The increasing prevalence of mild cognitive impairment (MCI) in our rapidly aging population prompts the need for devising effective interventions to prevent the onset of cognitive impairment and delay its progression to dementia. The benefits of aerobic exercise on the cognitive function in older adults with MCI are well-documented. However, exercise protocols and outcome measurement tools in the current literature are highly heterogeneous. It is therefore imperative to develop standard exercise prescription protocol for the MCI population or to examine the effectiveness of the existing, well-established exercise guidelines. The World Health Organization (WHO) recommends adults (18 - 64 years of age) and older adults (65 years and older) to perform 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic physical activity per week to improve cardiorespiratory and muscular fitness, bone health, and reduce the risk of non-communicable diseases and depression. Nonetheless, few studies have determined the effectiveness of the WHO Global Recommendations on Physical Activity for Health guideline in improving cognitive function in older adults with MCI. This study thus aims to evaluate the effectiveness of the WHO Physical Activity Recommendations in improving cognitive function in older adults with MCI. In 2017, the American Academy of Neurology (AAN) updated the Practice Guideline for Mild Cognitive Impairment, in which they recommended patients diagnosed with MCI to perform exercise at least twice a week for at least 6 months to gain cognitive benefits. This recommendation was based on two class-II studies, in which a 6-month twice-a-week 90-minute multicomponent exercise program helped maintain global cognition, and selective attention improved significantly following a 6-month twice-a-week 60-minute multicomponent exercise program. While they provided pivotal insights into clinical practice, there were several limitations for these two studies. For instance, in the study conducted by Nagamatsu et al., only female subjects were recruited, and therefore lead to low generalizability. These two studies focused on multi-component exercise intervention which included resistance training, aerobic training, and balance training, and the duration of each component was short (around 20 - 30 minutes). Studies that focus on single exercise modality with longer session duration are warranted to unveil the efficacy of a certain exercise modality in improving cognitive function. In this study, we will evaluate the effectiveness of aerobic exercise on improving cognitive function in older adults with MCI. We intend to follow the WHO Recommendations, focusing on evaluating the effect of different exercise intensities (moderate versus vigorous) and frequencies (once versus thrice per week) of aerobic exercise on improving the cognitive function in older adults with mild cognitive impairment. In particular, the AAN also suggested that physical activity of at least twice a week is necessary to produce cognitive benefits. We, therefore, aim to investigate whether one session per week would also suffice to improve the cognitive function in older adults with MCI. Aims: To examine the effectiveness of 12-week WHO Global Recommendations on Physical Activity for Health in practice in improving the cognitive function in older adults with MCI.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
50
Control Group
once-a-week walking exercise at moderate intensity
thrice-a-week walking exercise at moderate intensity
once-a-week walking exercise at vigorous intensity
thrice-a-week walking exercise at vigorous intensity
Li Kai Shing Faculty of Medicine
Hong Kong, Southern District, Hong Kong
Global cognition-Hong Kong Montreal Cognitive Assessment (HK-MoCA) score
Age- and education-corrected Hong Kong Montreal Cognitive Assessment (HK-MoCA). The HK-MoCA is a validated assessment for cognitive screening that takes into account different domains of cognition, which will enable the researchers to achieve a better understanding of the global cognitive profile of the individual. Higher score indicates better global cognitive performance.
Time frame: 3-month follow-up
Objective cognitive score
The NIH Toolbox Cognitive Function Battery (CFB) will be used to evaluate the various cognitive domains \[15\]. CFB will be delivered on a tablet computer. A total objective cognitive score will be generated, while a higher score indicates better cognitive performance.
Time frame: 3-month follow-up
Working memory-Digit Span test
Working memory will be measured by Digit Span test in paper-pencil based manner. Higher score indicates better cognitive performance.
Time frame: 3-month follow-up
Working memory-Verbal Fluency Test
Verbal Fluency Test will be used to measure working memory. Higher score indicates better cognitive performance.
Time frame: 3-month follow-up
Executive function-Stroop test
Executive function will be measured by Stroop test. Shorter completion time indicates better performance.
Time frame: 3-month follow-up
Executive function-Trail Making test
Executive function will be measured by Trail Making test. Shorter completion time indicates better performance.
Time frame: 3-month follow-up
Subjective cognitive report
Cognitive self-report questionnaire (CSQR) will be used to test the subjective cognitive performance. CSQR is validated in HK and consists of 20 questions with overall score ranging from 0-100. Higher score indicates worse self-perception on cognitive performance.
Time frame: 3-month follow-up
Remission rate-Chinese Abbreviated Mild Cognitive Impairment Test (CAMCI)
Chinese Abbreviated Mild Cognitive Impairment Test (CAMCI) will be used to classify participants into MCI and non-MCI category. The remission rate will be calculated as remission rate = number of participants in non-MCI category / number of total participants.
Time frame: 3-month follow-up
Remission rate-Hong Kong Montreal Cognitive Assessment (HK-MoCA)
Age- and education-corrected Hong Kong Montreal Cognitive Assessment (HK-MoCA). The HK-MoCA is a validated assessment for cognitive screening that takes into account different domains of cognition, which will enable the researchers to achieve a better understanding of the cognitive profile of the individual. MoCA will be used to classify participants into MCI and non-MCI category. The remission rate will be calculated as remission rate = number of participants in non-MCI category / number of total participants.
Time frame: 3-month follow-up
VO2max
A VO2max test will be conducted using a calibrated motor-driven treadmill by continuous metabolic VO2 measurement using a COSMED Quark Series telemetric gas analysis system. The test will be performed using a modified bruce protocol. VO2, Borg's rating of perceived exertion (RPE) and heart rate (HR) will be continuously recorded. The maximal attainable heart rate will be recorded as the peak heart rate (HRpeak).
Time frame: 3-month follow-up
Body fat mass
Body fat mass of participants will be measured by dual-energy X-ray absorptiometry (DXA).
Time frame: 3-month follow-up
Lean mass
Lean mass of participants will be measured by dual-energy X-ray absorptiometry (DXA).
Time frame: 3-month follow-up
Bone mineral density
Bone mineral density of participants will be measured by dual-energy X-ray absorptiometry (DXA).
Time frame: 3-month follow-up
Habitual sleep
The Pittsburgh Sleep Quality Index (PSQI) is a standardized instrument to estimate sleep quantity and quality. The PSQI has been commonly used to distinguish people with primary insomnia from normal sleepers. The Chinese version of PSQI has been validated to have a satisfactory Cronbach's alpha of 0.82-0.83 and test-retest reliability of 0.85 among Hong Kong Chinese older adults. The overall score ranges from 0 to 24 while a higher score indicates worse sleep quality.
Time frame: 3-month follow-up
Quality of Life-12-item Short Form Survey (SF-12)
The 12-item Short Form Survey (SF-12) will be used to assess the quality of life of the participant and higher scores (physical and mental sub-scale) indicate better quality of life.
Time frame: 3-month follow-up
Depression level
Patient Health Questionnaire-9 (PHQ-9) will also be used to assess the mental health of the subjects. A PHQ-9 score of ≥ 10 has a sensitivity of 88% and a specificity of 88% for major depression. PHQ-9 scores of 5, 10, 15, and 20 correspond to mild, moderate, moderately severe, and severe depression, respectively. Results are similar in the primary care and obstetrics-gynecology samples. The PHQ-9 is a reliable and valid measure of depression severity and its brevity make the PHQ-9 a useful clinical and research tool.
Time frame: 3-month follow-up
Mental health
Hospital Anxiety and Depression Scale (HADS) will used to measure the mental health of participants. It is a 7-item questionnaire having an overall score that ranges from 0 to 21 (with sub-scales for both anxiety and depression), with a higher score indicating more severe symptoms.
Time frame: 3-month follow-up
Anxiety level
Generalized Anxiety Disorder 7-item (GAD-7) scale will be used to measure the anxiety level of participants. It is a 7-item questionnaire having an overall score that ranges from 0 to 21 with a higher score indicating more severe symptoms.
Time frame: 3-month follow-up
Physical activity
The International Physical Activity Questionnaire (IPAQ) will be used to assess the activity level of the subjects.
Time frame: 3-month follow-up
Balance performance
The balance ability of the subjects will be measured by single leg standing test. The longer standing duration indicates better balance performance.
Time frame: 3-month follow-up
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