Tai Chi Increases Grey Matter Volume in Older Adults

Posted in Memory & Mental Health

NHS Networks - Tai Chi & Chi-kung for rehabilitation

Tai Chi Increases Grey Matter Volume in Older Adults: A Brain Imaging Study.

The aim of this study is to investigate and compare how 12-weeks of Tai Chi Chuan and Baduanjin exercise can modulate brain structure and memory function in older adults. Magnetic Resonance Imaging(MRI) and memory function measurements (Wechsler Memory Scale-Chinese revised, WMS-CR)were applied at both the beginning and end of the study. Results showed that both Tai Chi Chuan and Baduanjin could significantly increase grey matter volume (GMV) in the insula, medial temporal lobe (MTL), and putamen after 12-weeks of exercise. No significant differences were observed in grey matter volume (GMV) between the Tai Chi Chuan and Baduanjin groups. We also found that compared to healthy controls, Tai Chi Chuan and Baduanjin significantly improved visual reproduction subscores on the WMS-CR. Baduanjin also improved mental control, recognition, touch and comprehension memory subscores of the WMS-CR compared to the control group. Memory quotient (MQ)and visual reproduction subscores were both associated with GMV increases in the putamen and hippocampus. Our results demonstrate the potential of Tai Chi Chuan and Baduanjin exercise for the prevention of memory deficits in older adults.

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1. Introduction

The average age of the world population is on the rise. By the year 2050, an estimated 21.1% (>2 billion) of the world’s population will be over the age of 60 [1]. As the population grows older, age-related diseases such as cognitive impairment present huge challenges to society [2]. Age-related memory loss, characterized by alterations affecting memory, is very common in older adults [3,4]. Previous studies indicate that memory dysfunctions are some of the first cognitive symptoms in mild cognitive impairment and Alzheimer’s disease (AD) [5].

In addition, previous neuroimaging studies have shown that aging is associated with reductions in brain volume, corticalthickness and white-matter integrity at various brain regions [6]. For instance, in a five-year longitudinal study of structural brain images in older adults, investigators [7] found both cross-sectional and longitudinal declines in brain volume, as well as in brain regions associated with cognition and memory, such as the prefrontal cortex, hippocampus, caudate, and cerebellum. Newberg et al. reported that an 8-week meditation program can improve neuropsychological function such as verbal fluency and logical memory in people with age-associated memory impairment and MCI. Functional neuroimaging changes have also shown significant increases in baseline CBF ratios in the prefrontal, superior frontal, and superior parietal cortices [8]. Additionally, Khalsa et al. demonstrated that Kirtan Kriya (KK), an easy, cost effective meditation technique, can significantly improve memory in people with subjective cognitive decline or mild cognitive impairment [9].

Current pharmaceutical treatments for the prevention of age-related memory and cognitive decline are far from satisfactory [10–12]. For instance, several large epidemiologic studies have failed to find a significant association between the use of nonsteroidal anti-inflammatory drugs and the development of AD [13]. In randomized drug trials in which patients received 25 mg of rofecoxibor placebo daily for up to 4 years, rofecoxib did not exhibit significant benefits in terms of reducing conversion to clinical AD [14]. In addition, it has been reported that a clinical trial on mild cognitive impairment using galantamine was terminated early due to the increased mortality in individuals receiving the experimental drug [15]. Thus, effective pharmacological treatments to prevent aging and cognitive decline are yet to be developed.

As a result, alternative low-cost, non-pharmacological methods are necessary and arising as promising treatments for preventing cognitive decline. Accumulating evidence suggests that physical activity and mental training exercises may decrease the risk of developing age-related memory deficits [10,16–19], as well as increase grey and white matter volume in older adults [16,17,19–24].

Recently, Tai Chi Chuan, a mind-body exercise combining low to moderate intensity slow movements, deep breathing and mental concentration, has drawn the attention of the public and researchers alike [25–27]. Tai Chi Chuan has several components, including physical, cognitive and social, which are believed to aid in maintaining cognition in older adults [28]. In a previous study [29], Zhang and colleagues compared the effects of 18 months of swimming, running, square dancing, and Tai Chi Chuan on cognitive function and emotion in older adults. They found that all of the physical intervention groups showed improvements in cognition and emotion, with the Tai Chi Chuan exercise group demonstrating the most robust effect [30]. Studies have shown that cardiovascular fitness plays an important role in the relationship between exercise and cognition [31]. Erickson and colleagues found that higher fitness levels and physical activity are associated with greater volume of the prefrontal cortex and the hippocampus in older adults [24]. However, Tai Chi Chuan is not acardiovascular exercise, thus the increases in physical activity from practicing Tai Chi Chuan may not be associated with improvements in cognition, and other factors such as social interaction may also play a role in Tai Chi Chuan’s effect on cognitive improvement [30], further supporting the assertion that the beneficial effects of Tai Chi Chuan and physical exercise are due to different underlying mechanisms.

The social component of Tai Chi Chuan, that is, practicing Tai Chi Chuan in a group, also seems to be an important factor in the effectiveness of Tai Chi Chuan on reducing the cognitive aging process [32,33]. A longitudinal population-based study of aging and dementia in Sweden found that social interactions were important for the prevention of cognitive decline [34]. Similarly, in a community-based study, researchers also found that a rich social network had a protective effect against dementia. Compared with married people living with a spouse, single people and those living alone had an increased risk of developing dementia [35].

Despite the individual significance of the social and physical components of Tai Chi Chuan, the multimodal nature of Tai Chi Chuan seems to be crucial in preventing cognitive decline and memory loss [28,36–43]. For instance, Mortimer and colleagues [44] compared the effects of Tai Chi Chuan to walking, social interaction, and no intervention on brain volume and cognition in older adults. They found that after 40 weeks of intervention, significant increases in brain volume were observed in the Tai Chi Chuan and social intervention groups compared to the no intervention group. The Tai Chi group also showed improvements in the Mattis Dementia Rating Scale score, the Trail Making Test (TMT) Parts A and B, the Auditory Verbal Learning Test, and verbal fluency. The social interaction group showed improvements in fewer neuropsychological indices than the Tai Chi group, and no significant differences in improvements were observed between the walking and no intervention groups.

In addition to Tai Chi Chuan, Baduanjin is another popular mind-body exercise [45]. Baduanjin exercise consists of 10 postures (including the beginning and ending posture), and is also a low-intensity exercise that can improve range of motion, strength, and general health [46]. Both Tai Chi Chuan and Baduanjin are considered multi-component interventions that integrate physical, psychosocial, emotional, spiritual, and behavioral elements. The only difference between the two exercises is the complexity; unlike Tai Chi Chuan, Baduanjin involves eight simple fixed movements of the arms with almost no movement of the legs. Due to the simplicity of Baduanjin, at least for beginners, it is easy for individuals to integrate the body movements with other techniques such as breathing.

Memory is a complicated brain function, which involves information encoding, storage and retrieval. Literature suggests that an expansive brain network is involved in different types and aspects of memory [47]. Previous literature demonstrates that mind-body exercises such as Tai Chi Chuan can modulate and improve verbal memory [38], working memory [48], and memory retrieval processes [49]. However, very few studies have investigated if Tai Chi Chuan and Baduanjin can improve global memory function, as well as how these exercises can modulate different subtypes and aspects of memory [30].

In a previous study, we used this dataset to investigate how Tai Chi Chuan and Baduanjin exercise modulates different aspects of cognition and memory using the Wechsler Memory Scale - Chinese Revision (WMS-CR), and resting state functional connectivity changes at the hippocampus [50] and dorsal lateral prefrontal cortex [51]. In this manuscript, we focus on whether Tai Chi Chuan and Baduanjin exercise can modulate different brain structures as measured by voxel-based morphometry (VBM). We also investigate how Tai Chi Chuan and Baduanjin can regulate the WMS-CR subscores, as well as the association between the GMV changes and WMS-CR score changes.

...In summary, we found that 12-weeks of intensive group Tai Chi Chuan or Baduanjin exercise can modulate global memory, as well as improve specific types and aspects of memory function. The brain mechanisms underlying the effects of both Tai Chi Chuan and Baduanjin seem to be slightly different, although both increase GMV at the MTL, putamen and insular, which are regions essential for memory and cognition. Our results imply that Tai Chi Chuan and Baduanjin might be effective methods for delay in memory decline.

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