Aerobic exercise led to an improvement in global cognitive ability and had a positive effect with a small effect size on memory in people with MCI. However, owing to the limitations of the included studies, these findings should be interpreted cautiously.

No abstract

IntroductionMild cognitive impairment (MCI) is an intermediate stage between the cognitive changes of normal aging and dementia characterised by a reduction in memory and/or other cognitive processes. An increasing number of studies have indicated that regular physical activity/exercise may have beneficial association with cognitive function of older adults with or without cognitive impairment. As a traditional Chinese Qigong exercise, Baduanjin may be even more beneficial in promoting cognitive ability in older adults with MCI, but the evidence is still insufficient. The main purpose of this study is to investigate the effect of Baduanjin exercise on neuropsychological outcomes of community-dwelling older adults with MCI, and to explore its mechanism of action from neuroimaging based on functional MRI (fMRI) and cerebrovascular function.Methods and analysisThe design of this study is a randomised, controlled trial with three parallel groups in a 1:1:1 allocation ratio with allocation concealment and assessor blinding. A total of 135 participants will be enrolled and randomised to the 24-week Baduanjin exercise intervention, 24-week brisk walking intervention and 24-week usual physical activity control group. Global cognitive function and the specific domains of cognition (memory, processing speed, executive function, attention and verbal learning and memory) will be assessed at baseline and 9, 17, 25 and 37 weeks after randomisation, while the structure and function of brain regions related to cognitive function and haemodynamic variables of the brain will be measured by fMRI and transcranial Doppler, respectively, at baseline and 25 and 37 weeks after randomisation.Ethics and disseminationEthics approval was given by the Medical Ethics Committee of the Second People's Hospital of Fujian Province (approval number 2014-KL045-02). The findings will be disseminated through peer-reviewed publications and at scientific conferences.Trial registration numberChiCTR-ICR-15005795; Pre-results.

BackgroundAmnestic mild cognitive impairment (aMCI) is characterized by cognitive functional decline, especially in memory. Resting-state functional magnetic resonance imaging (fMRI) has been widely used in neuroimaging studies that explore alterations between patients and normal individuals to elucidate the pathological mechanisms of different diseases. The current study was performed to investigate alterations in the functional connectivity of the default mode network (DMN) in aMCI patients compared to healthy elderly controls, as well as further define the association between neurological alterations and memory function.MethodsTwenty-five aMCI patients and 25 healthy individuals were recruited and underwent both fMRI and neuropsychological examinations. fMRI data was analyzed by independent component analysis.ResultsCompared to healthy individuals, aMCI patients exhibited a significant increase in functional connectivity between the DMN and right-middle and right-superior frontal gyri, left-middle occipital gyrus, and left-middle temporal gyrus, but reduced functional connectivity between the DMN and left-middle and left-inferior frontal gyri and left insula. These alterations were found to be associated with reduced memory function.ConclusionsaMCI patients exhibited abnormal functional connectivity between the DMN and certain brain regions which is associated with changes in memory function associated with aMCI.Electronic supplementary materialThe online version of this article (doi:10.1186/s12880-017-0221-9) contains supplementary material, which is available to authorized users.