuals makes activities in daily life easier, improves quality of life and reduces the impact of cognitive impairment.

Practical advice:
This research shows that cognitive and exercise interventions are effective in improving cognitive function in older adults. They can also be used to delay the onset or rate of cognitive decline, which could improve quality of life. Exercise alone has been shown to improve cognitive capacity and reduce the risk of co-morbidities associated with Alzheimers. Consideration of safety of individuals carrying out these multi-component interventions is important as the risk of falls, injury and adverse health problems are more prominent in old age. However, with safety considered, interventions can help delay the onset/severity of cognitive decline and improve function in those already experiencing impairment.

Further information/resources:
Further information on the effects of exercise and cognitive interventions on cognitive impairment:
 * What is Alzheimers Disease?: https://www.nia.nih.gov/health/what-alzheimers-disease
 * How exercise improves cognitive function and brain health: https://www.urologyofva.net/articles/category/healthy-living/3330548/08/01/2019/how-exercise-improves-cognitive-function-and-overall-brain-health
 * Interventions for Dementia: https://dementia.ie/interventions/
 * Exercise and boost memory skills: https://www.health.harvard.edu/mind-and-mood/exercise-can-boost-your-memory-and-thinking-skills