• ADCS-PACC [ Time Frame: 6 months ]
  The primary cognitive endpoint is the Alzheimer's Disease Cooperative Study-Preclinical Alzheimer Cognitive Composite (ADCS-PACC).
• Changes in resting state functional connectivity [ Time Frame: 6 months ]
  The primary imaging endpoint is to explore resting state functional connectivity of the hippocampus and dorsolateral prefrontal cortex (DLPFC), as measured by magnetic resonance imaging (MRI).
• Changes in grey matter volume [ Time Frame: 6 months ]
  The primary imaging endpoint is to assess brain grey matter volume changes using before and after BDJ exercise and magnetic resonance imaging (MRI).

• NIH-TB [ Time Frame: 6 months ]
  The secondary endpoints include NIH Toolbox (NIH-TB) Cognition Battery, which measures cognitive, emotional, sensory, and motor functions.
• Memory Complaints Questionnaire (MAC-Q) [ Time Frame: 6 months ]
  The secondary endpoints include the Memory Complaints Questionnaire (MAC-Q), which measures subjective cognitive decline.
• Patient Reported Outcomes Measurement Information System (PROMIS-29) [ Time Frame: 6 months ]
  The secondary endpoints include the Patient Reported Outcomes Measurement Information System (PROMIS-29), which measures physical, mental, and social health and wellbeing.
• Geriatric Depression Scale (GDS) [ Time Frame: 6 months ]
  The secondary endpoints include the Geriatric Depression Scale (GDS), which is a self-assessment that measures depression.
• CRP, proinflammatory cytokine IL-6, BDNF [ Time Frame: 6 months ]
  The secondary endpoints include measuring levels of C reactive protein (CRP), proinflammatory cytokine IL-6, and brain-derived neurotrophic factor (BDNF).
• LF/HF [ Time Frame: 6 months ]
  The secondary endpoints include measuring low frequency, high frequency, and LF to HF ratio (LF/HF) of heart rate variability as measured by ECG.

Subjective cognitive decline (SCD), the self-reported perception of memory or cognitive problems, is receiving increasing attention as a risk factor for the development of Alzheimer's disease (AD). Since SCD manifests before the onset of clinical impairment, it might be the optimal stage/window of time at which to intervene with preventative therapies for AD and age-related dementia before the progressive neurological loss and irreversible cognitive impairment.

Recently, mind-body interventions have demonstrated their potential in preventing cognitive decline. Nevertheless, these mind-body therapies encompass a family of complex practices, each with different characteristics and focus. Therefore, they may be associated with different mechanisms and treatment effects. Baduanjin (BDJ) is an innovative and simple mind-body exercise consisting of eight simple movements that can be easily practiced at home with video guidance, thereby making it a more suitable option for older adults with cognitive decline than other more complex exercises. In a previous study, the investigators found that BDJ significantly improved memory and executive function, resting state functional connectivity of the hippocampus and dorsolateral prefrontal cortex, and grey matter volume of the medial temporal area and putamen in older adults. In addition, the investigators found that BDJ could produce significantly greater cognitive function improvement, as measured by the Wechsler Memory Scale (WMS) sub-score, and more extensive grey matter brain volume changes at medial temperal lobe and putamen. A more recent pilot study showed that, compared to walking and health education, six months of BDJ significantly improved cognitive function in patients with MCI. These findings provide a solid foundation for the current application.

This proposal aims to investigate 1) the preventative effect of longitudinal BDJ on cognitive decline, 2) the modulation effect of BDJ on resting state functional connectivity of the hippocampus and bilateral dorsolateral prefrontal cortex, and 3) the modulation effect of BDJ on brain morphometry in individuals with SCD as compared to controls. The investigators believe that this study will 1) significantly improve the prevention of MCI and AD and directly benefit patients suffering from these highly prevalent disorders, 2) enhance the investigators' understandings of the neurobiology through which mind-body interventions affect cognition and health, and 3) advance the investigators' understandings of the pathophysiology and development of SCD, AD, and age-related dementia.

• Other: Baduanjin Exercise
  Subjects will participate in Baduanjin, a simple mind-body exercise, for 24 weeks.
• Other: Cognitive Fitness Program
  Subjects will complete paper puzzles (Sudoku, crosswords, etc.) for 24 weeks.

• Experimental: Baduanjin Group
  This group will participate in the Baduanjin exercise intervention for 24 weeks (three times/week for the first three months and two times/week for the last three months).
  Intervention: Other: Baduanjin Exercise
• Active Comparator: Control Group
  This group will participate in the Cognitive Fitness Program intervention for 24 weeks (three times/week for the first three months and two times/week for the last three months).
  Intervention: Other: Cognitive Fitness Program

Inclusion Criteria:

• 50 - 80 years old
• Self-reported experience of persistent decline in memory compared with a previous state (within the past 5 years), which was further confirmed by informants
• Concerns regarding memory problems
• Mini-Mental State Examination, Second Edition (MMSE-2) scores within the normal range
• Montreal Cognitive Assessment scores within the normal range (adjusted for age, sex, and education)
• Clinical Dementia Rating score of 0 (no memory loss or slight, inconsistent forgetfulness)

Exclusion Criteria:

• Unable to speak or read English
• Diagnosis of depression
• Other diseases that cause cognitive decline (e.g., traumatic brain injury, stroke, neurodegenerative diseases, brain tumor, Parkinson disease, encephalitis or epilepsy, thyroid dysfunction, severe anemia, syphilis)
• History of psychosis or congenital mental growth retardation
• Any delayed recall index greater than 1.5 SD below average on the California Verbal Learning Test, Second Edition
• Failing the Memory items on the MMSE-2 and MDRS-2, as well as the CVLT-II criterion
• Inability to participate in a 6-month intervention with a 3-month follow-up
• Any item = 0 on the Lawton-Brody Instrumental Activities of Daily Living Scale for cognitive reasons
• No available informant
• Previous diagnosis of MCI, AD, or other age-related dementia
• Previous Baduanjin experience